| Message ID | 20200524085259.24784-2-alex@ghiti.fr (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | vmalloc kernel mapping and relocatable kernel | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (1ef93962cf4293ec9e1bb3163cc4b7dcfc3de84f) |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 0 warnings, 1 checks, 260 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Sun, May 24, 2020 at 4:54 PM Alexandre Ghiti <alex@ghiti.fr> wrote: > > This is a preparatory patch for relocatable kernel. > > The kernel used to be linked at PAGE_OFFSET address and used to be loaded > physically at the beginning of the main memory. Therefore, we could use > the linear mapping for the kernel mapping. > > But the relocated kernel base address will be different from PAGE_OFFSET > and since in the linear mapping, two different virtual addresses cannot > point to the same physical address, the kernel mapping needs to lie outside > the linear mapping. > > In addition, because modules and BPF must be close to the kernel (inside > +-2GB window), the kernel is placed at the end of the vmalloc zone minus > 2GB, which leaves room for modules and BPF. The kernel could not be > placed at the beginning of the vmalloc zone since other vmalloc > allocations from the kernel could get all the +-2GB window around the > kernel which would prevent new modules and BPF programs to be loaded. > > Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> > --- > arch/riscv/boot/loader.lds.S | 3 +- > arch/riscv/include/asm/page.h | 10 +++++- > arch/riscv/include/asm/pgtable.h | 37 +++++++++++++------- > arch/riscv/kernel/head.S | 3 +- > arch/riscv/kernel/module.c | 4 +-- > arch/riscv/kernel/vmlinux.lds.S | 3 +- > arch/riscv/mm/init.c | 58 +++++++++++++++++++++++++------- > arch/riscv/mm/physaddr.c | 2 +- > 8 files changed, 87 insertions(+), 33 deletions(-) > > diff --git a/arch/riscv/boot/loader.lds.S b/arch/riscv/boot/loader.lds.S > index 47a5003c2e28..62d94696a19c 100644 > --- a/arch/riscv/boot/loader.lds.S > +++ b/arch/riscv/boot/loader.lds.S > @@ -1,13 +1,14 @@ > /* SPDX-License-Identifier: GPL-2.0 */ > > #include <asm/page.h> > +#include <asm/pgtable.h> > > OUTPUT_ARCH(riscv) > ENTRY(_start) > > SECTIONS > { > - . = PAGE_OFFSET; > + . = KERNEL_LINK_ADDR; > > .payload : { > *(.payload) > diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h > index 2d50f76efe48..48bb09b6a9b7 100644 > --- a/arch/riscv/include/asm/page.h > +++ b/arch/riscv/include/asm/page.h > @@ -90,18 +90,26 @@ typedef struct page *pgtable_t; > > #ifdef CONFIG_MMU > extern unsigned long va_pa_offset; > +extern unsigned long va_kernel_pa_offset; > extern unsigned long pfn_base; > #define ARCH_PFN_OFFSET (pfn_base) > #else > #define va_pa_offset 0 > +#define va_kernel_pa_offset 0 > #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT) > #endif /* CONFIG_MMU */ > > extern unsigned long max_low_pfn; > extern unsigned long min_low_pfn; > +extern unsigned long kernel_virt_addr; > > #define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset)) > -#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset) > +#define linear_mapping_va_to_pa(x) ((unsigned long)(x) - va_pa_offset) > +#define kernel_mapping_va_to_pa(x) \ > + ((unsigned long)(x) - va_kernel_pa_offset) > +#define __va_to_pa_nodebug(x) \ > + (((x) >= PAGE_OFFSET) ? \ > + linear_mapping_va_to_pa(x) : kernel_mapping_va_to_pa(x)) > > #ifdef CONFIG_DEBUG_VIRTUAL > extern phys_addr_t __virt_to_phys(unsigned long x); > diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > index 35b60035b6b0..25213cfaf680 100644 > --- a/arch/riscv/include/asm/pgtable.h > +++ b/arch/riscv/include/asm/pgtable.h > @@ -11,23 +11,29 @@ > > #include <asm/pgtable-bits.h> > > -#ifndef __ASSEMBLY__ > - > -/* Page Upper Directory not used in RISC-V */ > -#include <asm-generic/pgtable-nopud.h> > -#include <asm/page.h> > -#include <asm/tlbflush.h> > -#include <linux/mm_types.h> > - > -#ifdef CONFIG_MMU > +#ifndef CONFIG_MMU > +#define KERNEL_VIRT_ADDR PAGE_OFFSET > +#define KERNEL_LINK_ADDR PAGE_OFFSET > +#else > +/* > + * Leave 2GB for modules and BPF that must lie within a 2GB range around > + * the kernel. > + */ > +#define KERNEL_VIRT_ADDR (VMALLOC_END - SZ_2G + 1) > +#define KERNEL_LINK_ADDR KERNEL_VIRT_ADDR > > #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1) > #define VMALLOC_END (PAGE_OFFSET - 1) > #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) > > #define BPF_JIT_REGION_SIZE (SZ_128M) > -#define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE) > -#define BPF_JIT_REGION_END (VMALLOC_END) > +#define BPF_JIT_REGION_START (kernel_virt_addr) > +#define BPF_JIT_REGION_END (kernel_virt_addr + BPF_JIT_REGION_SIZE) It seems to have a potential risk here, the region of bpf is overlapping with kernel mapping, so if kernel size is bigger than 128MB, bpf region would be occupied and run out by kernel mapping. > + > +#ifdef CONFIG_64BIT > +#define VMALLOC_MODULE_START BPF_JIT_REGION_END > +#define VMALLOC_MODULE_END VMALLOC_END > +#endif > Although kernel_virt_addr is a fixed address now, I think it could be changed for the purpose of relocatable or KASLR, so if kernel_virt_addr is moved to far from VMALLOC_END than 2G, the region of module would be too big. In addition, the region of module could be +-2G around the kernel, so we don't be limited in one direction as before. It seems to me that the region of the module could be decided at runtime, for example, VMALLOC_MODULE_START is "&_end - 2G" and VMLLOC_MODULE_END is "&_start + 2G". I'm not sure whether the size of region of bpf has to be 128MB for some particular reason, if not, maybe the region of bpf could be the same with module to avoid being run out by module. > /* > * Roughly size the vmemmap space to be large enough to fit enough > @@ -57,9 +63,16 @@ > #define FIXADDR_SIZE PGDIR_SIZE > #endif > #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) > - > #endif > > +#ifndef __ASSEMBLY__ > + > +/* Page Upper Directory not used in RISC-V */ > +#include <asm-generic/pgtable-nopud.h> > +#include <asm/page.h> > +#include <asm/tlbflush.h> > +#include <linux/mm_types.h> > + > #ifdef CONFIG_64BIT > #include <asm/pgtable-64.h> > #else > diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > index 98a406474e7d..8f5bb7731327 100644 > --- a/arch/riscv/kernel/head.S > +++ b/arch/riscv/kernel/head.S > @@ -49,7 +49,8 @@ ENTRY(_start) > #ifdef CONFIG_MMU > relocate: > /* Relocate return address */ > - li a1, PAGE_OFFSET > + la a1, kernel_virt_addr > + REG_L a1, 0(a1) > la a2, _start > sub a1, a1, a2 > add ra, ra, a1 > diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c > index 8bbe5dbe1341..1a8fbe05accf 100644 > --- a/arch/riscv/kernel/module.c > +++ b/arch/riscv/kernel/module.c > @@ -392,12 +392,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > } > > #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) > -#define VMALLOC_MODULE_START \ > - max(PFN_ALIGN((unsigned long)&_end - SZ_2G), VMALLOC_START) > void *module_alloc(unsigned long size) > { > return __vmalloc_node_range(size, 1, VMALLOC_MODULE_START, > - VMALLOC_END, GFP_KERNEL, > + VMALLOC_MODULE_END, GFP_KERNEL, > PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, > __builtin_return_address(0)); > } > diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S > index 0339b6bbe11a..a9abde62909f 100644 > --- a/arch/riscv/kernel/vmlinux.lds.S > +++ b/arch/riscv/kernel/vmlinux.lds.S > @@ -4,7 +4,8 @@ > * Copyright (C) 2017 SiFive > */ > > -#define LOAD_OFFSET PAGE_OFFSET > +#include <asm/pgtable.h> > +#define LOAD_OFFSET KERNEL_LINK_ADDR > #include <asm/vmlinux.lds.h> > #include <asm/page.h> > #include <asm/cache.h> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index 27a334106708..17f108baec4f 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -22,6 +22,9 @@ > > #include "../kernel/head.h" > > +unsigned long kernel_virt_addr = KERNEL_VIRT_ADDR; > +EXPORT_SYMBOL(kernel_virt_addr); > + > unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] > __page_aligned_bss; > EXPORT_SYMBOL(empty_zero_page); > @@ -178,8 +181,12 @@ void __init setup_bootmem(void) > } > > #ifdef CONFIG_MMU > +/* Offset between linear mapping virtual address and kernel load address */ > unsigned long va_pa_offset; > EXPORT_SYMBOL(va_pa_offset); > +/* Offset between kernel mapping virtual address and kernel load address */ > +unsigned long va_kernel_pa_offset; > +EXPORT_SYMBOL(va_kernel_pa_offset); > unsigned long pfn_base; > EXPORT_SYMBOL(pfn_base); > > @@ -271,7 +278,7 @@ static phys_addr_t __init alloc_pmd(uintptr_t va) > if (mmu_enabled) > return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); > > - pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT; > + pmd_num = (va - kernel_virt_addr) >> PGDIR_SHIFT; > BUG_ON(pmd_num >= NUM_EARLY_PMDS); > return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD]; > } > @@ -372,14 +379,30 @@ static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size) > #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing." > #endif > > +static uintptr_t load_pa, load_sz; > + > +void create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size) > +{ > + uintptr_t va, end_va; > + > + end_va = kernel_virt_addr + load_sz; > + for (va = kernel_virt_addr; va < end_va; va += map_size) > + create_pgd_mapping(pgdir, va, > + load_pa + (va - kernel_virt_addr), > + map_size, PAGE_KERNEL_EXEC); > +} > + > asmlinkage void __init setup_vm(uintptr_t dtb_pa) > { > uintptr_t va, end_va; > - uintptr_t load_pa = (uintptr_t)(&_start); > - uintptr_t load_sz = (uintptr_t)(&_end) - load_pa; > uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE); > > + load_pa = (uintptr_t)(&_start); > + load_sz = (uintptr_t)(&_end) - load_pa; > + > va_pa_offset = PAGE_OFFSET - load_pa; > + va_kernel_pa_offset = kernel_virt_addr - load_pa; > + > pfn_base = PFN_DOWN(load_pa); > > /* > @@ -402,26 +425,22 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) > create_pmd_mapping(fixmap_pmd, FIXADDR_START, > (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE); > /* Setup trampoline PGD and PMD */ > - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, > + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, > (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE); > - create_pmd_mapping(trampoline_pmd, PAGE_OFFSET, > + create_pmd_mapping(trampoline_pmd, kernel_virt_addr, > load_pa, PMD_SIZE, PAGE_KERNEL_EXEC); > #else > /* Setup trampoline PGD */ > - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, > + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, > load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC); > #endif > > /* > - * Setup early PGD covering entire kernel which will allows > + * Setup early PGD covering entire kernel which will allow > * us to reach paging_init(). We map all memory banks later > * in setup_vm_final() below. > */ > - end_va = PAGE_OFFSET + load_sz; > - for (va = PAGE_OFFSET; va < end_va; va += map_size) > - create_pgd_mapping(early_pg_dir, va, > - load_pa + (va - PAGE_OFFSET), > - map_size, PAGE_KERNEL_EXEC); > + create_kernel_page_table(early_pg_dir, map_size); > > /* Create fixed mapping for early FDT parsing */ > end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE; > @@ -441,6 +460,7 @@ static void __init setup_vm_final(void) > uintptr_t va, map_size; > phys_addr_t pa, start, end; > struct memblock_region *reg; > + static struct vm_struct vm_kernel = { 0 }; > > /* Set mmu_enabled flag */ > mmu_enabled = true; > @@ -467,10 +487,22 @@ static void __init setup_vm_final(void) > for (pa = start; pa < end; pa += map_size) { > va = (uintptr_t)__va(pa); > create_pgd_mapping(swapper_pg_dir, va, pa, > - map_size, PAGE_KERNEL_EXEC); > + map_size, PAGE_KERNEL); > } > } > > + /* Map the kernel */ > + create_kernel_page_table(swapper_pg_dir, PMD_SIZE); > + > + /* Reserve the vmalloc area occupied by the kernel */ > + vm_kernel.addr = (void *)kernel_virt_addr; > + vm_kernel.phys_addr = load_pa; > + vm_kernel.size = (load_sz + PMD_SIZE) & ~(PMD_SIZE - 1); > + vm_kernel.flags = VM_MAP | VM_NO_GUARD; > + vm_kernel.caller = __builtin_return_address(0); > + > + vm_area_add_early(&vm_kernel); > + > /* Clear fixmap PTE and PMD mappings */ > clear_fixmap(FIX_PTE); > clear_fixmap(FIX_PMD); > diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c > index e8e4dcd39fed..35703d5ef5fd 100644 > --- a/arch/riscv/mm/physaddr.c > +++ b/arch/riscv/mm/physaddr.c > @@ -23,7 +23,7 @@ EXPORT_SYMBOL(__virt_to_phys); > > phys_addr_t __phys_addr_symbol(unsigned long x) > { > - unsigned long kernel_start = (unsigned long)PAGE_OFFSET; > + unsigned long kernel_start = (unsigned long)kernel_virt_addr; > unsigned long kernel_end = (unsigned long)_end; > > /* > -- > 2.20.1 >
Hi Zong, Le 5/26/20 à 5:43 AM, Zong Li a écrit : > On Sun, May 24, 2020 at 4:54 PM Alexandre Ghiti <alex@ghiti.fr> wrote: >> This is a preparatory patch for relocatable kernel. >> >> The kernel used to be linked at PAGE_OFFSET address and used to be loaded >> physically at the beginning of the main memory. Therefore, we could use >> the linear mapping for the kernel mapping. >> >> But the relocated kernel base address will be different from PAGE_OFFSET >> and since in the linear mapping, two different virtual addresses cannot >> point to the same physical address, the kernel mapping needs to lie outside >> the linear mapping. >> >> In addition, because modules and BPF must be close to the kernel (inside >> +-2GB window), the kernel is placed at the end of the vmalloc zone minus >> 2GB, which leaves room for modules and BPF. The kernel could not be >> placed at the beginning of the vmalloc zone since other vmalloc >> allocations from the kernel could get all the +-2GB window around the >> kernel which would prevent new modules and BPF programs to be loaded. >> >> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> >> --- >> arch/riscv/boot/loader.lds.S | 3 +- >> arch/riscv/include/asm/page.h | 10 +++++- >> arch/riscv/include/asm/pgtable.h | 37 +++++++++++++------- >> arch/riscv/kernel/head.S | 3 +- >> arch/riscv/kernel/module.c | 4 +-- >> arch/riscv/kernel/vmlinux.lds.S | 3 +- >> arch/riscv/mm/init.c | 58 +++++++++++++++++++++++++------- >> arch/riscv/mm/physaddr.c | 2 +- >> 8 files changed, 87 insertions(+), 33 deletions(-) >> >> diff --git a/arch/riscv/boot/loader.lds.S b/arch/riscv/boot/loader.lds.S >> index 47a5003c2e28..62d94696a19c 100644 >> --- a/arch/riscv/boot/loader.lds.S >> +++ b/arch/riscv/boot/loader.lds.S >> @@ -1,13 +1,14 @@ >> /* SPDX-License-Identifier: GPL-2.0 */ >> >> #include <asm/page.h> >> +#include <asm/pgtable.h> >> >> OUTPUT_ARCH(riscv) >> ENTRY(_start) >> >> SECTIONS >> { >> - . = PAGE_OFFSET; >> + . = KERNEL_LINK_ADDR; >> >> .payload : { >> *(.payload) >> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h >> index 2d50f76efe48..48bb09b6a9b7 100644 >> --- a/arch/riscv/include/asm/page.h >> +++ b/arch/riscv/include/asm/page.h >> @@ -90,18 +90,26 @@ typedef struct page *pgtable_t; >> >> #ifdef CONFIG_MMU >> extern unsigned long va_pa_offset; >> +extern unsigned long va_kernel_pa_offset; >> extern unsigned long pfn_base; >> #define ARCH_PFN_OFFSET (pfn_base) >> #else >> #define va_pa_offset 0 >> +#define va_kernel_pa_offset 0 >> #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT) >> #endif /* CONFIG_MMU */ >> >> extern unsigned long max_low_pfn; >> extern unsigned long min_low_pfn; >> +extern unsigned long kernel_virt_addr; >> >> #define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset)) >> -#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset) >> +#define linear_mapping_va_to_pa(x) ((unsigned long)(x) - va_pa_offset) >> +#define kernel_mapping_va_to_pa(x) \ >> + ((unsigned long)(x) - va_kernel_pa_offset) >> +#define __va_to_pa_nodebug(x) \ >> + (((x) >= PAGE_OFFSET) ? \ >> + linear_mapping_va_to_pa(x) : kernel_mapping_va_to_pa(x)) >> >> #ifdef CONFIG_DEBUG_VIRTUAL >> extern phys_addr_t __virt_to_phys(unsigned long x); >> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h >> index 35b60035b6b0..25213cfaf680 100644 >> --- a/arch/riscv/include/asm/pgtable.h >> +++ b/arch/riscv/include/asm/pgtable.h >> @@ -11,23 +11,29 @@ >> >> #include <asm/pgtable-bits.h> >> >> -#ifndef __ASSEMBLY__ >> - >> -/* Page Upper Directory not used in RISC-V */ >> -#include <asm-generic/pgtable-nopud.h> >> -#include <asm/page.h> >> -#include <asm/tlbflush.h> >> -#include <linux/mm_types.h> >> - >> -#ifdef CONFIG_MMU >> +#ifndef CONFIG_MMU >> +#define KERNEL_VIRT_ADDR PAGE_OFFSET >> +#define KERNEL_LINK_ADDR PAGE_OFFSET >> +#else >> +/* >> + * Leave 2GB for modules and BPF that must lie within a 2GB range around >> + * the kernel. >> + */ >> +#define KERNEL_VIRT_ADDR (VMALLOC_END - SZ_2G + 1) >> +#define KERNEL_LINK_ADDR KERNEL_VIRT_ADDR >> >> #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1) >> #define VMALLOC_END (PAGE_OFFSET - 1) >> #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) >> >> #define BPF_JIT_REGION_SIZE (SZ_128M) >> -#define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE) >> -#define BPF_JIT_REGION_END (VMALLOC_END) >> +#define BPF_JIT_REGION_START (kernel_virt_addr) >> +#define BPF_JIT_REGION_END (kernel_virt_addr + BPF_JIT_REGION_SIZE) > It seems to have a potential risk here, the region of bpf is > overlapping with kernel mapping, so if kernel size is bigger than > 128MB, bpf region would be occupied and run out by kernel mapping. > >> + >> +#ifdef CONFIG_64BIT >> +#define VMALLOC_MODULE_START BPF_JIT_REGION_END >> +#define VMALLOC_MODULE_END VMALLOC_END >> +#endif >> > Although kernel_virt_addr is a fixed address now, I think it could be > changed for the purpose of relocatable or KASLR, so if > kernel_virt_addr is moved to far from VMALLOC_END than 2G, the region > of module would be too big. Yes you're right, that's wrong to allow modules to lie outside the 2G window, thanks for noticing. > In addition, the region of module could be > +-2G around the kernel, so we don't be limited in one direction as > before. It seems to me that the region of the module could be decided > at runtime, for example, VMALLOC_MODULE_START is "&_end - 2G" and > VMLLOC_MODULE_END is "&_start + 2G". I had tried that, but as we need to make sure BPF region is different from the module's that makes the macro definitions really cumbersome. I'll give a try again anyway. And I tried to use _end and _start here but it failed, I have to debug this. > I'm not sure whether the size of > region of bpf has to be 128MB for some particular reason, if not, > maybe the region of bpf could be the same with module to avoid being > run out by module. On the contrary, BPF region must not be the same as module's since in that case, modules could take all the space and make BPF fail. Thanks for your review Zong, Alex > >> /* >> * Roughly size the vmemmap space to be large enough to fit enough >> @@ -57,9 +63,16 @@ >> #define FIXADDR_SIZE PGDIR_SIZE >> #endif >> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) >> - >> #endif >> >> +#ifndef __ASSEMBLY__ >> + >> +/* Page Upper Directory not used in RISC-V */ >> +#include <asm-generic/pgtable-nopud.h> >> +#include <asm/page.h> >> +#include <asm/tlbflush.h> >> +#include <linux/mm_types.h> >> + >> #ifdef CONFIG_64BIT >> #include <asm/pgtable-64.h> >> #else >> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S >> index 98a406474e7d..8f5bb7731327 100644 >> --- a/arch/riscv/kernel/head.S >> +++ b/arch/riscv/kernel/head.S >> @@ -49,7 +49,8 @@ ENTRY(_start) >> #ifdef CONFIG_MMU >> relocate: >> /* Relocate return address */ >> - li a1, PAGE_OFFSET >> + la a1, kernel_virt_addr >> + REG_L a1, 0(a1) >> la a2, _start >> sub a1, a1, a2 >> add ra, ra, a1 >> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c >> index 8bbe5dbe1341..1a8fbe05accf 100644 >> --- a/arch/riscv/kernel/module.c >> +++ b/arch/riscv/kernel/module.c >> @@ -392,12 +392,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, >> } >> >> #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) >> -#define VMALLOC_MODULE_START \ >> - max(PFN_ALIGN((unsigned long)&_end - SZ_2G), VMALLOC_START) >> void *module_alloc(unsigned long size) >> { >> return __vmalloc_node_range(size, 1, VMALLOC_MODULE_START, >> - VMALLOC_END, GFP_KERNEL, >> + VMALLOC_MODULE_END, GFP_KERNEL, >> PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, >> __builtin_return_address(0)); >> } >> diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S >> index 0339b6bbe11a..a9abde62909f 100644 >> --- a/arch/riscv/kernel/vmlinux.lds.S >> +++ b/arch/riscv/kernel/vmlinux.lds.S >> @@ -4,7 +4,8 @@ >> * Copyright (C) 2017 SiFive >> */ >> >> -#define LOAD_OFFSET PAGE_OFFSET >> +#include <asm/pgtable.h> >> +#define LOAD_OFFSET KERNEL_LINK_ADDR >> #include <asm/vmlinux.lds.h> >> #include <asm/page.h> >> #include <asm/cache.h> >> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c >> index 27a334106708..17f108baec4f 100644 >> --- a/arch/riscv/mm/init.c >> +++ b/arch/riscv/mm/init.c >> @@ -22,6 +22,9 @@ >> >> #include "../kernel/head.h" >> >> +unsigned long kernel_virt_addr = KERNEL_VIRT_ADDR; >> +EXPORT_SYMBOL(kernel_virt_addr); >> + >> unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] >> __page_aligned_bss; >> EXPORT_SYMBOL(empty_zero_page); >> @@ -178,8 +181,12 @@ void __init setup_bootmem(void) >> } >> >> #ifdef CONFIG_MMU >> +/* Offset between linear mapping virtual address and kernel load address */ >> unsigned long va_pa_offset; >> EXPORT_SYMBOL(va_pa_offset); >> +/* Offset between kernel mapping virtual address and kernel load address */ >> +unsigned long va_kernel_pa_offset; >> +EXPORT_SYMBOL(va_kernel_pa_offset); >> unsigned long pfn_base; >> EXPORT_SYMBOL(pfn_base); >> >> @@ -271,7 +278,7 @@ static phys_addr_t __init alloc_pmd(uintptr_t va) >> if (mmu_enabled) >> return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); >> >> - pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT; >> + pmd_num = (va - kernel_virt_addr) >> PGDIR_SHIFT; >> BUG_ON(pmd_num >= NUM_EARLY_PMDS); >> return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD]; >> } >> @@ -372,14 +379,30 @@ static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size) >> #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing." >> #endif >> >> +static uintptr_t load_pa, load_sz; >> + >> +void create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size) >> +{ >> + uintptr_t va, end_va; >> + >> + end_va = kernel_virt_addr + load_sz; >> + for (va = kernel_virt_addr; va < end_va; va += map_size) >> + create_pgd_mapping(pgdir, va, >> + load_pa + (va - kernel_virt_addr), >> + map_size, PAGE_KERNEL_EXEC); >> +} >> + >> asmlinkage void __init setup_vm(uintptr_t dtb_pa) >> { >> uintptr_t va, end_va; >> - uintptr_t load_pa = (uintptr_t)(&_start); >> - uintptr_t load_sz = (uintptr_t)(&_end) - load_pa; >> uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE); >> >> + load_pa = (uintptr_t)(&_start); >> + load_sz = (uintptr_t)(&_end) - load_pa; >> + >> va_pa_offset = PAGE_OFFSET - load_pa; >> + va_kernel_pa_offset = kernel_virt_addr - load_pa; >> + >> pfn_base = PFN_DOWN(load_pa); >> >> /* >> @@ -402,26 +425,22 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) >> create_pmd_mapping(fixmap_pmd, FIXADDR_START, >> (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE); >> /* Setup trampoline PGD and PMD */ >> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, >> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, >> (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE); >> - create_pmd_mapping(trampoline_pmd, PAGE_OFFSET, >> + create_pmd_mapping(trampoline_pmd, kernel_virt_addr, >> load_pa, PMD_SIZE, PAGE_KERNEL_EXEC); >> #else >> /* Setup trampoline PGD */ >> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, >> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, >> load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC); >> #endif >> >> /* >> - * Setup early PGD covering entire kernel which will allows >> + * Setup early PGD covering entire kernel which will allow >> * us to reach paging_init(). We map all memory banks later >> * in setup_vm_final() below. >> */ >> - end_va = PAGE_OFFSET + load_sz; >> - for (va = PAGE_OFFSET; va < end_va; va += map_size) >> - create_pgd_mapping(early_pg_dir, va, >> - load_pa + (va - PAGE_OFFSET), >> - map_size, PAGE_KERNEL_EXEC); >> + create_kernel_page_table(early_pg_dir, map_size); >> >> /* Create fixed mapping for early FDT parsing */ >> end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE; >> @@ -441,6 +460,7 @@ static void __init setup_vm_final(void) >> uintptr_t va, map_size; >> phys_addr_t pa, start, end; >> struct memblock_region *reg; >> + static struct vm_struct vm_kernel = { 0 }; >> >> /* Set mmu_enabled flag */ >> mmu_enabled = true; >> @@ -467,10 +487,22 @@ static void __init setup_vm_final(void) >> for (pa = start; pa < end; pa += map_size) { >> va = (uintptr_t)__va(pa); >> create_pgd_mapping(swapper_pg_dir, va, pa, >> - map_size, PAGE_KERNEL_EXEC); >> + map_size, PAGE_KERNEL); >> } >> } >> >> + /* Map the kernel */ >> + create_kernel_page_table(swapper_pg_dir, PMD_SIZE); >> + >> + /* Reserve the vmalloc area occupied by the kernel */ >> + vm_kernel.addr = (void *)kernel_virt_addr; >> + vm_kernel.phys_addr = load_pa; >> + vm_kernel.size = (load_sz + PMD_SIZE) & ~(PMD_SIZE - 1); >> + vm_kernel.flags = VM_MAP | VM_NO_GUARD; >> + vm_kernel.caller = __builtin_return_address(0); >> + >> + vm_area_add_early(&vm_kernel); >> + >> /* Clear fixmap PTE and PMD mappings */ >> clear_fixmap(FIX_PTE); >> clear_fixmap(FIX_PMD); >> diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c >> index e8e4dcd39fed..35703d5ef5fd 100644 >> --- a/arch/riscv/mm/physaddr.c >> +++ b/arch/riscv/mm/physaddr.c >> @@ -23,7 +23,7 @@ EXPORT_SYMBOL(__virt_to_phys); >> >> phys_addr_t __phys_addr_symbol(unsigned long x) >> { >> - unsigned long kernel_start = (unsigned long)PAGE_OFFSET; >> + unsigned long kernel_start = (unsigned long)kernel_virt_addr; >> unsigned long kernel_end = (unsigned long)_end; >> >> /* >> -- >> 2.20.1 >>
On Wed, May 27, 2020 at 1:06 AM Alex Ghiti <alex@ghiti.fr> wrote: > > Hi Zong, > > Le 5/26/20 à 5:43 AM, Zong Li a écrit : > > On Sun, May 24, 2020 at 4:54 PM Alexandre Ghiti <alex@ghiti.fr> wrote: > >> This is a preparatory patch for relocatable kernel. > >> > >> The kernel used to be linked at PAGE_OFFSET address and used to be loaded > >> physically at the beginning of the main memory. Therefore, we could use > >> the linear mapping for the kernel mapping. > >> > >> But the relocated kernel base address will be different from PAGE_OFFSET > >> and since in the linear mapping, two different virtual addresses cannot > >> point to the same physical address, the kernel mapping needs to lie outside > >> the linear mapping. > >> > >> In addition, because modules and BPF must be close to the kernel (inside > >> +-2GB window), the kernel is placed at the end of the vmalloc zone minus > >> 2GB, which leaves room for modules and BPF. The kernel could not be > >> placed at the beginning of the vmalloc zone since other vmalloc > >> allocations from the kernel could get all the +-2GB window around the > >> kernel which would prevent new modules and BPF programs to be loaded. > >> > >> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> > >> --- > >> arch/riscv/boot/loader.lds.S | 3 +- > >> arch/riscv/include/asm/page.h | 10 +++++- > >> arch/riscv/include/asm/pgtable.h | 37 +++++++++++++------- > >> arch/riscv/kernel/head.S | 3 +- > >> arch/riscv/kernel/module.c | 4 +-- > >> arch/riscv/kernel/vmlinux.lds.S | 3 +- > >> arch/riscv/mm/init.c | 58 +++++++++++++++++++++++++------- > >> arch/riscv/mm/physaddr.c | 2 +- > >> 8 files changed, 87 insertions(+), 33 deletions(-) > >> > >> diff --git a/arch/riscv/boot/loader.lds.S b/arch/riscv/boot/loader.lds.S > >> index 47a5003c2e28..62d94696a19c 100644 > >> --- a/arch/riscv/boot/loader.lds.S > >> +++ b/arch/riscv/boot/loader.lds.S > >> @@ -1,13 +1,14 @@ > >> /* SPDX-License-Identifier: GPL-2.0 */ > >> > >> #include <asm/page.h> > >> +#include <asm/pgtable.h> > >> > >> OUTPUT_ARCH(riscv) > >> ENTRY(_start) > >> > >> SECTIONS > >> { > >> - . = PAGE_OFFSET; > >> + . = KERNEL_LINK_ADDR; > >> > >> .payload : { > >> *(.payload) > >> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h > >> index 2d50f76efe48..48bb09b6a9b7 100644 > >> --- a/arch/riscv/include/asm/page.h > >> +++ b/arch/riscv/include/asm/page.h > >> @@ -90,18 +90,26 @@ typedef struct page *pgtable_t; > >> > >> #ifdef CONFIG_MMU > >> extern unsigned long va_pa_offset; > >> +extern unsigned long va_kernel_pa_offset; > >> extern unsigned long pfn_base; > >> #define ARCH_PFN_OFFSET (pfn_base) > >> #else > >> #define va_pa_offset 0 > >> +#define va_kernel_pa_offset 0 > >> #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT) > >> #endif /* CONFIG_MMU */ > >> > >> extern unsigned long max_low_pfn; > >> extern unsigned long min_low_pfn; > >> +extern unsigned long kernel_virt_addr; > >> > >> #define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset)) > >> -#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset) > >> +#define linear_mapping_va_to_pa(x) ((unsigned long)(x) - va_pa_offset) > >> +#define kernel_mapping_va_to_pa(x) \ > >> + ((unsigned long)(x) - va_kernel_pa_offset) > >> +#define __va_to_pa_nodebug(x) \ > >> + (((x) >= PAGE_OFFSET) ? \ > >> + linear_mapping_va_to_pa(x) : kernel_mapping_va_to_pa(x)) > >> > >> #ifdef CONFIG_DEBUG_VIRTUAL > >> extern phys_addr_t __virt_to_phys(unsigned long x); > >> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h > >> index 35b60035b6b0..25213cfaf680 100644 > >> --- a/arch/riscv/include/asm/pgtable.h > >> +++ b/arch/riscv/include/asm/pgtable.h > >> @@ -11,23 +11,29 @@ > >> > >> #include <asm/pgtable-bits.h> > >> > >> -#ifndef __ASSEMBLY__ > >> - > >> -/* Page Upper Directory not used in RISC-V */ > >> -#include <asm-generic/pgtable-nopud.h> > >> -#include <asm/page.h> > >> -#include <asm/tlbflush.h> > >> -#include <linux/mm_types.h> > >> - > >> -#ifdef CONFIG_MMU > >> +#ifndef CONFIG_MMU > >> +#define KERNEL_VIRT_ADDR PAGE_OFFSET > >> +#define KERNEL_LINK_ADDR PAGE_OFFSET > >> +#else > >> +/* > >> + * Leave 2GB for modules and BPF that must lie within a 2GB range around > >> + * the kernel. > >> + */ > >> +#define KERNEL_VIRT_ADDR (VMALLOC_END - SZ_2G + 1) > >> +#define KERNEL_LINK_ADDR KERNEL_VIRT_ADDR > >> > >> #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1) > >> #define VMALLOC_END (PAGE_OFFSET - 1) > >> #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) > >> > >> #define BPF_JIT_REGION_SIZE (SZ_128M) > >> -#define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE) > >> -#define BPF_JIT_REGION_END (VMALLOC_END) > >> +#define BPF_JIT_REGION_START (kernel_virt_addr) > >> +#define BPF_JIT_REGION_END (kernel_virt_addr + BPF_JIT_REGION_SIZE) > > It seems to have a potential risk here, the region of bpf is > > overlapping with kernel mapping, so if kernel size is bigger than > > 128MB, bpf region would be occupied and run out by kernel mapping. Is there the risk as I mentioned? > > > >> + > >> +#ifdef CONFIG_64BIT > >> +#define VMALLOC_MODULE_START BPF_JIT_REGION_END > >> +#define VMALLOC_MODULE_END VMALLOC_END > >> +#endif > >> > > Although kernel_virt_addr is a fixed address now, I think it could be > > changed for the purpose of relocatable or KASLR, so if > > kernel_virt_addr is moved to far from VMALLOC_END than 2G, the region > > of module would be too big. > > > Yes you're right, that's wrong to allow modules to lie outside > the 2G window, thanks for noticing. > > > > In addition, the region of module could be > > +-2G around the kernel, so we don't be limited in one direction as > > before. It seems to me that the region of the module could be decided > > at runtime, for example, VMALLOC_MODULE_START is "&_end - 2G" and > > VMLLOC_MODULE_END is "&_start + 2G". > > > I had tried that, but as we need to make sure BPF region is different > from the module's > that makes the macro definitions really cumbersome. I'll give a try > again anyway. And > I tried to use _end and _start here but it failed, I have to debug this. > > > > I'm not sure whether the size of > > region of bpf has to be 128MB for some particular reason, if not, > > maybe the region of bpf could be the same with module to avoid being > > run out by module. > > > On the contrary, BPF region must not be the same as module's since in > that case, > modules could take all the space and make BPF fail. ok, I got it. Thanks for the explaining. > > > Thanks for your review Zong, > > > Alex > > > > > >> /* > >> * Roughly size the vmemmap space to be large enough to fit enough > >> @@ -57,9 +63,16 @@ > >> #define FIXADDR_SIZE PGDIR_SIZE > >> #endif > >> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) > >> - > >> #endif > >> > >> +#ifndef __ASSEMBLY__ > >> + > >> +/* Page Upper Directory not used in RISC-V */ > >> +#include <asm-generic/pgtable-nopud.h> > >> +#include <asm/page.h> > >> +#include <asm/tlbflush.h> > >> +#include <linux/mm_types.h> > >> + > >> #ifdef CONFIG_64BIT > >> #include <asm/pgtable-64.h> > >> #else > >> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S > >> index 98a406474e7d..8f5bb7731327 100644 > >> --- a/arch/riscv/kernel/head.S > >> +++ b/arch/riscv/kernel/head.S > >> @@ -49,7 +49,8 @@ ENTRY(_start) > >> #ifdef CONFIG_MMU > >> relocate: > >> /* Relocate return address */ > >> - li a1, PAGE_OFFSET > >> + la a1, kernel_virt_addr > >> + REG_L a1, 0(a1) > >> la a2, _start > >> sub a1, a1, a2 > >> add ra, ra, a1 > >> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c > >> index 8bbe5dbe1341..1a8fbe05accf 100644 > >> --- a/arch/riscv/kernel/module.c > >> +++ b/arch/riscv/kernel/module.c > >> @@ -392,12 +392,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, > >> } > >> > >> #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) > >> -#define VMALLOC_MODULE_START \ > >> - max(PFN_ALIGN((unsigned long)&_end - SZ_2G), VMALLOC_START) > >> void *module_alloc(unsigned long size) > >> { > >> return __vmalloc_node_range(size, 1, VMALLOC_MODULE_START, > >> - VMALLOC_END, GFP_KERNEL, > >> + VMALLOC_MODULE_END, GFP_KERNEL, > >> PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, > >> __builtin_return_address(0)); > >> } > >> diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S > >> index 0339b6bbe11a..a9abde62909f 100644 > >> --- a/arch/riscv/kernel/vmlinux.lds.S > >> +++ b/arch/riscv/kernel/vmlinux.lds.S > >> @@ -4,7 +4,8 @@ > >> * Copyright (C) 2017 SiFive > >> */ > >> > >> -#define LOAD_OFFSET PAGE_OFFSET > >> +#include <asm/pgtable.h> > >> +#define LOAD_OFFSET KERNEL_LINK_ADDR > >> #include <asm/vmlinux.lds.h> > >> #include <asm/page.h> > >> #include <asm/cache.h> > >> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > >> index 27a334106708..17f108baec4f 100644 > >> --- a/arch/riscv/mm/init.c > >> +++ b/arch/riscv/mm/init.c > >> @@ -22,6 +22,9 @@ > >> > >> #include "../kernel/head.h" > >> > >> +unsigned long kernel_virt_addr = KERNEL_VIRT_ADDR; > >> +EXPORT_SYMBOL(kernel_virt_addr); > >> + > >> unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] > >> __page_aligned_bss; > >> EXPORT_SYMBOL(empty_zero_page); > >> @@ -178,8 +181,12 @@ void __init setup_bootmem(void) > >> } > >> > >> #ifdef CONFIG_MMU > >> +/* Offset between linear mapping virtual address and kernel load address */ > >> unsigned long va_pa_offset; > >> EXPORT_SYMBOL(va_pa_offset); > >> +/* Offset between kernel mapping virtual address and kernel load address */ > >> +unsigned long va_kernel_pa_offset; > >> +EXPORT_SYMBOL(va_kernel_pa_offset); > >> unsigned long pfn_base; > >> EXPORT_SYMBOL(pfn_base); > >> > >> @@ -271,7 +278,7 @@ static phys_addr_t __init alloc_pmd(uintptr_t va) > >> if (mmu_enabled) > >> return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); > >> > >> - pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT; > >> + pmd_num = (va - kernel_virt_addr) >> PGDIR_SHIFT; > >> BUG_ON(pmd_num >= NUM_EARLY_PMDS); > >> return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD]; > >> } > >> @@ -372,14 +379,30 @@ static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size) > >> #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing." > >> #endif > >> > >> +static uintptr_t load_pa, load_sz; > >> + > >> +void create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size) > >> +{ > >> + uintptr_t va, end_va; > >> + > >> + end_va = kernel_virt_addr + load_sz; > >> + for (va = kernel_virt_addr; va < end_va; va += map_size) > >> + create_pgd_mapping(pgdir, va, > >> + load_pa + (va - kernel_virt_addr), > >> + map_size, PAGE_KERNEL_EXEC); > >> +} > >> + > >> asmlinkage void __init setup_vm(uintptr_t dtb_pa) > >> { > >> uintptr_t va, end_va; > >> - uintptr_t load_pa = (uintptr_t)(&_start); > >> - uintptr_t load_sz = (uintptr_t)(&_end) - load_pa; > >> uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE); > >> > >> + load_pa = (uintptr_t)(&_start); > >> + load_sz = (uintptr_t)(&_end) - load_pa; > >> + > >> va_pa_offset = PAGE_OFFSET - load_pa; > >> + va_kernel_pa_offset = kernel_virt_addr - load_pa; > >> + > >> pfn_base = PFN_DOWN(load_pa); > >> > >> /* > >> @@ -402,26 +425,22 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) > >> create_pmd_mapping(fixmap_pmd, FIXADDR_START, > >> (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE); > >> /* Setup trampoline PGD and PMD */ > >> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, > >> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, > >> (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE); > >> - create_pmd_mapping(trampoline_pmd, PAGE_OFFSET, > >> + create_pmd_mapping(trampoline_pmd, kernel_virt_addr, > >> load_pa, PMD_SIZE, PAGE_KERNEL_EXEC); > >> #else > >> /* Setup trampoline PGD */ > >> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, > >> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, > >> load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC); > >> #endif > >> > >> /* > >> - * Setup early PGD covering entire kernel which will allows > >> + * Setup early PGD covering entire kernel which will allow > >> * us to reach paging_init(). We map all memory banks later > >> * in setup_vm_final() below. > >> */ > >> - end_va = PAGE_OFFSET + load_sz; > >> - for (va = PAGE_OFFSET; va < end_va; va += map_size) > >> - create_pgd_mapping(early_pg_dir, va, > >> - load_pa + (va - PAGE_OFFSET), > >> - map_size, PAGE_KERNEL_EXEC); > >> + create_kernel_page_table(early_pg_dir, map_size); > >> > >> /* Create fixed mapping for early FDT parsing */ > >> end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE; > >> @@ -441,6 +460,7 @@ static void __init setup_vm_final(void) > >> uintptr_t va, map_size; > >> phys_addr_t pa, start, end; > >> struct memblock_region *reg; > >> + static struct vm_struct vm_kernel = { 0 }; > >> > >> /* Set mmu_enabled flag */ > >> mmu_enabled = true; > >> @@ -467,10 +487,22 @@ static void __init setup_vm_final(void) > >> for (pa = start; pa < end; pa += map_size) { > >> va = (uintptr_t)__va(pa); > >> create_pgd_mapping(swapper_pg_dir, va, pa, > >> - map_size, PAGE_KERNEL_EXEC); > >> + map_size, PAGE_KERNEL); > >> } > >> } > >> > >> + /* Map the kernel */ > >> + create_kernel_page_table(swapper_pg_dir, PMD_SIZE); > >> + > >> + /* Reserve the vmalloc area occupied by the kernel */ > >> + vm_kernel.addr = (void *)kernel_virt_addr; > >> + vm_kernel.phys_addr = load_pa; > >> + vm_kernel.size = (load_sz + PMD_SIZE) & ~(PMD_SIZE - 1); > >> + vm_kernel.flags = VM_MAP | VM_NO_GUARD; > >> + vm_kernel.caller = __builtin_return_address(0); > >> + > >> + vm_area_add_early(&vm_kernel); > >> + > >> /* Clear fixmap PTE and PMD mappings */ > >> clear_fixmap(FIX_PTE); > >> clear_fixmap(FIX_PMD); > >> diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c > >> index e8e4dcd39fed..35703d5ef5fd 100644 > >> --- a/arch/riscv/mm/physaddr.c > >> +++ b/arch/riscv/mm/physaddr.c > >> @@ -23,7 +23,7 @@ EXPORT_SYMBOL(__virt_to_phys); > >> > >> phys_addr_t __phys_addr_symbol(unsigned long x) > >> { > >> - unsigned long kernel_start = (unsigned long)PAGE_OFFSET; > >> + unsigned long kernel_start = (unsigned long)kernel_virt_addr; > >> unsigned long kernel_end = (unsigned long)_end; > >> > >> /* > >> -- > >> 2.20.1 > >>
Le 5/27/20 à 2:05 AM, Zong Li a écrit : > On Wed, May 27, 2020 at 1:06 AM Alex Ghiti <alex@ghiti.fr> wrote: >> Hi Zong, >> >> Le 5/26/20 à 5:43 AM, Zong Li a écrit : >>> On Sun, May 24, 2020 at 4:54 PM Alexandre Ghiti <alex@ghiti.fr> wrote: >>>> This is a preparatory patch for relocatable kernel. >>>> >>>> The kernel used to be linked at PAGE_OFFSET address and used to be loaded >>>> physically at the beginning of the main memory. Therefore, we could use >>>> the linear mapping for the kernel mapping. >>>> >>>> But the relocated kernel base address will be different from PAGE_OFFSET >>>> and since in the linear mapping, two different virtual addresses cannot >>>> point to the same physical address, the kernel mapping needs to lie outside >>>> the linear mapping. >>>> >>>> In addition, because modules and BPF must be close to the kernel (inside >>>> +-2GB window), the kernel is placed at the end of the vmalloc zone minus >>>> 2GB, which leaves room for modules and BPF. The kernel could not be >>>> placed at the beginning of the vmalloc zone since other vmalloc >>>> allocations from the kernel could get all the +-2GB window around the >>>> kernel which would prevent new modules and BPF programs to be loaded. >>>> >>>> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> >>>> --- >>>> arch/riscv/boot/loader.lds.S | 3 +- >>>> arch/riscv/include/asm/page.h | 10 +++++- >>>> arch/riscv/include/asm/pgtable.h | 37 +++++++++++++------- >>>> arch/riscv/kernel/head.S | 3 +- >>>> arch/riscv/kernel/module.c | 4 +-- >>>> arch/riscv/kernel/vmlinux.lds.S | 3 +- >>>> arch/riscv/mm/init.c | 58 +++++++++++++++++++++++++------- >>>> arch/riscv/mm/physaddr.c | 2 +- >>>> 8 files changed, 87 insertions(+), 33 deletions(-) >>>> >>>> diff --git a/arch/riscv/boot/loader.lds.S b/arch/riscv/boot/loader.lds.S >>>> index 47a5003c2e28..62d94696a19c 100644 >>>> --- a/arch/riscv/boot/loader.lds.S >>>> +++ b/arch/riscv/boot/loader.lds.S >>>> @@ -1,13 +1,14 @@ >>>> /* SPDX-License-Identifier: GPL-2.0 */ >>>> >>>> #include <asm/page.h> >>>> +#include <asm/pgtable.h> >>>> >>>> OUTPUT_ARCH(riscv) >>>> ENTRY(_start) >>>> >>>> SECTIONS >>>> { >>>> - . = PAGE_OFFSET; >>>> + . = KERNEL_LINK_ADDR; >>>> >>>> .payload : { >>>> *(.payload) >>>> diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h >>>> index 2d50f76efe48..48bb09b6a9b7 100644 >>>> --- a/arch/riscv/include/asm/page.h >>>> +++ b/arch/riscv/include/asm/page.h >>>> @@ -90,18 +90,26 @@ typedef struct page *pgtable_t; >>>> >>>> #ifdef CONFIG_MMU >>>> extern unsigned long va_pa_offset; >>>> +extern unsigned long va_kernel_pa_offset; >>>> extern unsigned long pfn_base; >>>> #define ARCH_PFN_OFFSET (pfn_base) >>>> #else >>>> #define va_pa_offset 0 >>>> +#define va_kernel_pa_offset 0 >>>> #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT) >>>> #endif /* CONFIG_MMU */ >>>> >>>> extern unsigned long max_low_pfn; >>>> extern unsigned long min_low_pfn; >>>> +extern unsigned long kernel_virt_addr; >>>> >>>> #define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset)) >>>> -#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset) >>>> +#define linear_mapping_va_to_pa(x) ((unsigned long)(x) - va_pa_offset) >>>> +#define kernel_mapping_va_to_pa(x) \ >>>> + ((unsigned long)(x) - va_kernel_pa_offset) >>>> +#define __va_to_pa_nodebug(x) \ >>>> + (((x) >= PAGE_OFFSET) ? \ >>>> + linear_mapping_va_to_pa(x) : kernel_mapping_va_to_pa(x)) >>>> >>>> #ifdef CONFIG_DEBUG_VIRTUAL >>>> extern phys_addr_t __virt_to_phys(unsigned long x); >>>> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h >>>> index 35b60035b6b0..25213cfaf680 100644 >>>> --- a/arch/riscv/include/asm/pgtable.h >>>> +++ b/arch/riscv/include/asm/pgtable.h >>>> @@ -11,23 +11,29 @@ >>>> >>>> #include <asm/pgtable-bits.h> >>>> >>>> -#ifndef __ASSEMBLY__ >>>> - >>>> -/* Page Upper Directory not used in RISC-V */ >>>> -#include <asm-generic/pgtable-nopud.h> >>>> -#include <asm/page.h> >>>> -#include <asm/tlbflush.h> >>>> -#include <linux/mm_types.h> >>>> - >>>> -#ifdef CONFIG_MMU >>>> +#ifndef CONFIG_MMU >>>> +#define KERNEL_VIRT_ADDR PAGE_OFFSET >>>> +#define KERNEL_LINK_ADDR PAGE_OFFSET >>>> +#else >>>> +/* >>>> + * Leave 2GB for modules and BPF that must lie within a 2GB range around >>>> + * the kernel. >>>> + */ >>>> +#define KERNEL_VIRT_ADDR (VMALLOC_END - SZ_2G + 1) >>>> +#define KERNEL_LINK_ADDR KERNEL_VIRT_ADDR >>>> >>>> #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1) >>>> #define VMALLOC_END (PAGE_OFFSET - 1) >>>> #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) >>>> >>>> #define BPF_JIT_REGION_SIZE (SZ_128M) >>>> -#define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE) >>>> -#define BPF_JIT_REGION_END (VMALLOC_END) >>>> +#define BPF_JIT_REGION_START (kernel_virt_addr) >>>> +#define BPF_JIT_REGION_END (kernel_virt_addr + BPF_JIT_REGION_SIZE) >>> It seems to have a potential risk here, the region of bpf is >>> overlapping with kernel mapping, so if kernel size is bigger than >>> 128MB, bpf region would be occupied and run out by kernel mapping. > Is there the risk as I mentioned? Sorry I forgot to answer this one: I was confident that 128MB was large enough for kernel and BPF. But I see no reason to leave this risk so I'll change kernel_virt_addr for _end so BPF will have its 128MB reserved. Thanks ! Alex > >>>> + >>>> +#ifdef CONFIG_64BIT >>>> +#define VMALLOC_MODULE_START BPF_JIT_REGION_END >>>> +#define VMALLOC_MODULE_END VMALLOC_END >>>> +#endif >>>> >>> Although kernel_virt_addr is a fixed address now, I think it could be >>> changed for the purpose of relocatable or KASLR, so if >>> kernel_virt_addr is moved to far from VMALLOC_END than 2G, the region >>> of module would be too big. >> >> Yes you're right, that's wrong to allow modules to lie outside >> the 2G window, thanks for noticing. >> >> >>> In addition, the region of module could be >>> +-2G around the kernel, so we don't be limited in one direction as >>> before. It seems to me that the region of the module could be decided >>> at runtime, for example, VMALLOC_MODULE_START is "&_end - 2G" and >>> VMLLOC_MODULE_END is "&_start + 2G". >> >> I had tried that, but as we need to make sure BPF region is different >> from the module's >> that makes the macro definitions really cumbersome. I'll give a try >> again anyway. And >> I tried to use _end and _start here but it failed, I have to debug this. >> >> >>> I'm not sure whether the size of >>> region of bpf has to be 128MB for some particular reason, if not, >>> maybe the region of bpf could be the same with module to avoid being >>> run out by module. >> >> On the contrary, BPF region must not be the same as module's since in >> that case, >> modules could take all the space and make BPF fail. > ok, I got it. Thanks for the explaining. > > >> >> Thanks for your review Zong, >> >> >> Alex >> >> >>>> /* >>>> * Roughly size the vmemmap space to be large enough to fit enough >>>> @@ -57,9 +63,16 @@ >>>> #define FIXADDR_SIZE PGDIR_SIZE >>>> #endif >>>> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) >>>> - >>>> #endif >>>> >>>> +#ifndef __ASSEMBLY__ >>>> + >>>> +/* Page Upper Directory not used in RISC-V */ >>>> +#include <asm-generic/pgtable-nopud.h> >>>> +#include <asm/page.h> >>>> +#include <asm/tlbflush.h> >>>> +#include <linux/mm_types.h> >>>> + >>>> #ifdef CONFIG_64BIT >>>> #include <asm/pgtable-64.h> >>>> #else >>>> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S >>>> index 98a406474e7d..8f5bb7731327 100644 >>>> --- a/arch/riscv/kernel/head.S >>>> +++ b/arch/riscv/kernel/head.S >>>> @@ -49,7 +49,8 @@ ENTRY(_start) >>>> #ifdef CONFIG_MMU >>>> relocate: >>>> /* Relocate return address */ >>>> - li a1, PAGE_OFFSET >>>> + la a1, kernel_virt_addr >>>> + REG_L a1, 0(a1) >>>> la a2, _start >>>> sub a1, a1, a2 >>>> add ra, ra, a1 >>>> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c >>>> index 8bbe5dbe1341..1a8fbe05accf 100644 >>>> --- a/arch/riscv/kernel/module.c >>>> +++ b/arch/riscv/kernel/module.c >>>> @@ -392,12 +392,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, >>>> } >>>> >>>> #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) >>>> -#define VMALLOC_MODULE_START \ >>>> - max(PFN_ALIGN((unsigned long)&_end - SZ_2G), VMALLOC_START) >>>> void *module_alloc(unsigned long size) >>>> { >>>> return __vmalloc_node_range(size, 1, VMALLOC_MODULE_START, >>>> - VMALLOC_END, GFP_KERNEL, >>>> + VMALLOC_MODULE_END, GFP_KERNEL, >>>> PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, >>>> __builtin_return_address(0)); >>>> } >>>> diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S >>>> index 0339b6bbe11a..a9abde62909f 100644 >>>> --- a/arch/riscv/kernel/vmlinux.lds.S >>>> +++ b/arch/riscv/kernel/vmlinux.lds.S >>>> @@ -4,7 +4,8 @@ >>>> * Copyright (C) 2017 SiFive >>>> */ >>>> >>>> -#define LOAD_OFFSET PAGE_OFFSET >>>> +#include <asm/pgtable.h> >>>> +#define LOAD_OFFSET KERNEL_LINK_ADDR >>>> #include <asm/vmlinux.lds.h> >>>> #include <asm/page.h> >>>> #include <asm/cache.h> >>>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c >>>> index 27a334106708..17f108baec4f 100644 >>>> --- a/arch/riscv/mm/init.c >>>> +++ b/arch/riscv/mm/init.c >>>> @@ -22,6 +22,9 @@ >>>> >>>> #include "../kernel/head.h" >>>> >>>> +unsigned long kernel_virt_addr = KERNEL_VIRT_ADDR; >>>> +EXPORT_SYMBOL(kernel_virt_addr); >>>> + >>>> unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] >>>> __page_aligned_bss; >>>> EXPORT_SYMBOL(empty_zero_page); >>>> @@ -178,8 +181,12 @@ void __init setup_bootmem(void) >>>> } >>>> >>>> #ifdef CONFIG_MMU >>>> +/* Offset between linear mapping virtual address and kernel load address */ >>>> unsigned long va_pa_offset; >>>> EXPORT_SYMBOL(va_pa_offset); >>>> +/* Offset between kernel mapping virtual address and kernel load address */ >>>> +unsigned long va_kernel_pa_offset; >>>> +EXPORT_SYMBOL(va_kernel_pa_offset); >>>> unsigned long pfn_base; >>>> EXPORT_SYMBOL(pfn_base); >>>> >>>> @@ -271,7 +278,7 @@ static phys_addr_t __init alloc_pmd(uintptr_t va) >>>> if (mmu_enabled) >>>> return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); >>>> >>>> - pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT; >>>> + pmd_num = (va - kernel_virt_addr) >> PGDIR_SHIFT; >>>> BUG_ON(pmd_num >= NUM_EARLY_PMDS); >>>> return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD]; >>>> } >>>> @@ -372,14 +379,30 @@ static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size) >>>> #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing." >>>> #endif >>>> >>>> +static uintptr_t load_pa, load_sz; >>>> + >>>> +void create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size) >>>> +{ >>>> + uintptr_t va, end_va; >>>> + >>>> + end_va = kernel_virt_addr + load_sz; >>>> + for (va = kernel_virt_addr; va < end_va; va += map_size) >>>> + create_pgd_mapping(pgdir, va, >>>> + load_pa + (va - kernel_virt_addr), >>>> + map_size, PAGE_KERNEL_EXEC); >>>> +} >>>> + >>>> asmlinkage void __init setup_vm(uintptr_t dtb_pa) >>>> { >>>> uintptr_t va, end_va; >>>> - uintptr_t load_pa = (uintptr_t)(&_start); >>>> - uintptr_t load_sz = (uintptr_t)(&_end) - load_pa; >>>> uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE); >>>> >>>> + load_pa = (uintptr_t)(&_start); >>>> + load_sz = (uintptr_t)(&_end) - load_pa; >>>> + >>>> va_pa_offset = PAGE_OFFSET - load_pa; >>>> + va_kernel_pa_offset = kernel_virt_addr - load_pa; >>>> + >>>> pfn_base = PFN_DOWN(load_pa); >>>> >>>> /* >>>> @@ -402,26 +425,22 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) >>>> create_pmd_mapping(fixmap_pmd, FIXADDR_START, >>>> (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE); >>>> /* Setup trampoline PGD and PMD */ >>>> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, >>>> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, >>>> (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE); >>>> - create_pmd_mapping(trampoline_pmd, PAGE_OFFSET, >>>> + create_pmd_mapping(trampoline_pmd, kernel_virt_addr, >>>> load_pa, PMD_SIZE, PAGE_KERNEL_EXEC); >>>> #else >>>> /* Setup trampoline PGD */ >>>> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, >>>> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, >>>> load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC); >>>> #endif >>>> >>>> /* >>>> - * Setup early PGD covering entire kernel which will allows >>>> + * Setup early PGD covering entire kernel which will allow >>>> * us to reach paging_init(). We map all memory banks later >>>> * in setup_vm_final() below. >>>> */ >>>> - end_va = PAGE_OFFSET + load_sz; >>>> - for (va = PAGE_OFFSET; va < end_va; va += map_size) >>>> - create_pgd_mapping(early_pg_dir, va, >>>> - load_pa + (va - PAGE_OFFSET), >>>> - map_size, PAGE_KERNEL_EXEC); >>>> + create_kernel_page_table(early_pg_dir, map_size); >>>> >>>> /* Create fixed mapping for early FDT parsing */ >>>> end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE; >>>> @@ -441,6 +460,7 @@ static void __init setup_vm_final(void) >>>> uintptr_t va, map_size; >>>> phys_addr_t pa, start, end; >>>> struct memblock_region *reg; >>>> + static struct vm_struct vm_kernel = { 0 }; >>>> >>>> /* Set mmu_enabled flag */ >>>> mmu_enabled = true; >>>> @@ -467,10 +487,22 @@ static void __init setup_vm_final(void) >>>> for (pa = start; pa < end; pa += map_size) { >>>> va = (uintptr_t)__va(pa); >>>> create_pgd_mapping(swapper_pg_dir, va, pa, >>>> - map_size, PAGE_KERNEL_EXEC); >>>> + map_size, PAGE_KERNEL); >>>> } >>>> } >>>> >>>> + /* Map the kernel */ >>>> + create_kernel_page_table(swapper_pg_dir, PMD_SIZE); >>>> + >>>> + /* Reserve the vmalloc area occupied by the kernel */ >>>> + vm_kernel.addr = (void *)kernel_virt_addr; >>>> + vm_kernel.phys_addr = load_pa; >>>> + vm_kernel.size = (load_sz + PMD_SIZE) & ~(PMD_SIZE - 1); >>>> + vm_kernel.flags = VM_MAP | VM_NO_GUARD; >>>> + vm_kernel.caller = __builtin_return_address(0); >>>> + >>>> + vm_area_add_early(&vm_kernel); >>>> + >>>> /* Clear fixmap PTE and PMD mappings */ >>>> clear_fixmap(FIX_PTE); >>>> clear_fixmap(FIX_PMD); >>>> diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c >>>> index e8e4dcd39fed..35703d5ef5fd 100644 >>>> --- a/arch/riscv/mm/physaddr.c >>>> +++ b/arch/riscv/mm/physaddr.c >>>> @@ -23,7 +23,7 @@ EXPORT_SYMBOL(__virt_to_phys); >>>> >>>> phys_addr_t __phys_addr_symbol(unsigned long x) >>>> { >>>> - unsigned long kernel_start = (unsigned long)PAGE_OFFSET; >>>> + unsigned long kernel_start = (unsigned long)kernel_virt_addr; >>>> unsigned long kernel_end = (unsigned long)_end; >>>> >>>> /* >>>> -- >>>> 2.20.1 >>>>
Hi Alexandre,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on powerpc/next]
[also build test WARNING on linus/master v5.7-rc7 next-20200526]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]
url: https://github.com/0day-ci/linux/commits/Alexandre-Ghiti/vmalloc-kernel-mapping-and-relocatable-kernel/20200524-170109
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: riscv-allyesconfig (attached as .config)
compiler: riscv64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=riscv
If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@intel.com>
All warnings (new ones prefixed by >>, old ones prefixed by <<):
>> arch/riscv/mm/init.c:383:6: warning: no previous prototype for 'create_kernel_page_table' [-Wmissing-prototypes]
383 | void create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
| ^~~~~~~~~~~~~~~~~~~~~~~~
vim +/create_kernel_page_table +383 arch/riscv/mm/init.c
382
> 383 void create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size)
384 {
385 uintptr_t va, end_va;
386
387 end_va = kernel_virt_addr + load_sz;
388 for (va = kernel_virt_addr; va < end_va; va += map_size)
389 create_pgd_mapping(pgdir, va,
390 load_pa + (va - kernel_virt_addr),
391 map_size, PAGE_KERNEL_EXEC);
392 }
393
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Hi Zong, Le 5/27/20 à 3:29 AM, Alex Ghiti a écrit : > Le 5/27/20 à 2:05 AM, Zong Li a écrit : >> On Wed, May 27, 2020 at 1:06 AM Alex Ghiti <alex@ghiti.fr> wrote: >>> Hi Zong, >>> >>> Le 5/26/20 à 5:43 AM, Zong Li a écrit : >>>> On Sun, May 24, 2020 at 4:54 PM Alexandre Ghiti <alex@ghiti.fr> wrote: >>>>> This is a preparatory patch for relocatable kernel. >>>>> >>>>> The kernel used to be linked at PAGE_OFFSET address and used to be >>>>> loaded >>>>> physically at the beginning of the main memory. Therefore, we >>>>> could use >>>>> the linear mapping for the kernel mapping. >>>>> >>>>> But the relocated kernel base address will be different from >>>>> PAGE_OFFSET >>>>> and since in the linear mapping, two different virtual addresses >>>>> cannot >>>>> point to the same physical address, the kernel mapping needs to >>>>> lie outside >>>>> the linear mapping. >>>>> >>>>> In addition, because modules and BPF must be close to the kernel >>>>> (inside >>>>> +-2GB window), the kernel is placed at the end of the vmalloc zone >>>>> minus >>>>> 2GB, which leaves room for modules and BPF. The kernel could not be >>>>> placed at the beginning of the vmalloc zone since other vmalloc >>>>> allocations from the kernel could get all the +-2GB window around the >>>>> kernel which would prevent new modules and BPF programs to be loaded. >>>>> >>>>> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> >>>>> --- >>>>> arch/riscv/boot/loader.lds.S | 3 +- >>>>> arch/riscv/include/asm/page.h | 10 +++++- >>>>> arch/riscv/include/asm/pgtable.h | 37 +++++++++++++------- >>>>> arch/riscv/kernel/head.S | 3 +- >>>>> arch/riscv/kernel/module.c | 4 +-- >>>>> arch/riscv/kernel/vmlinux.lds.S | 3 +- >>>>> arch/riscv/mm/init.c | 58 >>>>> +++++++++++++++++++++++++------- >>>>> arch/riscv/mm/physaddr.c | 2 +- >>>>> 8 files changed, 87 insertions(+), 33 deletions(-) >>>>> >>>>> diff --git a/arch/riscv/boot/loader.lds.S >>>>> b/arch/riscv/boot/loader.lds.S >>>>> index 47a5003c2e28..62d94696a19c 100644 >>>>> --- a/arch/riscv/boot/loader.lds.S >>>>> +++ b/arch/riscv/boot/loader.lds.S >>>>> @@ -1,13 +1,14 @@ >>>>> /* SPDX-License-Identifier: GPL-2.0 */ >>>>> >>>>> #include <asm/page.h> >>>>> +#include <asm/pgtable.h> >>>>> >>>>> OUTPUT_ARCH(riscv) >>>>> ENTRY(_start) >>>>> >>>>> SECTIONS >>>>> { >>>>> - . = PAGE_OFFSET; >>>>> + . = KERNEL_LINK_ADDR; >>>>> >>>>> .payload : { >>>>> *(.payload) >>>>> diff --git a/arch/riscv/include/asm/page.h >>>>> b/arch/riscv/include/asm/page.h >>>>> index 2d50f76efe48..48bb09b6a9b7 100644 >>>>> --- a/arch/riscv/include/asm/page.h >>>>> +++ b/arch/riscv/include/asm/page.h >>>>> @@ -90,18 +90,26 @@ typedef struct page *pgtable_t; >>>>> >>>>> #ifdef CONFIG_MMU >>>>> extern unsigned long va_pa_offset; >>>>> +extern unsigned long va_kernel_pa_offset; >>>>> extern unsigned long pfn_base; >>>>> #define ARCH_PFN_OFFSET (pfn_base) >>>>> #else >>>>> #define va_pa_offset 0 >>>>> +#define va_kernel_pa_offset 0 >>>>> #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT) >>>>> #endif /* CONFIG_MMU */ >>>>> >>>>> extern unsigned long max_low_pfn; >>>>> extern unsigned long min_low_pfn; >>>>> +extern unsigned long kernel_virt_addr; >>>>> >>>>> #define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + >>>>> va_pa_offset)) >>>>> -#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset) >>>>> +#define linear_mapping_va_to_pa(x) ((unsigned long)(x) - >>>>> va_pa_offset) >>>>> +#define kernel_mapping_va_to_pa(x) \ >>>>> + ((unsigned long)(x) - va_kernel_pa_offset) >>>>> +#define __va_to_pa_nodebug(x) \ >>>>> + (((x) >= PAGE_OFFSET) ? \ >>>>> + linear_mapping_va_to_pa(x) : >>>>> kernel_mapping_va_to_pa(x)) >>>>> >>>>> #ifdef CONFIG_DEBUG_VIRTUAL >>>>> extern phys_addr_t __virt_to_phys(unsigned long x); >>>>> diff --git a/arch/riscv/include/asm/pgtable.h >>>>> b/arch/riscv/include/asm/pgtable.h >>>>> index 35b60035b6b0..25213cfaf680 100644 >>>>> --- a/arch/riscv/include/asm/pgtable.h >>>>> +++ b/arch/riscv/include/asm/pgtable.h >>>>> @@ -11,23 +11,29 @@ >>>>> >>>>> #include <asm/pgtable-bits.h> >>>>> >>>>> -#ifndef __ASSEMBLY__ >>>>> - >>>>> -/* Page Upper Directory not used in RISC-V */ >>>>> -#include <asm-generic/pgtable-nopud.h> >>>>> -#include <asm/page.h> >>>>> -#include <asm/tlbflush.h> >>>>> -#include <linux/mm_types.h> >>>>> - >>>>> -#ifdef CONFIG_MMU >>>>> +#ifndef CONFIG_MMU >>>>> +#define KERNEL_VIRT_ADDR PAGE_OFFSET >>>>> +#define KERNEL_LINK_ADDR PAGE_OFFSET >>>>> +#else >>>>> +/* >>>>> + * Leave 2GB for modules and BPF that must lie within a 2GB range >>>>> around >>>>> + * the kernel. >>>>> + */ >>>>> +#define KERNEL_VIRT_ADDR (VMALLOC_END - SZ_2G + 1) >>>>> +#define KERNEL_LINK_ADDR KERNEL_VIRT_ADDR >>>>> >>>>> #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1) >>>>> #define VMALLOC_END (PAGE_OFFSET - 1) >>>>> #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) >>>>> >>>>> #define BPF_JIT_REGION_SIZE (SZ_128M) >>>>> -#define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE) >>>>> -#define BPF_JIT_REGION_END (VMALLOC_END) >>>>> +#define BPF_JIT_REGION_START (kernel_virt_addr) >>>>> +#define BPF_JIT_REGION_END (kernel_virt_addr + >>>>> BPF_JIT_REGION_SIZE) >>>> It seems to have a potential risk here, the region of bpf is >>>> overlapping with kernel mapping, so if kernel size is bigger than >>>> 128MB, bpf region would be occupied and run out by kernel mapping. >> Is there the risk as I mentioned? > > > Sorry I forgot to answer this one: I was confident that 128MB was > large enough for kernel > and BPF. But I see no reason to leave this risk so I'll change > kernel_virt_addr for _end so > BPF will have its 128MB reserved. > > Thanks ! > > Alex > > >> >>>>> + >>>>> +#ifdef CONFIG_64BIT >>>>> +#define VMALLOC_MODULE_START BPF_JIT_REGION_END >>>>> +#define VMALLOC_MODULE_END VMALLOC_END >>>>> +#endif >>>>> >>>> Although kernel_virt_addr is a fixed address now, I think it could be >>>> changed for the purpose of relocatable or KASLR, so if >>>> kernel_virt_addr is moved to far from VMALLOC_END than 2G, the region >>>> of module would be too big. >>> >>> Yes you're right, that's wrong to allow modules to lie outside >>> the 2G window, thanks for noticing. >>> >>> >>>> In addition, the region of module could be >>>> +-2G around the kernel, so we don't be limited in one direction as >>>> before. It seems to me that the region of the module could be decided >>>> at runtime, for example, VMALLOC_MODULE_START is "&_end - 2G" and >>>> VMLLOC_MODULE_END is "&_start + 2G". >>> >>> I had tried that, but as we need to make sure BPF region is different >>> from the module's >>> that makes the macro definitions really cumbersome. I'll give a try >>> again anyway. And >>> I tried to use _end and _start here but it failed, I have to debug >>> this. I gave more thought about that and it is actually not possible to use the 2GB before and after the kernel: modules can call exported functions from each other, so we need to make sure that the "distance" between 2 modules is at most 2GB. And I assume BPF comes with the same restrictions with respect to modules so the kernel + BPF + modules must live in the same 2GB region. I'll come with a v4 quickly, Thanks, Alex >>> >>> >>>> I'm not sure whether the size of >>>> region of bpf has to be 128MB for some particular reason, if not, >>>> maybe the region of bpf could be the same with module to avoid being >>>> run out by module. >>> >>> On the contrary, BPF region must not be the same as module's since in >>> that case, >>> modules could take all the space and make BPF fail. >> ok, I got it. Thanks for the explaining. >> >> >>> >>> Thanks for your review Zong, >>> >>> >>> Alex >>> >>> >>>>> /* >>>>> * Roughly size the vmemmap space to be large enough to fit enough >>>>> @@ -57,9 +63,16 @@ >>>>> #define FIXADDR_SIZE PGDIR_SIZE >>>>> #endif >>>>> #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) >>>>> - >>>>> #endif >>>>> >>>>> +#ifndef __ASSEMBLY__ >>>>> + >>>>> +/* Page Upper Directory not used in RISC-V */ >>>>> +#include <asm-generic/pgtable-nopud.h> >>>>> +#include <asm/page.h> >>>>> +#include <asm/tlbflush.h> >>>>> +#include <linux/mm_types.h> >>>>> + >>>>> #ifdef CONFIG_64BIT >>>>> #include <asm/pgtable-64.h> >>>>> #else >>>>> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S >>>>> index 98a406474e7d..8f5bb7731327 100644 >>>>> --- a/arch/riscv/kernel/head.S >>>>> +++ b/arch/riscv/kernel/head.S >>>>> @@ -49,7 +49,8 @@ ENTRY(_start) >>>>> #ifdef CONFIG_MMU >>>>> relocate: >>>>> /* Relocate return address */ >>>>> - li a1, PAGE_OFFSET >>>>> + la a1, kernel_virt_addr >>>>> + REG_L a1, 0(a1) >>>>> la a2, _start >>>>> sub a1, a1, a2 >>>>> add ra, ra, a1 >>>>> diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c >>>>> index 8bbe5dbe1341..1a8fbe05accf 100644 >>>>> --- a/arch/riscv/kernel/module.c >>>>> +++ b/arch/riscv/kernel/module.c >>>>> @@ -392,12 +392,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, >>>>> const char *strtab, >>>>> } >>>>> >>>>> #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) >>>>> -#define VMALLOC_MODULE_START \ >>>>> - max(PFN_ALIGN((unsigned long)&_end - SZ_2G), VMALLOC_START) >>>>> void *module_alloc(unsigned long size) >>>>> { >>>>> return __vmalloc_node_range(size, 1, VMALLOC_MODULE_START, >>>>> - VMALLOC_END, GFP_KERNEL, >>>>> + VMALLOC_MODULE_END, GFP_KERNEL, >>>>> PAGE_KERNEL_EXEC, 0, >>>>> NUMA_NO_NODE, >>>>> __builtin_return_address(0)); >>>>> } >>>>> diff --git a/arch/riscv/kernel/vmlinux.lds.S >>>>> b/arch/riscv/kernel/vmlinux.lds.S >>>>> index 0339b6bbe11a..a9abde62909f 100644 >>>>> --- a/arch/riscv/kernel/vmlinux.lds.S >>>>> +++ b/arch/riscv/kernel/vmlinux.lds.S >>>>> @@ -4,7 +4,8 @@ >>>>> * Copyright (C) 2017 SiFive >>>>> */ >>>>> >>>>> -#define LOAD_OFFSET PAGE_OFFSET >>>>> +#include <asm/pgtable.h> >>>>> +#define LOAD_OFFSET KERNEL_LINK_ADDR >>>>> #include <asm/vmlinux.lds.h> >>>>> #include <asm/page.h> >>>>> #include <asm/cache.h> >>>>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c >>>>> index 27a334106708..17f108baec4f 100644 >>>>> --- a/arch/riscv/mm/init.c >>>>> +++ b/arch/riscv/mm/init.c >>>>> @@ -22,6 +22,9 @@ >>>>> >>>>> #include "../kernel/head.h" >>>>> >>>>> +unsigned long kernel_virt_addr = KERNEL_VIRT_ADDR; >>>>> +EXPORT_SYMBOL(kernel_virt_addr); >>>>> + >>>>> unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] >>>>> __page_aligned_bss; >>>>> EXPORT_SYMBOL(empty_zero_page); >>>>> @@ -178,8 +181,12 @@ void __init setup_bootmem(void) >>>>> } >>>>> >>>>> #ifdef CONFIG_MMU >>>>> +/* Offset between linear mapping virtual address and kernel load >>>>> address */ >>>>> unsigned long va_pa_offset; >>>>> EXPORT_SYMBOL(va_pa_offset); >>>>> +/* Offset between kernel mapping virtual address and kernel load >>>>> address */ >>>>> +unsigned long va_kernel_pa_offset; >>>>> +EXPORT_SYMBOL(va_kernel_pa_offset); >>>>> unsigned long pfn_base; >>>>> EXPORT_SYMBOL(pfn_base); >>>>> >>>>> @@ -271,7 +278,7 @@ static phys_addr_t __init alloc_pmd(uintptr_t va) >>>>> if (mmu_enabled) >>>>> return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); >>>>> >>>>> - pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT; >>>>> + pmd_num = (va - kernel_virt_addr) >> PGDIR_SHIFT; >>>>> BUG_ON(pmd_num >= NUM_EARLY_PMDS); >>>>> return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD]; >>>>> } >>>>> @@ -372,14 +379,30 @@ static uintptr_t __init >>>>> best_map_size(phys_addr_t base, phys_addr_t size) >>>>> #error "setup_vm() is called from head.S before relocate so it >>>>> should not use absolute addressing." >>>>> #endif >>>>> >>>>> +static uintptr_t load_pa, load_sz; >>>>> + >>>>> +void create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size) >>>>> +{ >>>>> + uintptr_t va, end_va; >>>>> + >>>>> + end_va = kernel_virt_addr + load_sz; >>>>> + for (va = kernel_virt_addr; va < end_va; va += map_size) >>>>> + create_pgd_mapping(pgdir, va, >>>>> + load_pa + (va - kernel_virt_addr), >>>>> + map_size, PAGE_KERNEL_EXEC); >>>>> +} >>>>> + >>>>> asmlinkage void __init setup_vm(uintptr_t dtb_pa) >>>>> { >>>>> uintptr_t va, end_va; >>>>> - uintptr_t load_pa = (uintptr_t)(&_start); >>>>> - uintptr_t load_sz = (uintptr_t)(&_end) - load_pa; >>>>> uintptr_t map_size = best_map_size(load_pa, >>>>> MAX_EARLY_MAPPING_SIZE); >>>>> >>>>> + load_pa = (uintptr_t)(&_start); >>>>> + load_sz = (uintptr_t)(&_end) - load_pa; >>>>> + >>>>> va_pa_offset = PAGE_OFFSET - load_pa; >>>>> + va_kernel_pa_offset = kernel_virt_addr - load_pa; >>>>> + >>>>> pfn_base = PFN_DOWN(load_pa); >>>>> >>>>> /* >>>>> @@ -402,26 +425,22 @@ asmlinkage void __init setup_vm(uintptr_t >>>>> dtb_pa) >>>>> create_pmd_mapping(fixmap_pmd, FIXADDR_START, >>>>> (uintptr_t)fixmap_pte, PMD_SIZE, >>>>> PAGE_TABLE); >>>>> /* Setup trampoline PGD and PMD */ >>>>> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, >>>>> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, >>>>> (uintptr_t)trampoline_pmd, >>>>> PGDIR_SIZE, PAGE_TABLE); >>>>> - create_pmd_mapping(trampoline_pmd, PAGE_OFFSET, >>>>> + create_pmd_mapping(trampoline_pmd, kernel_virt_addr, >>>>> load_pa, PMD_SIZE, PAGE_KERNEL_EXEC); >>>>> #else >>>>> /* Setup trampoline PGD */ >>>>> - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, >>>>> + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, >>>>> load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC); >>>>> #endif >>>>> >>>>> /* >>>>> - * Setup early PGD covering entire kernel which will allows >>>>> + * Setup early PGD covering entire kernel which will allow >>>>> * us to reach paging_init(). We map all memory banks later >>>>> * in setup_vm_final() below. >>>>> */ >>>>> - end_va = PAGE_OFFSET + load_sz; >>>>> - for (va = PAGE_OFFSET; va < end_va; va += map_size) >>>>> - create_pgd_mapping(early_pg_dir, va, >>>>> - load_pa + (va - PAGE_OFFSET), >>>>> - map_size, PAGE_KERNEL_EXEC); >>>>> + create_kernel_page_table(early_pg_dir, map_size); >>>>> >>>>> /* Create fixed mapping for early FDT parsing */ >>>>> end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE; >>>>> @@ -441,6 +460,7 @@ static void __init setup_vm_final(void) >>>>> uintptr_t va, map_size; >>>>> phys_addr_t pa, start, end; >>>>> struct memblock_region *reg; >>>>> + static struct vm_struct vm_kernel = { 0 }; >>>>> >>>>> /* Set mmu_enabled flag */ >>>>> mmu_enabled = true; >>>>> @@ -467,10 +487,22 @@ static void __init setup_vm_final(void) >>>>> for (pa = start; pa < end; pa += map_size) { >>>>> va = (uintptr_t)__va(pa); >>>>> create_pgd_mapping(swapper_pg_dir, va, pa, >>>>> - map_size, >>>>> PAGE_KERNEL_EXEC); >>>>> + map_size, PAGE_KERNEL); >>>>> } >>>>> } >>>>> >>>>> + /* Map the kernel */ >>>>> + create_kernel_page_table(swapper_pg_dir, PMD_SIZE); >>>>> + >>>>> + /* Reserve the vmalloc area occupied by the kernel */ >>>>> + vm_kernel.addr = (void *)kernel_virt_addr; >>>>> + vm_kernel.phys_addr = load_pa; >>>>> + vm_kernel.size = (load_sz + PMD_SIZE) & ~(PMD_SIZE - 1); >>>>> + vm_kernel.flags = VM_MAP | VM_NO_GUARD; >>>>> + vm_kernel.caller = __builtin_return_address(0); >>>>> + >>>>> + vm_area_add_early(&vm_kernel); >>>>> + >>>>> /* Clear fixmap PTE and PMD mappings */ >>>>> clear_fixmap(FIX_PTE); >>>>> clear_fixmap(FIX_PMD); >>>>> diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c >>>>> index e8e4dcd39fed..35703d5ef5fd 100644 >>>>> --- a/arch/riscv/mm/physaddr.c >>>>> +++ b/arch/riscv/mm/physaddr.c >>>>> @@ -23,7 +23,7 @@ EXPORT_SYMBOL(__virt_to_phys); >>>>> >>>>> phys_addr_t __phys_addr_symbol(unsigned long x) >>>>> { >>>>> - unsigned long kernel_start = (unsigned long)PAGE_OFFSET; >>>>> + unsigned long kernel_start = (unsigned long)kernel_virt_addr; >>>>> unsigned long kernel_end = (unsigned long)_end; >>>>> >>>>> /* >>>>> -- >>>>> 2.20.1 >>>>>
diff --git a/arch/riscv/boot/loader.lds.S b/arch/riscv/boot/loader.lds.S index 47a5003c2e28..62d94696a19c 100644 --- a/arch/riscv/boot/loader.lds.S +++ b/arch/riscv/boot/loader.lds.S @@ -1,13 +1,14 @@ /* SPDX-License-Identifier: GPL-2.0 */ #include <asm/page.h> +#include <asm/pgtable.h> OUTPUT_ARCH(riscv) ENTRY(_start) SECTIONS { - . = PAGE_OFFSET; + . = KERNEL_LINK_ADDR; .payload : { *(.payload) diff --git a/arch/riscv/include/asm/page.h b/arch/riscv/include/asm/page.h index 2d50f76efe48..48bb09b6a9b7 100644 --- a/arch/riscv/include/asm/page.h +++ b/arch/riscv/include/asm/page.h @@ -90,18 +90,26 @@ typedef struct page *pgtable_t; #ifdef CONFIG_MMU extern unsigned long va_pa_offset; +extern unsigned long va_kernel_pa_offset; extern unsigned long pfn_base; #define ARCH_PFN_OFFSET (pfn_base) #else #define va_pa_offset 0 +#define va_kernel_pa_offset 0 #define ARCH_PFN_OFFSET (PAGE_OFFSET >> PAGE_SHIFT) #endif /* CONFIG_MMU */ extern unsigned long max_low_pfn; extern unsigned long min_low_pfn; +extern unsigned long kernel_virt_addr; #define __pa_to_va_nodebug(x) ((void *)((unsigned long) (x) + va_pa_offset)) -#define __va_to_pa_nodebug(x) ((unsigned long)(x) - va_pa_offset) +#define linear_mapping_va_to_pa(x) ((unsigned long)(x) - va_pa_offset) +#define kernel_mapping_va_to_pa(x) \ + ((unsigned long)(x) - va_kernel_pa_offset) +#define __va_to_pa_nodebug(x) \ + (((x) >= PAGE_OFFSET) ? \ + linear_mapping_va_to_pa(x) : kernel_mapping_va_to_pa(x)) #ifdef CONFIG_DEBUG_VIRTUAL extern phys_addr_t __virt_to_phys(unsigned long x); diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 35b60035b6b0..25213cfaf680 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -11,23 +11,29 @@ #include <asm/pgtable-bits.h> -#ifndef __ASSEMBLY__ - -/* Page Upper Directory not used in RISC-V */ -#include <asm-generic/pgtable-nopud.h> -#include <asm/page.h> -#include <asm/tlbflush.h> -#include <linux/mm_types.h> - -#ifdef CONFIG_MMU +#ifndef CONFIG_MMU +#define KERNEL_VIRT_ADDR PAGE_OFFSET +#define KERNEL_LINK_ADDR PAGE_OFFSET +#else +/* + * Leave 2GB for modules and BPF that must lie within a 2GB range around + * the kernel. + */ +#define KERNEL_VIRT_ADDR (VMALLOC_END - SZ_2G + 1) +#define KERNEL_LINK_ADDR KERNEL_VIRT_ADDR #define VMALLOC_SIZE (KERN_VIRT_SIZE >> 1) #define VMALLOC_END (PAGE_OFFSET - 1) #define VMALLOC_START (PAGE_OFFSET - VMALLOC_SIZE) #define BPF_JIT_REGION_SIZE (SZ_128M) -#define BPF_JIT_REGION_START (PAGE_OFFSET - BPF_JIT_REGION_SIZE) -#define BPF_JIT_REGION_END (VMALLOC_END) +#define BPF_JIT_REGION_START (kernel_virt_addr) +#define BPF_JIT_REGION_END (kernel_virt_addr + BPF_JIT_REGION_SIZE) + +#ifdef CONFIG_64BIT +#define VMALLOC_MODULE_START BPF_JIT_REGION_END +#define VMALLOC_MODULE_END VMALLOC_END +#endif /* * Roughly size the vmemmap space to be large enough to fit enough @@ -57,9 +63,16 @@ #define FIXADDR_SIZE PGDIR_SIZE #endif #define FIXADDR_START (FIXADDR_TOP - FIXADDR_SIZE) - #endif +#ifndef __ASSEMBLY__ + +/* Page Upper Directory not used in RISC-V */ +#include <asm-generic/pgtable-nopud.h> +#include <asm/page.h> +#include <asm/tlbflush.h> +#include <linux/mm_types.h> + #ifdef CONFIG_64BIT #include <asm/pgtable-64.h> #else diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 98a406474e7d..8f5bb7731327 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -49,7 +49,8 @@ ENTRY(_start) #ifdef CONFIG_MMU relocate: /* Relocate return address */ - li a1, PAGE_OFFSET + la a1, kernel_virt_addr + REG_L a1, 0(a1) la a2, _start sub a1, a1, a2 add ra, ra, a1 diff --git a/arch/riscv/kernel/module.c b/arch/riscv/kernel/module.c index 8bbe5dbe1341..1a8fbe05accf 100644 --- a/arch/riscv/kernel/module.c +++ b/arch/riscv/kernel/module.c @@ -392,12 +392,10 @@ int apply_relocate_add(Elf_Shdr *sechdrs, const char *strtab, } #if defined(CONFIG_MMU) && defined(CONFIG_64BIT) -#define VMALLOC_MODULE_START \ - max(PFN_ALIGN((unsigned long)&_end - SZ_2G), VMALLOC_START) void *module_alloc(unsigned long size) { return __vmalloc_node_range(size, 1, VMALLOC_MODULE_START, - VMALLOC_END, GFP_KERNEL, + VMALLOC_MODULE_END, GFP_KERNEL, PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE, __builtin_return_address(0)); } diff --git a/arch/riscv/kernel/vmlinux.lds.S b/arch/riscv/kernel/vmlinux.lds.S index 0339b6bbe11a..a9abde62909f 100644 --- a/arch/riscv/kernel/vmlinux.lds.S +++ b/arch/riscv/kernel/vmlinux.lds.S @@ -4,7 +4,8 @@ * Copyright (C) 2017 SiFive */ -#define LOAD_OFFSET PAGE_OFFSET +#include <asm/pgtable.h> +#define LOAD_OFFSET KERNEL_LINK_ADDR #include <asm/vmlinux.lds.h> #include <asm/page.h> #include <asm/cache.h> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 27a334106708..17f108baec4f 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -22,6 +22,9 @@ #include "../kernel/head.h" +unsigned long kernel_virt_addr = KERNEL_VIRT_ADDR; +EXPORT_SYMBOL(kernel_virt_addr); + unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)] __page_aligned_bss; EXPORT_SYMBOL(empty_zero_page); @@ -178,8 +181,12 @@ void __init setup_bootmem(void) } #ifdef CONFIG_MMU +/* Offset between linear mapping virtual address and kernel load address */ unsigned long va_pa_offset; EXPORT_SYMBOL(va_pa_offset); +/* Offset between kernel mapping virtual address and kernel load address */ +unsigned long va_kernel_pa_offset; +EXPORT_SYMBOL(va_kernel_pa_offset); unsigned long pfn_base; EXPORT_SYMBOL(pfn_base); @@ -271,7 +278,7 @@ static phys_addr_t __init alloc_pmd(uintptr_t va) if (mmu_enabled) return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); - pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT; + pmd_num = (va - kernel_virt_addr) >> PGDIR_SHIFT; BUG_ON(pmd_num >= NUM_EARLY_PMDS); return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD]; } @@ -372,14 +379,30 @@ static uintptr_t __init best_map_size(phys_addr_t base, phys_addr_t size) #error "setup_vm() is called from head.S before relocate so it should not use absolute addressing." #endif +static uintptr_t load_pa, load_sz; + +void create_kernel_page_table(pgd_t *pgdir, uintptr_t map_size) +{ + uintptr_t va, end_va; + + end_va = kernel_virt_addr + load_sz; + for (va = kernel_virt_addr; va < end_va; va += map_size) + create_pgd_mapping(pgdir, va, + load_pa + (va - kernel_virt_addr), + map_size, PAGE_KERNEL_EXEC); +} + asmlinkage void __init setup_vm(uintptr_t dtb_pa) { uintptr_t va, end_va; - uintptr_t load_pa = (uintptr_t)(&_start); - uintptr_t load_sz = (uintptr_t)(&_end) - load_pa; uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE); + load_pa = (uintptr_t)(&_start); + load_sz = (uintptr_t)(&_end) - load_pa; + va_pa_offset = PAGE_OFFSET - load_pa; + va_kernel_pa_offset = kernel_virt_addr - load_pa; + pfn_base = PFN_DOWN(load_pa); /* @@ -402,26 +425,22 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) create_pmd_mapping(fixmap_pmd, FIXADDR_START, (uintptr_t)fixmap_pte, PMD_SIZE, PAGE_TABLE); /* Setup trampoline PGD and PMD */ - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, (uintptr_t)trampoline_pmd, PGDIR_SIZE, PAGE_TABLE); - create_pmd_mapping(trampoline_pmd, PAGE_OFFSET, + create_pmd_mapping(trampoline_pmd, kernel_virt_addr, load_pa, PMD_SIZE, PAGE_KERNEL_EXEC); #else /* Setup trampoline PGD */ - create_pgd_mapping(trampoline_pg_dir, PAGE_OFFSET, + create_pgd_mapping(trampoline_pg_dir, kernel_virt_addr, load_pa, PGDIR_SIZE, PAGE_KERNEL_EXEC); #endif /* - * Setup early PGD covering entire kernel which will allows + * Setup early PGD covering entire kernel which will allow * us to reach paging_init(). We map all memory banks later * in setup_vm_final() below. */ - end_va = PAGE_OFFSET + load_sz; - for (va = PAGE_OFFSET; va < end_va; va += map_size) - create_pgd_mapping(early_pg_dir, va, - load_pa + (va - PAGE_OFFSET), - map_size, PAGE_KERNEL_EXEC); + create_kernel_page_table(early_pg_dir, map_size); /* Create fixed mapping for early FDT parsing */ end_va = __fix_to_virt(FIX_FDT) + FIX_FDT_SIZE; @@ -441,6 +460,7 @@ static void __init setup_vm_final(void) uintptr_t va, map_size; phys_addr_t pa, start, end; struct memblock_region *reg; + static struct vm_struct vm_kernel = { 0 }; /* Set mmu_enabled flag */ mmu_enabled = true; @@ -467,10 +487,22 @@ static void __init setup_vm_final(void) for (pa = start; pa < end; pa += map_size) { va = (uintptr_t)__va(pa); create_pgd_mapping(swapper_pg_dir, va, pa, - map_size, PAGE_KERNEL_EXEC); + map_size, PAGE_KERNEL); } } + /* Map the kernel */ + create_kernel_page_table(swapper_pg_dir, PMD_SIZE); + + /* Reserve the vmalloc area occupied by the kernel */ + vm_kernel.addr = (void *)kernel_virt_addr; + vm_kernel.phys_addr = load_pa; + vm_kernel.size = (load_sz + PMD_SIZE) & ~(PMD_SIZE - 1); + vm_kernel.flags = VM_MAP | VM_NO_GUARD; + vm_kernel.caller = __builtin_return_address(0); + + vm_area_add_early(&vm_kernel); + /* Clear fixmap PTE and PMD mappings */ clear_fixmap(FIX_PTE); clear_fixmap(FIX_PMD); diff --git a/arch/riscv/mm/physaddr.c b/arch/riscv/mm/physaddr.c index e8e4dcd39fed..35703d5ef5fd 100644 --- a/arch/riscv/mm/physaddr.c +++ b/arch/riscv/mm/physaddr.c @@ -23,7 +23,7 @@ EXPORT_SYMBOL(__virt_to_phys); phys_addr_t __phys_addr_symbol(unsigned long x) { - unsigned long kernel_start = (unsigned long)PAGE_OFFSET; + unsigned long kernel_start = (unsigned long)kernel_virt_addr; unsigned long kernel_end = (unsigned long)_end; /*
This is a preparatory patch for relocatable kernel. The kernel used to be linked at PAGE_OFFSET address and used to be loaded physically at the beginning of the main memory. Therefore, we could use the linear mapping for the kernel mapping. But the relocated kernel base address will be different from PAGE_OFFSET and since in the linear mapping, two different virtual addresses cannot point to the same physical address, the kernel mapping needs to lie outside the linear mapping. In addition, because modules and BPF must be close to the kernel (inside +-2GB window), the kernel is placed at the end of the vmalloc zone minus 2GB, which leaves room for modules and BPF. The kernel could not be placed at the beginning of the vmalloc zone since other vmalloc allocations from the kernel could get all the +-2GB window around the kernel which would prevent new modules and BPF programs to be loaded. Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> --- arch/riscv/boot/loader.lds.S | 3 +- arch/riscv/include/asm/page.h | 10 +++++- arch/riscv/include/asm/pgtable.h | 37 +++++++++++++------- arch/riscv/kernel/head.S | 3 +- arch/riscv/kernel/module.c | 4 +-- arch/riscv/kernel/vmlinux.lds.S | 3 +- arch/riscv/mm/init.c | 58 +++++++++++++++++++++++++------- arch/riscv/mm/physaddr.c | 2 +- 8 files changed, 87 insertions(+), 33 deletions(-)