| Message ID | 0557d3ec898c1d0ea2fc59fa8757618e524c5d94.1727858295.git.christophe.leroy@csgroup.eu (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] powerpc/vdso: Add a page for non-time data | expand |
Hi Christophe, On Wed, Oct 02, 2024 at 10:39:28AM GMT, Christophe Leroy wrote: > The page containing VDSO time data is swapped with the one containing > TIME namespace data when a process uses a non-root time namespace. > For other data like powerpc specific data and RNG data, it means > tracking whether time namespace is the root one or not to know which > page to use. > > Simplify the logic behind by moving time data out of first data page > so that the first data page which contains everything else always > remains the first page. Time data is in the second or third page > depending on selected time namespace. > > While we are playing with get_datapage macro, directly take into > account the data offset inside the macro instead of adding that offset > afterwards. FYI I am currently working on a series to unify the storage of the VDSO data for most architectures, including powerpc. This will also include a dedicated rng data page. That generic infrastructure would replace the need for Patch 1. Obviously, if your series gets applied, I can adapt mine for that. If you are about to also modify other architectures in a similar way, we may want to coordinate. > Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> > --- > arch/powerpc/include/asm/vdso_datapage.h | 24 +++++++----------------- > arch/powerpc/kernel/vdso.c | 16 ++++++++++------ > arch/powerpc/kernel/vdso/cacheflush.S | 2 +- > arch/powerpc/kernel/vdso/datapage.S | 4 ++-- > arch/powerpc/kernel/vdso/getrandom.S | 3 +-- > arch/powerpc/kernel/vdso/gettimeofday.S | 5 ++--- > arch/powerpc/kernel/vdso/vdso32.lds.S | 2 +- > arch/powerpc/kernel/vdso/vdso64.lds.S | 2 +- > 8 files changed, 25 insertions(+), 33 deletions(-) Thomas
Le 02/10/2024 à 10:54, Thomas Weißschuh a écrit : > [Vous ne recevez pas souvent de courriers de thomas.weissschuh@linutronix.de. D?couvrez pourquoi ceci est important ? https://aka.ms/LearnAboutSenderIdentification ] > > Hi Christophe, > > On Wed, Oct 02, 2024 at 10:39:28AM GMT, Christophe Leroy wrote: >> The page containing VDSO time data is swapped with the one containing >> TIME namespace data when a process uses a non-root time namespace. >> For other data like powerpc specific data and RNG data, it means >> tracking whether time namespace is the root one or not to know which >> page to use. >> >> Simplify the logic behind by moving time data out of first data page >> so that the first data page which contains everything else always >> remains the first page. Time data is in the second or third page >> depending on selected time namespace. >> >> While we are playing with get_datapage macro, directly take into >> account the data offset inside the macro instead of adding that offset >> afterwards. > > FYI > > I am currently working on a series to unify the storage of the > VDSO data for most architectures, including powerpc. > This will also include a dedicated rng data page. > > That generic infrastructure would replace the need for Patch 1. > Obviously, if your series gets applied, I can adapt mine for that. > > If you are about to also modify other architectures in a similar way, > we may want to coordinate. > I'm not going to do anything on other architectures. Indeed my patch is an outcome of the discussion at https://patchwork.ozlabs.org/project/linuxppc-dev/patch/ffd7fc255e194d1e2b0aa3d9d129e826c53219d4.1725611321.git.christophe.leroy@csgroup.eu/ I'm all fine if you are doing something generic for all architectures. For powerpc will it handle the entire non-time data, not only rng ? The purpose being to revert https://github.com/torvalds/linux/commit/c73049389e58c01e2e3bbfae900c8daeee177191 Christophe
Hi Christophe, On Wed, Oct 02, 2024 at 12:10:08PM GMT, Christophe Leroy wrote: > Le 02/10/2024 à 10:54, Thomas Weißschuh a écrit : > > On Wed, Oct 02, 2024 at 10:39:28AM GMT, Christophe Leroy wrote: > > > The page containing VDSO time data is swapped with the one containing > > > TIME namespace data when a process uses a non-root time namespace. > > > For other data like powerpc specific data and RNG data, it means > > > tracking whether time namespace is the root one or not to know which > > > page to use. > > > > > > Simplify the logic behind by moving time data out of first data page > > > so that the first data page which contains everything else always > > > remains the first page. Time data is in the second or third page > > > depending on selected time namespace. > > > > > > While we are playing with get_datapage macro, directly take into > > > account the data offset inside the macro instead of adding that offset > > > afterwards. > > > > FYI > > > > I am currently working on a series to unify the storage of the > > VDSO data for most architectures, including powerpc. > > This will also include a dedicated rng data page. > > > > That generic infrastructure would replace the need for Patch 1. > > Obviously, if your series gets applied, I can adapt mine for that. > > > > If you are about to also modify other architectures in a similar way, > > we may want to coordinate. > > > > I'm not going to do anything on other architectures. Ack. > Indeed my patch is an outcome of the discussion at > https://patchwork.ozlabs.org/project/linuxppc-dev/patch/ffd7fc255e194d1e2b0aa3d9d129e826c53219d4.1725611321.git.christophe.leroy@csgroup.eu/ > > I'm all fine if you are doing something generic for all architectures. For > powerpc will it handle the entire non-time data, not only rng ? The purpose > being to revert https://github.com/torvalds/linux/commit/c73049389e58c01e2e3bbfae900c8daeee177191 Yes, it can handle arbitrary arch-specific non-time-related data in addition to the rng data. (In addition it also handles arch-specific time-related data) The code introduced by the linked patch is gone in my series. Thomas
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h index 248dee138f7b..33069afccb3c 100644 --- a/arch/powerpc/include/asm/vdso_datapage.h +++ b/arch/powerpc/include/asm/vdso_datapage.h @@ -82,8 +82,9 @@ struct vdso_arch_data { __u32 syscall_map[SYSCALL_MAP_SIZE]; /* Map of syscalls */ __u32 compat_syscall_map[SYSCALL_MAP_SIZE]; /* Map of compat syscalls */ - struct vdso_data data[CS_BASES]; struct vdso_rng_data rng_data; + + struct vdso_data data[CS_BASES] __aligned(1 << CONFIG_PAGE_SHIFT); }; #else /* CONFIG_PPC64 */ @@ -95,8 +96,9 @@ struct vdso_arch_data { __u64 tb_ticks_per_sec; /* Timebase tics / sec 0x38 */ __u32 syscall_map[SYSCALL_MAP_SIZE]; /* Map of syscalls */ __u32 compat_syscall_map[0]; /* No compat syscalls on PPC32 */ - struct vdso_data data[CS_BASES]; struct vdso_rng_data rng_data; + + struct vdso_data data[CS_BASES] __aligned(1 << CONFIG_PAGE_SHIFT); }; #endif /* CONFIG_PPC64 */ @@ -105,29 +107,17 @@ extern struct vdso_arch_data *vdso_data; #else /* __ASSEMBLY__ */ -.macro get_datapage ptr +.macro get_datapage ptr offset=0 bcl 20, 31, .+4 999: mflr \ptr - addis \ptr, \ptr, (_vdso_datapage - 999b)@ha - addi \ptr, \ptr, (_vdso_datapage - 999b)@l + addis \ptr, \ptr, (_vdso_datapage - 999b + \offset)@ha + addi \ptr, \ptr, (_vdso_datapage - 999b + \offset)@l .endm #include <asm/asm-offsets.h> #include <asm/page.h> -.macro get_realdatapage ptr scratch - get_datapage \ptr -#ifdef CONFIG_TIME_NS - lwz \scratch, VDSO_CLOCKMODE_OFFSET(\ptr) - xoris \scratch, \scratch, VDSO_CLOCKMODE_TIMENS@h - xori \scratch, \scratch, VDSO_CLOCKMODE_TIMENS@l - cntlzw \scratch, \scratch - rlwinm \scratch, \scratch, PAGE_SHIFT - 5, 1 << PAGE_SHIFT - add \ptr, \ptr, \scratch -#endif -.endm - #endif /* __ASSEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index ee4b9d676cff..6166c1862c06 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -48,12 +48,13 @@ long sys_ni_syscall(void); */ static union { struct vdso_arch_data data; - u8 page[PAGE_SIZE]; + u8 page[2 * PAGE_SIZE]; } vdso_data_store __page_aligned_data; struct vdso_arch_data *vdso_data = &vdso_data_store.data; enum vvar_pages { - VVAR_DATA_PAGE_OFFSET, + VVAR_BASE_PAGE_OFFSET, + VVAR_TIME_PAGE_OFFSET, VVAR_TIMENS_PAGE_OFFSET, VVAR_NR_PAGES, }; @@ -119,7 +120,7 @@ static struct vm_special_mapping vdso64_spec __ro_after_init = { #ifdef CONFIG_TIME_NS struct vdso_data *arch_get_vdso_data(void *vvar_page) { - return ((struct vdso_arch_data *)vvar_page)->data; + return vvar_page; } /* @@ -153,11 +154,14 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, unsigned long pfn; switch (vmf->pgoff) { - case VVAR_DATA_PAGE_OFFSET: + case VVAR_BASE_PAGE_OFFSET: + pfn = virt_to_pfn(vdso_data); + break; + case VVAR_TIME_PAGE_OFFSET: if (timens_page) pfn = page_to_pfn(timens_page); else - pfn = virt_to_pfn(vdso_data); + pfn = virt_to_pfn(vdso_data->data); break; #ifdef CONFIG_TIME_NS case VVAR_TIMENS_PAGE_OFFSET: @@ -170,7 +174,7 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm, */ if (!timens_page) return VM_FAULT_SIGBUS; - pfn = virt_to_pfn(vdso_data); + pfn = virt_to_pfn(vdso_data->data); break; #endif /* CONFIG_TIME_NS */ default: diff --git a/arch/powerpc/kernel/vdso/cacheflush.S b/arch/powerpc/kernel/vdso/cacheflush.S index 3b2479bd2f9a..0085ae464dac 100644 --- a/arch/powerpc/kernel/vdso/cacheflush.S +++ b/arch/powerpc/kernel/vdso/cacheflush.S @@ -30,7 +30,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE) #ifdef CONFIG_PPC64 mflr r12 .cfi_register lr,r12 - get_realdatapage r10, r11 + get_datapage r10 mtlr r12 .cfi_restore lr #endif diff --git a/arch/powerpc/kernel/vdso/datapage.S b/arch/powerpc/kernel/vdso/datapage.S index 2b19b6201a33..db8e167f0166 100644 --- a/arch/powerpc/kernel/vdso/datapage.S +++ b/arch/powerpc/kernel/vdso/datapage.S @@ -28,7 +28,7 @@ V_FUNCTION_BEGIN(__kernel_get_syscall_map) mflr r12 .cfi_register lr,r12 mr. r4,r3 - get_realdatapage r3, r11 + get_datapage r3 mtlr r12 #ifdef __powerpc64__ addi r3,r3,CFG_SYSCALL_MAP64 @@ -52,7 +52,7 @@ V_FUNCTION_BEGIN(__kernel_get_tbfreq) .cfi_startproc mflr r12 .cfi_register lr,r12 - get_realdatapage r3, r11 + get_datapage r3 #ifndef __powerpc64__ lwz r4,(CFG_TB_TICKS_PER_SEC + 4)(r3) #endif diff --git a/arch/powerpc/kernel/vdso/getrandom.S b/arch/powerpc/kernel/vdso/getrandom.S index f3bbf931931c..3deddcf89f99 100644 --- a/arch/powerpc/kernel/vdso/getrandom.S +++ b/arch/powerpc/kernel/vdso/getrandom.S @@ -31,8 +31,7 @@ PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1) .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT #endif - get_realdatapage r8, r11 - addi r8, r8, VDSO_RNG_DATA_OFFSET + get_datapage r8 VDSO_RNG_DATA_OFFSET bl CFUNC(DOTSYM(\funct)) PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) #ifdef __powerpc64__ diff --git a/arch/powerpc/kernel/vdso/gettimeofday.S b/arch/powerpc/kernel/vdso/gettimeofday.S index 5540d7021fa2..5333848322ca 100644 --- a/arch/powerpc/kernel/vdso/gettimeofday.S +++ b/arch/powerpc/kernel/vdso/gettimeofday.S @@ -32,11 +32,10 @@ PPC_STL r2, PPC_MIN_STKFRM + STK_GOT(r1) .cfi_rel_offset r2, PPC_MIN_STKFRM + STK_GOT #endif - get_datapage r5 .ifeq \call_time - addi r5, r5, VDSO_DATA_OFFSET + get_datapage r5 VDSO_DATA_OFFSET .else - addi r4, r5, VDSO_DATA_OFFSET + get_datapage r4 VDSO_DATA_OFFSET .endif bl CFUNC(DOTSYM(\funct)) PPC_LL r0, PPC_MIN_STKFRM + PPC_LR_STKOFF(r1) diff --git a/arch/powerpc/kernel/vdso/vdso32.lds.S b/arch/powerpc/kernel/vdso/vdso32.lds.S index 7b41d5d256e8..1a1b0b6d681a 100644 --- a/arch/powerpc/kernel/vdso/vdso32.lds.S +++ b/arch/powerpc/kernel/vdso/vdso32.lds.S @@ -16,7 +16,7 @@ OUTPUT_ARCH(powerpc:common) SECTIONS { - PROVIDE(_vdso_datapage = . - 2 * PAGE_SIZE); + PROVIDE(_vdso_datapage = . - 3 * PAGE_SIZE); . = SIZEOF_HEADERS; .hash : { *(.hash) } :text diff --git a/arch/powerpc/kernel/vdso/vdso64.lds.S b/arch/powerpc/kernel/vdso/vdso64.lds.S index 9481e4b892ed..e21b5506cad6 100644 --- a/arch/powerpc/kernel/vdso/vdso64.lds.S +++ b/arch/powerpc/kernel/vdso/vdso64.lds.S @@ -16,7 +16,7 @@ OUTPUT_ARCH(powerpc:common64) SECTIONS { - PROVIDE(_vdso_datapage = . - 2 * PAGE_SIZE); + PROVIDE(_vdso_datapage = . - 3 * PAGE_SIZE); . = SIZEOF_HEADERS; .hash : { *(.hash) } :text
The page containing VDSO time data is swapped with the one containing TIME namespace data when a process uses a non-root time namespace. For other data like powerpc specific data and RNG data, it means tracking whether time namespace is the root one or not to know which page to use. Simplify the logic behind by moving time data out of first data page so that the first data page which contains everything else always remains the first page. Time data is in the second or third page depending on selected time namespace. While we are playing with get_datapage macro, directly take into account the data offset inside the macro instead of adding that offset afterwards. Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- arch/powerpc/include/asm/vdso_datapage.h | 24 +++++++----------------- arch/powerpc/kernel/vdso.c | 16 ++++++++++------ arch/powerpc/kernel/vdso/cacheflush.S | 2 +- arch/powerpc/kernel/vdso/datapage.S | 4 ++-- arch/powerpc/kernel/vdso/getrandom.S | 3 +-- arch/powerpc/kernel/vdso/gettimeofday.S | 5 ++--- arch/powerpc/kernel/vdso/vdso32.lds.S | 2 +- arch/powerpc/kernel/vdso/vdso64.lds.S | 2 +- 8 files changed, 25 insertions(+), 33 deletions(-)