diff mbox series

[V3,10/17] riscv: compat: Add elf.h implementation

Message ID 20220120073911.99857-11-guoren@kernel.org
State New
Headers show
Series riscv: compat: Add COMPAT mode support for rv64 | expand

Commit Message

Guo Ren Jan. 20, 2022, 7:39 a.m. UTC 
From: Guo Ren <guoren@linux.alibaba.com>

Implement necessary type and macro for compat elf. See the code
comment for detail.

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
---
 arch/riscv/include/asm/elf.h | 51 +++++++++++++++++++++++++++++++++++-
 1 file changed, 50 insertions(+), 1 deletion(-)

Comments

Arnd Bergmann Jan. 20, 2022, 9:36 a.m. UTC | #1 
On Thu, Jan 20, 2022 at 8:39 AM <guoren@kernel.org> wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Implement necessary type and macro for compat elf. See the code
> comment for detail.
>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>

Reviewed-by: Arnd Bergmann <arnd@arndb.de>

> +
> +/*
> + * FIXME: not sure SET_PERSONALITY for compat process is right!
> + */
> +#define SET_PERSONALITY(ex)                                    \
> +do {    if ((ex).e_ident[EI_CLASS] == ELFCLASS32)              \
> +               set_thread_flag(TIF_32BIT);                     \
> +       else                                                    \
> +               clear_thread_flag(TIF_32BIT);                   \
> +       if (personality(current->personality) != PER_LINUX32)   \
> +               set_personality(PER_LINUX |                     \
> +                       (current->personality & (~PER_MASK)));  \
> +} while (0)
> +

The implementation looks good to me now,  you can remove that comment above it.

        Arnd
Guo Ren Jan. 20, 2022, 1:35 p.m. UTC | #2 
On Thu, Jan 20, 2022 at 9:33 PM Arnd Bergmann <arnd@arndb.de> wrote:
>
> On Thu, Jan 20, 2022 at 8:39 AM <guoren@kernel.org> wrote:
> > From: Guo Ren <guoren@linux.alibaba.com>
> >
> > Implement necessary type and macro for compat elf. See the code
> > comment for detail.
> >
> > Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
>
> > +
> > +/*
> > + * FIXME: not sure SET_PERSONALITY for compat process is right!
> > + */
> > +#define SET_PERSONALITY(ex)                                    \
> > +do {    if ((ex).e_ident[EI_CLASS] == ELFCLASS32)              \
> > +               set_thread_flag(TIF_32BIT);                     \
> > +       else                                                    \
> > +               clear_thread_flag(TIF_32BIT);                   \
> > +       if (personality(current->personality) != PER_LINUX32)   \
> > +               set_personality(PER_LINUX |                     \
> > +                       (current->personality & (~PER_MASK)));  \
> > +} while (0)
> > +
>
> The implementation looks good to me now,  you can remove that comment above it.
Thx for pointing it out. I forgot.

>
>         Arnd
diff mbox series

Patch

diff --git a/arch/riscv/include/asm/elf.h b/arch/riscv/include/asm/elf.h
index f53c40026c7a..353b4589c79c 100644
--- a/arch/riscv/include/asm/elf.h
+++ b/arch/riscv/include/asm/elf.h
@@ -8,6 +8,8 @@ 
 #ifndef _ASM_RISCV_ELF_H
 #define _ASM_RISCV_ELF_H
 
+#include <uapi/linux/elf.h>
+#include <linux/compat.h>
 #include <uapi/asm/elf.h>
 #include <asm/auxvec.h>
 #include <asm/byteorder.h>
@@ -18,11 +20,13 @@ 
  */
 #define ELF_ARCH	EM_RISCV
 
+#ifndef ELF_CLASS
 #ifdef CONFIG_64BIT
 #define ELF_CLASS	ELFCLASS64
 #else
 #define ELF_CLASS	ELFCLASS32
 #endif
+#endif
 
 #define ELF_DATA	ELFDATA2LSB
 
@@ -31,6 +35,15 @@ 
  */
 #define elf_check_arch(x) ((x)->e_machine == EM_RISCV)
 
+#ifdef CONFIG_COMPAT
+/*
+ * Use the same code with elf_check_arch, because elf32_hdr &
+ * elf64_hdr e_machine's offset are different. The checker is
+ * a little bit simple compare to other architectures.
+ */
+#define compat_elf_check_arch(x) ((x)->e_machine == EM_RISCV)
+#endif
+
 #define CORE_DUMP_USE_REGSET
 #define ELF_EXEC_PAGESIZE	(PAGE_SIZE)
 
@@ -43,8 +56,14 @@ 
 #define ELF_ET_DYN_BASE		((TASK_SIZE / 3) * 2)
 
 #ifdef CONFIG_64BIT
+#ifdef CONFIG_COMPAT
+#define STACK_RND_MASK		(test_thread_flag(TIF_32BIT) ? \
+				 0x7ff >> (PAGE_SHIFT - 12) : \
+				 0x3ffff >> (PAGE_SHIFT - 12))
+#else
 #define STACK_RND_MASK		(0x3ffff >> (PAGE_SHIFT - 12))
 #endif
+#endif
 /*
  * This yields a mask that user programs can use to figure out what
  * instruction set this CPU supports.  This could be done in user space,
@@ -60,11 +79,19 @@  extern unsigned long elf_hwcap;
  */
 #define ELF_PLATFORM	(NULL)
 
+#define COMPAT_ELF_PLATFORM	(NULL)
+
 #ifdef CONFIG_MMU
 #define ARCH_DLINFO						\
 do {								\
+	/*							\
+	 * Note that we add ulong after elf_addr_t because	\
+	 * casting current->mm->context.vdso triggers a cast	\
+	 * warning of cast from pointer to integer for		\
+	 * COMPAT ELFCLASS32.					\
+	 */							\
 	NEW_AUX_ENT(AT_SYSINFO_EHDR,				\
-		(elf_addr_t)current->mm->context.vdso);		\
+		(elf_addr_t)(ulong)current->mm->context.vdso);	\
 	NEW_AUX_ENT(AT_L1I_CACHESIZE,				\
 		get_cache_size(1, CACHE_TYPE_INST));		\
 	NEW_AUX_ENT(AT_L1I_CACHEGEOMETRY,			\
@@ -90,4 +117,26 @@  do {							\
 		*(struct user_regs_struct *)regs;	\
 } while (0);
 
+#ifdef CONFIG_COMPAT
+
+/*
+ * FIXME: not sure SET_PERSONALITY for compat process is right!
+ */
+#define SET_PERSONALITY(ex)					\
+do {    if ((ex).e_ident[EI_CLASS] == ELFCLASS32)		\
+		set_thread_flag(TIF_32BIT);			\
+	else							\
+		clear_thread_flag(TIF_32BIT);			\
+	if (personality(current->personality) != PER_LINUX32)	\
+		set_personality(PER_LINUX |			\
+			(current->personality & (~PER_MASK)));	\
+} while (0)
+
+#define COMPAT_ELF_ET_DYN_BASE		((TASK_SIZE_32 / 3) * 2)
+
+/* rv32 registers */
+typedef compat_ulong_t			compat_elf_greg_t;
+typedef compat_elf_greg_t		compat_elf_gregset_t[ELF_NGREG];
+
+#endif /* CONFIG_COMPAT */
 #endif /* _ASM_RISCV_ELF_H */