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[amd64] clean PRSTATUS_SIZE/SET_PR_FPVALID up properly 

To get rid of hardcoded size/offset in those macros we need to have
a definition of i386 variant of struct elf_prstatus.  However, we can't
do that in asm/compat.h - the types needed for that are not there and
adding an include of asm/user32.h into asm/compat.h would cause a lot
of mess.

That could be conveniently done in elfcore-compat.h, but currently there
is nowhere to put arch-dependent parts of it - no asm/elfcore-compat.h.
So we introduce a new file (asm/elfcore-compat.h, present on architectures
that have CONFIG_ARCH_HAS_ELFCORE_COMPAT set, currently only on x86),
have it pulled by linux/elfcore-compat.h and move the definitions there.

As a side benefit, we don't need to worry about accidental inclusion of
that file into binfmt_elf.c itself, so we don't need the dance with
COMPAT_PRSTATUS_SIZE, etc. - only fs/compat_binfmt_elf.c will see
that header.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-06-13 23:03:25 -04:00
parent f2485a2dc9
commit 7facdc426f
6 changed files with 46 additions and 29 deletions
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3
arch/Kconfig
View File

@ -1105,6 +1105,9 @@ config HAVE_ARCH_PFN_VALID
config ARCH_SUPPORTS_DEBUG_PAGEALLOC
bool
config ARCH_HAS_ELFCORE_COMPAT
bool
source "kernel/gcov/Kconfig"
source "scripts/gcc-plugins/Kconfig"

1
arch/x86/Kconfig
View File

@ -31,6 +31,7 @@ config X86_64
select MODULES_USE_ELF_RELA
select NEED_DMA_MAP_STATE
select SWIOTLB
select ARCH_HAS_ELFCORE_COMPAT
config FORCE_DYNAMIC_FTRACE
def_bool y

14
arch/x86/include/asm/compat.h
View File

@ -159,20 +159,6 @@ struct compat_shmid64_ds {
compat_ulong_t __unused5;
};
/*
* The type of struct elf_prstatus.pr_reg in compatible core dumps.
*/
typedef struct user_regs_struct compat_elf_gregset_t;
/* Full regset -- prstatus on x32, otherwise on ia32 */
#define COMPAT_PRSTATUS_SIZE (user_64bit_mode(task_pt_regs(current)) \
? sizeof(struct compat_elf_prstatus) \
: 144)
#define COMPAT_SET_PR_FPVALID(S) \
(*(user_64bit_mode(task_pt_regs(current)) \
? &(S)->pr_fpvalid \
: (int *)((void *)(S) + 140)) = 1)
#ifdef CONFIG_X86_X32_ABI
#define COMPAT_USE_64BIT_TIME \
(!!(task_pt_regs(current)->orig_ax & __X32_SYSCALL_BIT))

31
arch/x86/include/asm/elfcore-compat.h Normal file
View File

@ -0,0 +1,31 @@
#ifndef _ASM_X86_ELFCORE_COMPAT_H
#define _ASM_X86_ELFCORE_COMPAT_H
#include <asm/user32.h>
/*
* On amd64 we have two 32bit ABIs - i386 and x32. The latter
* has bigger registers, so we use it for compat_elf_regset_t.
* The former uses i386_elf_prstatus and PRSTATUS_SIZE/SET_PR_FPVALID
* are used to choose the size and location of ->pr_fpvalid of
* the layout actually used.
*/
typedef struct user_regs_struct compat_elf_gregset_t;
struct i386_elf_prstatus
{
struct compat_elf_prstatus_common common;
struct user_regs_struct32 pr_reg;
compat_int_t pr_fpvalid;
};
#define PRSTATUS_SIZE \
(user_64bit_mode(task_pt_regs(current)) \
? sizeof(struct compat_elf_prstatus) \
: sizeof(struct i386_elf_prstatus))
#define SET_PR_FPVALID(S) \
(*(user_64bit_mode(task_pt_regs(current)) \
? &(S)->pr_fpvalid \
: &((struct i386_elf_prstatus *)(S))->pr_fpvalid) = 1)
#endif

8
fs/compat_binfmt_elf.c
View File

@ -96,14 +96,6 @@
#define ELF_EXEC_PAGESIZE COMPAT_ELF_EXEC_PAGESIZE
#endif
#ifdef COMPAT_PRSTATUS_SIZE
#define PRSTATUS_SIZE COMPAT_PRSTATUS_SIZE
#endif
#ifdef COMPAT_SET_PR_FPVALID
#define SET_PR_FPVALID(S) COMPAT_SET_PR_FPVALID(S)
#endif
#ifdef COMPAT_ELF_PLAT_INIT
#undef ELF_PLAT_INIT
#define ELF_PLAT_INIT COMPAT_ELF_PLAT_INIT

18
include/linux/elfcore-compat.h
View File

@ -33,13 +33,6 @@ struct compat_elf_prstatus_common
struct old_timeval32 pr_cstime;
};
struct compat_elf_prstatus
{
struct compat_elf_prstatus_common common;
compat_elf_gregset_t pr_reg;
compat_int_t pr_fpvalid;
};
struct compat_elf_prpsinfo
{
char pr_state;
@ -54,4 +47,15 @@ struct compat_elf_prpsinfo
char pr_psargs[ELF_PRARGSZ];
};
#ifdef CONFIG_ARCH_HAS_ELFCORE_COMPAT
#include <asm/elfcore-compat.h>
#endif
struct compat_elf_prstatus
{
struct compat_elf_prstatus_common common;
compat_elf_gregset_t pr_reg;
compat_int_t pr_fpvalid;
};
#endif /* _LINUX_ELFCORE_COMPAT_H */