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x86/entry/x32: Rename __x32_compat_sys_* to __x64_compat_sys_* 

The SYSCALL macros are mapped to symbols as follows:

  __SYSCALL_COMMON(nr, sym)  -->  __x64_<sym>
  __SYSCALL_X32(nr, sym)     -->  __x32_<sym>

Originally, the syscalls in the x32 special range (512-547) were all
compat.

This assumption is now broken after the following commits:

  55db9c0e85 ("net: remove compat_sys_{get,set}sockopt")
  5f764d624a ("fs: remove the compat readv/writev syscalls")
  598b3cec83 ("fs: remove compat_sys_vmsplice")
  c3973b401e ("mm: remove compat_process_vm_{readv,writev}")

Those commits redefined __x32_sys_* to __x64_sys_* because there is no stub
like __x32_sys_*.

Defining them as follows is more sensible and cleaner.

  __SYSCALL_COMMON(nr, sym)  -->  __x64_<sym>
  __SYSCALL_X32(nr, sym)     -->  __x64_<sym>

This works because both x86_64 and x32 use the same ABI (RDI, RSI, RDX,
R10, R8, R9)

The ugly #define __x32_sys_* will go away.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210517073815.97426-2-masahiroy@kernel.org
This commit is contained in:
Masahiro Yamada 2021-05-17 16:38:09 +09:00 committed by Thomas Gleixner
parent 41f45fb045
commit 2e958a8a51
2 changed files with 7 additions and 19 deletions
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16
arch/x86/entry/syscall_x32.c
View File

@ -8,27 +8,15 @@
#include <asm/unistd.h>
#include <asm/syscall.h>
/*
* Reuse the 64-bit entry points for the x32 versions that occupy different
* slots in the syscall table.
*/
#define __x32_sys_readv __x64_sys_readv
#define __x32_sys_writev __x64_sys_writev
#define __x32_sys_getsockopt __x64_sys_getsockopt
#define __x32_sys_setsockopt __x64_sys_setsockopt
#define __x32_sys_vmsplice __x64_sys_vmsplice
#define __x32_sys_process_vm_readv __x64_sys_process_vm_readv
#define __x32_sys_process_vm_writev __x64_sys_process_vm_writev
#define __SYSCALL_64(nr, sym)
#define __SYSCALL_X32(nr, sym) extern long __x32_##sym(const struct pt_regs *);
#define __SYSCALL_X32(nr, sym) extern long __x64_##sym(const struct pt_regs *);
#define __SYSCALL_COMMON(nr, sym) extern long __x64_##sym(const struct pt_regs *);
#include <asm/syscalls_64.h>
#undef __SYSCALL_X32
#undef __SYSCALL_COMMON
#define __SYSCALL_X32(nr, sym) [nr] = __x32_##sym,
#define __SYSCALL_X32(nr, sym) [nr] = __x64_##sym,
#define __SYSCALL_COMMON(nr, sym) [nr] = __x64_##sym,
asmlinkage const sys_call_ptr_t x32_sys_call_table[__NR_x32_syscall_max+1] = {

10
arch/x86/include/asm/syscall_wrapper.h
View File

@ -17,7 +17,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
* __x64_sys_*() - 64-bit native syscall
* __ia32_sys_*() - 32-bit native syscall or common compat syscall
* __ia32_compat_sys_*() - 32-bit compat syscall
* __x32_compat_sys_*() - 64-bit X32 compat syscall
* __x64_compat_sys_*() - 64-bit X32 compat syscall
*
* The registers are decoded according to the ABI:
* 64-bit: RDI, RSI, RDX, R10, R8, R9
@ -166,17 +166,17 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
* with x86_64 obviously do not need such care.
*/
#define __X32_COMPAT_SYS_STUB0(name) \
__SYS_STUB0(x32, compat_sys_##name)
__SYS_STUB0(x64, compat_sys_##name)
#define __X32_COMPAT_SYS_STUBx(x, name, ...) \
__SYS_STUBx(x32, compat_sys##name, \
__SYS_STUBx(x64, compat_sys##name, \
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
#define __X32_COMPAT_COND_SYSCALL(name) \
__COND_SYSCALL(x32, compat_sys_##name)
__COND_SYSCALL(x64, compat_sys_##name)
#define __X32_COMPAT_SYS_NI(name) \
__SYS_NI(x32, compat_sys_##name)
__SYS_NI(x64, compat_sys_##name)
#else /* CONFIG_X86_X32 */
#define __X32_COMPAT_SYS_STUB0(name)
#define __X32_COMPAT_SYS_STUBx(x, name, ...)