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x86/entry: Drop asmlinkage from syscalls

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asmlinkage is no longer required since the syscall ABI is now fully under
x86 architecture control.  This makes the 32-bit native syscalls a bit more
effecient by passing in regs via EAX instead of on the stack.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Link: https://lkml.kernel.org/r/20200313195144.164260-18-brgerst@gmail.com
This commit is contained in:
Brian Gerst
2020-03-13 15:51:43 -04:00
committed by Thomas Gleixner
parent 25c619e59b
commit 0f78ff1711
5 changed files with 19 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/x86/entry/syscall_32.c
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@@ -8,7 +8,7 @@
#include <asm/unistd.h> #include <asm/unistd.h>
#include <asm/syscall.h> #include <asm/syscall.h>
#define __SYSCALL_I386(nr, sym) extern asmlinkage long __ia32_##sym(const struct pt_regs *); #define __SYSCALL_I386(nr, sym) extern long __ia32_##sym(const struct pt_regs *);
#include <asm/syscalls_32.h> #include <asm/syscalls_32.h>
#undef __SYSCALL_I386 #undef __SYSCALL_I386

2
arch/x86/entry/syscall_64.c
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@@ -11,7 +11,7 @@
#define __SYSCALL_X32(nr, sym) #define __SYSCALL_X32(nr, sym)
#define __SYSCALL_COMMON(nr, sym) __SYSCALL_64(nr, sym) #define __SYSCALL_COMMON(nr, sym) __SYSCALL_64(nr, sym)
#define __SYSCALL_64(nr, sym) extern asmlinkage long __x64_##sym(const struct pt_regs *); #define __SYSCALL_64(nr, sym) extern long __x64_##sym(const struct pt_regs *);
#include <asm/syscalls_64.h> #include <asm/syscalls_64.h>
#undef __SYSCALL_64 #undef __SYSCALL_64

4
arch/x86/entry/syscall_x32.c
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@@ -10,8 +10,8 @@
#define __SYSCALL_64(nr, sym) #define __SYSCALL_64(nr, sym)
#define __SYSCALL_X32(nr, sym) extern asmlinkage long __x32_##sym(const struct pt_regs *); #define __SYSCALL_X32(nr, sym) extern long __x32_##sym(const struct pt_regs *);
#define __SYSCALL_COMMON(nr, sym) extern asmlinkage 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> #include <asm/syscalls_64.h>
#undef __SYSCALL_X32 #undef __SYSCALL_X32
#undef __SYSCALL_COMMON #undef __SYSCALL_COMMON

2
arch/x86/include/asm/syscall.h
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@@ -16,7 +16,7 @@
#include <asm/thread_info.h> /* for TS_COMPAT */ #include <asm/thread_info.h> /* for TS_COMPAT */
#include <asm/unistd.h> #include <asm/unistd.h>
typedef asmlinkage long (*sys_call_ptr_t)(const struct pt_regs *); typedef long (*sys_call_ptr_t)(const struct pt_regs *);
extern const sys_call_ptr_t sys_call_table[]; extern const sys_call_ptr_t sys_call_table[];
#if defined(CONFIG_X86_32) #if defined(CONFIG_X86_32)

31
arch/x86/include/asm/syscall_wrapper.h
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@@ -8,8 +8,8 @@
struct pt_regs; struct pt_regs;
extern asmlinkage long __x64_sys_ni_syscall(const struct pt_regs *regs); extern long __x64_sys_ni_syscall(const struct pt_regs *regs);
extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs); extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
/* /*
* Instead of the generic __SYSCALL_DEFINEx() definition, the x86 version takes * Instead of the generic __SYSCALL_DEFINEx() definition, the x86 version takes
@@ -66,22 +66,21 @@ extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs);
,,(unsigned int)regs->di,,(unsigned int)regs->bp) ,,(unsigned int)regs->di,,(unsigned int)regs->bp)
#define __SYS_STUB0(abi, name) \ #define __SYS_STUB0(abi, name) \
asmlinkage long __##abi##_##name(const struct pt_regs *regs); \ long __##abi##_##name(const struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
asmlinkage long __##abi##_##name(const struct pt_regs *regs) \ long __##abi##_##name(const struct pt_regs *regs) \
__alias(__do_##name); __alias(__do_##name);
#define __SYS_STUBx(abi, name, ...) \ #define __SYS_STUBx(abi, name, ...) \
asmlinkage long __##abi##_##name(const struct pt_regs *regs); \ long __##abi##_##name(const struct pt_regs *regs); \
ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \ ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
asmlinkage long __##abi##_##name(const struct pt_regs *regs) \ long __##abi##_##name(const struct pt_regs *regs) \
{ \ { \
return __se_##name(__VA_ARGS__); \ return __se_##name(__VA_ARGS__); \
} }
#define __COND_SYSCALL(abi, name) \ #define __COND_SYSCALL(abi, name) \
asmlinkage __weak long \ __weak long __##abi##_##name(const struct pt_regs *__unused) \
__##abi##_##name(const struct pt_regs *__unused) \
{ \ { \
return sys_ni_syscall(); \ return sys_ni_syscall(); \
} }
@@ -192,11 +191,11 @@ extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs);
* of them. * of them.
*/ */
#define COMPAT_SYSCALL_DEFINE0(name) \ #define COMPAT_SYSCALL_DEFINE0(name) \
static asmlinkage long \ static long \
__do_compat_sys_##name(const struct pt_regs *__unused); \ __do_compat_sys_##name(const struct pt_regs *__unused); \
__IA32_COMPAT_SYS_STUB0(name) \ __IA32_COMPAT_SYS_STUB0(name) \
__X32_COMPAT_SYS_STUB0(name) \ __X32_COMPAT_SYS_STUB0(name) \
static asmlinkage long \ static long \
__do_compat_sys_##name(const struct pt_regs *__unused) __do_compat_sys_##name(const struct pt_regs *__unused)
#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \ #define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
@@ -248,12 +247,10 @@ extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs);
*/ */
#define SYSCALL_DEFINE0(sname) \ #define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \ SYSCALL_METADATA(_##sname, 0); \
static asmlinkage long \ static long __do_sys_##sname(const struct pt_regs *__unused); \
__do_sys_##sname(const struct pt_regs *__unused); \
__X64_SYS_STUB0(sname) \ __X64_SYS_STUB0(sname) \
__IA32_SYS_STUB0(sname) \ __IA32_SYS_STUB0(sname) \
static asmlinkage long \ static long __do_sys_##sname(const struct pt_regs *__unused)
__do_sys_##sname(const struct pt_regs *__unused)
#define COND_SYSCALL(name) \ #define COND_SYSCALL(name) \
__X64_COND_SYSCALL(name) \ __X64_COND_SYSCALL(name) \
@@ -268,8 +265,8 @@ extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs);
* For VSYSCALLS, we need to declare these three syscalls with the new * For VSYSCALLS, we need to declare these three syscalls with the new
* pt_regs-based calling convention for in-kernel use. * pt_regs-based calling convention for in-kernel use.
*/ */
asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs); long __x64_sys_getcpu(const struct pt_regs *regs);
asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs); long __x64_sys_gettimeofday(const struct pt_regs *regs);
asmlinkage long __x64_sys_time(const struct pt_regs *regs); long __x64_sys_time(const struct pt_regs *regs);
#endif /* _ASM_X86_SYSCALL_WRAPPER_H */ #endif /* _ASM_X86_SYSCALL_WRAPPER_H */