[PATCH v4 17/18] x86: Drop asmlinkage from syscalls
From: Brian Gerst
Date: Fri Mar 13 2020 - 15:52:41 EST
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@xxxxxxxxx>
Reviewed-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
arch/x86/entry/syscall_32.c | 2 +-
arch/x86/entry/syscall_64.c | 2 +-
arch/x86/entry/syscall_x32.c | 4 ++--
arch/x86/include/asm/syscall.h | 2 +-
arch/x86/include/asm/syscall_wrapper.h | 31 ++++++++++++--------------
5 files changed, 19 insertions(+), 22 deletions(-)
diff --git a/arch/x86/entry/syscall_32.c b/arch/x86/entry/syscall_32.c
index 097413c705ad..86eb0d89d46f 100644
--- a/arch/x86/entry/syscall_32.c
+++ b/arch/x86/entry/syscall_32.c
@@ -8,7 +8,7 @@
#include <asm/unistd.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>
#undef __SYSCALL_I386
diff --git a/arch/x86/entry/syscall_64.c b/arch/x86/entry/syscall_64.c
index 66d3e65e3b6b..1594ec72bcbb 100644
--- a/arch/x86/entry/syscall_64.c
+++ b/arch/x86/entry/syscall_64.c
@@ -11,7 +11,7 @@
#define __SYSCALL_X32(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>
#undef __SYSCALL_64
diff --git a/arch/x86/entry/syscall_x32.c b/arch/x86/entry/syscall_x32.c
index 2fb09efd7b40..3d8d70d3896c 100644
--- a/arch/x86/entry/syscall_x32.c
+++ b/arch/x86/entry/syscall_x32.c
@@ -10,8 +10,8 @@
#define __SYSCALL_64(nr, sym)
-#define __SYSCALL_X32(nr, sym) extern asmlinkage long __x32_##sym(const struct pt_regs *);
-#define __SYSCALL_COMMON(nr, sym) extern asmlinkage long __x64_##sym(const struct pt_regs *);
+#define __SYSCALL_X32(nr, sym) extern long __x32_##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
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index bb427d8cb1ef..7cbf733d11af 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -16,7 +16,7 @@
#include <asm/thread_info.h> /* for TS_COMPAT */
#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[];
#if defined(CONFIG_X86_32)
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 5e13e2caf2e4..e10efa1454bc 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -8,8 +8,8 @@
struct pt_regs;
-extern asmlinkage long __x64_sys_ni_syscall(const struct pt_regs *regs);
-extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs);
+extern long __x64_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
@@ -66,22 +66,21 @@ extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs);
,,(unsigned int)regs->di,,(unsigned int)regs->bp)
#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); \
- asmlinkage long __##abi##_##name(const struct pt_regs *regs) \
+ long __##abi##_##name(const struct pt_regs *regs) \
__alias(__do_##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); \
- asmlinkage long __##abi##_##name(const struct pt_regs *regs) \
+ long __##abi##_##name(const struct pt_regs *regs) \
{ \
return __se_##name(__VA_ARGS__); \
}
#define __COND_SYSCALL(abi, name) \
- asmlinkage __weak long \
- __##abi##_##name(const struct pt_regs *__unused) \
+ __weak long __##abi##_##name(const struct pt_regs *__unused) \
{ \
return sys_ni_syscall(); \
}
@@ -192,11 +191,11 @@ extern asmlinkage long __ia32_sys_ni_syscall(const struct pt_regs *regs);
* of them.
*/
#define COMPAT_SYSCALL_DEFINE0(name) \
- static asmlinkage long \
+ static long \
__do_compat_sys_##name(const struct pt_regs *__unused); \
__IA32_COMPAT_SYS_STUB0(name) \
__X32_COMPAT_SYS_STUB0(name) \
- static asmlinkage long \
+ static long \
__do_compat_sys_##name(const struct pt_regs *__unused)
#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) \
SYSCALL_METADATA(_##sname, 0); \
- static asmlinkage long \
- __do_sys_##sname(const struct pt_regs *__unused); \
+ static long __do_sys_##sname(const struct pt_regs *__unused); \
__X64_SYS_STUB0(sname) \
__IA32_SYS_STUB0(sname) \
- static asmlinkage long \
- __do_sys_##sname(const struct pt_regs *__unused)
+ static long __do_sys_##sname(const struct pt_regs *__unused)
#define 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
* pt_regs-based calling convention for in-kernel use.
*/
-asmlinkage long __x64_sys_getcpu(const struct pt_regs *regs);
-asmlinkage long __x64_sys_gettimeofday(const struct pt_regs *regs);
-asmlinkage long __x64_sys_time(const struct pt_regs *regs);
+long __x64_sys_getcpu(const struct pt_regs *regs);
+long __x64_sys_gettimeofday(const struct pt_regs *regs);
+long __x64_sys_time(const struct pt_regs *regs);
#endif /* _ASM_X86_SYSCALL_WRAPPER_H */
--
2.24.1