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Subject[tip: x86/entry] x86/entry: Drop asmlinkage from syscalls
The following commit has been merged into the x86/entry branch of tip:

Commit-ID: 0f78ff17112d8b3469b805ff4ea9780cc1e5c93b
Gitweb: https://git.kernel.org/tip/0f78ff17112d8b3469b805ff4ea9780cc1e5c93b
Author: Brian Gerst <brgerst@gmail.com>
AuthorDate: Fri, 13 Mar 2020 15:51:43 -04:00
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Sat, 21 Mar 2020 16:03:25 +01:00

x86/entry: Drop asmlinkage from syscalls

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

---
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 097413c..86eb0d8 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 66d3e65..1594ec7 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 2fb09ef..3d8d70d 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 e413c83..6435294 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 5e13e2c..e10efa1 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 */
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