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Subject[PATCH v3 2/8] x86, syscalls: Refactor SYSCALL_DEFINE0 macros
Date
Pull the common code out from the SYSCALL_DEFINE0 macros into a new
__SYS_STUB0 macro. Also conditionalize the X64 version in preparation for
enabling syscall wrappers on 32-bit native kernels.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
arch/x86/include/asm/syscall_wrapper.h | 73 +++++++++++---------------
1 file changed, 32 insertions(+), 41 deletions(-)

diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 7a4c2aff52c6..2b1ae55c52ee 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -21,6 +21,12 @@ struct pt_regs;
,,(unsigned int)regs->dx,,(unsigned int)regs->si \
,,(unsigned int)regs->di,,(unsigned int)regs->bp)

+#define __SYS_STUB0(abi, name) \
+ asmlinkage long __##abi##_##name(const struct pt_regs *regs); \
+ ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
+ asmlinkage 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); \
ALLOW_ERROR_INJECTION(__##abi##_##name, ERRNO); \
@@ -30,10 +36,14 @@ struct pt_regs;
}

#ifdef CONFIG_X86_64
+#define __X64_SYS_STUB0(name) \
+ __SYS_STUB0(x64, sys_##name)
+
#define __X64_SYS_STUBx(x, name, ...) \
__SYS_STUBx(x64, sys##name, \
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
#else /* CONFIG_X86_64 */
+#define __X64_SYS_STUB0(name)
#define __X64_SYS_STUBx(x, name, ...)
#endif /* CONFIG_X86_64 */

@@ -46,34 +56,20 @@ struct pt_regs;
* kernel/sys_ni.c and SYS_NI in kernel/time/posix-stubs.c to cover this
* case as well.
*/
-#define __IA32_COMPAT_SYS_STUB0(x, name) \
- asmlinkage long __ia32_compat_sys_##name(const struct pt_regs *regs);\
- ALLOW_ERROR_INJECTION(__ia32_compat_sys_##name, ERRNO); \
- asmlinkage long __ia32_compat_sys_##name(const struct pt_regs *regs)\
- { \
- return __se_compat_sys_##name(); \
- }
+#define __IA32_COMPAT_SYS_STUB0(name) \
+ __SYS_STUB0(ia32, compat_sys_##name)

#define __IA32_COMPAT_SYS_STUBx(x, name, ...) \
__SYS_STUBx(ia32, compat_sys##name, \
SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__))

+#define __IA32_SYS_STUB0(name) \
+ __SYS_STUB0(ia32, sys_##name)
+
#define __IA32_SYS_STUBx(x, name, ...) \
__SYS_STUBx(ia32, sys##name, \
SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__))

-/*
- * To keep the naming coherent, re-define SYSCALL_DEFINE0 to create an alias
- * named __ia32_sys_*()
- */
-
-#define SYSCALL_DEFINE0(sname) \
- SYSCALL_METADATA(_##sname, 0); \
- asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\
- ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \
- SYSCALL_ALIAS(__ia32_sys_##sname, __x64_sys_##sname); \
- asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused)
-
#define COND_SYSCALL(name) \
asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused) \
{ \
@@ -89,7 +85,9 @@ struct pt_regs;
SYSCALL_ALIAS(__ia32_sys_##name, sys_ni_posix_timers)

#else /* CONFIG_IA32_EMULATION */
+#define __IA32_COMPAT_SYS_STUB0(name)
#define __IA32_COMPAT_SYS_STUBx(x, name, ...)
+#define __IA32_SYS_STUB0(name)
#define __IA32_SYS_STUBx(x, name, ...)
#endif /* CONFIG_IA32_EMULATION */

@@ -100,20 +98,15 @@ struct pt_regs;
* of the x86-64-style parameter ordering of x32 syscalls. The syscalls common
* with x86_64 obviously do not need such care.
*/
-#define __X32_COMPAT_SYS_STUB0(x, name, ...) \
- asmlinkage long __x32_compat_sys_##name(const struct pt_regs *regs);\
- ALLOW_ERROR_INJECTION(__x32_compat_sys_##name, ERRNO); \
- asmlinkage long __x32_compat_sys_##name(const struct pt_regs *regs)\
- { \
- return __se_compat_sys_##name();\
- }
+#define __X32_COMPAT_SYS_STUB0(name) \
+ __SYS_STUB0(x32, compat_sys_##name)

#define __X32_COMPAT_SYS_STUBx(x, name, ...) \
__SYS_STUBx(x32, compat_sys##name, \
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))

#else /* CONFIG_X86_X32 */
-#define __X32_COMPAT_SYS_STUB0(x, name)
+#define __X32_COMPAT_SYS_STUB0(name)
#define __X32_COMPAT_SYS_STUBx(x, name, ...)
#endif /* CONFIG_X86_X32 */

@@ -125,15 +118,12 @@ struct pt_regs;
* of them.
*/
#define COMPAT_SYSCALL_DEFINE0(name) \
- static long __se_compat_sys_##name(void); \
- static inline long __do_compat_sys_##name(void); \
- __IA32_COMPAT_SYS_STUB0(x, name) \
- __X32_COMPAT_SYS_STUB0(x, name) \
- static long __se_compat_sys_##name(void) \
- { \
- return __do_compat_sys_##name(); \
- } \
- static inline long __do_compat_sys_##name(void)
+ static asmlinkage long \
+ __do_compat_sys_##name(const struct pt_regs *__unused); \
+ __IA32_COMPAT_SYS_STUB0(name) \
+ __X32_COMPAT_SYS_STUB0(name) \
+ static asmlinkage long \
+ __do_compat_sys_##name(const struct pt_regs *__unused)

#define COMPAT_SYSCALL_DEFINEx(x, name, ...) \
static long \
@@ -221,13 +211,14 @@ struct pt_regs;
* SYSCALL_DEFINEx() -- which is essential for the COND_SYSCALL() and SYS_NI()
* macros to work correctly.
*/
-#ifndef SYSCALL_DEFINE0
#define SYSCALL_DEFINE0(sname) \
SYSCALL_METADATA(_##sname, 0); \
- asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused);\
- ALLOW_ERROR_INJECTION(__x64_sys_##sname, ERRNO); \
- asmlinkage long __x64_sys_##sname(const struct pt_regs *__unused)
-#endif
+ static asmlinkage 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)

#ifndef COND_SYSCALL
#define COND_SYSCALL(name) \
--
2.24.1
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