[PATCH v4 03/18] x86, syscalls: Refactor COND_SYSCALL macros

From: Brian Gerst
Date: Fri Mar 13 2020 - 15:52:20 EST


Pull the common code out from the COND_SYSCALL macros into a new
__COND_SYSCALL macro. Also conditionalize the X64 version in preparation
for enabling syscall wrappers on 32-bit native kernels.

Signed-off-by: Brian Gerst <brgerst@xxxxxxxxx>
Reviewed-by: Dominik Brodowski <linux@xxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
arch/x86/include/asm/syscall_wrapper.h | 44 +++++++++++++++-----------
1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 45ad60571166..0117b25e6753 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -35,6 +35,13 @@ struct pt_regs;
return __se_##name(__VA_ARGS__); \
}

+#define __COND_SYSCALL(abi, name) \
+ asmlinkage __weak long \
+ __##abi##_##name(const struct pt_regs *__unused) \
+ { \
+ return sys_ni_syscall(); \
+ }
+
#ifdef CONFIG_X86_64
#define __X64_SYS_STUB0(name) \
__SYS_STUB0(x64, sys_##name)
@@ -42,9 +49,13 @@ struct pt_regs;
#define __X64_SYS_STUBx(x, name, ...) \
__SYS_STUBx(x64, sys##name, \
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
+
+#define __X64_COND_SYSCALL(name) \
+ __COND_SYSCALL(x64, sys_##name)
#else /* CONFIG_X86_64 */
#define __X64_SYS_STUB0(name)
#define __X64_SYS_STUBx(x, name, ...)
+#define __X64_COND_SYSCALL(name)
#endif /* CONFIG_X86_64 */

#ifdef CONFIG_IA32_EMULATION
@@ -63,6 +74,9 @@ struct pt_regs;
__SYS_STUBx(ia32, compat_sys##name, \
SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__))

+#define __IA32_COMPAT_COND_SYSCALL(name) \
+ __COND_SYSCALL(ia32, compat_sys_##name)
+
#define __IA32_SYS_STUB0(name) \
__SYS_STUB0(ia32, sys_##name)

@@ -70,15 +84,8 @@ struct pt_regs;
__SYS_STUBx(ia32, sys##name, \
SC_IA32_REGS_TO_ARGS(x, __VA_ARGS__))

-#define COND_SYSCALL(name) \
- asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused) \
- { \
- return sys_ni_syscall(); \
- } \
- asmlinkage __weak long __ia32_sys_##name(const struct pt_regs *__unused)\
- { \
- return sys_ni_syscall(); \
- }
+#define __IA32_COND_SYSCALL(name) \
+ __COND_SYSCALL(ia32, sys_##name)

#define SYS_NI(name) \
SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers); \
@@ -87,8 +94,10 @@ struct pt_regs;
#else /* CONFIG_IA32_EMULATION */
#define __IA32_COMPAT_SYS_STUB0(name)
#define __IA32_COMPAT_SYS_STUBx(x, name, ...)
+#define __IA32_COMPAT_COND_SYSCALL(name)
#define __IA32_SYS_STUB0(name)
#define __IA32_SYS_STUBx(x, name, ...)
+#define __IA32_COND_SYSCALL(name)
#endif /* CONFIG_IA32_EMULATION */


@@ -105,9 +114,12 @@ struct pt_regs;
__SYS_STUBx(x32, compat_sys##name, \
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))

+#define __X32_COMPAT_COND_SYSCALL(name) \
+ __COND_SYSCALL(x32, compat_sys_##name)
#else /* CONFIG_X86_X32 */
#define __X32_COMPAT_SYS_STUB0(name)
#define __X32_COMPAT_SYS_STUBx(x, name, ...)
+#define __X32_COMPAT_COND_SYSCALL(name)
#endif /* CONFIG_X86_X32 */


@@ -142,8 +154,8 @@ struct pt_regs;
* kernel/time/posix-stubs.c to cover this case as well.
*/
#define COND_SYSCALL_COMPAT(name) \
- cond_syscall(__ia32_compat_sys_##name); \
- cond_syscall(__x32_compat_sys_##name)
+ __IA32_COMPAT_COND_SYSCALL(name) \
+ __X32_COMPAT_COND_SYSCALL(name)

#define COMPAT_SYS_NI(name) \
SYSCALL_ALIAS(__ia32_compat_sys_##name, sys_ni_posix_timers); \
@@ -215,13 +227,9 @@ struct pt_regs;
static asmlinkage long \
__do_sys_##sname(const struct pt_regs *__unused)

-#ifndef COND_SYSCALL
-#define COND_SYSCALL(name) \
- asmlinkage __weak long __x64_sys_##name(const struct pt_regs *__unused) \
- { \
- return sys_ni_syscall(); \
- }
-#endif
+#define COND_SYSCALL(name) \
+ __X64_COND_SYSCALL(name) \
+ __IA32_COND_SYSCALL(name)

#ifndef SYS_NI
#define SYS_NI(name) SYSCALL_ALIAS(__x64_sys_##name, sys_ni_posix_timers);
--
2.24.1