* [PATCH 2/2] x86/entry/x32: rename __x32_compat_sys_* to __x64_compat_sys_*
2021-02-13 4:57 [PATCH 1/2] x86/syscalls: fix -Wmissing-prototypes warnings from COND_SYSCALL() Masahiro Yamada
@ 2021-02-13 4:57 ` Masahiro Yamada
0 siblings, 0 replies; 2+ messages in thread
From: Masahiro Yamada @ 2021-02-13 4:57 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, Borislav Petkov, x86,
H . Peter Anvin
Cc: linux-kernel,
Micka���l Sala���n,
Masahiro Yamada, Andy Lutomirski, Brian Gerst, Dominik Brodowski
In arch/x86/entry/syscall_x32.c, the macros are mapped to symbols
as follows:
__SYSCALL_COMMON(nr, sym) --> __x64_<sym>
__SYSCALL_X32(nr, sym) --> __x32_<sym>
Originally, the syscalls in the x32 special range (512-547) were all
compat.
This assumption is now broken after the following commits:
55db9c0e8534 ("net: remove compat_sys_{get,set}sockopt")
5f764d624a89 ("fs: remove the compat readv/writev syscalls")
598b3cec831f ("fs: remove compat_sys_vmsplice")
c3973b401ef2 ("mm: remove compat_process_vm_{readv,writev}")
Those commits redefined __x32_sys_* to __x64_sys_* because there is
no stub like __x32_sys_*.
I think defining as follows is more sensible and cleaner.
__SYSCALL_COMMON(nr, sym) --> __x64_<sym>
__SYSCALL_X32(nr, sym) --> __x64_<sym>
This works because both x86_64 and x32 use the same ABI
(RDI, RSI, RDX, R10, R8, R9)
The ugly #define __x32_sys_* will go away.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
---
arch/x86/entry/syscall_x32.c | 16 ++--------------
arch/x86/include/asm/syscall_wrapper.h | 10 +++++-----
2 files changed, 7 insertions(+), 19 deletions(-)
diff --git a/arch/x86/entry/syscall_x32.c b/arch/x86/entry/syscall_x32.c
index f2fe0a33bcfd..3fea8fb9cd6a 100644
--- a/arch/x86/entry/syscall_x32.c
+++ b/arch/x86/entry/syscall_x32.c
@@ -8,27 +8,15 @@
#include <asm/unistd.h>
#include <asm/syscall.h>
-/*
- * Reuse the 64-bit entry points for the x32 versions that occupy different
- * slots in the syscall table.
- */
-#define __x32_sys_readv __x64_sys_readv
-#define __x32_sys_writev __x64_sys_writev
-#define __x32_sys_getsockopt __x64_sys_getsockopt
-#define __x32_sys_setsockopt __x64_sys_setsockopt
-#define __x32_sys_vmsplice __x64_sys_vmsplice
-#define __x32_sys_process_vm_readv __x64_sys_process_vm_readv
-#define __x32_sys_process_vm_writev __x64_sys_process_vm_writev
-
#define __SYSCALL_64(nr, sym)
-#define __SYSCALL_X32(nr, sym) extern long __x32_##sym(const struct pt_regs *);
+#define __SYSCALL_X32(nr, sym) extern 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>
#undef __SYSCALL_X32
#undef __SYSCALL_COMMON
-#define __SYSCALL_X32(nr, sym) [nr] = __x32_##sym,
+#define __SYSCALL_X32(nr, sym) [nr] = __x64_##sym,
#define __SYSCALL_COMMON(nr, sym) [nr] = __x64_##sym,
asmlinkage const sys_call_ptr_t x32_sys_call_table[__NR_x32_syscall_max+1] = {
diff --git a/arch/x86/include/asm/syscall_wrapper.h b/arch/x86/include/asm/syscall_wrapper.h
index 80c08c7d5e72..6a2827d0681f 100644
--- a/arch/x86/include/asm/syscall_wrapper.h
+++ b/arch/x86/include/asm/syscall_wrapper.h
@@ -17,7 +17,7 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
* __x64_sys_*() - 64-bit native syscall
* __ia32_sys_*() - 32-bit native syscall or common compat syscall
* __ia32_compat_sys_*() - 32-bit compat syscall
- * __x32_compat_sys_*() - 64-bit X32 compat syscall
+ * __x64_compat_sys_*() - 64-bit X32 compat syscall
*
* The registers are decoded according to the ABI:
* 64-bit: RDI, RSI, RDX, R10, R8, R9
@@ -166,17 +166,17 @@ extern long __ia32_sys_ni_syscall(const struct pt_regs *regs);
* with x86_64 obviously do not need such care.
*/
#define __X32_COMPAT_SYS_STUB0(name) \
- __SYS_STUB0(x32, compat_sys_##name)
+ __SYS_STUB0(x64, compat_sys_##name)
#define __X32_COMPAT_SYS_STUBx(x, name, ...) \
- __SYS_STUBx(x32, compat_sys##name, \
+ __SYS_STUBx(x64, compat_sys##name, \
SC_X86_64_REGS_TO_ARGS(x, __VA_ARGS__))
#define __X32_COMPAT_COND_SYSCALL(name) \
- __COND_SYSCALL(x32, compat_sys_##name)
+ __COND_SYSCALL(x64, compat_sys_##name)
#define __X32_COMPAT_SYS_NI(name) \
- __SYS_NI(x32, compat_sys_##name)
+ __SYS_NI(x64, compat_sys_##name)
#else /* CONFIG_X86_X32 */
#define __X32_COMPAT_SYS_STUB0(name)
#define __X32_COMPAT_SYS_STUBx(x, name, ...)
--
2.27.0
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