x86/entry/x32: Rename __x32_compat_sys_* to __x64_compat_sys_*

The SYSCALL 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_*.

Defining them 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 <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

arch/x86/entry/syscall_x32.c

···
 #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] = {

arch/x86/include/asm/syscall_wrapper.h

···
  * __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
···
  * 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, ...)