linux-kernel - [PATCH 1/2] x86/x32: Use __x64 prefix for X32 compat syscalls

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Date:   Tue, 16 Jun 2020 10:23:14 -0400
From:   Brian Gerst <brgerst@...il.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>,
        Andy Lutomirski <luto@...nel.org>,
        Christoph Hellwig <hch@....de>, Arnd Bergmann <arnd@...db.de>,
        Brian Gerst <brgerst@...il.com>
Subject: [PATCH 1/2] x86/x32: Use __x64 prefix for X32 compat syscalls

The ABI prefix for syscalls specifies the argument register mapping, so
there is no specific reason to continue using the __x32 prefix for the
compat syscalls.  This change will allow using native syscalls in the X32
specific portion of the syscall table.

Signed-off-by: Brian Gerst <brgerst@...il.com>
---
 arch/x86/entry/syscall_x32.c           |  8 +++-----
 arch/x86/include/asm/syscall_wrapper.h | 10 +++++-----
 2 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/arch/x86/entry/syscall_x32.c b/arch/x86/entry/syscall_x32.c
index 3d8d70d3896c..f993e6254043 100644
--- a/arch/x86/entry/syscall_x32.c
+++ b/arch/x86/entry/syscall_x32.c
@@ -9,15 +9,13 @@
 #include <asm/syscall.h>
 
 #define __SYSCALL_64(nr, sym)
+#define __SYSCALL_COMMON(nr, sym) __SYSCALL_X32(nr, sym)
 
-#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 *);
+#define __SYSCALL_X32(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_COMMON(nr, sym) [nr] = __x64_##sym,
+#define __SYSCALL_X32(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 a84333adeef2..267fae9904ff 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
@@ -165,17 +165,17 @@ 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, ...)
-- 
2.26.2