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[PATCH] Add REGISTERS_CLOBBERED_BY_SYSCALL for x86-64
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Date: Tue, 15 Dec 2015 12:57:25 -0800
- Subject: [PATCH] Add REGISTERS_CLOBBERED_BY_SYSCALL for x86-64
- Authentication-results: sourceware.org; auth=none
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
X86-64 system calls use a different calling convention, which clobbers
CC, %r11 an %rcx registers. Define REGISTERS_CLOBBERED_BY_SYSCALL for
x86-64 inline asm statements.
Tested on x86-64. OK for master?
H.J.
---
* sysdeps/unix/sysv/linux/x86_64/sysdep.h
(REGISTERS_CLOBBERED_BY_SYSCALL): New.
(INTERNAL_SYSCALL_NCS): Use it.
(INTERNAL_SYSCALL_NCS_TYPES): Likewise.
---
sysdeps/unix/sysv/linux/x86_64/sysdep.h | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
index fc132f6..c364d08 100644
--- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
@@ -218,6 +218,9 @@
# undef INTERNAL_SYSCALL_DECL
# define INTERNAL_SYSCALL_DECL(err) do { } while (0)
+/* Registers clobbered by syscall. */
+# define REGISTERS_CLOBBERED_BY_SYSCALL "cc", "r11", "cx"
+
# define INTERNAL_SYSCALL_NCS(name, err, nr, args...) \
({ \
unsigned long int resultvar; \
@@ -226,7 +229,7 @@
asm volatile ( \
"syscall\n\t" \
: "=a" (resultvar) \
- : "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx"); \
+ : "0" (name) ASM_ARGS_##nr : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
(long int) resultvar; })
# undef INTERNAL_SYSCALL
# define INTERNAL_SYSCALL(name, err, nr, args...) \
@@ -240,7 +243,7 @@
asm volatile ( \
"syscall\n\t" \
: "=a" (resultvar) \
- : "0" (name) ASM_ARGS_##nr : "memory", "cc", "r11", "cx"); \
+ : "0" (name) ASM_ARGS_##nr : "memory", REGISTERS_CLOBBERED_BY_SYSCALL); \
(long int) resultvar; })
# undef INTERNAL_SYSCALL_TYPES
# define INTERNAL_SYSCALL_TYPES(name, err, nr, args...) \
--
2.5.0