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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2013-04-24 12:58:39 +0200
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2013-04-26 09:07:05 +0200
commit616498813b11ffefe1ed36b9f2e4fd2cdbd22f15 (patch)
tree1748b3171ab5cf1ada0c0bbeef285352c37edfcd /arch/s390/include/asm/elf.h
parentdc7ee00d4771b3218b10e09e1071ee6eb176d381 (diff)
downloadlinux-linaro-stable-616498813b11ffefe1ed36b9f2e4fd2cdbd22f15.tar.gz
s390: system call path micro optimization
Add a pointer to the system call table to the thread_info structure. The TIF_31BIT bit is set or cleared by SET_PERSONALITY exactly once for the lifetime of a process. With the pointer to the correct system call table in thread_info the system call code in entry64.S path can drop the check for TIF_31BIT which saves a couple of instructions. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/elf.h')
-rw-r--r--arch/s390/include/asm/elf.h22
1 files changed, 18 insertions, 4 deletions
diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h
index 27ec2c3f95ac..78f4f8711d58 100644
--- a/arch/s390/include/asm/elf.h
+++ b/arch/s390/include/asm/elf.h
@@ -120,6 +120,7 @@
#include <asm/ptrace.h>
#include <asm/compat.h>
+#include <asm/syscall.h>
#include <asm/user.h>
typedef s390_fp_regs elf_fpregset_t;
@@ -181,18 +182,31 @@ extern unsigned long elf_hwcap;
extern char elf_platform[];
#define ELF_PLATFORM (elf_platform)
-#ifdef CONFIG_64BIT
+#ifndef CONFIG_COMPAT
+#define SET_PERSONALITY(ex) \
+do { \
+ set_personality(PER_LINUX | \
+ (current->personality & (~PER_MASK))); \
+ current_thread_info()->sys_call_table = \
+ (unsigned long) &sys_call_table; \
+} while (0)
+#else /* CONFIG_COMPAT */
#define SET_PERSONALITY(ex) \
do { \
if (personality(current->personality) != PER_LINUX32) \
set_personality(PER_LINUX | \
(current->personality & ~PER_MASK)); \
- if ((ex).e_ident[EI_CLASS] == ELFCLASS32) \
+ if ((ex).e_ident[EI_CLASS] == ELFCLASS32) { \
set_thread_flag(TIF_31BIT); \
- else \
+ current_thread_info()->sys_call_table = \
+ (unsigned long) &sys_call_table_emu; \
+ } else { \
clear_thread_flag(TIF_31BIT); \
+ current_thread_info()->sys_call_table = \
+ (unsigned long) &sys_call_table; \
+ } \
} while (0)
-#endif /* CONFIG_64BIT */
+#endif /* CONFIG_COMPAT */
#define STACK_RND_MASK 0x7ffUL