diff options
| author | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2013-04-24 12:58:39 +0200 |
|---|---|---|
| committer | Martin Schwidefsky <schwidefsky@de.ibm.com> | 2013-04-26 09:07:05 +0200 |
| commit | 616498813b11ffefe1ed36b9f2e4fd2cdbd22f15 (patch) | |
| tree | 1748b3171ab5cf1ada0c0bbeef285352c37edfcd /arch/s390/include/asm | |
| parent | dc7ee00d4771b3218b10e09e1071ee6eb176d381 (diff) | |
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')
| -rw-r--r-- | arch/s390/include/asm/elf.h | 22 | ||||
| -rw-r--r-- | arch/s390/include/asm/syscall.h | 1 | ||||
| -rw-r--r-- | arch/s390/include/asm/thread_info.h | 1 |
3 files changed, 20 insertions, 4 deletions
diff --git a/arch/s390/include/asm/elf.h b/arch/s390/include/asm/elf.h index 27ec2c3f95a..78f4f8711d5 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 diff --git a/arch/s390/include/asm/syscall.h b/arch/s390/include/asm/syscall.h index fe7b99759e1..cd29d2f4e4f 100644 --- a/arch/s390/include/asm/syscall.h +++ b/arch/s390/include/asm/syscall.h @@ -23,6 +23,7 @@ * type here is what we want [need] for both 32 bit and 64 bit systems. */ extern const unsigned int sys_call_table[]; +extern const unsigned int sys_call_table_emu[]; static inline long syscall_get_nr(struct task_struct *task, struct pt_regs *regs) diff --git a/arch/s390/include/asm/thread_info.h b/arch/s390/include/asm/thread_info.h index 9e2cfe0349c..51035e5d86c 100644 --- a/arch/s390/include/asm/thread_info.h +++ b/arch/s390/include/asm/thread_info.h @@ -41,6 +41,7 @@ struct thread_info { struct task_struct *task; /* main task structure */ struct exec_domain *exec_domain; /* execution domain */ unsigned long flags; /* low level flags */ + unsigned long sys_call_table; /* System call table address */ unsigned int cpu; /* current CPU */ int preempt_count; /* 0 => preemptable, <0 => BUG */ struct restart_block restart_block; |