diff options
| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-08-20 18:13:37 +0300 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-08-25 12:32:48 +0300 |
| commit | 3302caddf10ad50710dbb7a94ccbdb3ad5bf1412 (patch) | |
| tree | 4a25e5f4dffa272d4c86450290bbeff3c7be6005 /arch/arm/include/asm | |
| parent | 01e09a28167c338684606b70797422da3bbb6650 (diff) | |
| download | linux-3302caddf10ad50710dbb7a94ccbdb3ad5bf1412.tar.xz | |
ARM: entry: efficiency cleanups
Make the "fast" syscall return path fast again. The addition of IRQ
tracing and context tracking has made this path grossly inefficient.
We can do much better if these options are enabled if we save the
syscall return code on the stack - we then don't need to save a bunch
of registers around every single callout to C code.
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/include/asm')
| -rw-r--r-- | arch/arm/include/asm/assembler.h | 16 | ||||
| -rw-r--r-- | arch/arm/include/asm/thread_info.h | 20 |
2 files changed, 20 insertions, 16 deletions
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h index 742495eb5526..5a5504f90d5f 100644 --- a/arch/arm/include/asm/assembler.h +++ b/arch/arm/include/asm/assembler.h @@ -108,29 +108,37 @@ .endm #endif - .macro asm_trace_hardirqs_off + .macro asm_trace_hardirqs_off, save=1 #if defined(CONFIG_TRACE_IRQFLAGS) + .if \save stmdb sp!, {r0-r3, ip, lr} + .endif bl trace_hardirqs_off + .if \save ldmia sp!, {r0-r3, ip, lr} + .endif #endif .endm - .macro asm_trace_hardirqs_on, cond=al + .macro asm_trace_hardirqs_on, cond=al, save=1 #if defined(CONFIG_TRACE_IRQFLAGS) /* * actually the registers should be pushed and pop'd conditionally, but * after bl the flags are certainly clobbered */ + .if \save stmdb sp!, {r0-r3, ip, lr} + .endif bl\cond trace_hardirqs_on + .if \save ldmia sp!, {r0-r3, ip, lr} + .endif #endif .endm - .macro disable_irq + .macro disable_irq, save=1 disable_irq_notrace - asm_trace_hardirqs_off + asm_trace_hardirqs_off \save .endm .macro enable_irq diff --git a/arch/arm/include/asm/thread_info.h b/arch/arm/include/asm/thread_info.h index bd32eded3e50..71e0ffcedf8e 100644 --- a/arch/arm/include/asm/thread_info.h +++ b/arch/arm/include/asm/thread_info.h @@ -136,22 +136,18 @@ extern int vfp_restore_user_hwstate(struct user_vfp __user *, /* * thread information flags: - * TIF_SYSCALL_TRACE - syscall trace active - * TIF_SYSCAL_AUDIT - syscall auditing active - * TIF_SIGPENDING - signal pending - * TIF_NEED_RESCHED - rescheduling necessary - * TIF_NOTIFY_RESUME - callback before returning to user * TIF_USEDFPU - FPU was used by this task this quantum (SMP) * TIF_POLLING_NRFLAG - true if poll_idle() is polling TIF_NEED_RESCHED */ -#define TIF_SIGPENDING 0 -#define TIF_NEED_RESCHED 1 +#define TIF_SIGPENDING 0 /* signal pending */ +#define TIF_NEED_RESCHED 1 /* rescheduling necessary */ #define TIF_NOTIFY_RESUME 2 /* callback before returning to user */ -#define TIF_UPROBE 7 -#define TIF_SYSCALL_TRACE 8 -#define TIF_SYSCALL_AUDIT 9 -#define TIF_SYSCALL_TRACEPOINT 10 -#define TIF_SECCOMP 11 /* seccomp syscall filtering active */ +#define TIF_UPROBE 3 /* breakpointed or singlestepping */ +#define TIF_SYSCALL_TRACE 4 /* syscall trace active */ +#define TIF_SYSCALL_AUDIT 5 /* syscall auditing active */ +#define TIF_SYSCALL_TRACEPOINT 6 /* syscall tracepoint instrumentation */ +#define TIF_SECCOMP 7 /* seccomp syscall filtering active */ + #define TIF_NOHZ 12 /* in adaptive nohz mode */ #define TIF_USING_IWMMXT 17 #define TIF_MEMDIE 18 /* is terminating due to OOM killer */ |