From 3302caddf10ad50710dbb7a94ccbdb3ad5bf1412 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 20 Aug 2015 16:13:37 +0100 Subject: 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 Signed-off-by: Russell King --- arch/arm/include/asm/assembler.h | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'arch/arm/include/asm/assembler.h') 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 -- cgit v1.2.3