diff options
Diffstat (limited to 'arch/arm64/include/asm/assembler.h')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 7b076ccd1a54..6ac38f7cf824 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -15,6 +15,7 @@ #include <asm-generic/export.h> #include <asm/asm-offsets.h> +#include <asm/alternative.h> #include <asm/cpufeature.h> #include <asm/cputype.h> #include <asm/debug-monitors.h> @@ -701,19 +702,32 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU .endm /* - * Check whether preempt-disabled code should yield as soon as it - * is able. This is the case if re-enabling preemption a single - * time results in a preempt count of zero, and the TIF_NEED_RESCHED - * flag is set. (Note that the latter is stored negated in the - * top word of the thread_info::preempt_count field) + * Check whether preempt/bh-disabled asm code should yield as soon as + * it is able. This is the case if we are currently running in task + * context, and either a softirq is pending, or the TIF_NEED_RESCHED + * flag is set and re-enabling preemption a single time would result in + * a preempt count of zero. (Note that the TIF_NEED_RESCHED flag is + * stored negated in the top word of the thread_info::preempt_count + * field) */ - .macro cond_yield, lbl:req, tmp:req -#ifdef CONFIG_PREEMPTION + .macro cond_yield, lbl:req, tmp:req, tmp2:req get_current_task \tmp ldr \tmp, [\tmp, #TSK_TI_PREEMPT] + /* + * If we are serving a softirq, there is no point in yielding: the + * softirq will not be preempted no matter what we do, so we should + * run to completion as quickly as we can. + */ + tbnz \tmp, #SOFTIRQ_SHIFT, .Lnoyield_\@ +#ifdef CONFIG_PREEMPTION sub \tmp, \tmp, #PREEMPT_DISABLE_OFFSET cbz \tmp, \lbl #endif + adr_l \tmp, irq_stat + IRQ_CPUSTAT_SOFTIRQ_PENDING + this_cpu_offset \tmp2 + ldr w\tmp, [\tmp, \tmp2] + cbnz w\tmp, \lbl // yield on pending softirq in task context +.Lnoyield_\@: .endm /* |