diff options
Diffstat (limited to 'arch/arm64/include/asm/assembler.h')
| -rw-r--r-- | arch/arm64/include/asm/assembler.h | 114 |
1 files changed, 33 insertions, 81 deletions
diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index ca31594d3d6c..ab569b0b45fc 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> @@ -23,6 +24,14 @@ #include <asm/ptrace.h> #include <asm/thread_info.h> + /* + * Provide a wxN alias for each wN register so what we can paste a xN + * reference after a 'w' to obtain the 32-bit version. + */ + .irp n,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30 + wx\n .req w\n + .endr + .macro save_and_disable_daif, flags mrs \flags, daif msr daifset, #0xf @@ -40,9 +49,9 @@ msr daif, \flags .endm - /* IRQ is the lowest priority flag, unconditionally unmask the rest. */ - .macro enable_da_f - msr daifclr, #(8 | 4 | 1) + /* IRQ/FIQ are the lowest priority flags, unconditionally unmask the rest. */ + .macro enable_da + msr daifclr, #(8 | 4) .endm /* @@ -50,7 +59,7 @@ */ .macro save_and_disable_irq, flags mrs \flags, daif - msr daifset, #2 + msr daifset, #3 .endm .macro restore_irq, flags @@ -692,90 +701,33 @@ USER(\label, ic ivau, \tmp2) // invalidate I line PoU isb .endm -/* - * Check whether to yield to another runnable task from kernel mode NEON code - * (which runs with preemption disabled). - * - * if_will_cond_yield_neon - * // pre-yield patchup code - * do_cond_yield_neon - * // post-yield patchup code - * endif_yield_neon <label> - * - * where <label> is optional, and marks the point where execution will resume - * after a yield has been performed. If omitted, execution resumes right after - * the endif_yield_neon invocation. Note that the entire sequence, including - * the provided patchup code, will be omitted from the image if - * CONFIG_PREEMPTION is not defined. - * - * As a convenience, in the case where no patchup code is required, the above - * sequence may be abbreviated to - * - * cond_yield_neon <label> - * - * Note that the patchup code does not support assembler directives that change - * the output section, any use of such directives is undefined. - * - * The yield itself consists of the following: - * - Check whether the preempt count is exactly 1 and a reschedule is also - * needed. If so, calling of preempt_enable() in kernel_neon_end() will - * trigger a reschedule. If it is not the case, yielding is pointless. - * - Disable and re-enable kernel mode NEON, and branch to the yield fixup - * code. - * - * This macro sequence may clobber all CPU state that is not guaranteed by the - * AAPCS to be preserved across an ordinary function call. - */ - - .macro cond_yield_neon, lbl - if_will_cond_yield_neon - do_cond_yield_neon - endif_yield_neon \lbl - .endm - - .macro if_will_cond_yield_neon -#ifdef CONFIG_PREEMPTION - get_current_task x0 - ldr x0, [x0, #TSK_TI_PREEMPT] - sub x0, x0, #PREEMPT_DISABLE_OFFSET - cbz x0, .Lyield_\@ - /* fall through to endif_yield_neon */ - .subsection 1 -.Lyield_\@ : -#else - .section ".discard.cond_yield_neon", "ax" -#endif - .endm - - .macro do_cond_yield_neon - bl kernel_neon_end - bl kernel_neon_begin - .endm - - .macro endif_yield_neon, lbl - .ifnb \lbl - b \lbl - .else - b .Lyield_out_\@ - .endif - .previous -.Lyield_out_\@ : - .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 /* |