diff options
-rw-r--r-- | arch/arm/include/asm/assembler.h | 16 | ||||
-rw-r--r-- | arch/arm/include/asm/thread_info.h | 20 | ||||
-rw-r--r-- | arch/arm/kernel/entry-common.S | 61 | ||||
-rw-r--r-- | arch/arm/kernel/signal.c | 6 |
4 files changed, 71 insertions, 32 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 */ diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S index 92828a1dec80..dd3721d1185e 100644 --- a/arch/arm/kernel/entry-common.S +++ b/arch/arm/kernel/entry-common.S @@ -24,35 +24,55 @@ .align 5 +#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING)) /* - * This is the fast syscall return path. We do as little as - * possible here, and this includes saving r0 back into the SVC - * stack. + * This is the fast syscall return path. We do as little as possible here, + * such as avoiding writing r0 to the stack. We only use this path if we + * have tracing and context tracking disabled - the overheads from those + * features make this path too inefficient. */ ret_fast_syscall: UNWIND(.fnstart ) UNWIND(.cantunwind ) - disable_irq @ disable interrupts + disable_irq_notrace @ disable interrupts ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing - tst r1, #_TIF_SYSCALL_WORK - bne __sys_trace_return - tst r1, #_TIF_WORK_MASK + tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK bne fast_work_pending - asm_trace_hardirqs_on /* perform architecture specific actions before user return */ arch_ret_to_user r1, lr - ct_user_enter restore_user_regs fast = 1, offset = S_OFF UNWIND(.fnend ) +ENDPROC(ret_fast_syscall) -/* - * Ok, we need to do extra processing, enter the slow path. - */ + /* Ok, we need to do extra processing, enter the slow path. */ fast_work_pending: str r0, [sp, #S_R0+S_OFF]! @ returned r0 -work_pending: + /* fall through to work_pending */ +#else +/* + * The "replacement" ret_fast_syscall for when tracing or context tracking + * is enabled. As we will need to call out to some C functions, we save + * r0 first to avoid needing to save registers around each C function call. + */ +ret_fast_syscall: + UNWIND(.fnstart ) + UNWIND(.cantunwind ) + str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 + disable_irq_notrace @ disable interrupts + ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing + tst r1, #_TIF_SYSCALL_WORK | _TIF_WORK_MASK + beq no_work_pending + UNWIND(.fnend ) +ENDPROC(ret_fast_syscall) + + /* Slower path - fall through to work_pending */ +#endif + + tst r1, #_TIF_SYSCALL_WORK + bne __sys_trace_return_nosave +slow_work_pending: mov r0, sp @ 'regs' mov r2, why @ 'syscall' bl do_work_pending @@ -64,16 +84,19 @@ work_pending: /* * "slow" syscall return path. "why" tells us if this was a real syscall. + * IRQs may be enabled here, so always disable them. Note that we use the + * "notrace" version to avoid calling into the tracing code unnecessarily. + * do_work_pending() will update this state if necessary. */ ENTRY(ret_to_user) ret_slow_syscall: - disable_irq @ disable interrupts + disable_irq_notrace @ disable interrupts ENTRY(ret_to_user_from_irq) ldr r1, [tsk, #TI_FLAGS] tst r1, #_TIF_WORK_MASK - bne work_pending + bne slow_work_pending no_work_pending: - asm_trace_hardirqs_on + asm_trace_hardirqs_on save = 0 /* perform architecture specific actions before user return */ arch_ret_to_user r1, lr @@ -251,6 +274,12 @@ __sys_trace_return: bl syscall_trace_exit b ret_slow_syscall +__sys_trace_return_nosave: + asm_trace_hardirqs_off save=0 + mov r0, sp + bl syscall_trace_exit + b ret_slow_syscall + .align 5 #ifdef CONFIG_ALIGNMENT_TRAP .type __cr_alignment, #object diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c index 423663e23791..b6cda06b455f 100644 --- a/arch/arm/kernel/signal.c +++ b/arch/arm/kernel/signal.c @@ -562,6 +562,12 @@ static int do_signal(struct pt_regs *regs, int syscall) asmlinkage int do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall) { + /* + * The assembly code enters us with IRQs off, but it hasn't + * informed the tracing code of that for efficiency reasons. + * Update the trace code with the current status. + */ + trace_hardirqs_off(); do { if (likely(thread_flags & _TIF_NEED_RESCHED)) { schedule(); |