From 3cb5f1a3e58c0bd70d47d9907cc5c65192281dee Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 23 Dec 2010 19:46:06 +0000 Subject: [PATCH] powerpc/ppc64/tracing: Add stack frame to calls of trace_hardirqs_on/off When an interrupt occurs in userspace, we can call trace_hardirqs_on/off() With one level stack. But if we have irqsoff tracing enabled, it checks both CALLER_ADDR0 and CALLER_ADDR1. The second call goes two stack frames up. If this is from user space, then there may not exist a second stack. Add a second stack when calling trace_hardirqs_on/off() otherwise the following oops might occur: Oops: Kernel access of bad area, sig: 11 [#1] PREEMPT SMP NR_CPUS=2 PA Semi PWRficient last sysfs file: /sys/block/sda/size Modules linked in: ohci_hcd ehci_hcd usbcore NIP: c0000000000e1c00 LR: c0000000000034d4 CTR: 000000011012c440 REGS: c00000003e2f3af0 TRAP: 0300 Not tainted (2.6.37-rc6+) MSR: 9000000000001032 CR: 48044444 XER: 20000000 DAR: 00000001ffb9db50, DSISR: 0000000040000000 TASK = c00000003e1a00a0[2088] 'emacs' THREAD: c00000003e2f0000 CPU: 1 GPR00: 0000000000000001 c00000003e2f3d70 c00000000084e0d0 c0000000008816e8 GPR04: 000000001034c678 000000001032e8f9 0000000010336540 0000000040020000 GPR08: 0000000040020000 00000001ffb9db40 c00000003e2f3e30 0000000060000000 GPR12: 100000000000f032 c00000000fff0280 000000001032e8c9 0000000000000008 GPR16: 00000000105be9c0 00000000105be950 00000000105be9b0 00000000105be950 GPR20: 00000000ffb9dc50 00000000ffb9dbf0 00000000102f0000 00000000102f0000 GPR24: 00000000102e0000 00000000102f0000 0000000010336540 c0000000009ded38 GPR28: 00000000102e0000 c0000000000034d4 c0000000007ccb10 c00000003e2f3d70 NIP [c0000000000e1c00] .trace_hardirqs_off+0xb0/0x1d0 LR [c0000000000034d4] decrementer_common+0xd4/0x100 Call Trace: [c00000003e2f3d70] [c00000003e2f3e30] 0xc00000003e2f3e30 (unreliable) [c00000003e2f3e30] [c0000000000034d4] decrementer_common+0xd4/0x100 Instruction dump: 81690000 7f8b0000 419e0018 f84a0028 60000000 60000000 60000000 e95f0000 80030000 e92a0000 eb6301f8 2f800000 41fe00dc a06d000a eb1e8050 ---[ end trace 4ec7fd2be9240928 ]--- Reported-by: Joerg Sommer Signed-off-by: Steven Rostedt Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/irqflags.h | 40 +++++++++++++++++++++-------- 1 file changed, 30 insertions(+), 10 deletions(-) diff --git a/arch/powerpc/include/asm/irqflags.h b/arch/powerpc/include/asm/irqflags.h index b85d8ddbb666..b0b06d85788d 100644 --- a/arch/powerpc/include/asm/irqflags.h +++ b/arch/powerpc/include/asm/irqflags.h @@ -12,24 +12,44 @@ #else #ifdef CONFIG_TRACE_IRQFLAGS +#ifdef CONFIG_IRQSOFF_TRACER +/* + * Since the ftrace irqsoff latency trace checks CALLER_ADDR1, + * which is the stack frame here, we need to force a stack frame + * in case we came from user space. + */ +#define TRACE_WITH_FRAME_BUFFER(func) \ + mflr r0; \ + stdu r1, -32(r1); \ + std r0, 16(r1); \ + stdu r1, -32(r1); \ + bl func; \ + ld r1, 0(r1); \ + ld r1, 0(r1); +#else +#define TRACE_WITH_FRAME_BUFFER(func) \ + bl func; +#endif + /* * Most of the CPU's IRQ-state tracing is done from assembly code; we * have to call a C function so call a wrapper that saves all the * C-clobbered registers. */ -#define TRACE_ENABLE_INTS bl .trace_hardirqs_on -#define TRACE_DISABLE_INTS bl .trace_hardirqs_off -#define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip) \ - cmpdi en,0; \ - bne 95f; \ - stb en,PACASOFTIRQEN(r13); \ - bl .trace_hardirqs_off; \ - b skip; \ -95: bl .trace_hardirqs_on; \ +#define TRACE_ENABLE_INTS TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_on) +#define TRACE_DISABLE_INTS TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_off) + +#define TRACE_AND_RESTORE_IRQ_PARTIAL(en,skip) \ + cmpdi en,0; \ + bne 95f; \ + stb en,PACASOFTIRQEN(r13); \ + TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_off) \ + b skip; \ +95: TRACE_WITH_FRAME_BUFFER(.trace_hardirqs_on) \ li en,1; #define TRACE_AND_RESTORE_IRQ(en) \ TRACE_AND_RESTORE_IRQ_PARTIAL(en,96f); \ - stb en,PACASOFTIRQEN(r13); \ + stb en,PACASOFTIRQEN(r13); \ 96: #else #define TRACE_ENABLE_INTS -- 2.20.1