From 2cd76629f6c40f7b227ba7b3885ce10e6ec0face Mon Sep 17 00:00:00 2001 From: Kevin Hao Date: Thu, 10 Nov 2011 16:04:17 +0000 Subject: powerpc/trace: Add a dummy stack frame for trace_hardirqs_off The trace_hardirqs_off will use CALLER_ADDR0 and CALLER_ADDR1. If an exception occurs in user mode, there is only one stack frame on the stack and accessing the CALLER_ADDR1 will causes the following call trace. So we create a dummy stack frame to make trace_hardirqs_off happy. WARNING: at kernel/smp.c:459 Modules linked in: NIP: c0093280 LR: c00930a0 CTR: c0010780 REGS: edb87ae0 TRAP: 0700 Not tainted (3.1.0) MSR: 00021002 CR: 28002888 XER: 00000000 TASK = edce2ac0[17658] 'mthread-lock-on' THREAD: edb86000 CPU: 5 GPR00: 00000001 edb87b90 edce2ac0 00000005 c0019594 edb87bd8 00000001 00000fe3 GPR08: 00041000 c084138c 4e20120d edb87b90 48002888 1001aa7c 00000000 00000000 GPR16: 48830000 10012a8c 00000000 10000af4 00000001 c0810000 00000000 00000000 GPR24: ee9aa920 c0816a18 00000000 00000005 c0019594 edb87bd8 ee20178c edb87b90 NIP [c0093280] smp_call_function_many+0x214/0x2b4 LR [c00930a0] smp_call_function_many+0x34/0x2b4 Call Trace: [edb87b90] [c00930a0] smp_call_function_many+0x34/0x2b4 (unreliable) [edb87bd0] [c00194ec] __flush_tlb_page+0xac/0x100 [edb87c00] [c001957c] flush_tlb_page+0x3c/0x54 [edb87c10] [c00180ac] ptep_set_access_flags+0x74/0x12c [edb87c40] [c0128068] handle_pte_fault+0x2f0/0x9ac [edb87cb0] [c0128c3c] handle_mm_fault+0x104/0x1dc [edb87ce0] [c05f40f4] do_page_fault+0x2dc/0x630 [edb87e50] [c001078c] handle_page_fault+0xc/0x80 Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/entry_32.S | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'arch/powerpc') diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index 56212bc0ab0..4f80cf1ce77 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -215,7 +215,22 @@ reenable_mmu: /* re-enable mmu so we can */ stw r9,8(r1) stw r11,12(r1) stw r3,ORIG_GPR3(r1) + /* + * The trace_hardirqs_off will use CALLER_ADDR0 and CALLER_ADDR1. + * If from user mode there is only one stack frame on the stack, and + * accessing CALLER_ADDR1 will cause oops. So we need create a dummy + * stack frame to make trace_hardirqs_off happy. + */ + andi. r12,r12,MSR_PR + beq 11f + stwu r1,-16(r1) + bl trace_hardirqs_off + addi r1,r1,16 + b 12f + +11: bl trace_hardirqs_off +12: lwz r0,GPR0(r1) lwz r3,ORIG_GPR3(r1) lwz r4,GPR4(r1) -- cgit v1.2.3-70-g09d2