From 1a18a66446f3f289b05b634f18012424d82aa63a Mon Sep 17 00:00:00 2001 From: Kevin Hao Date: Fri, 17 Jan 2014 12:25:28 +0800 Subject: powerpc: Set the correct ksp_limit on ppc32 when switching to irq stack Guenter Roeck has got the following call trace on a p2020 board: Kernel stack overflow in process eb3e5a00, r1=eb79df90 CPU: 0 PID: 2838 Comm: ssh Not tainted 3.13.0-rc8-juniper-00146-g19eca00 #4 task: eb3e5a00 ti: c0616000 task.ti: ef440000 NIP: c003a420 LR: c003a410 CTR: c0017518 REGS: eb79dee0 TRAP: 0901 Not tainted (3.13.0-rc8-juniper-00146-g19eca00) MSR: 00029000 CR: 24008444 XER: 00000000 GPR00: c003a410 eb79df90 eb3e5a00 00000000 eb05d900 00000001 65d87646 00000000 GPR08: 00000000 020b8000 00000000 00000000 44008442 NIP [c003a420] __do_softirq+0x94/0x1ec LR [c003a410] __do_softirq+0x84/0x1ec Call Trace: [eb79df90] [c003a410] __do_softirq+0x84/0x1ec (unreliable) [eb79dfe0] [c003a970] irq_exit+0xbc/0xc8 [eb79dff0] [c000cc1c] call_do_irq+0x24/0x3c [ef441f20] [c00046a8] do_IRQ+0x8c/0xf8 [ef441f40] [c000e7f4] ret_from_except+0x0/0x18 --- Exception: 501 at 0xfcda524 LR = 0x10024900 Instruction dump: 7c781b78 3b40000a 3a73b040 543c0024 3a800000 3b3913a0 7ef5bb78 48201bf9 5463103a 7d3b182e 7e89b92e 7c008146 <3ba00000> 7e7e9b78 48000014 57fff87f Kernel panic - not syncing: kernel stack overflow CPU: 0 PID: 2838 Comm: ssh Not tainted 3.13.0-rc8-juniper-00146-g19eca00 #4 Call Trace: The reason is that we have used the wrong register to calculate the ksp_limit in commit cbc9565ee826 (powerpc: Remove ksp_limit on ppc64). Just fix it. As suggested by Benjamin Herrenschmidt, also add the C prototype of the function in the comment in order to avoid such kind of errors in the future. Cc: stable@vger.kernel.org # 3.12 Reported-by: Guenter Roeck Tested-by: Guenter Roeck Signed-off-by: Kevin Hao Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/kernel/misc_32.S | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/kernel/misc_32.S b/arch/powerpc/kernel/misc_32.S index 879f09620f83..7c6bb4b17b49 100644 --- a/arch/powerpc/kernel/misc_32.S +++ b/arch/powerpc/kernel/misc_32.S @@ -57,11 +57,14 @@ _GLOBAL(call_do_softirq) mtlr r0 blr +/* + * void call_do_irq(struct pt_regs *regs, struct thread_info *irqtp); + */ _GLOBAL(call_do_irq) mflr r0 stw r0,4(r1) lwz r10,THREAD+KSP_LIMIT(r2) - addi r11,r3,THREAD_INFO_GAP + addi r11,r4,THREAD_INFO_GAP stwu r1,THREAD_SIZE-STACK_FRAME_OVERHEAD(r4) mr r1,r4 stw r10,8(r1) -- cgit v1.2.3