From 5d6a03ebc88f82b0b0adcec24eabb9eb2fcd97db Mon Sep 17 00:00:00 2001 From: "Naveen N. Rao" Date: Wed, 4 Apr 2018 16:11:16 +0530 Subject: powerpc/hw_breakpoint: Only disable hw breakpoint if cpu supports it We get the below warning if we try to use kexec on P9: kexec_core: Starting new kernel WARNING: CPU: 0 PID: 1223 at arch/powerpc/kernel/process.c:826 __set_breakpoint+0xb4/0x140 [snip] NIP __set_breakpoint+0xb4/0x140 LR kexec_prepare_cpus_wait+0x58/0x150 Call Trace: 0xc0000000ee70fb20 (unreliable) 0xc0000000ee70fb20 default_machine_kexec+0x234/0x2c0 machine_kexec+0x84/0x90 kernel_kexec+0xd8/0xe0 SyS_reboot+0x214/0x2c0 system_call+0x58/0x6c This happens since we are trying to clear hw breakpoint on POWER9, though we don't have CPU_FTR_DAWR enabled. Guard __set_breakpoint() within hw_breakpoint_disable() with ppc_breakpoint_available() to address this. Fixes: 9654153158d3 ("powerpc: Disable DAWR in the base POWER9 CPU features") Signed-off-by: Naveen N. Rao Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/hw_breakpoint.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch/powerpc') diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h index 90c708e5e7c4..8e7b09703ca4 100644 --- a/arch/powerpc/include/asm/hw_breakpoint.h +++ b/arch/powerpc/include/asm/hw_breakpoint.h @@ -80,7 +80,8 @@ static inline void hw_breakpoint_disable(void) brk.address = 0; brk.type = 0; brk.len = 0; - __set_breakpoint(&brk); + if (ppc_breakpoint_available()) + __set_breakpoint(&brk); } extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs); int hw_breakpoint_handler(struct die_args *args); -- cgit v1.2.3