From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) (using TLSv1 with cipher ADH-CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 40qKDL6RRpzF16f for ; Mon, 21 May 2018 23:21:21 +1000 (AEST) From: Michal Suchanek To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Balbir Singh , Nicholas Piggin , Breno Leitao , "Naveen N. Rao" , Vaibhav Jain , "Guilherme G. Piccoli" , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Cc: Michal Suchanek Subject: [PATCH] powerpc/xmon: really enable xmon when a breakpoint is set Date: Mon, 21 May 2018 15:21:08 +0200 Message-Id: <20180521132108.7938-1-msuchanek@suse.de> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , When single-stepping kernel code from xmon without a debug hook enabled the kernel crashes. This can happen when kernel starts with xmon on crash disabled but xmon is entered using sysrq. Commit e1368d0c9edb ("powerpc/xmon: Setup debugger hooks when first break-point is set") adds force_enable_xmon function that prints "xmon: Enabling debugger hooks" but does not enable them. Add the call to xmon_init to install the debugger hooks in force_enable_xmon and also call force_enable_xmon when single-stepping in xmon. Fixes: e1368d0c9edb ("powerpc/xmon: Setup debugger hooks when first break-point is set") Signed-off-by: Michal Suchanek --- arch/powerpc/xmon/xmon.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c index a0842f1ff72c..504bd1c3d8b0 100644 --- a/arch/powerpc/xmon/xmon.c +++ b/arch/powerpc/xmon/xmon.c @@ -179,6 +179,9 @@ static const char *getvecname(unsigned long vec); static int do_spu_cmd(void); +static void xmon_init(int enable); +static inline void force_enable_xmon(void); + #ifdef CONFIG_44x static void dump_tlb_44x(void); #endif @@ -1094,6 +1097,7 @@ static int do_step(struct pt_regs *regs) unsigned int instr; int stepped; + force_enable_xmon(); /* check we are in 64-bit kernel mode, translation enabled */ if ((regs->msr & (MSR_64BIT|MSR_PR|MSR_IR)) == (MSR_64BIT|MSR_IR)) { if (mread(regs->nip, &instr, 4) == 4) { @@ -1275,6 +1279,7 @@ static inline void force_enable_xmon(void) if (!xmon_on) { printf("xmon: Enabling debugger hooks\n"); xmon_on = 1; + xmon_init(1); } } -- 2.13.6