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Biederman" , Michael Ellerman , Michael Neuling , Murilo Opsfelder Araujo , Nicholas Piggin , Paul Mackerras , Simon Guo , Sukadev Bhattiprolu , "Tobin C . Harding" , linuxppc-dev@lists.ozlabs.org Subject: [PATCH 7/7] powerpc/traps: Show instructions on exceptions Date: Tue, 24 Jul 2018 16:27:20 -0300 X-Mailer: git-send-email 2.17.1 In-Reply-To: <20180724192720.32417-1-muriloo@linux.ibm.com> References: <20180724192720.32417-1-muriloo@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 18072419-0064-0000-0000-0000032F2952 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00009424; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000266; SDB=6.01065573; UDB=6.00547380; IPR=6.00843431; MB=3.00022305; MTD=3.00000008; XFM=3.00000015; UTC=2018-07-24 19:28:19 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18072419-0065-0000-0000-00003A0EC691 Message-Id: <20180724192720.32417-8-muriloo@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-07-24_06:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=873 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1806210000 definitions=main-1807240204 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Move show_instructions() declaration to arch/powerpc/include/asm/stacktrace.h and include asm/stracktrace.h in arch/powerpc/kernel/process.c, which contains the implementation. Modify show_instructions() not to call __kernel_text_address(), allowing userspace instruction dump. probe_kernel_address(), which returns -EFAULT if something goes wrong, is still being called. Call show_instructions() in arch/powerpc/kernel/traps.c to dump instructions at faulty location, useful to debugging. Before this patch, an unhandled signal message looked like: Jul 24 09:57:00 localhost kernel: pandafault[10524]: segfault (11) at 00000000100007d0 nip 000000001000061c lr 00007fffbd295100 code 2 in pandafault[10000000+10000] After this patch, it looks like: Jul 24 09:57:00 localhost kernel: pandafault[10524]: segfault (11) at 00000000100007d0 nip 000000001000061c lr 00007fffbd295100 code 2 in pandafault[10000000+10000] Jul 24 09:57:00 localhost kernel: Instruction dump: Jul 24 09:57:00 localhost kernel: 4bfffeec 4bfffee8 3c401002 38427f00 fbe1fff8 f821ffc1 7c3f0b78 3d22fffe Jul 24 09:57:00 localhost kernel: 392988d0 f93f0020 e93f0020 39400048 <99490000> 39200000 7d234b78 383f0040 Signed-off-by: Murilo Opsfelder Araujo --- arch/powerpc/include/asm/stacktrace.h | 7 +++++++ arch/powerpc/kernel/process.c | 6 +++--- arch/powerpc/kernel/traps.c | 3 +++ 3 files changed, 13 insertions(+), 3 deletions(-) create mode 100644 arch/powerpc/include/asm/stacktrace.h diff --git a/arch/powerpc/include/asm/stacktrace.h b/arch/powerpc/include/asm/stacktrace.h new file mode 100644 index 000000000000..46e5ef451578 --- /dev/null +++ b/arch/powerpc/include/asm/stacktrace.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_POWERPC_STACKTRACE_H +#define _ASM_POWERPC_STACKTRACE_H + +void show_instructions(struct pt_regs *regs); + +#endif /* _ASM_POWERPC_STACKTRACE_H */ diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index b1af3390249c..ee1d63e03c52 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -52,6 +52,7 @@ #include #include #include +#include #include #include #include @@ -1261,7 +1262,7 @@ struct task_struct *__switch_to(struct task_struct *prev, static int instructions_to_print = 16; -static void show_instructions(struct pt_regs *regs) +void show_instructions(struct pt_regs *regs) { int i; unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 * @@ -1283,8 +1284,7 @@ static void show_instructions(struct pt_regs *regs) pc = (unsigned long)phys_to_virt(pc); #endif - if (!__kernel_text_address(pc) || - probe_kernel_address((unsigned int __user *)pc, instr)) { + if (probe_kernel_address((unsigned int __user *)pc, instr)) { pr_cont("XXXXXXXX "); } else { if (regs->nip == pc) diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index e55ee639d010..3beca17ac1b1 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -70,6 +70,7 @@ #include #include #include +#include #if defined(CONFIG_DEBUGGER) || defined(CONFIG_KEXEC_CORE) int (*__debugger)(struct pt_regs *regs) __read_mostly; @@ -357,6 +358,8 @@ static void show_signal_msg(int signr, struct pt_regs *regs, int code, print_vma_addr(KERN_CONT " in ", regs->nip); pr_cont("\n"); + + show_instructions(regs); } void _exception_pkey(int signr, struct pt_regs *regs, int code, -- 2.17.1