From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
mikey@neuling.org
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [RFC PATCH v1 13/13] powerpc/hw_breakpoint: move instruction stepping out of hw_breakpoint_handler()
Date: Tue, 25 Jun 2019 10:58:19 +0000 (UTC) [thread overview]
Message-ID: <347a44cbfdd864c8ab5440d8915710cb1648a05a.1561459984.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <cover.1561459983.git.christophe.leroy@c-s.fr>
On 8xx, breakpoints stop after executing the instruction, so
stepping/emulation is not needed. Move it into a sub-function and
remove the #ifdefs.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/kernel/hw_breakpoint.c | 60 ++++++++++++++++++++-----------------
1 file changed, 33 insertions(+), 27 deletions(-)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index b71d3837d673..a6a509b9fd13 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -198,15 +198,43 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)
/*
* Handle debug exception notifications.
*/
+static bool stepping_handler(struct pt_regs *regs, struct perf_event *bp,
+ unsigned long addr)
+{
+ int stepped;
+ unsigned int instr;
+
+ /* Do not emulate user-space instructions, instead single-step them */
+ if (user_mode(regs)) {
+ current->thread.last_hit_ubp = bp;
+ regs->msr |= MSR_SE;
+ return false;
+ }
+
+ stepped = 0;
+ instr = 0;
+ if (!__get_user_inatomic(instr, (unsigned int *) regs->nip))
+ stepped = emulate_step(regs, instr);
+
+ /*
+ * emulate_step() could not execute it. We've failed in reliably
+ * handling the hw-breakpoint. Unregister it and throw a warning
+ * message to let the user know about it.
+ */
+ if (!stepped) {
+ WARN(1, "Unable to handle hardware breakpoint. Breakpoint at "
+ "0x%lx will be disabled.", addr);
+ perf_event_disable_inatomic(bp);
+ return false;
+ }
+ return true;
+}
+
int hw_breakpoint_handler(struct die_args *args)
{
int rc = NOTIFY_STOP;
struct perf_event *bp;
struct pt_regs *regs = args->regs;
-#ifndef CONFIG_PPC_8xx
- int stepped = 1;
- unsigned int instr;
-#endif
struct arch_hw_breakpoint *info;
unsigned long dar = regs->dar;
@@ -251,31 +279,9 @@ int hw_breakpoint_handler(struct die_args *args)
(dar - bp->attr.bp_addr < bp->attr.bp_len)))
info->type |= HW_BRK_TYPE_EXTRANEOUS_IRQ;
-#ifndef CONFIG_PPC_8xx
- /* Do not emulate user-space instructions, instead single-step them */
- if (user_mode(regs)) {
- current->thread.last_hit_ubp = bp;
- regs->msr |= MSR_SE;
+ if (!IS_ENABLED(CONFIG_PPC_8xx) && !stepping_handler(regs, bp, info->address))
goto out;
- }
- stepped = 0;
- instr = 0;
- if (!__get_user_inatomic(instr, (unsigned int *) regs->nip))
- stepped = emulate_step(regs, instr);
-
- /*
- * emulate_step() could not execute it. We've failed in reliably
- * handling the hw-breakpoint. Unregister it and throw a warning
- * message to let the user know about it.
- */
- if (!stepped) {
- WARN(1, "Unable to handle hardware breakpoint. Breakpoint at "
- "0x%lx will be disabled.", info->address);
- perf_event_disable_inatomic(bp);
- goto out;
- }
-#endif
/*
* As a policy, the callback is invoked in a 'trigger-after-execute'
* fashion
--
2.13.3
prev parent reply other threads:[~2019-06-25 10:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-25 10:58 [RFC PATCH v1 00/13] Reduce ifdef mess in ptrace Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 01/13] powerpc: move ptrace into a subdirectory Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 02/13] powerpc/ptrace: drop unnecessary #ifdefs CONFIG_PPC64 Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 03/13] powerpc/ptrace: drop PARAMETER_SAVE_AREA_OFFSET Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 04/13] powerpc/ptrace: split out VSX related functions Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 05/13] powerpc/ptrace: split out ALTIVEC " Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 06/13] powerpc/ptrace: split out SPE " Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 07/13] powerpc/ptrace: split out TRANSACTIONAL_MEM " Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 08/13] powerpc/ptrace: move register viewing functions out of ptrace.c Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 09/13] powerpc/ptrace: split out ADV_DEBUG_REGS related functions Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 10/13] powerpc/ptrace: create ptrace_get_debugreg() Christophe Leroy
2019-06-25 10:58 ` [RFC PATCH v1 11/13] powerpc/ptrace: create ppc_gethwdinfo() Christophe Leroy
2019-06-25 13:21 ` Mathieu Malaterre
2019-06-25 10:58 ` [RFC PATCH v1 12/13] powerpc/ptrace: move ptrace_triggered() into hw_breakpoint.c Christophe Leroy
2019-06-25 10:58 ` Christophe Leroy [this message]
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