5.4-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Gray bgray@linux.ibm.com
[ Upstream commit 27646b2e02b096a6936b3e3b6ba334ae20763eab ]
It can be easy to miss that the notifier mechanism invokes the callbacks in an atomic context, so add some comments to that effect on the two handlers we register here.
Signed-off-by: Benjamin Gray bgray@linux.ibm.com Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://msgid.link/20230829063457.54157-4-bgray@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kernel/hw_breakpoint.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c index 1007ec36b4cb9..fb736fdb4193f 100644 --- a/arch/powerpc/kernel/hw_breakpoint.c +++ b/arch/powerpc/kernel/hw_breakpoint.c @@ -247,6 +247,11 @@ static bool stepping_handler(struct pt_regs *regs, struct perf_event *bp, return false; }
+/* + * Handle a DABR or DAWR exception. + * + * Called in atomic context. + */ int hw_breakpoint_handler(struct die_args *args) { int rc = NOTIFY_STOP; @@ -315,6 +320,8 @@ NOKPROBE_SYMBOL(hw_breakpoint_handler);
/* * Handle single-step exceptions following a DABR hit. + * + * Called in atomic context. */ static int single_step_dabr_instruction(struct die_args *args) { @@ -355,6 +362,8 @@ NOKPROBE_SYMBOL(single_step_dabr_instruction);
/* * Handle debug exception notifications. + * + * Called in atomic context. */ int hw_breakpoint_exceptions_notify( struct notifier_block *unused, unsigned long val, void *data)