[3/9] arm64: Introduce arm64_force_sig_info and hook up in arm64_notify_die

Commit Message

Will Deacon Feb. 22, 2018, 2 p.m. UTC

In preparation for consolidating our handling of printing unhandled
signals, introduce a wrapper around force_sig_info which can act as
the canonical place for dealing with show_unhandled_signals.

Initially, we just hook this up to arm64_notify_die.

Signed-off-by: Will Deacon <[e-mail]>
---
 arch/arm64/include/asm/traps.h |  2 ++
 arch/arm64/kernel/traps.c      | 28 +++++++++++++++++++++++++++-
 2 files changed, 29 insertions(+), 1 deletion(-)

Comments

Mark Rutland Feb. 22, 2018, 3:39 p.m. UTC | #1

On Thu, Feb 22, 2018 at 02:00:51PM +0000, Will Deacon wrote:
> +void arm64_force_sig_info(struct siginfo *info, const char *str,
> +			  struct task_struct *tsk)
> +{
> +	unsigned int esr = tsk->thread.fault_code;
> +	struct pt_regs *regs = task_pt_regs(tsk);
> +
> +	if (!unhandled_signal(tsk, info->si_signo))
> +		goto send_sig;
> +
> +	if (!show_unhandled_signals_ratelimited())
> +		goto send_sig;
> +
> +	pr_info("%s[%d]: unhandled exception: ", tsk->comm, task_pid_nr(tsk));
> +	if (esr)
> +		pr_cont("%s, ESR 0x%03x, ", esr_get_class_string(esr), esr);

Can we make that 0x%08x please? ESR_ELx.EC occupies bits 31-26...

I guess this was copied from __do_user_fault, and it's odd there, as
wherever that's called the EC is non-zero.

Thanks,
Mark.

Patch

diff --git a/arch/arm64/include/asm/traps.h b/arch/arm64/include/asm/traps.h
index 1ee63dc38579..c320f3bf6c57 100644
--- a/arch/arm64/include/asm/traps.h
+++ b/arch/arm64/include/asm/traps.h
@@ -37,6 +37,8 @@  void register_undef_hook(struct undef_hook *hook);
 void unregister_undef_hook(struct undef_hook *hook);
 void force_signal_inject(int signal, int code, unsigned long address);
 void arm64_notify_segfault(unsigned long addr);
+void arm64_force_sig_info(struct siginfo *info, const char *str,
+			  struct task_struct *tsk);
 
 /*
  * Move regs->pc to next instruction and do necessary setup before it
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index 3f52c07b4bf4..b46b5be5bd6d 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -223,13 +223,39 @@  void die(const char *str, struct pt_regs *regs, int err)
 		do_exit(SIGSEGV);
 }
 
+void arm64_force_sig_info(struct siginfo *info, const char *str,
+			  struct task_struct *tsk)
+{
+	unsigned int esr = tsk->thread.fault_code;
+	struct pt_regs *regs = task_pt_regs(tsk);
+
+	if (!unhandled_signal(tsk, info->si_signo))
+		goto send_sig;
+
+	if (!show_unhandled_signals_ratelimited())
+		goto send_sig;
+
+	pr_info("%s[%d]: unhandled exception: ", tsk->comm, task_pid_nr(tsk));
+	if (esr)
+		pr_cont("%s, ESR 0x%03x, ", esr_get_class_string(esr), esr);
+
+	pr_cont("%s", str);
+	print_vma_addr(KERN_CONT " in ", regs->pc);
+	pr_cont("\n");
+	__show_regs(regs);
+
+send_sig:
+	force_sig_info(info->si_signo, info, tsk);
+}
+
 void arm64_notify_die(const char *str, struct pt_regs *regs,
 		      struct siginfo *info, int err)
 {
 	if (user_mode(regs)) {
+		WARN_ON(regs != current_pt_regs());
 		current->thread.fault_address = 0;
 		current->thread.fault_code = err;
-		force_sig_info(info->si_signo, info, current);
+		arm64_force_sig_info(info, str, current);
 	} else {
 		die(str, regs, err);
 	}