Commit efd11235 authored Jul 30, 2018 by Will Deacon

arm64: svc: Ensure hardirq tracing is updated before return



We always run userspace with interrupts enabled, but with the recent
conversion of the syscall entry/exit code to C, we don't inform the
hardirq tracing code that interrupts are about to become enabled by
virtue of restoring the EL0 SPSR.

This patch ensures that trace_hardirqs_on() is called on the syscall
return path when we return to the assembly code with interrupts still
disabled.

Fixes: f37099b6 ("arm64: convert syscall trace logic to C")
Reported-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

parent ba70ffa7

arch/arm64/kernel/syscall.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -91,8 +91,15 @@ static void el0_svc_common(struct pt_regs *regs, int scno, int sc_nr,
		if (!has_syscall_work(flags) && !IS_ENABLED(CONFIG_DEBUG_RSEQ)) {
		local_daif_mask();
		flags = current_thread_info()->flags;
		if (!has_syscall_work(flags))
		if (!has_syscall_work(flags)) {
		/*
		* We're off to userspace, where interrupts are
		* always enabled after we restore the flags from
		* the SPSR.
		*/
		trace_hardirqs_on();
		return;
		}
		local_daif_restore(DAIF_PROCCTX);
		}

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