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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: f37099b699 ("arm64: convert syscall trace logic to C")
Reported-by: Julien Grall <julien.grall@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
hifive-unleashed-5.1
Will Deacon 2018-07-30 17:43:39 +01:00
parent ba70ffa7d2
commit efd112353b
1 changed files with 8 additions and 1 deletions
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9
arch/arm64/kernel/syscall.c
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@ -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);
}