For el0_dbg and el0_error, DAIF bits get explicitly cleared before
calling ct_user_exit.
When context tracking is disabled, DAIF gets set (almost) immediately
after. When context tracking is enabled, among the first things done
is disabling IRQs.
What is actually needed is:
- PSR.D = 0 so the system can be debugged (should be already the case)
- PSR.A = 0 so async error can be handled during context tracking
Do not clear PSR.I in those two locations.
Signed-off-by: Julien Thierry <[email protected]>
Cc:Catalin Marinas <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Marc Zyngier <[email protected]>
---
arch/arm64/kernel/entry.S | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index cd0c7af..89ab6bd 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -870,7 +870,7 @@ el0_dbg:
mov x1, x25
mov x2, sp
bl do_debug_exception
- enable_daif
+ enable_da_f
ct_user_exit
b ret_to_user
el0_inv:
@@ -922,7 +922,7 @@ el0_error_naked:
enable_dbg
mov x0, sp
bl do_serror
- enable_daif
+ enable_da_f
ct_user_exit
b ret_to_user
ENDPROC(el0_error)
--
1.9.1
Hi Julien,
On 06/06/2019 10:31, Julien Thierry wrote:
> For el0_dbg and el0_error, DAIF bits get explicitly cleared before
> calling ct_user_exit.
>
> When context tracking is disabled, DAIF gets set (almost) immediately
> after. When context tracking is enabled, among the first things done
> is disabling IRQs.
>
> What is actually needed is:
> - PSR.D = 0 so the system can be debugged (should be already the case)
> - PSR.A = 0 so async error can be handled during context tracking
>
> Do not clear PSR.I in those two locations.
(last time I looked at this I wrongly assumed ct_user_exit() should be run with interrupts
masked, but that isn't what you're saying).
Reviewed-by: James Morse <[email protected]>
Thanks,
James