linux-kernel - [PATCH v2 1/5] arm64: Do not enable IRQs for ct_user

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Message-Id: <1556553607-46531-2-git-send-email-julien.thierry@arm.com>
Date:   Mon, 29 Apr 2019 17:00:03 +0100
From:   Julien Thierry <julien.thierry@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-kernel@...r.kernel.org, rostedt@...dmis.org,
        marc.zyngier@....com, yuzenghui@...wei.com,
        wanghaibin.wang@...wei.com, james.morse@....com,
        will.deacon@....com, catalin.marinas@....com, mark.rutland@....com,
        liwei391@...wei.com, Julien Thierry <julien.thierry@....com>
Subject: [PATCH v2 1/5] arm64: Do not enable IRQs for ct_user_exit

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 <julien.thierry@....com>
Cc:Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will.deacon@....com>
Cc: Mark Rutland <mark.rutland@....com>
Cc: Marc Zyngier <marc.zyngier@....com>
---
 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 c50a7a7..6a38903 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -855,7 +855,7 @@ 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:
@@ -907,7 +907,7 @@ 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