From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 4/6] ARM: virt: avoid clobbering lr when forcing svc mode
Date: Fri, 11 Jan 2013 15:34:15 +0000 [thread overview]
Message-ID: <1357918457-20469-5-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1357918457-20469-1-git-send-email-will.deacon@arm.com>
From: Russell King <rmk+kernel@arm.linux.org.uk>
The safe_svcmode_maskall macro is used to ensure that we are running in
svc mode, causing an exception return from hvc mode if required.
This patch removes the unneeded lr clobber from the macro and operates
entirely on the temporary parameter register instead.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[will: updated comment]
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm/include/asm/assembler.h | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index eb87200..05ee9ee 100644
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -246,18 +246,14 @@
*
* This macro is intended for forcing the CPU into SVC mode at boot time.
* you cannot return to the original mode.
- *
- * Beware, it also clobers LR.
*/
.macro safe_svcmode_maskall reg:req
#if __LINUX_ARM_ARCH__ >= 6
mrs \reg , cpsr
- mov lr , \reg
- and lr , lr , #MODE_MASK
- cmp lr , #HYP_MODE
- orr \reg , \reg , #PSR_I_BIT | PSR_F_BIT
+ eor \reg, \reg, #HYP_MODE
+ tst \reg, #MODE_MASK
bic \reg , \reg , #MODE_MASK
- orr \reg , \reg , #SVC_MODE
+ orr \reg , \reg , #PSR_I_BIT | PSR_F_BIT | SVC_MODE
THUMB( orr \reg , \reg , #PSR_T_BIT )
bne 1f
orr \reg, \reg, #PSR_A_BIT
--
1.8.0
next prev parent reply other threads:[~2013-01-11 15:34 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-11 15:34 [PATCH 0/6] Random collection of hyp-boot fixes and updates Will Deacon
2013-01-11 15:34 ` [PATCH 1/6] ARM: virt: Avoid bx instruction for compatibility with <=ARMv4 Will Deacon
2013-01-11 15:34 ` [PATCH 2/6] ARM: virt: boot secondary CPUs through the right entry point Will Deacon
2013-01-11 15:34 ` [PATCH 3/6] ARM: virt: simplify __hyp_stub_install epilog Will Deacon
2013-01-11 15:34 ` Will Deacon [this message]
2013-01-11 15:34 ` [PATCH 5/6] ARM: virt: use PSR_N_BIT for detecting boot CPU mode mismatch Will Deacon
2013-01-11 15:34 ` [PATCH 6/6] ARM: virt: hide CONFIG_ARM_VIRT_EXT from user Will Deacon
2013-01-11 15:42 ` Christopher Covington
2013-01-11 16:43 ` Will Deacon
2013-01-11 17:22 ` Christopher Covington
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