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From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/6] ARM: virt: Avoid bx instruction for compatibility with <=ARMv4
Date: Fri, 11 Jan 2013 15:34:12 +0000	[thread overview]
Message-ID: <1357918457-20469-2-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1357918457-20469-1-git-send-email-will.deacon@arm.com>

From: Dave Martin <dave.martin@linaro.org>

Non-T variants of ARMv4 do not support the bx instruction.

However, __hyp_stub_install is always called from the same
instruction set used to build the bulk of the kernel, so bx should
not be necessary.

This patch uses the traditional "mov pc" instead of bx.

Cc: <stable@vger.kernel.org>
Signed-off-by: Dave Martin <dave.martin@linaro.org>
[will: fixed up remaining bx instruction]
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
 arch/arm/kernel/hyp-stub.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S
index 65b2417..3c60256 100644
--- a/arch/arm/kernel/hyp-stub.S
+++ b/arch/arm/kernel/hyp-stub.S
@@ -99,7 +99,7 @@ ENTRY(__hyp_stub_install_secondary)
 	 * immediately.
 	 */
 	compare_cpu_mode_with_primary	r4, r5, r6, r7
-	bxne	lr
+	movne	pc, lr
 
 	/*
 	 * Once we have given up on one CPU, we do not try to install the
@@ -111,7 +111,7 @@ ENTRY(__hyp_stub_install_secondary)
 	 */
 
 	cmp	r4, #HYP_MODE
-	bxne	lr			@ give up if the CPU is not in HYP mode
+	movne	pc, lr			@ give up if the CPU is not in HYP mode
 
 /*
  * Configure HSCTLR to set correct exception endianness/instruction set
@@ -200,7 +200,7 @@ ENDPROC(__hyp_get_vectors)
 	@ fall through
 ENTRY(__hyp_set_vectors)
 	__HVC(0)
-	bx	lr
+	mov	pc, lr
 ENDPROC(__hyp_set_vectors)
 
 #ifndef ZIMAGE
-- 
1.8.0

  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 ` Will Deacon [this message]
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 ` [PATCH 4/6] ARM: virt: avoid clobbering lr when forcing svc mode Will Deacon
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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