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From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] arm64: sysreg: Fix use of XZR in write_sysreg_s
Date: Mon, 17 Oct 2016 18:20:59 +0100	[thread overview]
Message-ID: <1476724859-18818-1-git-send-email-will.deacon@arm.com> (raw)

Commit 8a71f0c656e0 ("arm64: sysreg: replace open-coded mrs_s/msr_s with
{read,write}_sysreg_s") introduced a write_sysreg_s macro for writing
to system registers that are not supported by binutils.

Unfortunately, this was implemented with the wrong template (%0 vs %x0),
so in the case that we are writing a constant 0, we will generate
invalid instruction syntax and bail with a cryptic assembler error:

  | Error: constant expression required

This patch fixes the template.

Signed-off-by: Will Deacon <will.deacon@arm.com>
---
 arch/arm64/include/asm/sysreg.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index e8d46e8e6079..6c80b3699cb8 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -286,7 +286,7 @@ asm(
 
 #define write_sysreg_s(v, r) do {					\
 	u64 __val = (u64)v;						\
-	asm volatile("msr_s " __stringify(r) ", %0" : : "rZ" (__val));	\
+	asm volatile("msr_s " __stringify(r) ", %x0" : : "rZ" (__val));	\
 } while (0)
 
 static inline void config_sctlr_el1(u32 clear, u32 set)
-- 
2.1.4

             reply	other threads:[~2016-10-17 17:20 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-17 17:20 Will Deacon [this message]
2016-10-17 18:19 ` [PATCH] arm64: sysreg: Fix use of XZR in write_sysreg_s Mark Rutland

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