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From: Giorgio Dal Molin <giorgio.nicole@arcor.de>
To: barebox@lists.infradead.org
Cc: Giorgio Dal Molin <giorgio.nicole@arcor.de>
Subject: [PATCH 2/2] ARM: sm.c: add the attribute 'volatile' to some asm() statements.
Date: Tue,  7 Apr 2020 17:32:17 +0200	[thread overview]
Message-ID: <20200407153217.6568-1-giorgio.nicole@arcor.de> (raw)

Prevent the compiler to eventually cache register values read/written
to/from CP15.

Signed-off-by: Giorgio Dal Molin <giorgio.nicole@arcor.de>
---
 arch/arm/cpu/sm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm/cpu/sm.c b/arch/arm/cpu/sm.c
index cb33d9625..f5a1edbd4 100644
--- a/arch/arm/cpu/sm.c
+++ b/arch/arm/cpu/sm.c
@@ -26,7 +26,7 @@ static unsigned int read_id_pfr1(void)
 {
 	unsigned int reg;
 
-	asm("mrc p15, 0, %0, c0, c1, 1\n" : "=r"(reg));
+	asm volatile ("mrc p15, 0, %0, c0, c1, 1\n" : "=r"(reg));
 	return reg;
 }
 
@@ -34,18 +34,18 @@ static u32 read_nsacr(void)
 {
 	unsigned int reg;
 
-	asm("mrc p15, 0, %0, c1, c1, 2\n" : "=r"(reg));
+	asm volatile ("mrc p15, 0, %0, c1, c1, 2\n" : "=r"(reg));
 	return reg;
 }
 
 static void write_nsacr(u32 val)
 {
-	asm("mcr p15, 0, %0, c1, c1, 2" : : "r"(val));
+	asm volatile ("mcr p15, 0, %0, c1, c1, 2" : : "r"(val));
 }
 
 static void write_mvbar(u32 val)
 {
-	asm("mcr p15, 0, %0, c12, c0, 1" : : "r"(val));
+	asm volatile ("mcr p15, 0, %0, c12, c0, 1" : : "r"(val));
 }
 
 static int cpu_is_virt_capable(void)
-- 
2.26.0


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             reply	other threads:[~2020-04-07 15:32 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-07 15:32 Giorgio Dal Molin [this message]
2020-04-14 10:06 ` Sascha Hauer

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