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* [PATCH] ARM: footbridge: fix dc21285 PCI configuration accessors
@ 2020-10-18  8:42 Russell King
  0 siblings, 0 replies; only message in thread
From: Russell King @ 2020-10-18  8:42 UTC (permalink / raw)
  To: Bjorn Helgaas; +Cc: linux-pci, linux-arm-kernel

Building with gcc 4.9.2 reveals a latent bug in the PCI accessors
for Footbridge platforms, which causes a fatal alignment fault
while accessing IO memory. Fix this by making the assembly volatile.

Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
---
 arch/arm/mach-footbridge/dc21285.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mach-footbridge/dc21285.c b/arch/arm/mach-footbridge/dc21285.c
index 416462e3f5d6..f9713dc561cf 100644
--- a/arch/arm/mach-footbridge/dc21285.c
+++ b/arch/arm/mach-footbridge/dc21285.c
@@ -65,15 +65,15 @@ dc21285_read_config(struct pci_bus *bus, unsigned int devfn, int where,
 	if (addr)
 		switch (size) {
 		case 1:
-			asm("ldrb	%0, [%1, %2]"
+			asm volatile("ldrb	%0, [%1, %2]"
 				: "=r" (v) : "r" (addr), "r" (where) : "cc");
 			break;
 		case 2:
-			asm("ldrh	%0, [%1, %2]"
+			asm volatile("ldrh	%0, [%1, %2]"
 				: "=r" (v) : "r" (addr), "r" (where) : "cc");
 			break;
 		case 4:
-			asm("ldr	%0, [%1, %2]"
+			asm volatile("ldr	%0, [%1, %2]"
 				: "=r" (v) : "r" (addr), "r" (where) : "cc");
 			break;
 		}
@@ -99,17 +99,17 @@ dc21285_write_config(struct pci_bus *bus, unsigned int devfn, int where,
 	if (addr)
 		switch (size) {
 		case 1:
-			asm("strb	%0, [%1, %2]"
+			asm volatile("strb	%0, [%1, %2]"
 				: : "r" (value), "r" (addr), "r" (where)
 				: "cc");
 			break;
 		case 2:
-			asm("strh	%0, [%1, %2]"
+			asm volatile("strh	%0, [%1, %2]"
 				: : "r" (value), "r" (addr), "r" (where)
 				: "cc");
 			break;
 		case 4:
-			asm("str	%0, [%1, %2]"
+			asm volatile("str	%0, [%1, %2]"
 				: : "r" (value), "r" (addr), "r" (where)
 				: "cc");
 			break;
-- 
2.20.1


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2020-10-18  8:42 [PATCH] ARM: footbridge: fix dc21285 PCI configuration accessors Russell King

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