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Commit 5afaa1fc authored by Andre Przywara's avatar Andre Przywara Committed by Will Deacon
Browse files

arm64: add Cortex-A57 erratum 832075 workaround 



The ARM erratum 832075 applies to certain revisions of Cortex-A57,
one of the workarounds is to change device loads into using
load-aquire semantics.
This is achieved using the alternatives framework.

Signed-off-by: default avatarAndre Przywara <andre.przywara@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 301bcfac

arch/arm64/include/asm/cpufeature.h

+3 −2
Original line number Diff line number Diff line
@@ -22,8 +22,9 @@ 
#define cpu_feature(x)		ilog2(HWCAP_ ## x)



#define ARM64_WORKAROUND_CLEAN_CACHE		0

#define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE	1



#define NCAPS				1

#define NCAPS					2



#ifndef __ASSEMBLY__

arch/arm64/include/asm/io.h

+19 −4
Original line number Diff line number Diff line
@@ -28,6 +28,8 @@ 
#include <asm/barrier.h>

#include <asm/pgtable.h>

#include <asm/early_ioremap.h>

#include <asm/alternative.h>

#include <asm/cpufeature.h>



#include <xen/xen.h>
@@ -57,28 +59,41 @@ static inline void __raw_writeq(u64 val, volatile void __iomem *addr) 
static inline u8 __raw_readb(const volatile void __iomem *addr)

{

	u8 val;

	asm volatile("ldrb %w0, [%1]" : "=r" (val) : "r" (addr));

	asm volatile(ALTERNATIVE("ldrb %w0, [%1]",

				 "ldarb %w0, [%1]",

				 ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)

		     : "=r" (val) : "r" (addr));

	return val;

}



static inline u16 __raw_readw(const volatile void __iomem *addr)

{

	u16 val;

	asm volatile("ldrh %w0, [%1]" : "=r" (val) : "r" (addr));



	asm volatile(ALTERNATIVE("ldrh %w0, [%1]",

				 "ldarh %w0, [%1]",

				 ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)

		     : "=r" (val) : "r" (addr));

	return val;

}



static inline u32 __raw_readl(const volatile void __iomem *addr)

{

	u32 val;

	asm volatile("ldr %w0, [%1]" : "=r" (val) : "r" (addr));

	asm volatile(ALTERNATIVE("ldr %w0, [%1]",

				 "ldar %w0, [%1]",

				 ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)

		     : "=r" (val) : "r" (addr));

	return val;

}



static inline u64 __raw_readq(const volatile void __iomem *addr)

{

	u64 val;

	asm volatile("ldr %0, [%1]" : "=r" (val) : "r" (addr));

	asm volatile(ALTERNATIVE("ldr %0, [%1]",

				 "ldar %0, [%1]",

				 ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE)

		     : "=r" (val) : "r" (addr));

	return val;

}

arch/arm64/kernel/cpu_errata.c

+7 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <asm/cpufeature.h>



#define MIDR_CORTEX_A53 MIDR_CPU_PART(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)

#define MIDR_CORTEX_A57 MIDR_CPU_PART(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)



/*

 * Add a struct or another datatype to the union below if you need
@@ -71,6 +72,12 @@ struct arm64_cpu_capabilities arm64_errata[] = { 
		MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x02),

	},

	{

	/* Cortex-A57 r0p0 - r1p2 */

		.desc = "ARM erratum 832075",

		.capability = ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE,

		MIDR_RANGE(MIDR_CORTEX_A57, 0x00, 0x12),

	},

	{

	}

};