Commit 6d4e11c5 authored by Robert Richter's avatar Robert Richter Committed by Thomas Gleixner
Browse files

irqchip/gicv3: Workaround for Cavium ThunderX erratum 23154 



This patch implements Cavium ThunderX erratum 23154.

The gicv3 of ThunderX requires a modified version for reading the IAR
status to ensure data synchronization. Since this is in the fast-path
and called with each interrupt, runtime patching is used using jump
label patching for smallest overhead (no-op). This is the same
technique as used for tracepoints.

Signed-off-by: default avatarRobert Richter <rrichter@cavium.com>
Reviewed-by: default avatarMarc Zygnier <marc.zyngier@arm.com>
Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: Tirumalesh Chalamarla <tchalamarla@cavium.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/1442869119-1814-3-git-send-email-rric@kernel.org


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 30f21363

arch/arm64/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -348,6 +348,16 @@ config ARM64_ERRATUM_843419 


	  If unsure, say Y.



config CAVIUM_ERRATUM_23154

	bool "Cavium erratum 23154: Access to ICC_IAR1_EL1 is not sync'ed"

	default y

	help

	  The gicv3 of ThunderX requires a modified version for

	  reading the IAR status to ensure data synchronization

	  (access to icc_iar1_el1 is not sync'ed before and after).



	  If unsure, say Y.



endmenu

arch/arm64/include/asm/cpufeature.h

+2 −1
Original line number Diff line number Diff line
@@ -27,8 +27,9 @@ 
#define ARM64_HAS_SYSREG_GIC_CPUIF		3

#define ARM64_HAS_PAN				4

#define ARM64_HAS_LSE_ATOMICS			5

#define ARM64_WORKAROUND_CAVIUM_23154		6



#define ARM64_NCAPS				6

#define ARM64_NCAPS				7



#ifndef __ASSEMBLY__

arch/arm64/include/asm/cputype.h

+10 −7
Original line number Diff line number Diff line
@@ -64,6 +64,7 @@ 


#define ARM_CPU_IMP_ARM			0x41

#define ARM_CPU_IMP_APM			0x50

#define ARM_CPU_IMP_CAVIUM		0x43



#define ARM_CPU_PART_AEM_V8		0xD0F

#define ARM_CPU_PART_FOUNDATION		0xD00
@@ -72,6 +73,8 @@ 


#define APM_CPU_PART_POTENZA		0x000



#define CAVIUM_CPU_PART_THUNDERX	0x0A1



#define ID_AA64MMFR0_BIGENDEL0_SHIFT	16

#define ID_AA64MMFR0_BIGENDEL0_MASK	(0xf << ID_AA64MMFR0_BIGENDEL0_SHIFT)

#define ID_AA64MMFR0_BIGENDEL0(mmfr0)	\

arch/arm64/kernel/cpu_errata.c

+9 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 


#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)

#define MIDR_THUNDERX	MIDR_CPU_PART(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX)



#define CPU_MODEL_MASK (MIDR_IMPLEMENTOR_MASK | MIDR_PARTNUM_MASK | \

			MIDR_ARCHITECTURE_MASK)
@@ -81,6 +82,14 @@ const struct arm64_cpu_capabilities arm64_errata[] = { 
		.capability = ARM64_WORKAROUND_845719,

		MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x04),

	},

#endif

#ifdef CONFIG_CAVIUM_ERRATUM_23154

	{

	/* Cavium ThunderX, pass 1.x */

		.desc = "Cavium erratum 23154",

		.capability = ARM64_WORKAROUND_CAVIUM_23154,

		MIDR_RANGE(MIDR_THUNDERX, 0x00, 0x01),

	},

#endif

	{

	}

drivers/irqchip/irq-gic-v3.c

+41 −1
Original line number Diff line number Diff line
@@ -109,7 +109,7 @@ static void gic_redist_wait_for_rwp(void) 
}



/* Low level accessors */

static u64 __maybe_unused gic_read_iar(void)

static u64 gic_read_iar_common(void)

{

	u64 irqstat;
@@ -117,6 +117,38 @@ static u64 __maybe_unused gic_read_iar(void) 
	return irqstat;

}



/*

 * Cavium ThunderX erratum 23154

 *

 * The gicv3 of ThunderX requires a modified version for reading the

 * IAR status to ensure data synchronization (access to icc_iar1_el1

 * is not sync'ed before and after).

 */

static u64 gic_read_iar_cavium_thunderx(void)

{

	u64 irqstat;



	asm volatile(

		"nop;nop;nop;nop\n\t"

		"nop;nop;nop;nop\n\t"

		"mrs_s %0, " __stringify(ICC_IAR1_EL1) "\n\t"

		"nop;nop;nop;nop"

		: "=r" (irqstat));

	mb();



	return irqstat;

}



static struct static_key is_cavium_thunderx = STATIC_KEY_INIT_FALSE;



static u64 __maybe_unused gic_read_iar(void)

{

	if (static_key_false(&is_cavium_thunderx))

		return gic_read_iar_cavium_thunderx();

	else

		return gic_read_iar_common();

}



static void __maybe_unused gic_write_pmr(u64 val)

{

	asm volatile("msr_s " __stringify(ICC_PMR_EL1) ", %0" : : "r" (val));
@@ -836,6 +868,12 @@ static const struct irq_domain_ops gic_irq_domain_ops = { 
	.free = gic_irq_domain_free,

};



static void gicv3_enable_quirks(void)

{

	if (cpus_have_cap(ARM64_WORKAROUND_CAVIUM_23154))

		static_key_slow_inc(&is_cavium_thunderx);

}



static int __init gic_of_init(struct device_node *node, struct device_node *parent)

{

	void __iomem *dist_base;
@@ -901,6 +939,8 @@ static int __init gic_of_init(struct device_node *node, struct device_node *pare 
	gic_data.nr_redist_regions = nr_redist_regions;

	gic_data.redist_stride = redist_stride;



	gicv3_enable_quirks();



	/*

	 * Find out how many interrupts are supported.

	 * The GIC only supports up to 1020 interrupt sources (SGI+PPI+SPI)

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