ARM: 7197/1: errata: Remove SMP dependency for erratum 751472 (ba90c516) · Commits · 戴 / test

Activation conditions for a workaround should not be encoded in the workaround's direct dependencies if this makes otherwise reasonable configuration choices impossible. This patches uses the SMP/UP patching facilities instead to compile out the workaround if the configuration means that it is definitely not needed. This means that configs for buggy silicon can simply select ARM_ERRATA_751472, without preventing a UP kernel from being built or duplicatiing knowledge about when to activate the workaround. This seems the correct way to do things, because the erratum is a property of the silicon, irrespective of what the kernel config happens to be. Signed-off-by:

Dave Martin <dave.martin@linaro.org> Signed-off-by:

Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/Kconfig

+1 −1

Original line number	Diff line number	Diff line
		@@ -1282,7 +1282,7 @@ config ARM_ERRATA_743622

		config ARM_ERRATA_751472
		bool "ARM errata: Interrupted ICIALLUIS may prevent completion of broadcasted operation"
		depends on CPU_V7 && SMP
		depends on CPU_V7
		help
		This option enables the workaround for the 751472 Cortex-A9 (prior
		to r3p0) erratum. An interrupted ICIALLUIS operation may prevent the

arch/arm/mm/proc-v7.S

+4 −2

Original line number	Diff line number	Diff line
		@@ -363,11 +363,13 @@ __v7_setup:
		orreq r10, r10, #1 << 6 @ set bit #6
		mcreq p15, 0, r10, c15, c0, 1 @ write diagnostic register
		#endif
		#ifdef CONFIG_ARM_ERRATA_751472
		cmp r6, #0x30 @ present prior to r3p0
		#if defined(CONFIG_ARM_ERRATA_751472) && defined(CONFIG_SMP)
		ALT_SMP(cmp r6, #0x30) @ present prior to r3p0
		ALT_UP_B(1f)
		mrclt p15, 0, r10, c15, c0, 1 @ read diagnostic register
		orrlt r10, r10, #1 << 11 @ set bit #11
		mcrlt p15, 0, r10, c15, c0, 1 @ write diagnostic register
		1:
		#endif

		3: mov r10, #0

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