Messages in this thread Patch in this message | | | From | Masahiro Yamada <> | Subject | [PATCH 1/2] ARM: uniphier: fix up cache ops broadcast of ACTLR | Date | Tue, 29 Mar 2016 10:38:23 +0900 |
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The Boot ROM of the UniPhier ARMv7 SoCs sets ACTLR (Auxiliary Control Register) to different values for different secure states:
[1] Set ACTLR to 0x41 for Non-secure boot [2] Set ACTLR to 0x40 for Secure boot
[1] is okay, but [2] is a problem. Because of commit 1b3a02eb4523 ("ARMv7: Check whether the SMP/nAMP mode was already enabled"), if bit 6 (SMP bit) is already set, the kernel skips the ACTLR setting. In that case, bit 0 (FW bit) is never set, so cache ops is not broadcasted, causing a cache coherency problem.
To solve the problem, this commit sets the bit 0 of ACTLR if the bit 4 has already been set. This change is harmless for [1] because the Boot ROM has already set NSACR (Non-secure Access Control Register) bit 18 (NS_SMP bit) before switching to Non-secure state in order to allow write access to the ACTLR.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> ---
arch/arm/mach-uniphier/platsmp.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)
diff --git a/arch/arm/mach-uniphier/platsmp.c b/arch/arm/mach-uniphier/platsmp.c index db04142..285b684 100644 --- a/arch/arm/mach-uniphier/platsmp.c +++ b/arch/arm/mach-uniphier/platsmp.c @@ -170,6 +170,18 @@ static int __init uniphier_smp_enable_scu(void) return 0; } +static void __init uniphier_smp_fixup_cache_broadcast(void) +{ + u32 tmp; + + asm volatile( + "mrc p15, 0, %0, c1, c0, 1\n" + "tst %0, #(1 << 6)\n" + "orrne %0, #(1 << 0)\n" + "mcr p15, 0, %0, c1, c0, 1\n" + : "=r" (tmp) : : "memory", "cc"); +} + static void __init uniphier_smp_prepare_cpus(unsigned int max_cpus) { static cpumask_t only_cpu_0 = { CPU_BITS_CPU0 }; @@ -183,6 +195,8 @@ static void __init uniphier_smp_prepare_cpus(unsigned int max_cpus) if (ret) goto err; + uniphier_smp_fixup_cache_broadcast(); + return; err: pr_warn("disabling SMP\n"); @@ -209,9 +223,15 @@ static int __init uniphier_smp_boot_secondary(unsigned int cpu, return 0; } +static void __init uniphier_smp_secondary_init(unsigned int cpu) +{ + uniphier_smp_fixup_cache_broadcast(); +} + static const struct smp_operations uniphier_smp_ops __initconst = { .smp_prepare_cpus = uniphier_smp_prepare_cpus, .smp_boot_secondary = uniphier_smp_boot_secondary, + .smp_secondary_init = uniphier_smp_secondary_init, }; CPU_METHOD_OF_DECLARE(uniphier_smp, "socionext,uniphier-smp", &uniphier_smp_ops); -- 1.9.1
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