[PATCH 1/7] arm64: capabilities: Merge entries for ARM64_WORKAROUND_CLEAN_CACHE

Suzuki K Poulose
2018-11-26T15:09:56Z

On Mon, Nov 26, 2018 at 02:06:04PM +0000, Will Deacon wrote:
> On Mon, Nov 05, 2018 at 11:55:11AM +0000, Suzuki K Poulose wrote:
> > We have two entries for ARM64_WORKAROUND_CLEAN_CACHE capability :
> >
> > 1) ARM Errata 826319, 827319, 824069, 819472 on A53 r0p[012]
> > 2) ARM Errata 819472 on A53 r0p[01]
> >
> > Both have the same work around. Merge these entries to avoid
> > duplicate entries for a single capability.
> >
> > Cc: Will Deacon <will.deacon@arm.com>
> > Cc: Andre Przywara <andre.przywara@arm.com>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
> > ---
> > arch/arm64/kernel/cpu_errata.c | 19 +++++++------------
> > 1 file changed, 7 insertions(+), 12 deletions(-)
> >
> > diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
> > index a509e351..c825bc0 100644
> > --- a/arch/arm64/kernel/cpu_errata.c
> > +++ b/arch/arm64/kernel/cpu_errata.c
> > @@ -573,24 +573,19 @@ static const struct midr_range arm64_harden_el2_vectors[] = {
> > const struct arm64_cpu_capabilities arm64_errata[] = {
> > #if defined(CONFIG_ARM64_ERRATUM_826319) || \
> > defined(CONFIG_ARM64_ERRATUM_827319) || \
> > - defined(CONFIG_ARM64_ERRATUM_824069)
> > + defined(CONFIG_ARM64_ERRATUM_824069) || \
> > + defined(CONFIG_ARM64_ERRATUM_819472)
> > {
> > - /* Cortex-A53 r0p[012] */
> > - .desc = "ARM errata 826319, 827319, 824069",
> > + /*
> > + * Cortex-A53 r0p[012]: ARM errata 826319, 827319, 824069
> > + * Cortex-A53 r0p[01] : ARM errata 819472
> > + */
> > + .desc = "ARM errata 826319, 827319, 824069, 819472",
> > .capability = ARM64_WORKAROUND_CLEAN_CACHE,
> > ERRATA_MIDR_REV_RANGE(MIDR_CORTEX_A53, 0, 0, 2),
> > .cpu_enable = cpu_enable_cache_maint_trap,
>
> Isn't this a semantic change wrt the Kconfig options? After this change,
> if I /only/ set CONFIG_ARM64_ERRATUM_819472=y, then I still get the
> workaround applied for CPUs > r0[p01] which isn't what I asked for.

You're right. I could change this to :

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 787d785..56a921f 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -313,6 +313,11 @@ menu "Kernel Features"

menu "ARM errata workarounds via the alternatives framework"

+config ARM64_WORKAROUND_CLEAN_CACHE
+ default y
+ depends on ARM64_ERRATUM_826319 || ARM64_ERRATUM_827319 ||
+ ARM64_ERRATUM_824069 || ARM64_ERRATUM_819472
+
config ARM64_ERRATUM_826319
bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
default y
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index a509e351..80f2e66 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -570,24 +570,28 @@ static const struct midr_range arm64_harden_el2_vectors[] = {

#endif

-const struct arm64_cpu_capabilities arm64_errata[] = {
+#ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE
+static const struct midr_range workaround_clean_cache[] = {
#if defined(CONFIG_ARM64_ERRATUM_826319) || \
defined(CONFIG_ARM64_ERRATUM_827319) || \
defined(CONFIG_ARM64_ERRATUM_824069)
- {
- /* Cortex-A53 r0p[012] */
- .desc = "ARM errata 826319, 827319, 824069",
- .capability = ARM64_WORKAROUND_CLEAN_CACHE,
- ERRATA_MIDR_REV_RANGE(MIDR_CORTEX_A53, 0, 0, 2),
- .cpu_enable = cpu_enable_cache_maint_trap,
- },
+ /* Cortex-A53 r0p[012]: ARM errata 826319, 827319, 824069 */
+ MIDR_REV_RANGE(MIDR_CORTEX_A53, 0, 0, 2),
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_819472
+ /* Cortex-A53 r0p[01] : ARM errata 819472 */
+ MIDR_REV_RANGE(MIDR_CORTEX_A53, 0, 0, 1),
+#endif
+ {},
+};
#endif
-#ifdef CONFIG_ARM64_ERRATUM_819472
+
+const struct arm64_cpu_capabilities arm64_errata[] = {
+#ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE
{
- /* Cortex-A53 r0p[01] */
- .desc = "ARM errata 819472",
+ .desc = "ARM errata 826319, 827319, 824069, 819472",
.capability = ARM64_WORKAROUND_CLEAN_CACHE,
- ERRATA_MIDR_REV_RANGE(MIDR_CORTEX_A53, 0, 0, 1),
+ ERRATA_MIDR_REV_LIST(workaround_clean_cache),
.cpu_enable = cpu_enable_cache_maint_trap,
},
#endif

---

Cheers
Suzuki