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authorMarc Zyngier <marc.zyngier@arm.com>2017-02-20 18:34:48 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2017-04-07 11:22:09 +0100
commit6acc71ccac7187fc0ef85f10bd09c2058f21fab5 (patch)
treefa55e6e16bdd8b41537ba1d27abefb2c1b2a96ee /drivers/clocksource
parent8c64621bf9501902a3086a5e38135344b3161128 (diff)
arm64: arch_timer: Allows a CPU-specific erratum to only affect a subset of CPUs
Instead of applying a CPU-specific workaround to all CPUs in the system, allow it to only affect a subset of them (typical big-little case). This is done by turning the erratum pointer into a per-CPU variable. Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/arm_arch_timer.c42
1 files changed, 30 insertions, 12 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index a0c9ee80147e..4551587bcb44 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -235,7 +235,8 @@ static u64 notrace hisi_161010101_read_cntvct_el0(void)
#endif
#ifdef CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND
-const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround = NULL;
+DEFINE_PER_CPU(const struct arch_timer_erratum_workaround *,
+ timer_unstable_counter_workaround);
EXPORT_SYMBOL_GPL(timer_unstable_counter_workaround);
DEFINE_STATIC_KEY_FALSE(arch_timer_read_ool_enabled);
@@ -338,9 +339,18 @@ arch_timer_iterate_errata(enum arch_timer_erratum_match_type type,
}
static
-void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa)
+void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa,
+ bool local)
{
- timer_unstable_counter_workaround = wa;
+ int i;
+
+ if (local) {
+ __this_cpu_write(timer_unstable_counter_workaround, wa);
+ } else {
+ for_each_possible_cpu(i)
+ per_cpu(timer_unstable_counter_workaround, i) = wa;
+ }
+
static_branch_enable(&arch_timer_read_ool_enabled);
}
@@ -369,14 +379,17 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
return;
if (needs_unstable_timer_counter_workaround()) {
- if (wa != timer_unstable_counter_workaround)
+ const struct arch_timer_erratum_workaround *__wa;
+ __wa = __this_cpu_read(timer_unstable_counter_workaround);
+ if (__wa && wa != __wa)
pr_warn("Can't enable workaround for %s (clashes with %s\n)",
- wa->desc,
- timer_unstable_counter_workaround->desc);
- return;
+ wa->desc, __wa->desc);
+
+ if (__wa)
+ return;
}
- arch_timer_enable_workaround(wa);
+ arch_timer_enable_workaround(wa, local);
pr_info("Enabling %s workaround for %s\n",
local ? "local" : "global", wa->desc);
}
@@ -384,10 +397,15 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
#define erratum_handler(fn, r, ...) \
({ \
bool __val; \
- if (needs_unstable_timer_counter_workaround() && \
- timer_unstable_counter_workaround->fn) { \
- r = timer_unstable_counter_workaround->fn(__VA_ARGS__); \
- __val = true; \
+ if (needs_unstable_timer_counter_workaround()) { \
+ const struct arch_timer_erratum_workaround *__wa; \
+ __wa = __this_cpu_read(timer_unstable_counter_workaround); \
+ if (__wa && __wa->fn) { \
+ r = __wa->fn(__VA_ARGS__); \
+ __val = true; \
+ } else { \
+ __val = false; \
+ } \
} else { \
__val = false; \
} \