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Date: Mon, 8 Apr 2019 16:49:04 +0100
From: Marc Zyngier <marc.zyngier@....com>
To: linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: Russell King <linux@....linux.org.uk>,
Will Deacon <will.deacon@....com>,
Catalin Marinas <catalin.marinas@....com>,
Mark Rutland <mark.rutland@....com>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Wim Van Sebroeck <wim@...ux-watchdog.org>,
Guenter Roeck <linux@...ck-us.net>,
Valentin Schneider <valentin.schneider@....com>
Subject: [PATCH 4/7] clocksource/arm_arch_timer: Direcly assign set_next_event workaround
When a given timer is affected by an erratum and requires an
alternative implementation of set_next_event, we do a rather
complicated dance to detect and call the workaround on each
set_next_event call.
This is clearly idiotic, as we can perfectly detect whether
this CPU requires a workaround while setting up the clock event
device.
This only requires the CPU-specific detection to be done a bit
earlier, and we can then safely override the set_next_event pointer
if we have a workaround associated to that CPU.
Signed-off-by: Marc Zyngier <marc.zyngier@....com>
---
arch/arm/include/asm/arch_timer.h | 4 +++
arch/arm64/include/asm/arch_timer.h | 16 ++++++++++
drivers/clocksource/arm_arch_timer.c | 46 +++++-----------------------
3 files changed, 28 insertions(+), 38 deletions(-)
diff --git a/arch/arm/include/asm/arch_timer.h b/arch/arm/include/asm/arch_timer.h
index 0a8d7bba2cb0..3f0a0191f763 100644
--- a/arch/arm/include/asm/arch_timer.h
+++ b/arch/arm/include/asm/arch_timer.h
@@ -11,6 +11,10 @@
#include <clocksource/arm_arch_timer.h>
#ifdef CONFIG_ARM_ARCH_TIMER
+/* 32bit ARM doesn't know anything about timer errata... */
+#define has_erratum_handler(h) (false)
+#define erratum_handler(h) (arch_timer_##h)
+
int arch_timer_arch_init(void);
/*
diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h
index f2a234d6516c..c3762ffcc933 100644
--- a/arch/arm64/include/asm/arch_timer.h
+++ b/arch/arm64/include/asm/arch_timer.h
@@ -31,10 +31,26 @@
#include <clocksource/arm_arch_timer.h>
#if IS_ENABLED(CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND)
+#define has_erratum_handler(h) \
+ ({ \
+ const struct arch_timer_erratum_workaround *__wa; \
+ __wa = __this_cpu_read(timer_unstable_counter_workaround); \
+ (__wa && __wa->h); \
+ })
+
+#define erratum_handler(h) \
+ ({ \
+ const struct arch_timer_erratum_workaround *__wa; \
+ __wa = __this_cpu_read(timer_unstable_counter_workaround); \
+ (__wa && __wa->h) ? __wa->h : arch_timer_##h; \
+ })
+
extern struct static_key_false arch_timer_read_ool_enabled;
#define needs_unstable_timer_counter_workaround() \
static_branch_unlikely(&arch_timer_read_ool_enabled)
#else
+#define has_erratum_handler(h) false
+#define erratum_handler(h) (arch_timer_##h)
#define needs_unstable_timer_counter_workaround() false
#endif
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index aa4ec53281ce..c7f5b66d893c 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -613,36 +613,12 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t
local ? "local" : "global", wa->desc);
}
-#define erratum_handler(fn, r, ...) \
-({ \
- bool __val; \
- 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; \
- } \
- __val; \
-})
-
static bool arch_timer_this_cpu_has_cntvct_wa(void)
{
- const struct arch_timer_erratum_workaround *wa;
-
- wa = __this_cpu_read(timer_unstable_counter_workaround);
- return wa && wa->read_cntvct_el0;
+ return has_erratum_handler(read_cntvct_el0);
}
#else
#define arch_timer_check_ool_workaround(t,a) do { } while(0)
-#define erratum_set_next_event_tval_virt(...) ({BUG(); 0;})
-#define erratum_set_next_event_tval_phys(...) ({BUG(); 0;})
-#define erratum_handler(fn, r, ...) ({false;})
#define arch_timer_this_cpu_has_cntvct_wa() ({false;})
#endif /* CONFIG_ARM_ARCH_TIMER_OOL_WORKAROUND */
@@ -736,11 +712,6 @@ static __always_inline void set_next_event(const int access, unsigned long evt,
static int arch_timer_set_next_event_virt(unsigned long evt,
struct clock_event_device *clk)
{
- int ret;
-
- if (erratum_handler(set_next_event_virt, ret, evt, clk))
- return ret;
-
set_next_event(ARCH_TIMER_VIRT_ACCESS, evt, clk);
return 0;
}
@@ -748,11 +719,6 @@ static int arch_timer_set_next_event_virt(unsigned long evt,
static int arch_timer_set_next_event_phys(unsigned long evt,
struct clock_event_device *clk)
{
- int ret;
-
- if (erratum_handler(set_next_event_phys, ret, evt, clk))
- return ret;
-
set_next_event(ARCH_TIMER_PHYS_ACCESS, evt, clk);
return 0;
}
@@ -777,6 +743,10 @@ static void __arch_timer_setup(unsigned type,
clk->features = CLOCK_EVT_FEAT_ONESHOT;
if (type == ARCH_TIMER_TYPE_CP15) {
+ typeof(clk->set_next_event) sne;
+
+ arch_timer_check_ool_workaround(ate_match_local_cap_id, NULL);
+
if (arch_timer_c3stop)
clk->features |= CLOCK_EVT_FEAT_C3STOP;
clk->name = "arch_sys_timer";
@@ -787,20 +757,20 @@ static void __arch_timer_setup(unsigned type,
case ARCH_TIMER_VIRT_PPI:
clk->set_state_shutdown = arch_timer_shutdown_virt;
clk->set_state_oneshot_stopped = arch_timer_shutdown_virt;
- clk->set_next_event = arch_timer_set_next_event_virt;
+ sne = erratum_handler(set_next_event_virt);
break;
case ARCH_TIMER_PHYS_SECURE_PPI:
case ARCH_TIMER_PHYS_NONSECURE_PPI:
case ARCH_TIMER_HYP_PPI:
clk->set_state_shutdown = arch_timer_shutdown_phys;
clk->set_state_oneshot_stopped = arch_timer_shutdown_phys;
- clk->set_next_event = arch_timer_set_next_event_phys;
+ sne = erratum_handler(set_next_event_phys);
break;
default:
BUG();
}
- arch_timer_check_ool_workaround(ate_match_local_cap_id, NULL);
+ clk->set_next_event = sne;
} else {
clk->features |= CLOCK_EVT_FEAT_DYNIRQ;
clk->name = "arch_mem_timer";
--
2.20.1
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