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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.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by; Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Marc Zyngier 2019-04-08 16:49:04 +01:00 committed by Will Deacon
parent dea86a8003
commit 5ef19a161c
3 changed files with 28 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
arch/arm/include/asm/arch_timer.h
View File

@ -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);
/*

16
arch/arm64/include/asm/arch_timer.h
View File

@ -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

46
drivers/clocksource/arm_arch_timer.c
View File

@ -598,36 +598,12 @@ 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 */
@ -721,11 +697,6 @@ 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;
}
@ -733,11 +704,6 @@ 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;
}
@ -762,6 +728,10 @@ 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";
@ -772,20 +742,20 @@ 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";