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 <[email protected]> --- 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
