Allow printk time stamps/sched_clock() to be available from the early boot.
Signed-off-by: Pavel Tatashin <[email protected]> --- arch/arm64/kernel/setup.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index f4fc1e0544b7..4df41a66b403 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -40,6 +40,7 @@ #include <linux/efi.h> #include <linux/psci.h> #include <linux/sched/task.h> +#include <linux/sched_clock.h> #include <linux/mm.h> #include <asm/acpi.h> @@ -279,8 +280,26 @@ arch_initcall(reserve_memblock_reserved_regions); u64 __cpu_logical_map[NR_CPUS] = { [0 ... NR_CPUS-1] = INVALID_HWID }; +/* + * Get time stamps available early in boot, useful to identify boot time issues + * from the early boot. + */ +static __init void sched_clock_early_init(void) +{ + u64 freq = arch_timer_get_cntfrq(); + u64 (*read_time)(void) = arch_counter_get_cntvct; + + /* Early clock is available only on platforms with known freqs */ + if (!freq) + return; + + sched_clock_register(read_time, BITS_PER_LONG, freq); +} + void __init setup_arch(char **cmdline_p) { + sched_clock_early_init(); + init_mm.start_code = (unsigned long) _text; init_mm.end_code = (unsigned long) _etext; init_mm.end_data = (unsigned long) _edata; -- 2.19.1
