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author | Jan Janssen <medhefgo@web.de> | 2023-04-12 23:45:04 +0200 |
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committer | Jan Janssen <medhefgo@web.de> | 2023-04-13 15:39:14 +0200 |
commit | 706fd67e4a61e615e9d05427e00e7e676973d8f2 (patch) | |
tree | 86019453023653d8fad0f019280b0aea60a92515 | |
parent | 09614b35c01702b73c757d9ec374bf381d51b008 (diff) | |
download | systemd-706fd67e4a61e615e9d05427e00e7e676973d8f2.tar.gz |
boot: Rework timer frquency reading
This is in preparation for the next commit.
-rw-r--r-- | src/boot/efi/ticks.c | 49 |
1 files changed, 31 insertions, 18 deletions
diff --git a/src/boot/efi/ticks.c b/src/boot/efi/ticks.c index 84dfdc4542..7dd808ae19 100644 --- a/src/boot/efi/ticks.c +++ b/src/boot/efi/ticks.c @@ -5,7 +5,8 @@ #include "vmm.h" #if defined(__i386__) || defined(__x86_64__) -static uint64_t ticks_read(void) { + +static uint64_t ticks_read_arch(void) { /* The TSC might or might not be virtualized in VMs (and thus might not be accurate or start at zero * at boot), depending on hypervisor and CPU functionality. If it's not virtualized it's not useful * for keeping time, hence don't attempt to use it. */ @@ -14,36 +15,51 @@ static uint64_t ticks_read(void) { return __builtin_ia32_rdtsc(); } + +static uint64_t ticks_freq_arch(void) { + return 0; +} + #elif defined(__aarch64__) -static uint64_t ticks_read(void) { + +static uint64_t ticks_read_arch(void) { uint64_t val; asm volatile("mrs %0, cntvct_el0" : "=r"(val)); return val; } -#else -static uint64_t ticks_read(void) { - return 0; -} -#endif -#if defined(__aarch64__) -static uint64_t ticks_freq(void) { +static uint64_t ticks_freq_arch(void) { uint64_t freq; asm volatile("mrs %0, cntfrq_el0" : "=r"(freq)); return freq; } + #else -/* count TSC ticks during a millisecond delay */ + +static uint64_t ticks_read_arch(void) { + return 0; +} + +static uint64_t ticks_freq_arch(void) { + return 0; +} + +#endif + static uint64_t ticks_freq(void) { - uint64_t ticks_start, ticks_end; static uint64_t cache = 0; if (cache != 0) return cache; - ticks_start = ticks_read(); + cache = ticks_freq_arch(); + if (cache != 0) + return cache; + + /* As a fallback, count ticks during a millisecond delay. */ + uint64_t ticks_start = ticks_read_arch(); BS->Stall(1000); - ticks_end = ticks_read(); + uint64_t ticks_end = ticks_read_arch(); if (ticks_end < ticks_start) /* Check for an overflow (which is not that unlikely, given on some * archs the value is 32bit) */ @@ -52,16 +68,13 @@ static uint64_t ticks_freq(void) { cache = (ticks_end - ticks_start) * 1000UL; return cache; } -#endif uint64_t time_usec(void) { - uint64_t ticks, freq; - - ticks = ticks_read(); + uint64_t ticks = ticks_read_arch(); if (ticks == 0) return 0; - freq = ticks_freq(); + uint64_t freq = ticks_freq(); if (freq == 0) return 0; |