| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <efi.h> |
| #include <efilib.h> |
| |
| #include "ticks.h" |
| #include "util.h" |
| #include "vmm.h" |
| |
| #ifdef __x86_64__ |
| static uint64_t ticks_read(void) { |
| uint64_t a, d; |
| |
| /* 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. */ |
| if (in_hypervisor()) |
| return 0; |
| |
| __asm__ volatile ("rdtsc" : "=a" (a), "=d" (d)); |
| return (d << 32) | a; |
| } |
| #elif defined(__i386__) |
| static uint64_t ticks_read(void) { |
| uint64_t val; |
| |
| if (in_hypervisor()) |
| return 0; |
| |
| __asm__ volatile ("rdtsc" : "=A" (val)); |
| return val; |
| } |
| #elif defined(__aarch64__) |
| static uint64_t ticks_read(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) { |
| 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_freq(void) { |
| uint64_t ticks_start, ticks_end; |
| static uint64_t cache = 0; |
| |
| if (cache != 0) |
| return cache; |
| |
| ticks_start = ticks_read(); |
| BS->Stall(1000); |
| ticks_end = ticks_read(); |
| |
| if (ticks_end < ticks_start) /* Check for an overflow (which is not that unlikely, given on some |
| * archs the value is 32bit) */ |
| return 0; |
| |
| cache = (ticks_end - ticks_start) * 1000UL; |
| return cache; |
| } |
| #endif |
| |
| uint64_t time_usec(void) { |
| uint64_t ticks, freq; |
| |
| ticks = ticks_read(); |
| if (ticks == 0) |
| return 0; |
| |
| freq = ticks_freq(); |
| if (freq == 0) |
| return 0; |
| |
| return 1000UL * 1000UL * ticks / freq; |
| } |