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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:29:51 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 16:29:51 +0000 |
commit | 6e7a315eb67cb6c113cf37e1d66c4f11a51a2b3e (patch) | |
tree | 32451fa3cdd9321fb2591fada9891b2cb70a9cd1 /grub-core/kern/i386/efi/tsc.c | |
parent | Initial commit. (diff) | |
download | grub2-upstream/2.06.tar.xz grub2-upstream/2.06.zip |
Adding upstream version 2.06.upstream/2.06upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'grub-core/kern/i386/efi/tsc.c')
-rw-r--r-- | grub-core/kern/i386/efi/tsc.c | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/grub-core/kern/i386/efi/tsc.c b/grub-core/kern/i386/efi/tsc.c new file mode 100644 index 0000000..4b93ba8 --- /dev/null +++ b/grub-core/kern/i386/efi/tsc.c @@ -0,0 +1,40 @@ +/* kern/i386/tsc.c - x86 TSC time source implementation + * Requires Pentium or better x86 CPU that supports the RDTSC instruction. + * This module uses the PIT to calibrate the TSC to + * real time. + * + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2008 Free Software Foundation, Inc. + * + * GRUB is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * GRUB is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with GRUB. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <grub/types.h> +#include <grub/time.h> +#include <grub/misc.h> +#include <grub/i386/tsc.h> +#include <grub/efi/efi.h> +#include <grub/efi/api.h> + +int +grub_tsc_calibrate_from_efi (void) +{ + grub_uint64_t start_tsc, end_tsc; + /* Use EFI Time Service to calibrate TSC */ + start_tsc = grub_get_tsc (); + efi_call_1 (grub_efi_system_table->boot_services->stall, 1000); + end_tsc = grub_get_tsc (); + grub_tsc_rate = grub_divmod64 ((1ULL << 32), end_tsc - start_tsc, 0); + return 1; +} |