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author | Vincenzo Frascino <vincenzo.frascino@arm.com> | 2019-11-04 11:59:59 +0100 |
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committer | Russell King <rmk+kernel@armlinux.org.uk> | 2019-11-15 22:21:12 +0000 |
commit | 20e2fc42312f960f497ac2d617e3742754e1fa5e (patch) | |
tree | ab9fbc9045b6a56f735821d0da0280b1faaf6f04 /arch/arm/kernel | |
parent | 9f1984c6ae30e2a379751339ce3375a21099b5d4 (diff) | |
download | blackbird-op-linux-20e2fc42312f960f497ac2d617e3742754e1fa5e.tar.gz blackbird-op-linux-20e2fc42312f960f497ac2d617e3742754e1fa5e.zip |
ARM: 8930/1: Add support for generic vDSO
The arm vDSO library requires some adaptations to take advantage of
the newly introduced generic vDSO library.
Introduce the following changes:
- Modification vdso.c to be compliant with the common vdso datapage
- Use of lib/vdso for gettimeofday
- Implementation of elf note
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r-- | arch/arm/kernel/vdso.c | 87 |
1 files changed, 4 insertions, 83 deletions
diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c index 9bf16c93ee6a..c89ac1b9d28b 100644 --- a/arch/arm/kernel/vdso.c +++ b/arch/arm/kernel/vdso.c @@ -23,6 +23,8 @@ #include <asm/vdso.h> #include <asm/vdso_datapage.h> #include <clocksource/arm_arch_timer.h> +#include <vdso/helpers.h> +#include <vdso/vsyscall.h> #define MAX_SYMNAME 64 @@ -37,7 +39,7 @@ unsigned int vdso_total_pages __ro_after_init; * The VDSO data page. */ static union vdso_data_store vdso_data_store __page_aligned_data; -static struct vdso_data *vdso_data = &vdso_data_store.data; +struct vdso_data *vdso_data = vdso_data_store.data; static struct page *vdso_data_page __ro_after_init; static const struct vm_special_mapping vdso_data_mapping = { @@ -77,7 +79,7 @@ struct elfinfo { /* Cached result of boot-time check for whether the arch timer exists, * and if so, whether the virtual counter is useable. */ -static bool cntvct_ok __ro_after_init; +bool cntvct_ok __ro_after_init; static bool __init cntvct_functional(void) { @@ -262,84 +264,3 @@ void arm_install_vdso(struct mm_struct *mm, unsigned long addr) mm->context.vdso = addr; } -static void vdso_write_begin(struct vdso_data *vdata) -{ - ++vdso_data->seq_count; - smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */ -} - -static void vdso_write_end(struct vdso_data *vdata) -{ - smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */ - ++vdso_data->seq_count; -} - -static bool tk_is_cntvct(const struct timekeeper *tk) -{ - if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER)) - return false; - - if (!tk->tkr_mono.clock->archdata.vdso_direct) - return false; - - return true; -} - -/** - * update_vsyscall - update the vdso data page - * - * Increment the sequence counter, making it odd, indicating to - * userspace that an update is in progress. Update the fields used - * for coarse clocks and, if the architected system timer is in use, - * the fields used for high precision clocks. Increment the sequence - * counter again, making it even, indicating to userspace that the - * update is finished. - * - * Userspace is expected to sample seq_count before reading any other - * fields from the data page. If seq_count is odd, userspace is - * expected to wait until it becomes even. After copying data from - * the page, userspace must sample seq_count again; if it has changed - * from its previous value, userspace must retry the whole sequence. - * - * Calls to update_vsyscall are serialized by the timekeeping core. - */ -void update_vsyscall(struct timekeeper *tk) -{ - struct timespec64 *wtm = &tk->wall_to_monotonic; - - if (!cntvct_ok) { - /* The entry points have been zeroed, so there is no - * point in updating the data page. - */ - return; - } - - vdso_write_begin(vdso_data); - - vdso_data->tk_is_cntvct = tk_is_cntvct(tk); - vdso_data->xtime_coarse_sec = tk->xtime_sec; - vdso_data->xtime_coarse_nsec = (u32)(tk->tkr_mono.xtime_nsec >> - tk->tkr_mono.shift); - vdso_data->wtm_clock_sec = wtm->tv_sec; - vdso_data->wtm_clock_nsec = wtm->tv_nsec; - - if (vdso_data->tk_is_cntvct) { - vdso_data->cs_cycle_last = tk->tkr_mono.cycle_last; - vdso_data->xtime_clock_sec = tk->xtime_sec; - vdso_data->xtime_clock_snsec = tk->tkr_mono.xtime_nsec; - vdso_data->cs_mult = tk->tkr_mono.mult; - vdso_data->cs_shift = tk->tkr_mono.shift; - vdso_data->cs_mask = tk->tkr_mono.mask; - } - - vdso_write_end(vdso_data); - - flush_dcache_page(virt_to_page(vdso_data)); -} - -void update_vsyscall_tz(void) -{ - vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; - vdso_data->tz_dsttime = sys_tz.tz_dsttime; - flush_dcache_page(virt_to_page(vdso_data)); -} |