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authorVincenzo Frascino <vincenzo.frascino@arm.com>2019-11-04 11:59:59 +0100
committerRussell King <rmk+kernel@armlinux.org.uk>2019-11-15 22:21:12 +0000
commit20e2fc42312f960f497ac2d617e3742754e1fa5e (patch)
treeab9fbc9045b6a56f735821d0da0280b1faaf6f04 /arch/arm/kernel
parent9f1984c6ae30e2a379751339ce3375a21099b5d4 (diff)
downloadblackbird-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.c87
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));
-}
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