Expose the auxiliary clocks through the vDSO.
Architectures not using the generic vDSO time framework, namely SPARC64, are not supported.
Signed-off-by: Thomas Weißschuh thomas.weissschuh@linutronix.de --- include/vdso/datapage.h | 2 ++ lib/vdso/gettimeofday.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h index f4c96d9ce674abb07ccd8703f1a04da7631c1677..02533038640e53c40291c7e09139e0f9b32f502a 100644 --- a/include/vdso/datapage.h +++ b/include/vdso/datapage.h @@ -5,6 +5,7 @@ #ifndef __ASSEMBLY__
#include <linux/compiler.h> +#include <uapi/linux/bits.h> #include <uapi/linux/time.h> #include <uapi/linux/types.h> #include <uapi/asm-generic/errno-base.h> @@ -46,6 +47,7 @@ struct vdso_arch_data { #define VDSO_COARSE (BIT(CLOCK_REALTIME_COARSE) | \ BIT(CLOCK_MONOTONIC_COARSE)) #define VDSO_RAW (BIT(CLOCK_MONOTONIC_RAW)) +#define VDSO_AUX __GENMASK(CLOCK_AUX_LAST, CLOCK_AUX)
#define CS_HRES_COARSE 0 #define CS_RAW 1 diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index c383878bb5445a62d8fea6591e8550183852c2e6..3a54dbb8fe32849cd749e71ec2a8be44baf42816 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -2,6 +2,7 @@ /* * Generic userspace implementations of gettimeofday() and similar. */ +#include <vdso/auxclock.h> #include <vdso/datapage.h> #include <vdso/helpers.h>
@@ -74,7 +75,7 @@ static inline bool vdso_cycles_ok(u64 cycles) static __always_inline bool vdso_clockid_valid(clockid_t clock) { /* Check for negative values or invalid clocks */ - return likely((u32) clock < MAX_CLOCKS); + return likely((u32) clock < CLOCK_AUX_LAST); }
/* @@ -268,6 +269,48 @@ bool do_coarse(const struct vdso_time_data *vd, const struct vdso_clock *vc, return true; }
+static __always_inline +bool do_aux(const struct vdso_time_data *vd, clockid_t clock, struct __kernel_timespec *ts) +{ + const struct vdso_clock *vc; + u64 sec, ns; + u32 seq; + u8 idx; + + if (!IS_ENABLED(CONFIG_POSIX_AUX_CLOCKS)) + return false; + + idx = clock - CLOCK_AUX; + vc = &vd->aux_clock_data[idx]; + + do { + /* + * Open coded function vdso_read_begin() to handle + * VDSO_CLOCK_TIMENS. See comment in do_hres(). + */ + while ((seq = READ_ONCE(vc->seq)) & 1) { + if (IS_ENABLED(CONFIG_TIME_NS) && vc->clock_mode == VDSO_CLOCKMODE_TIMENS) { + vd = __arch_get_vdso_u_timens_data(vd); + vc = &vd->aux_clock_data[idx]; + break; + } + cpu_relax(); + } + smp_rmb(); + + /* Auxclock disabled? */ + if (vc->clock_mode == VDSO_CLOCKMODE_NONE) + return false; + + if (!vdso_get_timestamp(vd, vc, VDSO_BASE_AUX, &sec, &ns)) + return false; + } while (unlikely(vdso_read_retry(vc, seq))); + + vdso_set_timespec(ts, sec, ns); + + return true; +} + static __always_inline bool __cvdso_clock_gettime_common(const struct vdso_time_data *vd, clockid_t clock, struct __kernel_timespec *ts) @@ -289,6 +332,8 @@ __cvdso_clock_gettime_common(const struct vdso_time_data *vd, clockid_t clock, return do_coarse(vd, &vc[CS_HRES_COARSE], clock, ts); else if (msk & VDSO_RAW) vc = &vc[CS_RAW]; + else if (msk & VDSO_AUX) + return do_aux(vd, clock, ts); else return false;
@@ -433,6 +478,8 @@ bool __cvdso_clock_getres_common(const struct vdso_time_data *vd, clockid_t cloc * Preserves the behaviour of posix_get_coarse_res(). */ ns = LOW_RES_NSEC; + } else if (msk & VDSO_AUX) { + ns = aux_clock_resolution_ns(); } else { return false; }