[PATCH v3 07/12] arm: vdso: add support for clock_getres

[Mark Salyzyn]

Add clock_getres vdso support to match up with existing support in
the arcm64's vdso.

Signed-off-by: Mark Salyzyn <saly...@android.com>
Cc: James Morse <james.mo...@arm.com>
Cc: Russell King <li...@armlinux.org.uk>
Cc: Catalin Marinas <catalin.mari...@arm.com>
Cc: Will Deacon <will.dea...@arm.com>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Dmitry Safonov <dsafo...@virtuozzo.com>
Cc: John Stultz <john.stu...@linaro.org>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: Laura Abbott <labb...@redhat.com>
Cc: Kees Cook <keesc...@chromium.org>
Cc: Ard Biesheuvel <ard.biesheu...@linaro.org>
Cc: Andy Gross <andy.gr...@linaro.org>
Cc: Kevin Brodsky <kevin.brod...@arm.com>
Cc: Andrew Pinski <apin...@cavium.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-ker...@lists.infradead.org

v2:
- split first CL into 7 of 7 pieces

v3:
- rebase (unchanged)

---
 arch/arm/kernel/vdso.c        |  1 +
 arch/arm/vdso/vdso.lds.S      |  1 +
 arch/arm/vdso/vgettimeofday.c | 23 +++++++++++++++++++++++
 3 files changed, 25 insertions(+)

diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
index 7377638a3b00..287424541f3a 100644
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -189,6 +189,7 @@ static void __init patch_vdso(void *ehdr)
        if (!cntvct_ok) {
                vdso_nullpatch_one(&einfo, "__vdso_gettimeofday");
                vdso_nullpatch_one(&einfo, "__vdso_clock_gettime");
+               vdso_nullpatch_one(&einfo, "__vdso_clock_getres");
        }
 }
 
diff --git a/arch/arm/vdso/vdso.lds.S b/arch/arm/vdso/vdso.lds.S
index 89ca89f12d23..1d81e8c3acf6 100644
--- a/arch/arm/vdso/vdso.lds.S
+++ b/arch/arm/vdso/vdso.lds.S
@@ -82,6 +82,7 @@ VERSION
        global:
                __vdso_clock_gettime;
                __vdso_gettimeofday;
+               __vdso_clock_getres;
        local: *;
        };
 }
diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c
index b374c143d53e..841e7fd74a1b 100644
--- a/arch/arm/vdso/vgettimeofday.c
+++ b/arch/arm/vdso/vgettimeofday.c
@@ -31,6 +31,7 @@
 
 DEFINE_FALLBACK(gettimeofday, struct timeval *, tv, struct timezone *, tz)
 DEFINE_FALLBACK(clock_gettime, clockid_t, clock, struct timespec *, ts)
+DEFINE_FALLBACK(clock_getres, clockid_t, clock, struct timespec *, ts)
 
 static notrace u32 vdso_read_begin(const struct vdso_data *vd)
 {
@@ -320,3 +321,25 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct 
timezone *tz)
 
        return 0;
 }
+
+int __vdso_clock_getres(clockid_t clock_id, struct timespec *res)
+{
+       typeof(res->tv_nsec) nsec;
+
+       if (clock_id == CLOCK_REALTIME ||
+           clock_id == CLOCK_MONOTONIC ||
+           clock_id == CLOCK_MONOTONIC_RAW)
+               nsec = MONOTONIC_RES_NSEC;
+       else if (clock_id == CLOCK_REALTIME_COARSE ||
+                clock_id == CLOCK_MONOTONIC_COARSE)
+               nsec = LOW_RES_NSEC;
+       else
+               return clock_getres_fallback(clock_id, res);
+
+       if (likely(res != NULL)) {
+               res->tv_sec = 0;
+               res->tv_nsec = nsec;
+       }
+
+       return 0;
+}
-- 
2.15.0.rc2.357.g7e34df9404-goog