FROMLIST: [PATCH v5 06/12] arm: vdso: add support for clock_getres

(cherry picked from url https://patchwork.kernel.org/patch/10044545/)

Take an effort to recode the arm64 vdso code from assembler to C
previously submitted by Andrew Pinski <apinski@cavium.com>, rework
it for use in both arm and arm64, overlapping any optimizations
for each architecture. But instead of landing it in arm64, land the
result into lib/vdso and unify both implementations to simplify
future maintenance.

Add clock_getres vdso support to match up with existing support in
the arm64's vdso.

Signed-off-by: Mark Salyzyn <salyzyn@android.com>
Cc: James Morse <james.morse@arm.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dmitry Safonov <dsafonov@virtuozzo.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Andrew Pinski <apinski@cavium.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Bug: 63737556
Bug: 20045882
Change-Id: Ie37bf76d2992027f06a2cdd001d8654a860d2aac

diff --git a/arch/arm/kernel/vdso.c b/arch/arm/kernel/vdso.c
index 5d4d4951dac7e812ba2eafa2189dc7676d61ca41..8ab930b0bac036381931f27b00a75f1ab490c42d 100644 (file)
--- a/arch/arm/kernel/vdso.c
+++ b/arch/arm/kernel/vdso.c
@@ -171,6 +171,7 @@ 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/compiler.h b/arch/arm/vdso/compiler.h
index 3edddb705a1b5b15419250e0bc779bb547fc3c6c..c7751019246a61b61a64c5c11d42547d75ef9c1b 100644 (file)
--- a/arch/arm/vdso/compiler.h
+++ b/arch/arm/vdso/compiler.h
@@ -27,6 +27,7 @@
 #include <asm/processor.h>     /* for cpu_relax()                      */
 #include <asm/unistd.h>
 #include <linux/compiler.h>
+#include <linux/hrtimer.h>     /* for LOW_RES_NSEC and MONOTONIC_RES_NSEC */
 #include <linux/time.h>                /* for NSEC_PER_SEC                     */
 
 #ifndef CONFIG_AEABI

diff --git a/arch/arm/vdso/vdso.lds.S b/arch/arm/vdso/vdso.lds.S
index 89ca89f12d231c0b28f894062d09068d720d0cb3..1d81e8c3acf6bb9a00a5a578a262ba720bb861ca 100644 (file)
--- 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 a2c4db83edc46d7f6773fa7d3a7835324ad8cd8d..a354586f8a659936357ac2886dcd1bd719594b32 100644 (file)
--- a/arch/arm/vdso/vgettimeofday.c
+++ b/arch/arm/vdso/vgettimeofday.c
@@ -32,6 +32,7 @@
 
 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)
 {
@@ -301,3 +302,25 @@ notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 
        return 0;
 }
+
+int __vdso_clock_getres(clockid_t clock, struct timespec *res)
+{
+       long nsec;
+
+       if (clock == CLOCK_REALTIME ||
+           clock == CLOCK_MONOTONIC ||
+           clock == CLOCK_MONOTONIC_RAW)
+               nsec = MONOTONIC_RES_NSEC;
+       else if (clock == CLOCK_REALTIME_COARSE ||
+                clock == CLOCK_MONOTONIC_COARSE)
+               nsec = LOW_RES_NSEC;
+       else
+               return clock_getres_fallback(clock, res);
+
+       if (likely(res != NULL)) {
+               res->tv_sec = 0;
+               res->tv_nsec = nsec;
+       }
+
+       return 0;
+}