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To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , arnd@arndb.de, tglx@linutronix.de, vincenzo.frascino@arm.com, luto@kernel.org Date: Mon, 23 Dec 2019 14:31:03 +0000 (UTC) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191223_063113_290936_2C7D795D X-CRM114-Status: GOOD ( 12.19 ) X-Spam-Score: -0.2 (/) X-Spam-Report: SpamAssassin version 3.4.2 on bombadil.infradead.org summary: Content analysis details: (-0.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at https://www.dnswl.org/, no trust [93.17.236.30 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 SPF_HELO_NONE SPF: HELO does not publish an SPF Record -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature -0.1 DKIM_VALID_EF Message has a valid DKIM or DK signature from envelope-from domain X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org On powerpc, VDSO functions and syscalls cannot be implemented in C because the Linux kernel ABI requires that CR[SO] bit is set in case of error and cleared when no error. As this cannot be done in C, C VDSO functions and syscall'based fallback need a trampoline in ASM. By moving the fallback calls out of the common code, arches like powerpc can implement both the call to C VDSO and the fallback call in a single trampoline function. The two advantages are: - No need play back and forth with CR[SO] and negative return value. - No stack frame is required in VDSO C functions for the fallbacks. The performance improvement is significant on powerpc. Signed-off-by: Christophe Leroy --- arch/arm/vdso/vgettimeofday.c | 28 +++++++++++++++--- arch/arm64/kernel/vdso/vgettimeofday.c | 21 ++++++++++++-- arch/arm64/kernel/vdso32/vgettimeofday.c | 35 ++++++++++++++++++++--- arch/mips/vdso/vgettimeofday.c | 49 +++++++++++++++++++++++++++----- arch/x86/entry/vdso/vclock_gettime.c | 42 +++++++++++++++++++++++---- lib/vdso/gettimeofday.c | 31 ++++---------------- 6 files changed, 156 insertions(+), 50 deletions(-) diff --git a/arch/arm/vdso/vgettimeofday.c b/arch/arm/vdso/vgettimeofday.c index 1976c6f325a4..5451afb715e6 100644 --- a/arch/arm/vdso/vgettimeofday.c +++ b/arch/arm/vdso/vgettimeofday.c @@ -10,25 +10,45 @@ int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts) { - return __cvdso_clock_gettime32(clock, ts); + int ret = __cvdso_clock_gettime32(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime32_fallback(clock, &ts); } int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts) { - return __cvdso_clock_gettime(clock, ts); + int ret = __cvdso_clock_gettime(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime_fallback(clock, ts); } int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) { - return __cvdso_gettimeofday(tv, tz); + int ret = __cvdso_gettimeofday(tv, tz); + + if (likely(!ret)) + return ret; + + return gettimeofday_fallback(tv, tz); } int __vdso_clock_getres(clockid_t clock_id, struct old_timespec32 *res) { - return __cvdso_clock_getres_time32(clock_id, res); + int ret = __cvdso_clock_getres_time32(clock_id, res); + + if (likely(!ret)) + return ret; + + return clock_getres32_fallback(clock, res); } /* Avoid unresolved references emitted by GCC */ diff --git a/arch/arm64/kernel/vdso/vgettimeofday.c b/arch/arm64/kernel/vdso/vgettimeofday.c index 747635501a14..62694876b216 100644 --- a/arch/arm64/kernel/vdso/vgettimeofday.c +++ b/arch/arm64/kernel/vdso/vgettimeofday.c @@ -11,17 +11,32 @@ int __kernel_clock_gettime(clockid_t clock, struct __kernel_timespec *ts) { - return __cvdso_clock_gettime(clock, ts); + int ret = __cvdso_clock_gettime(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime_fallback(clock, ts); } int __kernel_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) { - return __cvdso_gettimeofday(tv, tz); + int ret = __cvdso_gettimeofday(tv, tz); + + if (likely(!ret)) + return ret; + + return gettimeofday_fallback(tv, tz); } int __kernel_clock_getres(clockid_t clock_id, struct __kernel_timespec *res) { - return __cvdso_clock_getres(clock_id, res); + int ret = __cvdso_clock_getres(clock_id, res); + + if (likely(!ret)) + return ret; + + return clock_getres_fallback(clock, res); } diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c index 54fc1c2ce93f..6770d2bedd1f 100644 --- a/arch/arm64/kernel/vdso32/vgettimeofday.c +++ b/arch/arm64/kernel/vdso32/vgettimeofday.c @@ -11,37 +11,64 @@ int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts) { + int ret; + /* The checks below are required for ABI consistency with arm */ if ((u32)ts >= TASK_SIZE_32) return -EFAULT; - return __cvdso_clock_gettime32(clock, ts); + ret = __cvdso_clock_gettime32(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime32_fallback(clock, &ts); } int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts) { + int ret; + /* The checks below are required for ABI consistency with arm */ if ((u32)ts >= TASK_SIZE_32) return -EFAULT; - return __cvdso_clock_gettime(clock, ts); + ret = __cvdso_clock_gettime(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime_fallback(clock, ts); } int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) { - return __cvdso_gettimeofday(tv, tz); + int ret = __cvdso_gettimeofday(tv, tz); + + if (likely(!ret)) + return ret; + + return gettimeofday_fallback(tv, tz); } int __vdso_clock_getres(clockid_t clock_id, struct old_timespec32 *res) { + int ret; + struct __kernel_timespec ts; + /* The checks below are required for ABI consistency with arm */ if ((u32)res >= TASK_SIZE_32) return -EFAULT; - return __cvdso_clock_getres_time32(clock_id, res); + ret = __cvdso_clock_getres_time32(clock_id, res); + + if (likely(!ret)) + return ret; + + return clock_getres32_fallback(clock, res); } /* Avoid unresolved references emitted by GCC */ diff --git a/arch/mips/vdso/vgettimeofday.c b/arch/mips/vdso/vgettimeofday.c index 6ebdc37c89fc..02758c58454c 100644 --- a/arch/mips/vdso/vgettimeofday.c +++ b/arch/mips/vdso/vgettimeofday.c @@ -14,25 +14,45 @@ int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts) { - return __cvdso_clock_gettime32(clock, ts); + int ret = __cvdso_clock_gettime32(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime32_fallback(clock, ts); } int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) { - return __cvdso_gettimeofday(tv, tz); + int ret = __cvdso_gettimeofday(tv, tz); + + if (likely(!ret)) + return ret; + + return gettimeofday_fallback(tv, tz); } int __vdso_clock_getres(clockid_t clock_id, struct old_timespec32 *res) { - return __cvdso_clock_getres_time32(clock_id, res); + int ret = __cvdso_clock_getres_time32(clock_id, res); + + if (likely(!ret)) + return ret; + + return clock_getres32_fallback(clock, res); } int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts) { - return __cvdso_clock_gettime(clock, ts); + int ret = __cvdso_clock_gettime(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime_fallback(clock, ts); } #else @@ -40,19 +60,34 @@ int __vdso_clock_gettime64(clockid_t clock, int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts) { - return __cvdso_clock_gettime(clock, ts); + int ret = __cvdso_clock_gettime(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime_fallback(clock, ts); } int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) { - return __cvdso_gettimeofday(tv, tz); + int ret = __cvdso_gettimeofday(tv, tz); + + if (likely(!ret)) + return ret; + + return gettimeofday_fallback(tv, tz); } int __vdso_clock_getres(clockid_t clock_id, struct __kernel_timespec *res) { - return __cvdso_clock_getres(clock_id, res); + int ret = __cvdso_clock_getres(clock_id, res); + + if (likely(!ret)) + return ret; + + return clock_getres_fallback(clock, res); } #endif diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index 7d70935b6758..fde511cfe284 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -19,7 +19,12 @@ extern __kernel_old_time_t __vdso_time(__kernel_old_time_t *t); int __vdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) { - return __cvdso_gettimeofday(tv, tz); + int ret = __cvdso_gettimeofday(tv, tz); + + if (likely(!ret)) + return ret; + + return gettimeofday_fallback(tv, tz); } int gettimeofday(struct __kernel_old_timeval *, struct timezone *) @@ -40,7 +45,12 @@ extern int __vdso_clock_getres(clockid_t clock, struct __kernel_timespec *res); int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts) { - return __cvdso_clock_gettime(clock, ts); + int ret = __cvdso_clock_gettime(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime_fallback(clock, ts); } int clock_gettime(clockid_t, struct __kernel_timespec *) @@ -49,7 +59,12 @@ int clock_gettime(clockid_t, struct __kernel_timespec *) int __vdso_clock_getres(clockid_t clock, struct __kernel_timespec *res) { - return __cvdso_clock_getres(clock, res); + int ret = __cvdso_clock_getres(clock_id, res); + + if (likely(!ret)) + return ret; + + return clock_getres_fallback(clock, res); } int clock_getres(clockid_t, struct __kernel_timespec *) __attribute__((weak, alias("__vdso_clock_getres"))); @@ -61,7 +76,12 @@ extern int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res); int __vdso_clock_gettime(clockid_t clock, struct old_timespec32 *ts) { - return __cvdso_clock_gettime32(clock, ts); + int ret = __cvdso_clock_gettime32(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime32_fallback(clock, ts); } int clock_gettime(clockid_t, struct old_timespec32 *) @@ -69,7 +89,12 @@ int clock_gettime(clockid_t, struct old_timespec32 *) int __vdso_clock_gettime64(clockid_t clock, struct __kernel_timespec *ts) { - return __cvdso_clock_gettime(clock, ts); + int ret = __cvdso_clock_gettime(clock, ts); + + if (likely(!ret)) + return ret; + + return clock_gettime_fallback(clock, ts); } int clock_gettime64(clockid_t, struct __kernel_timespec *) @@ -77,7 +102,12 @@ int clock_gettime64(clockid_t, struct __kernel_timespec *) int __vdso_clock_getres(clockid_t clock, struct old_timespec32 *res) { - return __cvdso_clock_getres_time32(clock, res); + int ret = __cvdso_clock_getres_time32(clock, res); + + if (likely(!ret)) + return ret; + + return clock_getres32_fallback(clock, res); } int clock_getres(clockid_t, struct old_timespec32 *) diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index 59189ed49352..4618e274f1d5 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -16,9 +16,6 @@ * - __arch_get_vdso_data(): to get the vdso datapage. * - __arch_get_hw_counter(): to get the hw counter based on the * clock_mode. - * - gettimeofday_fallback(): fallback for gettimeofday. - * - clock_gettime_fallback(): fallback for clock_gettime. - * - clock_getres_fallback(): fallback for clock_getres. */ #ifdef ENABLE_COMPAT_VDSO #include @@ -110,23 +107,14 @@ __cvdso_clock_gettime_common(clockid_t clock, struct __kernel_timespec *ts) static __maybe_unused int __cvdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts) { - int ret = __cvdso_clock_gettime_common(clock, ts); - - if (unlikely(ret)) - return clock_gettime_fallback(clock, ts); - return 0; + return __cvdso_clock_gettime_common(clock, ts); } static __maybe_unused int __cvdso_clock_gettime32(clockid_t clock, struct old_timespec32 *res) { struct __kernel_timespec ts; - int ret; - - ret = __cvdso_clock_gettime_common(clock, &ts); - - if (unlikely(ret)) - return clock_gettime32_fallback(clock, res); + int ret = __cvdso_clock_gettime_common(clock, &ts); if (likely(!ret)) { res->tv_sec = ts.tv_sec; @@ -144,7 +132,7 @@ __cvdso_gettimeofday(struct __kernel_old_timeval *tv, struct timezone *tz) struct __kernel_timespec ts; if (do_hres(&vd[CS_HRES_COARSE], CLOCK_REALTIME, &ts)) - return gettimeofday_fallback(tv, tz); + return -1; tv->tv_sec = ts.tv_sec; tv->tv_usec = (u32)ts.tv_nsec / NSEC_PER_USEC; @@ -218,23 +206,14 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res) int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res) { - int ret = __cvdso_clock_getres_common(clock, res); - - if (unlikely(ret)) - return clock_getres_fallback(clock, res); - return 0; + return __cvdso_clock_getres_common(clock, res); } static __maybe_unused int __cvdso_clock_getres_time32(clockid_t clock, struct old_timespec32 *res) { struct __kernel_timespec ts; - int ret; - - ret = __cvdso_clock_getres_common(clock, &ts); - - if (unlikely(ret)) - return clock_getres32_fallback(clock, res); + int ret = __cvdso_clock_getres_common(clock, &ts); if (likely(!ret && res)) { res->tv_sec = ts.tv_sec;