From: Huacai Chen chenhc@lemote.com
[ Upstream commit 52338415cf4d4064ae6b8dd972dadbda841da4fa ]
The update of the VDSO data is depending on __arch_use_vsyscall() returning True. This is a leftover from the attempt to map the features of various architectures 1:1 into generic code.
The usage of __arch_use_vsyscall() in the actual vsyscall implementations got dropped and replaced by the requirement for the architecture code to return U64_MAX if the global clocksource is not usable in the VDSO.
But the __arch_use_vsyscall() check in the update code stayed which causes the VDSO data to be stale or invalid when an architecture actually implements that function and returns False when the current clocksource is not usable in the VDSO.
As a consequence the VDSO implementations of clock_getres(), time(), clock_gettime(CLOCK_.*_COARSE) operate on invalid data and return bogus information.
Remove the __arch_use_vsyscall() check from the VDSO update function and update the VDSO data unconditionally.
[ tglx: Massaged changelog and removed the now useless implementations in asm-generic/ARM64/MIPS ]
Fixes: 44f57d788e7deecb50 ("timekeeping: Provide a generic update_vsyscall() implementation") Signed-off-by: Huacai Chen chenhc@lemote.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Andy Lutomirski luto@kernel.org Cc: Vincenzo Frascino vincenzo.frascino@arm.com Cc: Arnd Bergmann arnd@arndb.de Cc: Paul Burton paul.burton@mips.com Cc: linux-mips@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/1571887709-11447-1-git-send-email-chenhc@lemote.co... Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/include/asm/vdso/vsyscall.h | 7 ------- include/asm-generic/vdso/vsyscall.h | 7 ------- kernel/time/vsyscall.c | 9 +++------ 3 files changed, 3 insertions(+), 20 deletions(-)
diff --git a/arch/arm64/include/asm/vdso/vsyscall.h b/arch/arm64/include/asm/vdso/vsyscall.h index 0c731bfc7c8c7..0c20a7c1bee50 100644 --- a/arch/arm64/include/asm/vdso/vsyscall.h +++ b/arch/arm64/include/asm/vdso/vsyscall.h @@ -30,13 +30,6 @@ int __arm64_get_clock_mode(struct timekeeper *tk) } #define __arch_get_clock_mode __arm64_get_clock_mode
-static __always_inline -int __arm64_use_vsyscall(struct vdso_data *vdata) -{ - return !vdata[CS_HRES_COARSE].clock_mode; -} -#define __arch_use_vsyscall __arm64_use_vsyscall - static __always_inline void __arm64_update_vsyscall(struct vdso_data *vdata, struct timekeeper *tk) { diff --git a/include/asm-generic/vdso/vsyscall.h b/include/asm-generic/vdso/vsyscall.h index e94b19782c92f..ce41032086193 100644 --- a/include/asm-generic/vdso/vsyscall.h +++ b/include/asm-generic/vdso/vsyscall.h @@ -25,13 +25,6 @@ static __always_inline int __arch_get_clock_mode(struct timekeeper *tk) } #endif /* __arch_get_clock_mode */
-#ifndef __arch_use_vsyscall -static __always_inline int __arch_use_vsyscall(struct vdso_data *vdata) -{ - return 1; -} -#endif /* __arch_use_vsyscall */ - #ifndef __arch_update_vsyscall static __always_inline void __arch_update_vsyscall(struct vdso_data *vdata, struct timekeeper *tk) diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c index 4bc37ac3bb052..5ee0f77094107 100644 --- a/kernel/time/vsyscall.c +++ b/kernel/time/vsyscall.c @@ -110,8 +110,7 @@ void update_vsyscall(struct timekeeper *tk) nsec = nsec + tk->wall_to_monotonic.tv_nsec; vdso_ts->sec += __iter_div_u64_rem(nsec, NSEC_PER_SEC, &vdso_ts->nsec);
- if (__arch_use_vsyscall(vdata)) - update_vdso_data(vdata, tk); + update_vdso_data(vdata, tk);
__arch_update_vsyscall(vdata, tk);
@@ -124,10 +123,8 @@ void update_vsyscall_tz(void) { struct vdso_data *vdata = __arch_get_k_vdso_data();
- if (__arch_use_vsyscall(vdata)) { - vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest; - vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime; - } + vdata[CS_HRES_COARSE].tz_minuteswest = sys_tz.tz_minuteswest; + vdata[CS_HRES_COARSE].tz_dsttime = sys_tz.tz_dsttime;
__arch_sync_vdso_data(vdata); }