The patch below does not apply to the 4.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 552263456215ada7ee8700ce022d12b0cffe4802 Mon Sep 17 00:00:00 2001
From: Vincenzo Frascino vincenzo.frascino@arm.com Date: Mon, 2 Dec 2019 07:57:29 +0000 Subject: [PATCH] powerpc: Fix vDSO clock_getres()
clock_getres in the vDSO library has to preserve the same behaviour of posix_get_hrtimer_res().
In particular, posix_get_hrtimer_res() does: sec = 0; ns = hrtimer_resolution; and hrtimer_resolution depends on the enablement of the high resolution timers that can happen either at compile or at run time.
Fix the powerpc vdso implementation of clock_getres keeping a copy of hrtimer_resolution in vdso data and using that directly.
Fixes: a7f290dad32e ("[PATCH] powerpc: Merge vdso's and add vdso support to 32 bits kernel") Cc: stable@vger.kernel.org Signed-off-by: Vincenzo Frascino vincenzo.frascino@arm.com Reviewed-by: Christophe Leroy christophe.leroy@c-s.fr Acked-by: Shuah Khan skhan@linuxfoundation.org [chleroy: changed CLOCK_REALTIME_RES to CLOCK_HRTIMER_RES] Signed-off-by: Christophe Leroy christophe.leroy@c-s.fr Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/a55eca3a5e85233838c2349783bcb5164dae1d09.157527321...
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h index a115970a6809..40f13f3626d3 100644 --- a/arch/powerpc/include/asm/vdso_datapage.h +++ b/arch/powerpc/include/asm/vdso_datapage.h @@ -83,6 +83,7 @@ struct vdso_data { __s64 wtom_clock_sec; /* Wall to monotonic clock sec */ __s64 stamp_xtime_sec; /* xtime secs as at tb_orig_stamp */ __s64 stamp_xtime_nsec; /* xtime nsecs as at tb_orig_stamp */ + __u32 hrtimer_res; /* hrtimer resolution */ __u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls */ __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */ }; @@ -105,6 +106,7 @@ struct vdso_data { __s32 stamp_xtime_sec; /* xtime seconds as at tb_orig_stamp */ __s32 stamp_xtime_nsec; /* xtime nsecs as at tb_orig_stamp */ __u32 stamp_sec_fraction; /* fractional seconds of stamp_xtime */ + __u32 hrtimer_res; /* hrtimer resolution */ __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */ __u32 dcache_block_size; /* L1 d-cache block size */ __u32 icache_block_size; /* L1 i-cache block size */ diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c index f22bd6d1fe93..3d47aec7becf 100644 --- a/arch/powerpc/kernel/asm-offsets.c +++ b/arch/powerpc/kernel/asm-offsets.c @@ -388,6 +388,7 @@ int main(void) OFFSET(STAMP_XTIME_SEC, vdso_data, stamp_xtime_sec); OFFSET(STAMP_XTIME_NSEC, vdso_data, stamp_xtime_nsec); OFFSET(STAMP_SEC_FRAC, vdso_data, stamp_sec_fraction); + OFFSET(CLOCK_HRTIMER_RES, vdso_data, hrtimer_res); OFFSET(CFG_ICACHE_BLOCKSZ, vdso_data, icache_block_size); OFFSET(CFG_DCACHE_BLOCKSZ, vdso_data, dcache_block_size); OFFSET(CFG_ICACHE_LOGBLOCKSZ, vdso_data, icache_log_block_size); @@ -413,7 +414,6 @@ int main(void) DEFINE(CLOCK_REALTIME_COARSE, CLOCK_REALTIME_COARSE); DEFINE(CLOCK_MONOTONIC_COARSE, CLOCK_MONOTONIC_COARSE); DEFINE(NSEC_PER_SEC, NSEC_PER_SEC); - DEFINE(CLOCK_REALTIME_RES, MONOTONIC_RES_NSEC);
#ifdef CONFIG_BUG DEFINE(BUG_ENTRY_SIZE, sizeof(struct bug_entry)); diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 2d13cea13954..1168e8b37e30 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -960,6 +960,7 @@ void update_vsyscall(struct timekeeper *tk) vdso_data->stamp_xtime_sec = xt.tv_sec; vdso_data->stamp_xtime_nsec = xt.tv_nsec; vdso_data->stamp_sec_fraction = frac_sec; + vdso_data->hrtimer_res = hrtimer_resolution; smp_wmb(); ++(vdso_data->tb_update_count); } diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S index c8e6902cb01b..3306672f57a9 100644 --- a/arch/powerpc/kernel/vdso32/gettimeofday.S +++ b/arch/powerpc/kernel/vdso32/gettimeofday.S @@ -154,12 +154,15 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) cror cr0*4+eq,cr0*4+eq,cr1*4+eq bne cr0,99f
+ mflr r12 + .cfi_register lr,r12 + bl __get_datapage@local /* get data page */ + lwz r5, CLOCK_HRTIMER_RES(r3) + mtlr r12 li r3,0 cmpli cr0,r4,0 crclr cr0*4+so beqlr - lis r5,CLOCK_REALTIME_RES@h - ori r5,r5,CLOCK_REALTIME_RES@l stw r3,TSPC32_TV_SEC(r4) stw r5,TSPC32_TV_NSEC(r4) blr diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S index 1f24e411af80..1c9a04703250 100644 --- a/arch/powerpc/kernel/vdso64/gettimeofday.S +++ b/arch/powerpc/kernel/vdso64/gettimeofday.S @@ -186,12 +186,15 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) cror cr0*4+eq,cr0*4+eq,cr1*4+eq bne cr0,99f
+ mflr r12 + .cfi_register lr,r12 + bl V_LOCAL_FUNC(__get_datapage) + lwz r5, CLOCK_HRTIMER_RES(r3) + mtlr r12 li r3,0 cmpldi cr0,r4,0 crclr cr0*4+so beqlr - lis r5,CLOCK_REALTIME_RES@h - ori r5,r5,CLOCK_REALTIME_RES@l std r3,TSPC64_TV_SEC(r4) std r5,TSPC64_TV_NSEC(r4) blr