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()

References: bsc#1065729

Patch-mainline: v5.5-rc1

Git-commit: 552263456215ada7ee8700ce022d12b0cffe4802

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/a55eca3a5e85233838c2349783bcb5164dae1d09.1575273217.git.christophe.leroy@c-s.fr

Acked-by: Michal Suchanek <msuchanek@suse.de>

---

 arch/powerpc/include/asm/vdso_datapage.h  | 2 ++

 arch/powerpc/kernel/asm-offsets.c         | 2 +-

 arch/powerpc/kernel/time.c                | 1 +

 arch/powerpc/kernel/vdso32/gettimeofday.S | 7 +++++--

 arch/powerpc/kernel/vdso64/gettimeofday.S | 7 +++++--

 5 files changed, 14 insertions(+), 5 deletions(-)

--- a/arch/powerpc/include/asm/vdso_datapage.h

+++ b/arch/powerpc/include/asm/vdso_datapage.h

@@ -86,6 +86,7 @@ struct vdso_data {

 	__s32 wtom_clock_nsec;			/* Wall to monotonic clock nsec */

 	__s64 wtom_clock_sec;			/* Wall to monotonic clock sec */

 	struct timespec stamp_xtime;		/* xtime 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 */

 };

@@ -107,6 +108,7 @@ struct vdso_data {

 	__s32 wtom_clock_nsec;

 	struct timespec stamp_xtime;	/* xtime 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     */

--- a/arch/powerpc/kernel/asm-offsets.c

+++ b/arch/powerpc/kernel/asm-offsets.c

@@ -374,6 +374,7 @@ int main(void)

 	OFFSET(WTOM_CLOCK_NSEC, vdso_data, wtom_clock_nsec);

 	OFFSET(STAMP_XTIME, vdso_data, stamp_xtime);

 	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);

@@ -402,7 +403,6 @@ int main(void)

 	DEFINE(CLOCK_REALTIME, CLOCK_REALTIME);

 	DEFINE(CLOCK_MONOTONIC, CLOCK_MONOTONIC);

 	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));

--- a/arch/powerpc/kernel/time.c

+++ b/arch/powerpc/kernel/time.c

@@ -876,6 +876,7 @@ void update_vsyscall_old(struct timespec

 	vdso_data->wtom_clock_nsec = wtm->tv_nsec;

 	vdso_data->stamp_xtime = *wall_time;

 	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