arm64: vdso: move vdso_fix into struct vdso_data

hulk inclusion
category: bugfix
bugzilla: 16082
CVE: NA

-------------------------------------------------

Using static key type may cause segmentation fault in bionic,
change type of vdso_fix to bool and move it int struct vdso_data.

On Hi1620,
without this patch, gettimeofday costs 0.02775:
./gettimeofday -E -C 200 -L -S -W -N "gettimeofday"
Running:        gettimeofday# ./gettimeofday -E -C 200 -L -S -W -N gettimeofday
             prc thr   usecs/call      samples   errors cnt/samp
gettimeofday   1   1      0.02775          174        0    20000

with this patch, gettimeofday costs 0.02701:
./gettimeofday -E -C 200 -L -S -W -N "gettimeofday"
Running:        gettimeofday# ./gettimeofday -E -C 200 -L -S -W -N gettimeofday
             prc thr   usecs/call      samples   errors cnt/samp
gettimeofday   1   1      0.02701          170        0    20000

On Hi1616,
without this patch, gettimeofday costs 0.03396:
./gettimeofday -E -C 200 -L -S -W -N "gettimeofday"
Running:        gettimeofday# ./gettimeofday -E -C 200 -L -S -W -N gettimeofday
             prc thr   usecs/call      samples   errors cnt/samp
gettimeofday   1   1      0.03396          194        0    20000

with this patch, gettimeofday costs 0.03660:
./gettimeofday -E -C 200 -L -S -W -N "gettimeofday"
Running:        gettimeofday# ./gettimeofday -E -C 200 -L -S -W -N gettimeofday
             prc thr   usecs/call      samples   errors cnt/samp
gettimeofday   1   1      0.03660          200        0    20000
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Reviewed-by: NXuefeng Wang <wxf.wang@hisilicon.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

arch/arm64/include/asm/clocksource.h

@@ -4,6 +4,7 @@
 
 struct arch_clocksource_data {
 	bool vdso_direct;	/* Usable for direct VDSO access? */
+	bool vdso_fix;		/* Need avoid the clock bug in VDSO? */
 };
 
 #endif

arch/arm64/include/asm/vdso_datapage.h

@@ -39,6 +39,7 @@ struct vdso_data {
 	__u32 tz_dsttime;
 	__u32 use_syscall;
 	__u32 hrtimer_res;
+	__u32 vdso_fix;		/* Avoid the clock bug in VDSO */
 };
 
 #endif /* !__ASSEMBLY__ */

arch/arm64/kernel/asm-offsets.c

@@ -122,6 +122,7 @@ int main(void)
   DEFINE(VDSO_TZ_MINWEST,	offsetof(struct vdso_data, tz_minuteswest));
   DEFINE(VDSO_TZ_DSTTIME,	offsetof(struct vdso_data, tz_dsttime));
   DEFINE(VDSO_USE_SYSCALL,	offsetof(struct vdso_data, use_syscall));
+  DEFINE(VDSO_FIX,		offsetof(struct vdso_data, vdso_fix));
   BLANK();
   DEFINE(TVAL_TV_SEC,		offsetof(struct timeval, tv_sec));
   DEFINE(TVAL_TV_USEC,		offsetof(struct timeval, tv_usec));

arch/arm64/kernel/vdso.c

@@ -224,6 +224,7 @@ void update_vsyscall(struct timekeeper *tk)
 	smp_wmb();
 
 	vdso_data->use_syscall			= use_syscall;
+	vdso_data->vdso_fix			= tk->tkr_mono.clock->archdata.vdso_fix;
 	vdso_data->xtime_coarse_sec		= tk->xtime_sec;
 	vdso_data->xtime_coarse_nsec		= tk->tkr_mono.xtime_nsec >>
 							tk->tkr_mono.shift;

arch/arm64/kernel/vdso/gettimeofday.c

@@ -29,7 +29,6 @@
 #include <linux/hrtimer.h>
 
 extern struct vdso_data _vdso_data;
-DECLARE_STATIC_KEY_FALSE(vdso_fix);
 
 static notrace int gettimeofday_fallback(struct timeval *_tv,
 					 struct timezone *_tz)
@@ -120,7 +119,7 @@ static notrace u64 get_clock_shifted_nsec(u64 cycle_last, u64 mult)
 	/* Read the virtual counter. */
 	isb();
 	asm volatile("mrs %0, cntvct_el0" : "=r" (res) :: "memory");
-	if (static_branch_unlikely(&vdso_fix)) {
+	if (_vdso_data.vdso_fix) {
 		u64 new;
 		int retries = 50;
 

drivers/clocksource/arm_arch_timer.c

@@ -76,7 +76,7 @@ static bool arch_timer_c3stop;
 static bool arch_timer_mem_use_virtual;
 static bool arch_counter_suspend_stop;
 static bool vdso_default = true;
-DEFINE_STATIC_KEY_FALSE(vdso_fix);
+static bool vdso_fix;
 
 static cpumask_t evtstrm_available = CPU_MASK_NONE;
 static bool evtstrm_enable = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);
@@ -553,7 +553,7 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa
 	if (wa->read_cntvct_el0) {
 		clocksource_counter.archdata.vdso_direct = true;
 		vdso_default = true;
-		static_branch_enable(&vdso_fix);
+		vdso_fix = true;
 	}
 }
 
@@ -857,8 +857,7 @@ static void arch_counter_set_user_access(void)
 	 * need to be workaround. The vdso may have been already
 	 * disabled though.
 	 */
-	if (arch_timer_this_cpu_has_cntvct_wa() &&
-	    !static_branch_unlikely(&vdso_fix))
+	if (arch_timer_this_cpu_has_cntvct_wa() && !vdso_fix)
 		pr_info("CPU%d: Trapping CNTVCT access\n", smp_processor_id());
 	else
 		cntkctl |= ARCH_TIMER_USR_VCT_ACCESS_EN;
@@ -993,6 +992,7 @@ static void __init arch_counter_register(unsigned type)
 			arch_timer_read_counter = arch_counter_get_cntpct;
 
 		clocksource_counter.archdata.vdso_direct = vdso_default;
+		clocksource_counter.archdata.vdso_fix = vdso_fix;
 	} else {
 		arch_timer_read_counter = arch_counter_get_cntvct_mem;
 	}