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Date:   Mon, 17 Feb 2020 19:18:49 -0000
From:   "tip-bot2 for Thomas Gleixner" <tip-bot2@linutronix.de>
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Subject: [tip: timers/core] ARM/arm64: vdso: Use common vdso clock mode storage
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        x86 <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
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The following commit has been merged into the timers/core branch of tip:

Commit-ID:     5e3c6a312a0946d2d83e32359612cbb925a8bed0
Gitweb:        https://git.kernel.org/tip/5e3c6a312a0946d2d83e32359612cbb925a8bed0
Author:        Thomas Gleixner <tglx@linutronix.de>
AuthorDate:    Fri, 07 Feb 2020 13:38:58 +01:00
Committer:     Thomas Gleixner <tglx@linutronix.de>
CommitterDate: Mon, 17 Feb 2020 20:12:16 +01:00

ARM/arm64: vdso: Use common vdso clock mode storage

Convert ARM/ARM64 to the generic VDSO clock mode storage. This needs to
happen in one go as they share the clocksource driver.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Link: https://lkml.kernel.org/r/20200207124403.363235229@linutronix.de


---
 arch/arm/Kconfig                                  |  1 +-
 arch/arm/include/asm/clocksource.h                |  5 +--
 arch/arm/include/asm/vdso/gettimeofday.h          | 12 ++++++--
 arch/arm/include/asm/vdso/vsyscall.h              | 21 +--------------
 arch/arm/mm/Kconfig                               |  1 +-
 arch/arm64/Kconfig                                |  2 +-
 arch/arm64/include/asm/clocksource.h              |  5 +--
 arch/arm64/include/asm/vdso/compat_gettimeofday.h | 11 +++----
 arch/arm64/include/asm/vdso/gettimeofday.h        | 11 +++----
 arch/arm64/include/asm/vdso/vsyscall.h            |  9 +------
 drivers/clocksource/arm_arch_timer.c              |  8 ++---
 11 files changed, 29 insertions(+), 57 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 97864aa..03bbfc3 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -3,7 +3,6 @@ config ARM
 	bool
 	default y
 	select ARCH_32BIT_OFF_T
-	select ARCH_CLOCKSOURCE_DATA
 	select ARCH_HAS_BINFMT_FLAT
 	select ARCH_HAS_DEBUG_VIRTUAL if MMU
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
diff --git a/arch/arm/include/asm/clocksource.h b/arch/arm/include/asm/clocksource.h
index 0b350a7..73beb7f 100644
--- a/arch/arm/include/asm/clocksource.h
+++ b/arch/arm/include/asm/clocksource.h
@@ -1,8 +1,7 @@
 #ifndef _ASM_CLOCKSOURCE_H
 #define _ASM_CLOCKSOURCE_H
 
-struct arch_clocksource_data {
-	bool vdso_direct;	/* Usable for direct VDSO access? */
-};
+#define VDSO_ARCH_CLOCKMODES	\
+	VDSO_CLOCKMODE_ARCHTIMER
 
 #endif
diff --git a/arch/arm/include/asm/vdso/gettimeofday.h b/arch/arm/include/asm/vdso/gettimeofday.h
index f4757d3..07d791c 100644
--- a/arch/arm/include/asm/vdso/gettimeofday.h
+++ b/arch/arm/include/asm/vdso/gettimeofday.h
@@ -117,15 +117,21 @@ static __always_inline u64 __arch_get_hw_counter(int clock_mode)
 #ifdef CONFIG_ARM_ARCH_TIMER
 	u64 cycle_now;
 
-	if (!clock_mode)
-		return -EINVAL;
+	/*
+	 * Core checks for mode already, so this raced against a concurrent
+	 * update. Return something. Core will do another round and then
+	 * see the mode change and fallback to the syscall.
+	 */
+	if (clock_mode == VDSO_CLOCKMODE_NONE)
+		return 0;
 
 	isb();
 	cycle_now = read_sysreg(CNTVCT);
 
 	return cycle_now;
 #else
-	return -EINVAL; /* use fallback */
+	/* Make GCC happy. This is compiled out anyway */
+	return 0;
 #endif
 }
 
diff --git a/arch/arm/include/asm/vdso/vsyscall.h b/arch/arm/include/asm/vdso/vsyscall.h
index 85a7e58..002f9ed 100644
--- a/arch/arm/include/asm/vdso/vsyscall.h
+++ b/arch/arm/include/asm/vdso/vsyscall.h
@@ -11,18 +11,6 @@
 extern struct vdso_data *vdso_data;
 extern bool cntvct_ok;
 
-static __always_inline
-bool tk_is_cntvct(const struct timekeeper *tk)
-{
-	if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
-		return false;
-
-	if (!tk->tkr_mono.clock->archdata.vdso_direct)
-		return false;
-
-	return true;
-}
-
 /*
  * Update the vDSO data page to keep in sync with kernel timekeeping.
  */
@@ -41,15 +29,6 @@ bool __arm_update_vdso_data(void)
 #define __arch_update_vdso_data __arm_update_vdso_data
 
 static __always_inline
-int __arm_get_clock_mode(struct timekeeper *tk)
-{
-	u32 __tk_is_cntvct = tk_is_cntvct(tk);
-
-	return __tk_is_cntvct;
-}
-#define __arch_get_clock_mode __arm_get_clock_mode
-
-static __always_inline
 void __arm_sync_vdso_data(struct vdso_data *vdata)
 {
 	flush_dcache_page(virt_to_page(vdata));
diff --git a/arch/arm/mm/Kconfig b/arch/arm/mm/Kconfig
index 65e4482..865e888 100644
--- a/arch/arm/mm/Kconfig
+++ b/arch/arm/mm/Kconfig
@@ -900,6 +900,7 @@ config VDSO
 	select GENERIC_TIME_VSYSCALL
 	select GENERIC_VDSO_32
 	select GENERIC_GETTIMEOFDAY
+	select GENERIC_VDSO_CLOCK_MODE
 	help
 	  Place in the process address space an ELF shared object
 	  providing fast implementations of gettimeofday and
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 0b30e88..7809d49 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -9,7 +9,6 @@ config ARM64
 	select ACPI_MCFG if (ACPI && PCI)
 	select ACPI_SPCR_TABLE if ACPI
 	select ACPI_PPTT if ACPI
-	select ARCH_CLOCKSOURCE_DATA
 	select ARCH_HAS_DEBUG_VIRTUAL
 	select ARCH_HAS_DEVMEM_IS_ALLOWED
 	select ARCH_HAS_DMA_PREP_COHERENT
@@ -111,6 +110,7 @@ config ARM64
 	select GENERIC_STRNLEN_USER
 	select GENERIC_TIME_VSYSCALL
 	select GENERIC_GETTIMEOFDAY
+	select GENERIC_VDSO_CLOCK_MODE
 	select HANDLE_DOMAIN_IRQ
 	select HARDIRQS_SW_RESEND
 	select HAVE_PCI
diff --git a/arch/arm64/include/asm/clocksource.h b/arch/arm64/include/asm/clocksource.h
index 0ece64a..eb82e9d 100644
--- a/arch/arm64/include/asm/clocksource.h
+++ b/arch/arm64/include/asm/clocksource.h
@@ -2,8 +2,7 @@
 #ifndef _ASM_CLOCKSOURCE_H
 #define _ASM_CLOCKSOURCE_H
 
-struct arch_clocksource_data {
-	bool vdso_direct;	/* Usable for direct VDSO access? */
-};
+#define VDSO_ARCH_CLOCKMODES	\
+	VDSO_CLOCKMODE_ARCHTIMER
 
 #endif
diff --git a/arch/arm64/include/asm/vdso/compat_gettimeofday.h b/arch/arm64/include/asm/vdso/compat_gettimeofday.h
index 537b1e6..81b0c39 100644
--- a/arch/arm64/include/asm/vdso/compat_gettimeofday.h
+++ b/arch/arm64/include/asm/vdso/compat_gettimeofday.h
@@ -12,8 +12,6 @@
 
 #include <asm/vdso/compat_barrier.h>
 
-#define __VDSO_USE_SYSCALL		ULLONG_MAX
-
 #define VDSO_HAS_CLOCK_GETRES		1
 
 #define BUILD_VDSO32			1
@@ -117,11 +115,12 @@ static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
 	u64 res;
 
 	/*
-	 * clock_mode == 0 implies that vDSO are enabled otherwise
-	 * fallback on syscall.
+	 * Core checks for mode already, so this raced against a concurrent
+	 * update. Return something. Core will do another round and then
+	 * see the mode change and fallback to the syscall.
 	 */
-	if (clock_mode)
-		return __VDSO_USE_SYSCALL;
+	if (clock_mode == VDSO_CLOCKMODE_NONE)
+		return 0;
 
 	/*
 	 * This isb() is required to prevent that the counter value
diff --git a/arch/arm64/include/asm/vdso/gettimeofday.h b/arch/arm64/include/asm/vdso/gettimeofday.h
index b08f476..5a53443 100644
--- a/arch/arm64/include/asm/vdso/gettimeofday.h
+++ b/arch/arm64/include/asm/vdso/gettimeofday.h
@@ -10,8 +10,6 @@
 #include <asm/unistd.h>
 #include <uapi/linux/time.h>
 
-#define __VDSO_USE_SYSCALL		ULLONG_MAX
-
 #define VDSO_HAS_CLOCK_GETRES		1
 
 static __always_inline
@@ -71,11 +69,12 @@ static __always_inline u64 __arch_get_hw_counter(s32 clock_mode)
 	u64 res;
 
 	/*
-	 * clock_mode == 0 implies that vDSO are enabled otherwise
-	 * fallback on syscall.
+	 * Core checks for mode already, so this raced against a concurrent
+	 * update. Return something. Core will do another round and then
+	 * see the mode change and fallback to the syscall.
 	 */
-	if (clock_mode)
-		return __VDSO_USE_SYSCALL;
+	if (clock_mode == VDSO_CLOCKMODE_NONE)
+		return 0;
 
 	/*
 	 * This isb() is required to prevent that the counter value
diff --git a/arch/arm64/include/asm/vdso/vsyscall.h b/arch/arm64/include/asm/vdso/vsyscall.h
index 0c20a7c..f94b145 100644
--- a/arch/arm64/include/asm/vdso/vsyscall.h
+++ b/arch/arm64/include/asm/vdso/vsyscall.h
@@ -22,15 +22,6 @@ struct vdso_data *__arm64_get_k_vdso_data(void)
 #define __arch_get_k_vdso_data __arm64_get_k_vdso_data
 
 static __always_inline
-int __arm64_get_clock_mode(struct timekeeper *tk)
-{
-	u32 use_syscall = !tk->tkr_mono.clock->archdata.vdso_direct;
-
-	return use_syscall;
-}
-#define __arch_get_clock_mode __arm64_get_clock_mode
-
-static __always_inline
 void __arm64_update_vsyscall(struct vdso_data *vdata, struct timekeeper *tk)
 {
 	vdata[CS_HRES_COARSE].mask	= VDSO_PRECISION_MASK;
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
index 9a5464c..ee2420d 100644
--- a/drivers/clocksource/arm_arch_timer.c
+++ b/drivers/clocksource/arm_arch_timer.c
@@ -69,7 +69,7 @@ static enum arch_timer_ppi_nr arch_timer_uses_ppi = ARCH_TIMER_VIRT_PPI;
 static bool arch_timer_c3stop;
 static bool arch_timer_mem_use_virtual;
 static bool arch_counter_suspend_stop;
-static bool vdso_default = true;
+static enum vdso_clock_mode vdso_default = VDSO_CLOCKMODE_ARCHTIMER;
 
 static cpumask_t evtstrm_available = CPU_MASK_NONE;
 static bool evtstrm_enable = IS_ENABLED(CONFIG_ARM_ARCH_TIMER_EVTSTREAM);
@@ -560,8 +560,8 @@ void arch_timer_enable_workaround(const struct arch_timer_erratum_workaround *wa
 	 * change both the default value and the vdso itself.
 	 */
 	if (wa->read_cntvct_el0) {
-		clocksource_counter.archdata.vdso_direct = false;
-		vdso_default = false;
+		clocksource_counter.vdso_clock_mode = VDSO_CLOCKMODE_NONE;
+		vdso_default = VDSO_CLOCKMODE_NONE;
 	}
 }
 
@@ -979,7 +979,7 @@ static void __init arch_counter_register(unsigned type)
 		}
 
 		arch_timer_read_counter = rd;
-		clocksource_counter.archdata.vdso_direct = vdso_default;
+		clocksource_counter.vdso_clock_mode = vdso_default;
 	} else {
 		arch_timer_read_counter = arch_counter_get_cntvct_mem;
 	}