Merge branch 'for-next/8.6-timers' into for-next/core

* for-next/8.6-timers:
  arm64: Add HWCAP for self-synchronising virtual counter
  arm64: Add handling of CNTVCTSS traps
  arm64: Add CNT{P,V}CTSS_EL0 alternatives to cnt{p,v}ct_el0
  arm64: Add a capability for FEAT_ECV
  clocksource/drivers/arch_arm_timer: Move workaround synchronisation around
  clocksource/drivers/arm_arch_timer: Fix masking for high freq counters
  clocksource/drivers/arm_arch_timer: Drop unnecessary ISB on CVAL programming
  clocksource/drivers/arm_arch_timer: Remove any trace of the TVAL programming interface
  clocksource/drivers/arm_arch_timer: Work around broken CVAL implementations
  clocksource/drivers/arm_arch_timer: Advertise 56bit timer to the core code
  clocksource/drivers/arm_arch_timer: Move MMIO timer programming over to CVAL
  clocksource/drivers/arm_arch_timer: Fix MMIO base address vs callback ordering issue
  clocksource/drivers/arm_arch_timer: Move drop _tval from erratum function names
  clocksource/drivers/arm_arch_timer: Move system register timer programming over to CVAL
  clocksource/drivers/arm_arch_timer: Extend write side of timer register accessors to u64
  clocksource/drivers/arm_arch_timer: Drop CNT*_TVAL read accessors
  clocksource/arm_arch_timer: Add build-time guards for unhandled register accesses

Documentation/arm64/cpu-feature-registers.rst

@@ -235,7 +235,15 @@ infrastructure:
      | DPB                          | [3-0]   |    y    |
      +------------------------------+---------+---------+
 
-  6) ID_AA64MMFR2_EL1 - Memory model feature register 2
+  6) ID_AA64MMFR0_EL1 - Memory model feature register 0
+
+     +------------------------------+---------+---------+
+     | Name                         |  bits   | visible |
+     +------------------------------+---------+---------+
+     | ECV                          | [63-60] |    y    |
+     +------------------------------+---------+---------+
+
+  7) ID_AA64MMFR2_EL1 - Memory model feature register 2
 
      +------------------------------+---------+---------+
      | Name                         |  bits   | visible |
@@ -243,7 +251,7 @@ infrastructure:
      | AT                           | [35-32] |    y    |
      +------------------------------+---------+---------+
 
-  7) ID_AA64ZFR0_EL1 - SVE feature ID register 0
+  8) ID_AA64ZFR0_EL1 - SVE feature ID register 0
 
      +------------------------------+---------+---------+
      | Name                         |  bits   | visible |

Documentation/arm64/elf_hwcaps.rst

@@ -247,6 +247,10 @@ HWCAP2_MTE
     Functionality implied by ID_AA64PFR1_EL1.MTE == 0b0010, as described
     by Documentation/arm64/memory-tagging-extension.rst.
 
+HWCAP2_ECV
+
+    Functionality implied by ID_AA64MMFR0_EL1.ECV == 0b0001.
+
 4. Unused AT_HWCAP bits
 -----------------------
 

arch/arm/include/asm/arch_timer.h

@@ -7,6 +7,7 @@
 #include <asm/hwcap.h>
 #include <linux/clocksource.h>
 #include <linux/init.h>
+#include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/types.h>
 
 #include <clocksource/arm_arch_timer.h>
@@ -24,29 +25,35 @@ int arch_timer_arch_init(void);
  * the code. At least it does so with a recent GCC (4.6.3).
  */
 static __always_inline
-void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
+void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u64 val)
 {
 	if (access == ARCH_TIMER_PHYS_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
-			asm volatile("mcr p15, 0, %0, c14, c2, 1" : : "r" (val));
+			asm volatile("mcr p15, 0, %0, c14, c2, 1" : : "r" ((u32)val));
+			isb();
 			break;
-		case ARCH_TIMER_REG_TVAL:
-			asm volatile("mcr p15, 0, %0, c14, c2, 0" : : "r" (val));
+		case ARCH_TIMER_REG_CVAL:
+			asm volatile("mcrr p15, 2, %Q0, %R0, c14" : : "r" (val));
 			break;
+		default:
+			BUILD_BUG();
 		}
 	} else if (access == ARCH_TIMER_VIRT_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
-			asm volatile("mcr p15, 0, %0, c14, c3, 1" : : "r" (val));
+			asm volatile("mcr p15, 0, %0, c14, c3, 1" : : "r" ((u32)val));
+			isb();
 			break;
-		case ARCH_TIMER_REG_TVAL:
-			asm volatile("mcr p15, 0, %0, c14, c3, 0" : : "r" (val));
+		case ARCH_TIMER_REG_CVAL:
+			asm volatile("mcrr p15, 3, %Q0, %R0, c14" : : "r" (val));
 			break;
+		default:
+			BUILD_BUG();
 		}
+	} else {
+		BUILD_BUG();
 	}
-
-	isb();
 }
 
 static __always_inline
@@ -59,19 +66,19 @@ u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
 		case ARCH_TIMER_REG_CTRL:
 			asm volatile("mrc p15, 0, %0, c14, c2, 1" : "=r" (val));
 			break;
-		case ARCH_TIMER_REG_TVAL:
-			asm volatile("mrc p15, 0, %0, c14, c2, 0" : "=r" (val));
-			break;
+		default:
+			BUILD_BUG();
 		}
 	} else if (access == ARCH_TIMER_VIRT_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
 			asm volatile("mrc p15, 0, %0, c14, c3, 1" : "=r" (val));
 			break;
-		case ARCH_TIMER_REG_TVAL:
-			asm volatile("mrc p15, 0, %0, c14, c3, 0" : "=r" (val));
-			break;
+		default:
+			BUILD_BUG();
 		}
+	} else {
+		BUILD_BUG();
 	}
 
 	return val;

arch/arm64/include/asm/arch_timer.h

@@ -32,7 +32,7 @@
 	({								\
 		const struct arch_timer_erratum_workaround *__wa;	\
 		__wa = __this_cpu_read(timer_unstable_counter_workaround); \
-		(__wa && __wa->h) ? __wa->h : arch_timer_##h;		\
+		(__wa && __wa->h) ? ({ isb(); __wa->h;}) : arch_timer_##h; \
 	})
 
 #else
@@ -52,8 +52,6 @@ struct arch_timer_erratum_workaround {
 	enum arch_timer_erratum_match_type match_type;
 	const void *id;
 	const char *desc;
-	u32 (*read_cntp_tval_el0)(void);
-	u32 (*read_cntv_tval_el0)(void);
 	u64 (*read_cntpct_el0)(void);
 	u64 (*read_cntvct_el0)(void);
 	int (*set_next_event_phys)(unsigned long, struct clock_event_device *);
@@ -64,25 +62,28 @@ struct arch_timer_erratum_workaround {
 DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *,
 		timer_unstable_counter_workaround);
 
-/* inline sysreg accessors that make erratum_handler() work */
-static inline notrace u32 arch_timer_read_cntp_tval_el0(void)
+static inline notrace u64 arch_timer_read_cntpct_el0(void)
 {
-	return read_sysreg(cntp_tval_el0);
-}
+	u64 cnt;
 
-static inline notrace u32 arch_timer_read_cntv_tval_el0(void)
-{
-	return read_sysreg(cntv_tval_el0);
-}
+	asm volatile(ALTERNATIVE("isb\n mrs %0, cntpct_el0",
+				 "nop\n" __mrs_s("%0", SYS_CNTPCTSS_EL0),
+				 ARM64_HAS_ECV)
+		     : "=r" (cnt));
 
-static inline notrace u64 arch_timer_read_cntpct_el0(void)
-{
-	return read_sysreg(cntpct_el0);
+	return cnt;
 }
 
 static inline notrace u64 arch_timer_read_cntvct_el0(void)
 {
-	return read_sysreg(cntvct_el0);
+	u64 cnt;
+
+	asm volatile(ALTERNATIVE("isb\n mrs %0, cntvct_el0",
+				 "nop\n" __mrs_s("%0", SYS_CNTVCTSS_EL0),
+				 ARM64_HAS_ECV)
+		     : "=r" (cnt));
+
+	return cnt;
 }
 
 #define arch_timer_reg_read_stable(reg)					\
@@ -102,51 +103,58 @@ static inline notrace u64 arch_timer_read_cntvct_el0(void)
  * the code.
  */
 static __always_inline
-void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u32 val)
+void arch_timer_reg_write_cp15(int access, enum arch_timer_reg reg, u64 val)
 {
 	if (access == ARCH_TIMER_PHYS_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
 			write_sysreg(val, cntp_ctl_el0);
+			isb();
 			break;
-		case ARCH_TIMER_REG_TVAL:
-			write_sysreg(val, cntp_tval_el0);
+		case ARCH_TIMER_REG_CVAL:
+			write_sysreg(val, cntp_cval_el0);
 			break;
+		default:
+			BUILD_BUG();
 		}
 	} else if (access == ARCH_TIMER_VIRT_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
 			write_sysreg(val, cntv_ctl_el0);
+			isb();
 			break;
-		case ARCH_TIMER_REG_TVAL:
-			write_sysreg(val, cntv_tval_el0);
+		case ARCH_TIMER_REG_CVAL:
+			write_sysreg(val, cntv_cval_el0);
 			break;
+		default:
+			BUILD_BUG();
 		}
+	} else {
+		BUILD_BUG();
 	}
-
-	isb();
 }
 
 static __always_inline
-u32 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
+u64 arch_timer_reg_read_cp15(int access, enum arch_timer_reg reg)
 {
 	if (access == ARCH_TIMER_PHYS_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
 			return read_sysreg(cntp_ctl_el0);
-		case ARCH_TIMER_REG_TVAL:
-			return arch_timer_reg_read_stable(cntp_tval_el0);
+		default:
+			BUILD_BUG();
 		}
 	} else if (access == ARCH_TIMER_VIRT_ACCESS) {
 		switch (reg) {
 		case ARCH_TIMER_REG_CTRL:
 			return read_sysreg(cntv_ctl_el0);
-		case ARCH_TIMER_REG_TVAL:
-			return arch_timer_reg_read_stable(cntv_tval_el0);
+		default:
+			BUILD_BUG();
 		}
 	}
 
-	BUG();
+	BUILD_BUG();
+	unreachable();
 }
 
 static inline u32 arch_timer_get_cntfrq(void)
@@ -169,7 +177,6 @@ static __always_inline u64 __arch_counter_get_cntpct_stable(void)
 {
 	u64 cnt;
 
-	isb();
 	cnt = arch_timer_reg_read_stable(cntpct_el0);
 	arch_counter_enforce_ordering(cnt);
 	return cnt;
@@ -179,8 +186,10 @@ static __always_inline u64 __arch_counter_get_cntpct(void)
 {
 	u64 cnt;
 
-	isb();
-	cnt = read_sysreg(cntpct_el0);
+	asm volatile(ALTERNATIVE("isb\n mrs %0, cntpct_el0",
+				 "nop\n" __mrs_s("%0", SYS_CNTPCTSS_EL0),
+				 ARM64_HAS_ECV)
+		     : "=r" (cnt));
 	arch_counter_enforce_ordering(cnt);
 	return cnt;
 }
@@ -189,7 +198,6 @@ static __always_inline u64 __arch_counter_get_cntvct_stable(void)
 {
 	u64 cnt;
 
-	isb();
 	cnt = arch_timer_reg_read_stable(cntvct_el0);
 	arch_counter_enforce_ordering(cnt);
 	return cnt;
@@ -199,8 +207,10 @@ static __always_inline u64 __arch_counter_get_cntvct(void)
 {
 	u64 cnt;
 
-	isb();
-	cnt = read_sysreg(cntvct_el0);
+	asm volatile(ALTERNATIVE("isb\n mrs %0, cntvct_el0",
+				 "nop\n" __mrs_s("%0", SYS_CNTVCTSS_EL0),
+				 ARM64_HAS_ECV)
+		     : "=r" (cnt));
 	arch_counter_enforce_ordering(cnt);
 	return cnt;
 }

arch/arm64/include/asm/esr.h

@@ -227,6 +227,9 @@
 #define ESR_ELx_SYS64_ISS_SYS_CNTVCT	(ESR_ELx_SYS64_ISS_SYS_VAL(3, 3, 2, 14, 0) | \
 					 ESR_ELx_SYS64_ISS_DIR_READ)
 
+#define ESR_ELx_SYS64_ISS_SYS_CNTVCTSS	(ESR_ELx_SYS64_ISS_SYS_VAL(3, 3, 6, 14, 0) | \
+					 ESR_ELx_SYS64_ISS_DIR_READ)
+
 #define ESR_ELx_SYS64_ISS_SYS_CNTFRQ	(ESR_ELx_SYS64_ISS_SYS_VAL(3, 3, 0, 14, 0) | \
 					 ESR_ELx_SYS64_ISS_DIR_READ)
 
@@ -317,6 +320,9 @@
 #define ESR_ELx_CP15_64_ISS_SYS_CNTVCT	(ESR_ELx_CP15_64_ISS_SYS_VAL(1, 14) | \
 					 ESR_ELx_CP15_64_ISS_DIR_READ)
 
+#define ESR_ELx_CP15_64_ISS_SYS_CNTVCTSS (ESR_ELx_CP15_64_ISS_SYS_VAL(9, 14) | \
+					 ESR_ELx_CP15_64_ISS_DIR_READ)
+
 #define ESR_ELx_CP15_32_ISS_SYS_CNTFRQ	(ESR_ELx_CP15_32_ISS_SYS_VAL(0, 0, 14, 0) |\
 					 ESR_ELx_CP15_32_ISS_DIR_READ)
 

arch/arm64/include/asm/hwcap.h

@@ -105,6 +105,7 @@
 #define KERNEL_HWCAP_RNG		__khwcap2_feature(RNG)
 #define KERNEL_HWCAP_BTI		__khwcap2_feature(BTI)
 #define KERNEL_HWCAP_MTE		__khwcap2_feature(MTE)
+#define KERNEL_HWCAP_ECV		__khwcap2_feature(ECV)
 
 /*
  * This yields a mask that user programs can use to figure out what

arch/arm64/include/asm/sysreg.h

@@ -507,6 +507,9 @@
 
 #define SYS_CNTFRQ_EL0			sys_reg(3, 3, 14, 0, 0)
 
+#define SYS_CNTPCTSS_EL0		sys_reg(3, 3, 14, 0, 5)
+#define SYS_CNTVCTSS_EL0		sys_reg(3, 3, 14, 0, 6)
+
 #define SYS_CNTP_TVAL_EL0		sys_reg(3, 3, 14, 2, 0)
 #define SYS_CNTP_CTL_EL0		sys_reg(3, 3, 14, 2, 1)
 #define SYS_CNTP_CVAL_EL0		sys_reg(3, 3, 14, 2, 2)

arch/arm64/include/uapi/asm/hwcap.h

@@ -75,5 +75,6 @@
 #define HWCAP2_RNG		(1 << 16)
 #define HWCAP2_BTI		(1 << 17)
 #define HWCAP2_MTE		(1 << 18)
+#define HWCAP2_ECV		(1 << 19)
 
 #endif /* _UAPI__ASM_HWCAP_H */

arch/arm64/kernel/cpufeature.c

@@ -279,7 +279,7 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_ECV_SHIFT, 4, 0),
+	ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_ECV_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_FGT_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_EXS_SHIFT, 4, 0),
 	/*
@@ -1930,6 +1930,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.sign = FTR_UNSIGNED,
 		.min_field_value = 1,
 	},
+	{
+		.desc = "Enhanced Counter Virtualization",
+		.capability = ARM64_HAS_ECV,
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.matches = has_cpuid_feature,
+		.sys_reg = SYS_ID_AA64MMFR0_EL1,
+		.field_pos = ID_AA64MMFR0_ECV_SHIFT,
+		.sign = FTR_UNSIGNED,
+		.min_field_value = 1,
+	},
 #ifdef CONFIG_ARM64_PAN
 	{
 		.desc = "Privileged Access Never",
@@ -2451,6 +2461,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = {
 #ifdef CONFIG_ARM64_MTE
 	HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_MTE_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_MTE, CAP_HWCAP, KERNEL_HWCAP_MTE),
 #endif /* CONFIG_ARM64_MTE */
+	HWCAP_CAP(SYS_ID_AA64MMFR0_EL1, ID_AA64MMFR0_ECV_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, KERNEL_HWCAP_ECV),
 	{},
 };
 

arch/arm64/kernel/cpuinfo.c

@@ -94,6 +94,7 @@ static const char *const hwcap_str[] = {
 	[KERNEL_HWCAP_RNG]		= "rng",
 	[KERNEL_HWCAP_BTI]		= "bti",
 	[KERNEL_HWCAP_MTE]		= "mte",
+	[KERNEL_HWCAP_ECV]		= "ecv",
 };
 
 #ifdef CONFIG_COMPAT

arch/arm64/kernel/traps.c

@@ -653,6 +653,12 @@ static const struct sys64_hook sys64_hooks[] = {
 		.esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
 		.handler = cntvct_read_handler,
 	},
+	{
+		/* Trap read access to CNTVCTSS_EL0 */
+		.esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
+		.esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCTSS,
+		.handler = cntvct_read_handler,
+	},
 	{
 		/* Trap read access to CNTFRQ_EL0 */
 		.esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
@@ -729,6 +735,11 @@ static const struct sys64_hook cp15_64_hooks[] = {
 		.esr_val = ESR_ELx_CP15_64_ISS_SYS_CNTVCT,
 		.handler = compat_cntvct_read_handler,
 	},
+	{
+		.esr_mask = ESR_ELx_CP15_64_ISS_SYS_MASK,
+		.esr_val = ESR_ELx_CP15_64_ISS_SYS_CNTVCTSS,
+		.handler = compat_cntvct_read_handler,
+	},
 	{},
 };
 

arch/arm64/tools/cpucaps

@@ -18,6 +18,7 @@ HAS_CRC32
 HAS_DCPODP
 HAS_DCPOP
 HAS_E0PD
+HAS_ECV
 HAS_EPAN
 HAS_GENERIC_AUTH
 HAS_GENERIC_AUTH_ARCH

include/clocksource/arm_arch_timer.h

@@ -24,7 +24,7 @@
 
 enum arch_timer_reg {
 	ARCH_TIMER_REG_CTRL,
-	ARCH_TIMER_REG_TVAL,
+	ARCH_TIMER_REG_CVAL,
 };
 
 enum arch_timer_ppi_nr {