Merge tag 'arch-timer-errata' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into clockevents/4.12

arm64 arch timer workaround series, including the base patches
that will also go via the arm64 tree.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>

Documentation/arm64/silicon-errata.txt

@@ -54,6 +54,7 @@ stable kernels.
 | ARM            | Cortex-A57      | #852523         | N/A                         |
 | ARM            | Cortex-A57      | #834220         | ARM64_ERRATUM_834220        |
 | ARM            | Cortex-A72      | #853709         | N/A                         |
+| ARM            | Cortex-A73      | #858921         | ARM64_ERRATUM_858921        |
 | ARM            | MMU-500         | #841119,#826419 | N/A                         |
 |                |                 |                 |                             |
 | Cavium         | ThunderX ITS    | #22375, #24313  | CAVIUM_ERRATUM_22375        |

arch/arm64/include/asm/arch_timer.h

@@ -25,6 +25,7 @@
 #include <linux/bug.h>
 #include <linux/init.h>
 #include <linux/jump_label.h>
+#include <linux/smp.h>
 #include <linux/types.h>
 
 #include <clocksource/arm_arch_timer.h>
@@ -37,24 +38,44 @@ extern struct static_key_false arch_timer_read_ool_enabled;
 #define needs_unstable_timer_counter_workaround()  false
 #endif
 
+enum arch_timer_erratum_match_type {
+	ate_match_dt,
+	ate_match_local_cap_id,
+	ate_match_acpi_oem_info,
+};
+
+struct clock_event_device;
 
 struct arch_timer_erratum_workaround {
-	const char *id;		/* Indicate the Erratum ID */
+	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_cntvct_el0)(void);
+	int (*set_next_event_phys)(unsigned long, struct clock_event_device *);
+	int (*set_next_event_virt)(unsigned long, struct clock_event_device *);
 };
 
-extern const struct arch_timer_erratum_workaround *timer_unstable_counter_workaround;
+DECLARE_PER_CPU(const struct arch_timer_erratum_workaround *,
+		timer_unstable_counter_workaround);
 
-#define arch_timer_reg_read_stable(reg) 		\
-({							\
-	u64 _val;					\
-	if (needs_unstable_timer_counter_workaround())		\
-		_val = timer_unstable_counter_workaround->read_##reg();\
-	else						\
-		_val = read_sysreg(reg);		\
-	_val;						\
+#define arch_timer_reg_read_stable(reg)					\
+({									\
+	u64 _val;							\
+	if (needs_unstable_timer_counter_workaround()) {		\
+		const struct arch_timer_erratum_workaround *wa;		\
+		preempt_disable();					\
+		wa = __this_cpu_read(timer_unstable_counter_workaround); \
+		if (wa && wa->read_##reg)				\
+			_val = wa->read_##reg();			\
+		else							\
+			_val = read_sysreg(reg);			\
+		preempt_enable();					\
+	} else {							\
+		_val = read_sysreg(reg);				\
+	}								\
+	_val;								\
 })
 
 /*

arch/arm64/include/asm/cpucaps.h

@@ -37,7 +37,8 @@
 #define ARM64_HAS_NO_FPSIMD			16
 #define ARM64_WORKAROUND_REPEAT_TLBI		17
 #define ARM64_WORKAROUND_QCOM_FALKOR_E1003	18
+#define ARM64_WORKAROUND_858921			19
 
-#define ARM64_NCAPS				19
+#define ARM64_NCAPS				20
 
 #endif /* __ASM_CPUCAPS_H */

arch/arm64/include/asm/cputype.h

@@ -80,6 +80,7 @@
 #define ARM_CPU_PART_FOUNDATION		0xD00
 #define ARM_CPU_PART_CORTEX_A57		0xD07
 #define ARM_CPU_PART_CORTEX_A53		0xD03
+#define ARM_CPU_PART_CORTEX_A73		0xD09
 
 #define APM_CPU_PART_POTENZA		0x000
 
@@ -92,6 +93,7 @@
 
 #define MIDR_CORTEX_A53 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A53)
 #define MIDR_CORTEX_A57 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A57)
+#define MIDR_CORTEX_A73 MIDR_CPU_MODEL(ARM_CPU_IMP_ARM, ARM_CPU_PART_CORTEX_A73)
 #define MIDR_THUNDERX	MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX)
 #define MIDR_THUNDERX_81XX MIDR_CPU_MODEL(ARM_CPU_IMP_CAVIUM, CAVIUM_CPU_PART_THUNDERX_81XX)
 #define MIDR_QCOM_FALKOR_V1 MIDR_CPU_MODEL(ARM_CPU_IMP_QCOM, QCOM_CPU_PART_FALKOR_V1)

arch/arm64/include/asm/esr.h

@@ -175,6 +175,8 @@
 #define ESR_ELx_SYS64_ISS_SYS_CTR_READ	(ESR_ELx_SYS64_ISS_SYS_CTR | \
 					 ESR_ELx_SYS64_ISS_DIR_READ)
 
+#define ESR_ELx_SYS64_ISS_SYS_CNTVCT	(ESR_ELx_SYS64_ISS_SYS_VAL(3, 3, 2, 14, 0) | \
+					 ESR_ELx_SYS64_ISS_DIR_READ)
 #ifndef __ASSEMBLY__
 #include <asm/types.h>
 

arch/arm64/kernel/cpu_errata.c

@@ -53,6 +53,13 @@ static int cpu_enable_trap_ctr_access(void *__unused)
 	.midr_range_min = min, \
 	.midr_range_max = max
 
+#define MIDR_ALL_VERSIONS(model) \
+	.def_scope = SCOPE_LOCAL_CPU, \
+	.matches = is_affected_midr_range, \
+	.midr_model = model, \
+	.midr_range_min = 0, \
+	.midr_range_max = (MIDR_VARIANT_MASK | MIDR_REVISION_MASK)
+
 const struct arm64_cpu_capabilities arm64_errata[] = {
 #if	defined(CONFIG_ARM64_ERRATUM_826319) || \
 	defined(CONFIG_ARM64_ERRATUM_827319) || \
@@ -150,6 +157,14 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
 			   MIDR_CPU_VAR_REV(0, 0),
 			   MIDR_CPU_VAR_REV(0, 0)),
 	},
+#endif
+#ifdef CONFIG_ARM64_ERRATUM_858921
+	{
+	/* Cortex-A73 all versions */
+		.desc = "ARM erratum 858921",
+		.capability = ARM64_WORKAROUND_858921,
+		MIDR_ALL_VERSIONS(MIDR_CORTEX_A73),
+	},
 #endif
 	{
 	}

arch/arm64/kernel/cpufeature.c

@@ -1090,20 +1090,29 @@ static void __init setup_feature_capabilities(void)
  * Check if the current CPU has a given feature capability.
  * Should be called from non-preemptible context.
  */
-bool this_cpu_has_cap(unsigned int cap)
+static bool __this_cpu_has_cap(const struct arm64_cpu_capabilities *cap_array,
+			       unsigned int cap)
 {
 	const struct arm64_cpu_capabilities *caps;
 
 	if (WARN_ON(preemptible()))
 		return false;
 
-	for (caps = arm64_features; caps->desc; caps++)
+	for (caps = cap_array; caps->desc; caps++)
 		if (caps->capability == cap && caps->matches)
 			return caps->matches(caps, SCOPE_LOCAL_CPU);
 
 	return false;
 }
 
+extern const struct arm64_cpu_capabilities arm64_errata[];
+
+bool this_cpu_has_cap(unsigned int cap)
+{
+	return (__this_cpu_has_cap(arm64_features, cap) ||
+		__this_cpu_has_cap(arm64_errata, cap));
+}
+
 void __init setup_cpu_features(void)
 {
 	u32 cwg;

arch/arm64/kernel/traps.c

@@ -505,6 +505,14 @@ static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
 	regs->pc += 4;
 }
 
+static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
+{
+	int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
+
+	pt_regs_write_reg(regs, rt, arch_counter_get_cntvct());
+	regs->pc += 4;
+}
+
 struct sys64_hook {
 	unsigned int esr_mask;
 	unsigned int esr_val;
@@ -523,6 +531,12 @@ static struct sys64_hook sys64_hooks[] = {
 		.esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
 		.handler = ctr_read_handler,
 	},
+	{
+		/* Trap read access to CNTVCT_EL0 */
+		.esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
+		.esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
+		.handler = cntvct_read_handler,
+	},
 	{},
 };
 

drivers/clocksource/Kconfig

@@ -368,6 +368,17 @@ config HISILICON_ERRATUM_161010101
 	  161010101. The workaround will be active if the hisilicon,erratum-161010101
 	  property is found in the timer node.
 
+config ARM64_ERRATUM_858921
+	bool "Workaround for Cortex-A73 erratum 858921"
+	default y
+	select ARM_ARCH_TIMER_OOL_WORKAROUND
+	depends on ARM_ARCH_TIMER && ARM64
+	help
+	  This option enables a workaround applicable to Cortex-A73
+	  (all versions), whose counter may return incorrect values.
+	  The workaround will be dynamically enabled when an affected
+	  core is detected.
+
 config ARM_GLOBAL_TIMER
 	bool "Support for the ARM global timer" if COMPILE_TEST
 	select CLKSRC_OF if OF