Merge "arm: traps: emulate a MRC instruction reading CNTFRQ register"

arch/arm/include/asm/traps.h

@@ -28,6 +28,8 @@ static inline int __in_irqentry_text(unsigned long ptr)
 	       ptr < (unsigned long)&__irqentry_text_end;
 }
 
+extern void get_timer_freq_hook_init(void);
+extern void get_timer_count_hook_init(void);
 extern void __init early_trap_init(void *);
 extern void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame);
 extern void ptrace_break(struct pt_regs *regs);

arch/arm/kernel/traps.c

@@ -28,6 +28,7 @@
 #include <linux/irq.h>
 
 #include <linux/atomic.h>
+#include <asm/arch_timer.h>
 #include <asm/cacheflush.h>
 #include <asm/exception.h>
 #include <asm/unistd.h>
@@ -711,6 +712,77 @@ late_initcall(arm_mrc_hook_init);
 
 #endif
 
+static int get_timer_count_trap(struct pt_regs *regs, unsigned int instr)
+{
+	u64 cval;
+	unsigned int res;
+	int rd = (instr >> 12) & 0xF;
+	int rn =  (instr >> 16) & 0xF;
+
+	res = arm_check_condition(instr, regs->ARM_cpsr);
+	if (res == ARM_OPCODE_CONDTEST_FAIL) {
+		regs->ARM_pc += 4;
+		return 0;
+	}
+
+	if (rd == 15 || rn == 15)
+		return 1;
+	cval = __arch_counter_get_cntvct();
+	regs->uregs[rd] = cval;
+	regs->uregs[rn] = cval >> 32;
+	regs->ARM_pc += 4;
+	return 0;
+}
+
+static struct undef_hook get_timer_count_hook = {
+	.instr_mask	= 0x0ff00fff,
+	.instr_val	= 0x0c500f1e,
+	.cpsr_mask	= MODE_MASK,
+	.cpsr_val	= USR_MODE,
+	.fn		= get_timer_count_trap,
+};
+
+void get_timer_count_hook_init(void)
+{
+	register_undef_hook(&get_timer_count_hook);
+}
+EXPORT_SYMBOL(get_timer_count_hook_init);
+
+static int get_freq_trap(struct pt_regs *regs, unsigned int instr)
+{
+	u32 fval;
+	unsigned int res;
+	int rd = (instr >> 12) & 0xF;
+
+	res = arm_check_condition(instr, regs->ARM_cpsr);
+	if (res == ARM_OPCODE_CONDTEST_FAIL) {
+		regs->ARM_pc += 4;
+		return 0;
+	}
+
+	if (rd == 15)
+		return 1;
+
+	fval = arch_timer_get_cntfrq();
+	regs->uregs[rd] = fval;
+	regs->ARM_pc += 4;
+	return 0;
+}
+
+static struct undef_hook get_freq_hook = {
+	.instr_mask	= 0x0fff0fff,
+	.instr_val	= 0x0e1e0f10,
+	.cpsr_mask	= MODE_MASK,
+	.cpsr_val	= USR_MODE,
+	.fn		= get_freq_trap,
+};
+
+void get_timer_freq_hook_init(void)
+{
+	register_undef_hook(&get_freq_hook);
+}
+EXPORT_SYMBOL(get_timer_freq_hook_init);
+
 /*
  * A data abort trap was taken, but we did not handle the instruction.
  * Try to abort the user program, or panic if it was the kernel.

arch/arm64/include/asm/traps.h

@@ -110,4 +110,6 @@ static inline u32 arm64_ras_serror_get_severity(u32 esr)
 
 bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned int esr);
 void __noreturn arm64_serror_panic(struct pt_regs *regs, u32 esr);
+static inline void get_timer_count_hook_init(void) {}
+static inline void get_timer_freq_hook_init(void) {}
 #endif

drivers/clocksource/Kconfig

@@ -387,7 +387,7 @@ config SUN50I_ERRATUM_UNKNOWN1
 
 config ARM_ARCH_TIMER_VCT_ACCESS
 	bool "Support for ARM architected timer virtual counter access in userspace"
-	default !ARM64
+	default n
 	depends on ARM_ARCH_TIMER
 	help
 	  This option enables support for reading the ARM architected timer's

drivers/clocksource/arm_arch_timer.c

@@ -26,6 +26,7 @@
 #include <linux/acpi.h>
 
 #include <asm/arch_timer.h>
+#include <asm/traps.h>
 #include <asm/virt.h>
 
 #include <clocksource/arm_arch_timer.h>
@@ -1519,6 +1520,8 @@ static int __init arch_timer_mem_of_init(struct device_node *np)
 	ret = arch_timer_mem_frame_register(frame);
 	if (!ret && !arch_timer_needs_of_probing())
 		ret = arch_timer_common_init();
+	get_timer_count_hook_init();
+	get_timer_freq_hook_init();
 out:
 	kfree(timer_mem);
 	return ret;