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Commit 7c3d147b authored by Shadab Naseem's avatar Shadab Naseem Committed by Lijuan Gao
Browse files

arm: traps: emulate a MRC instruction reading CNTFRQ register 



Emulate a MRC instruction reading CNTFRQ register.

Change-Id: I054121896d2173fc064aa75b4398178b04a701f7
Signed-off-by: default avatarShadab Naseem <snaseem@codeaurora.org>
parent f01ad8d1

arch/arm/include/asm/traps.h

+1 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ 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);

arch/arm/kernel/traps.c

+35 −0
Original line number Diff line number Diff line
@@ -748,6 +748,41 @@ void get_timer_count_hook_init(void) 
}

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

+1 −0
Original line number Diff line number Diff line
@@ -111,4 +111,5 @@ 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/arm_arch_timer.c

+1 −0
Original line number Diff line number Diff line
@@ -1521,6 +1521,7 @@ static int __init arch_timer_mem_of_init(struct device_node *np) 
	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;