core: allow Secure Partition TAs to access frequency timers

Standalone MM, a Secure Partition TA, requires access to a timer. This makes SPM disabling frequency timer access trap on entering SP TA. Signed-off-by: Pipat Methavanitpong <[email protected]>
OP-TEE · Jul 15, 2020 · e16252a · e16252a
1 parent 305a152
commit e16252a
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diff --git a/core/arch/arm/kernel/secure_partition.c b/core/arch/arm/kernel/secure_partition.c
@@ -77,9 +77,13 @@ static TEE_Result sec_part_enter_user_mode(struct sec_part_ctx *spc)
 	uint32_t exceptions = 0;
 	uint32_t panic_code = 0;
 	uint32_t panicked = 0;
+	uint64_t cntkctl;
 
 	exceptions = thread_mask_exceptions(THREAD_EXCP_ALL);
+	cntkctl = thread_get_cntkctl_el1();
+	thread_set_cntkctl_el1(cntkctl | 0x3);
 	__thread_enter_user_mode(&spc->regs, &panicked, &panic_code);
+	thread_set_cntkctl_el1(cntkctl);
 	thread_unmask_exceptions(exceptions);
 
 	clear_vfp_state(spc);

diff --git a/core/arch/arm/kernel/thread_a64.S b/core/arch/arm/kernel/thread_a64.S
@@ -69,6 +69,14 @@ FUNC thread_init_vbar , :
 END_FUNC thread_init_vbar
 DECLARE_KEEP_PAGER thread_init_vbar
 
+FUNC thread_get_cntkctl_el1 , :
+	mrs	x0, CNTKCTL_EL1
+	ret
+
+FUNC thread_set_cntkctl_el1 , :
+	msr	CNTKCTL_EL1, x0
+	ret
+
 /*
  * uint32_t __thread_enter_user_mode(struct thread_ctx_regs *regs,
  *				     uint32_t *exit_status0,

diff --git a/core/arch/arm/kernel/thread_private.h b/core/arch/arm/kernel/thread_private.h
@@ -176,6 +176,12 @@ void thread_set_irq_sp(vaddr_t sp);
 void thread_set_fiq_sp(vaddr_t sp);
 #endif /*ARM32*/
 
+/* Returns EL0 timer access permission */
+uint64_t thread_get_cntkctl_el1(void);
+
+/* Sets EL0 timer access permission */
+void thread_set_cntkctl_el1(uint64_t val);
+
 /* Checks stack canaries */
 void thread_check_canaries(void);