refactor(cm): introduce a real manage_extensions_nonsecure()
manage_extensions_nonsecure() is problematic because it updates both
context and in-place registers (unlike its secure/realm counterparts).
The in-place register updates make it particularly tricky, as those
never change for the lifetime of TF-A. However, they are only set when
exiting to NS world. As such, all of TF-A's execution before that
operates under a different context. This is inconsistent and could cause
problems.
This patch Introduce a real manage_extensions_nonsecure() which only
operates on the context structure. It also introduces a
cm_manage_extensions_el3() which only operates on register in-place that
are not context switched. It is called in BL31's entrypoints so that all
of TF-A executes with the same environment once all features have been
converted.
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: Ic579f86c41026d2054863ef44893e0ba4c591da9
diff --git a/bl31/bl31_main.c b/bl31/bl31_main.c
index e70eb55..8f1f043 100644
--- a/bl31/bl31_main.c
+++ b/bl31/bl31_main.c
@@ -112,6 +112,9 @@
******************************************************************************/
void bl31_main(void)
{
+ /* Init registers that never change for the lifetime of TF-A */
+ cm_manage_extensions_el3();
+
NOTICE("BL31: %s\n", version_string);
NOTICE("BL31: %s\n", build_message);
diff --git a/include/lib/el3_runtime/context_mgmt.h b/include/lib/el3_runtime/context_mgmt.h
index 1a76d8e..aa76f3b 100644
--- a/include/lib/el3_runtime/context_mgmt.h
+++ b/include/lib/el3_runtime/context_mgmt.h
@@ -37,6 +37,9 @@
void cm_prepare_el3_exit_ns(void);
#ifdef __aarch64__
+#if IMAGE_BL31
+void cm_manage_extensions_el3(void);
+#endif
#if CTX_INCLUDE_EL2_REGS
void cm_el2_sysregs_context_save(uint32_t security_state);
void cm_el2_sysregs_context_restore(uint32_t security_state);
@@ -84,6 +87,7 @@
#else
void *cm_get_next_context(void);
void cm_set_next_context(void *context);
+static inline void cm_manage_extensions_el3(void) {}
#endif /* __aarch64__ */
#endif /* CONTEXT_MGMT_H */
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 3760b8f..44177fa 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -37,6 +37,7 @@
CASSERT(((TWED_DELAY & ~SCR_TWEDEL_MASK) == 0U), assert_twed_delay_value_check);
#endif /* ENABLE_FEAT_TWED */
+static void manage_extensions_nonsecure(cpu_context_t *ctx);
static void manage_extensions_secure(cpu_context_t *ctx);
static void setup_el1_context(cpu_context_t *ctx, const struct entry_point_info *ep)
@@ -288,6 +289,8 @@
HCRX_EL2_INIT_VAL);
}
#endif /* CTX_INCLUDE_EL2_REGS */
+
+ manage_extensions_nonsecure(ctx);
}
/*******************************************************************************
@@ -504,9 +507,11 @@
/*******************************************************************************
* Enable architecture extensions on first entry to Non-secure world.
* When EL2 is implemented but unused `el2_unused` is non-zero, otherwise
- * it is zero.
+ * it is zero. This function updates some registers in-place and its contents
+ * are being prepared to be moved to cm_manage_extensions_el3 and
+ * cm_manage_extensions_nonsecure.
******************************************************************************/
-static void manage_extensions_nonsecure(bool el2_unused, cpu_context_t *ctx)
+static void manage_extensions_nonsecure_mixed(bool el2_unused, cpu_context_t *ctx)
{
#if IMAGE_BL31
if (is_feat_spe_supported()) {
@@ -549,6 +554,36 @@
}
/*******************************************************************************
+ * Enable architecture extensions for EL3 execution. This function only updates
+ * registers in-place which are expected to either never change or be
+ * overwritten by el3_exit.
+ ******************************************************************************/
+#if IMAGE_BL31
+void cm_manage_extensions_el3(void)
+{
+}
+#endif /* IMAGE_BL31 */
+
+/*******************************************************************************
+ * Enable architecture extensions on first entry to Non-secure world.
+ ******************************************************************************/
+static void manage_extensions_nonsecure(cpu_context_t *ctx)
+{
+#if IMAGE_BL31
+#endif /* IMAGE_BL31 */
+}
+
+/*******************************************************************************
+ * Enable architecture extensions in-place at EL2 on first entry to Non-secure
+ * world when EL2 is empty and unused.
+ ******************************************************************************/
+static void manage_extensions_nonsecure_el2_unused(void)
+{
+#if IMAGE_BL31
+#endif /* IMAGE_BL31 */
+}
+
+/*******************************************************************************
* Enable architecture extensions on first entry to Secure world.
******************************************************************************/
static void manage_extensions_secure(cpu_context_t *ctx)
@@ -845,8 +880,10 @@
*/
write_cnthp_ctl_el2(CNTHP_CTL_RESET_VAL &
~(CNTHP_CTL_ENABLE_BIT));
+
+ manage_extensions_nonsecure_el2_unused();
}
- manage_extensions_nonsecure(el2_unused, ctx);
+ manage_extensions_nonsecure_mixed(el2_unused, ctx);
}
cm_el1_sysregs_context_restore(security_state);
@@ -1167,7 +1204,7 @@
* direct register updates. Therefore, do this here
* instead of when setting up context.
*/
- manage_extensions_nonsecure(0, ctx);
+ manage_extensions_nonsecure_mixed(0, ctx);
/*
* Set the NS bit to be able to access the ICC_SRE_EL2
diff --git a/lib/psci/psci_common.c b/lib/psci/psci_common.c
index bfc09cc..8aa0cce 100644
--- a/lib/psci/psci_common.c
+++ b/lib/psci/psci_common.c
@@ -985,6 +985,9 @@
unsigned int parent_nodes[PLAT_MAX_PWR_LVL] = {0};
psci_power_state_t state_info = { {PSCI_LOCAL_STATE_RUN} };
+ /* Init registers that never change for the lifetime of TF-A */
+ cm_manage_extensions_el3();
+
/*
* Verify that we have been explicitly turned ON or resumed from
* suspend.