refactor(cpufeat): enable SYS_REG_TRACE for FEAT_STATE_CHECKED
At the moment we only support access to the trace unit by system
registers (SYS_REG_TRACE) to be either unconditionally compiled in, or
to be not supported at all.
Add support for runtime detection (ENABLE_SYS_REG_TRACE_FOR_NS=2), by
adding is_feat_sys_reg_trace_supported(). That function considers both
build time settings and runtime information (if needed), and is used
before we access SYS_REG_TRACE related registers.
The FVP platform decided to compile in support unconditionally (=1),
even though this is an optional feature, so it is not available with the
FVP model's default command line.
Change that to the now supported dynamic option (=2), so the right
decision can be made by the code at runtime.
Change-Id: I450a574a4f6bd9fc269887037049c94c906f54b2
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/lib/extensions/sys_reg_trace/aarch64/sys_reg_trace.c b/lib/extensions/sys_reg_trace/aarch64/sys_reg_trace.c
index 960d698..e61cb90 100644
--- a/lib/extensions/sys_reg_trace/aarch64/sys_reg_trace.c
+++ b/lib/extensions/sys_reg_trace/aarch64/sys_reg_trace.c
@@ -10,28 +10,17 @@
#include <arch_helpers.h>
#include <lib/extensions/sys_reg_trace.h>
-static bool sys_reg_trace_supported(void)
-{
- uint64_t features;
-
- features = read_id_aa64dfr0_el1() >> ID_AA64DFR0_TRACEVER_SHIFT;
- return ((features & ID_AA64DFR0_TRACEVER_MASK) ==
- ID_AA64DFR0_TRACEVER_SUPPORTED);
-}
-
void sys_reg_trace_enable(cpu_context_t *ctx)
{
uint64_t val;
- if (sys_reg_trace_supported()) {
- /* Retrieve CPTR_EL3 value from the given context 'ctx',
- * and update CPTR_EL3.TTA bit to 0.
- * This function is called while switching context to NS to
- * allow system trace register access to NS-EL2 and NS-EL1
- * when NS-EL2 is implemented but not used.
- */
- val = read_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3);
- val &= ~TTA_BIT;
- write_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3, val);
- }
+ /* Retrieve CPTR_EL3 value from the given context 'ctx',
+ * and update CPTR_EL3.TTA bit to 0.
+ * This function is called while switching context to NS to
+ * allow system trace register access to NS-EL2 and NS-EL1
+ * when NS-EL2 is implemented but not used.
+ */
+ val = read_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3);
+ val &= ~TTA_BIT;
+ write_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3, val);
}