AArch64: Disable Secure Cycle Counter
This patch fixes an issue when secure world timing information
can be leaked because Secure Cycle Counter is not disabled.
For ARMv8.5 the counter gets disabled by setting MDCR_El3.SCCD
bit on CPU cold/warm boot.
For the earlier architectures PMCR_EL0 register is saved/restored
on secure world entry/exit from/to Non-secure state, and cycle
counting gets disabled by setting PMCR_EL0.DP bit.
'include\aarch64\arch.h' header file was tided up and new
ARMv8.5-PMU related definitions were added.
Change-Id: I6f56db6bc77504634a352388990ad925a69ebbfa
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 05ba5ed..bd5b3aa 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -66,7 +66,7 @@
void cm_setup_context(cpu_context_t *ctx, const entry_point_info_t *ep)
{
unsigned int security_state;
- uint32_t scr_el3, pmcr_el0;
+ uint32_t scr_el3;
el3_state_t *state;
gp_regs_t *gp_regs;
unsigned long sctlr_elx, actlr_elx;
@@ -225,31 +225,10 @@
actlr_elx = read_actlr_el1();
write_ctx_reg((get_sysregs_ctx(ctx)), (CTX_ACTLR_EL1), (actlr_elx));
- if (security_state == SECURE) {
- /*
- * Initialise PMCR_EL0 for secure context only, setting all
- * fields rather than relying on hw. Some fields are
- * architecturally UNKNOWN on reset.
- *
- * PMCR_EL0.LC: Set to one so that cycle counter overflow, that
- * is recorded in PMOVSCLR_EL0[31], occurs on the increment
- * that changes PMCCNTR_EL0[63] from 1 to 0.
- *
- * PMCR_EL0.DP: Set to one so that the cycle counter,
- * PMCCNTR_EL0 does not count when event counting is prohibited.
- *
- * PMCR_EL0.X: Set to zero to disable export of events.
- *
- * PMCR_EL0.D: Set to zero so that, when enabled, PMCCNTR_EL0
- * counts on every clock cycle.
- */
- pmcr_el0 = ((PMCR_EL0_RESET_VAL | PMCR_EL0_LC_BIT
- | PMCR_EL0_DP_BIT)
- & ~(PMCR_EL0_X_BIT | PMCR_EL0_D_BIT));
- write_ctx_reg(get_sysregs_ctx(ctx), CTX_PMCR_EL0, pmcr_el0);
- }
-
- /* Populate EL3 state so that we've the right context before doing ERET */
+ /*
+ * Populate EL3 state so that we've the right context
+ * before doing ERET
+ */
state = get_el3state_ctx(ctx);
write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
write_ctx_reg(state, CTX_ELR_EL3, ep->pc);
@@ -441,6 +420,29 @@
* relying on hw. Some fields are architecturally
* UNKNOWN on reset.
*
+ * MDCR_EL2.HLP: Set to one so that event counter
+ * overflow, that is recorded in PMOVSCLR_EL0[0-30],
+ * occurs on the increment that changes
+ * PMEVCNTR<n>_EL0[63] from 1 to 0, when ARMv8.5-PMU is
+ * implemented. This bit is RES0 in versions of the
+ * architecture earlier than ARMv8.5, setting it to 1
+ * doesn't have any effect on them.
+ *
+ * MDCR_EL2.TTRF: Set to zero so that access to Trace
+ * Filter Control register TRFCR_EL1 at EL1 is not
+ * trapped to EL2. This bit is RES0 in versions of
+ * the architecture earlier than ARMv8.4.
+ *
+ * MDCR_EL2.HPMD: Set to one so that event counting is
+ * prohibited at EL2. This bit is RES0 in versions of
+ * the architecture earlier than ARMv8.1, setting it
+ * to 1 doesn't have any effect on them.
+ *
+ * MDCR_EL2.TPMS: Set to zero so that accesses to
+ * Statistical Profiling control registers from EL1
+ * do not trap to EL2. This bit is RES0 when SPE is
+ * not implemented.
+ *
* MDCR_EL2.TDRA: Set to zero so that Non-secure EL0 and
* EL1 System register accesses to the Debug ROM
* registers are not trapped to EL2.
@@ -469,13 +471,15 @@
* MDCR_EL2.HPMN: Set to value of PMCR_EL0.N which is the
* architecturally-defined reset value.
*/
- mdcr_el2 = ((MDCR_EL2_RESET_VAL |
- ((read_pmcr_el0() & PMCR_EL0_N_BITS)
- >> PMCR_EL0_N_SHIFT)) &
- ~(MDCR_EL2_TDRA_BIT | MDCR_EL2_TDOSA_BIT
- | MDCR_EL2_TDA_BIT | MDCR_EL2_TDE_BIT
- | MDCR_EL2_HPME_BIT | MDCR_EL2_TPM_BIT
- | MDCR_EL2_TPMCR_BIT));
+ mdcr_el2 = ((MDCR_EL2_RESET_VAL | MDCR_EL2_HLP |
+ MDCR_EL2_HPMD) |
+ ((read_pmcr_el0() & PMCR_EL0_N_BITS)
+ >> PMCR_EL0_N_SHIFT)) &
+ ~(MDCR_EL2_TTRF | MDCR_EL2_TPMS |
+ MDCR_EL2_TDRA_BIT | MDCR_EL2_TDOSA_BIT |
+ MDCR_EL2_TDA_BIT | MDCR_EL2_TDE_BIT |
+ MDCR_EL2_HPME_BIT | MDCR_EL2_TPM_BIT |
+ MDCR_EL2_TPMCR_BIT);
write_mdcr_el2(mdcr_el2);