Init and save / restore of PMCR_EL0 / PMCR
Currently TF does not initialise the PMCR_EL0 register in
the secure context or save/restore the register.
In particular, the DP field may not be set to one to prohibit
cycle counting in the secure state, even though event counting
generally is prohibited via the default setting of MDCR_EL3.SMPE
to 0.
This patch initialises PMCR_EL0.DP to one in the secure state
to prohibit cycle counting and also initialises other fields
that have an architectually UNKNOWN reset value.
Additionally, PMCR_EL0 is added to the list of registers that are
saved and restored during a world switch.
Similar changes are made for PMCR for the AArch32 execution state.
NOTE: secure world code at lower ELs that assume other values in PMCR_EL0
will be impacted.
Change-Id: Iae40e8c0a196d74053accf97063ebc257b4d2f3a
Signed-off-by: David Cunado <david.cunado@arm.com>
diff --git a/bl32/sp_min/aarch32/entrypoint.S b/bl32/sp_min/aarch32/entrypoint.S
index d868c53..cd9fe5c 100644
--- a/bl32/sp_min/aarch32/entrypoint.S
+++ b/bl32/sp_min/aarch32/entrypoint.S
@@ -162,6 +162,15 @@
stcopr r0, SCR
isb
+ /*
+ * Set PMCR.DP to 1 to prohibit cycle counting whilst in Secure Mode.
+ * Also, the PMCR.LC field has an architecturally UNKNOWN value on reset
+ * and so set to 1 as ARM has deprecated use of PMCR.LC=0.
+ */
+ ldcopr r0, PMCR
+ orr r0, r0, #(PMCR_LC_BIT | PMCR_DP_BIT)
+ stcopr r0, PMCR
+
ldr r0, [r2, #SMC_CTX_GPREG_R0] /* smc_fid */
/* Check whether an SMC64 is issued */
tst r0, #(FUNCID_CC_MASK << FUNCID_CC_SHIFT)
@@ -210,6 +219,15 @@
stcopr r0, SCR
isb
+ /*
+ * Set PMCR.DP to 1 to prohibit cycle counting whilst in Secure Mode.
+ * Also, the PMCR.LC field has an architecturally UNKNOWN value on reset
+ * and so set to 1 as ARM has deprecated use of PMCR.LC=0.
+ */
+ ldcopr r0, PMCR
+ orr r0, r0, #(PMCR_LC_BIT | PMCR_DP_BIT)
+ stcopr r0, PMCR
+
push {r2, r3}
bl sp_min_fiq
pop {r0, r3}