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/include/lib/aarch32/smcc_macros.S b/include/lib/aarch32/smcc_macros.S
index 7edf410..cf26175 100644
--- a/include/lib/aarch32/smcc_macros.S
+++ b/include/lib/aarch32/smcc_macros.S
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2017, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -13,6 +13,8 @@
* spsr, lr, sp registers and the `scr` register to the SMC context on entry
* due a SMC call. The `lr` of the current mode (monitor) is expected to be
* already saved. The `sp` must point to the `smc_ctx_t` to save to.
+ * Additionally, also save the 'pmcr' register as this is updated whilst
+ * executing in the secure world.
*/
.macro smcc_save_gp_mode_regs
/* Save r0 - r12 in the SMC context */
@@ -46,6 +48,8 @@
/* lr_mon is already saved by caller */
ldcopr r4, SCR
str r4, [sp, #SMC_CTX_SCR]
+ ldcopr r4, PMCR
+ str r4, [sp, #SMC_CTX_PMCR]
.endm
/*
@@ -70,6 +74,12 @@
stcopr r1, SCR
isb
+ /*
+ * Restore the PMCR register.
+ */
+ ldr r1, [r0, #SMC_CTX_PMCR]
+ stcopr r1, PMCR
+
/* Restore the banked registers including the current SPSR */
add r1, r0, #SMC_CTX_SP_USR
ldm r1!, {r4-r12}