AArch32: Disable Secure Cycle Counter
This patch changes implementation for disabling Secure Cycle
Counter. For ARMv8.5 the counter gets disabled by setting
SDCR.SCCD bit on CPU cold/warm boot. For the earlier
architectures PMCR register is saved/restored on secure
world entry/exit from/to Non-secure state, and cycle counting
gets disabled by setting PMCR.DP bit.
In 'include\aarch32\arch.h' header file new
ARMv8.5-PMU related definitions were added.
Change-Id: Ia8845db2ebe8de940d66dff479225a5b879316f8
Signed-off-by: Alexei Fedorov <Alexei.Fedorov@arm.com>
diff --git a/include/arch/aarch32/smccc_macros.S b/include/arch/aarch32/smccc_macros.S
index 1fe6c64..4ec2292 100644
--- a/include/arch/aarch32/smccc_macros.S
+++ b/include/arch/aarch32/smccc_macros.S
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -58,7 +58,6 @@
stm r0!, {r2}
stcopr r4, SCR
- isb
#else
/* Save the banked registers including the current SPSR and LR */
mrs r4, sp_usr
@@ -85,10 +84,34 @@
/* lr_mon is already saved by caller */
ldcopr r4, SCR
+
+#if ARM_ARCH_MAJOR > 7
+ /*
+ * Check if earlier initialization of SDCR.SCCD to 1
+ * failed, meaning that ARMv8-PMU is not implemented,
+ * cycle counting is not disabled and PMCR should be
+ * saved in Non-secure context.
+ */
+ ldcopr r5, SDCR
+ tst r5, #SDCR_SCCD_BIT
+ bne 1f
+#endif
+ /* Secure Cycle Counter is not disabled */
#endif
- str r4, [sp, #SMC_CTX_SCR]
- ldcopr r4, PMCR
- str r4, [sp, #SMC_CTX_PMCR]
+ ldcopr r5, PMCR
+
+ /* Check caller's security state */
+ tst r4, #SCR_NS_BIT
+ beq 2f
+
+ /* Save PMCR if called from Non-secure state */
+ str r5, [sp, #SMC_CTX_PMCR]
+
+ /* Disable cycle counter when event counting is prohibited */
+2: orr r5, r5, #PMCR_DP_BIT
+ stcopr r5, PMCR
+ isb
+1: str r4, [sp, #SMC_CTX_SCR]
.endm
/*
@@ -114,11 +137,30 @@
isb
/*
+ * Restore PMCR when returning to Non-secure state
+ */
+ tst r1, #SCR_NS_BIT
+ beq 2f
+
+ /*
+ * Back to Non-secure state
+ */
+#if ARM_ARCH_MAJOR > 7
+ /*
+ * Check if earlier initialization SDCR.SCCD to 1
+ * failed, meaning that ARMv8-PMU is not implemented and
+ * PMCR should be restored from Non-secure context.
+ */
+ ldcopr r1, SDCR
+ tst r1, #SDCR_SCCD_BIT
+ bne 2f
+#endif
+ /*
* Restore the PMCR register.
*/
ldr r1, [r0, #SMC_CTX_PMCR]
stcopr r1, PMCR
-
+2:
/* Restore the banked registers including the current SPSR */
add r1, r0, #SMC_CTX_SP_USR