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authorjohpow01 <john.powell@arm.com>2020-04-22 14:05:13 -0500
committerJohn <john.powell@arm.com>2020-05-19 21:49:52 +0000
commit6cac724d52cc8d6cac9b47f186cc47f4b3cf6bd6 (patch)
tree1dbf1feb70c4dbc8636b87f0fdb83766f0bac6e8 /plat/common
parentf1a1653ce17861441383ae58a3df929cb521c9d8 (diff)
downloadtrusted-firmware-a-6cac724d52cc8d6cac9b47f186cc47f4b3cf6bd6.tar.gz
Enable v8.6 WFE trap delays
This patch enables the v8.6 extension to add a delay before WFE traps are taken. A weak hook plat_arm_set_twedel_scr_el3 has been added in plat/common/aarch64/plat_common.c that disables this feature by default but platform-specific code can override it when needed. The only hook provided sets the TWED fields in SCR_EL3, there are similar fields in HCR_EL2, SCTLR_EL2, and SCTLR_EL1 to control WFE trap delays in lower ELs but these should be configured by code running at EL2 and/or EL1 depending on the platform configuration and is outside the scope of TF-A. Signed-off-by: John Powell <john.powell@arm.com> Change-Id: I0a9bb814205efeab693a3d0a0623e62144abba2d
Diffstat (limited to 'plat/common')
-rw-r--r--plat/common/aarch64/plat_common.c15
1 files changed, 15 insertions, 0 deletions
diff --git a/plat/common/aarch64/plat_common.c b/plat/common/aarch64/plat_common.c
index 63871d9e57..b8a4d012e8 100644
--- a/plat/common/aarch64/plat_common.c
+++ b/plat/common/aarch64/plat_common.c
@@ -11,6 +11,7 @@
#if RAS_EXTENSION
#include <lib/extensions/ras.h>
#endif
+#include <lib/extensions/twed.h>
#include <lib/xlat_tables/xlat_mmu_helpers.h>
#include <plat/common/platform.h>
@@ -20,6 +21,7 @@
* platforms but may also be overridden by a platform if required.
*/
#pragma weak bl31_plat_runtime_setup
+#pragma weak plat_arm_set_twedel_scr_el3
#if SDEI_SUPPORT
#pragma weak plat_sdei_handle_masked_trigger
@@ -100,3 +102,16 @@ void plat_ea_handler(unsigned int ea_reason, uint64_t syndrome, void *cookie,
#endif
panic();
}
+
+/*******************************************************************************
+ * In v8.6+ platforms with delayed trapping of WFE this hook sets the delay. It
+ * is a weak function definition so can be overridden depending on the
+ * requirements of a platform. The only hook provided is for the TWED fields
+ * in SCR_EL3, the TWED fields in HCR_EL2, SCTLR_EL2, and SCTLR_EL1 should be
+ * configured as needed in lower exception levels.
+ ******************************************************************************/
+
+uint32_t plat_arm_set_twedel_scr_el3(void)
+{
+ return TWED_DISABLED;
+}