diff --git a/docs/getting_started/porting-guide.rst b/docs/getting_started/porting-guide.rst index 2d17f12..2ad7256 100644 --- a/docs/getting_started/porting-guide.rst +++ b/docs/getting_started/porting-guide.rst @@ -1890,6 +1890,21 @@ of the system counter, which is retrieved from the first entry in the frequency modes table. +Function : plat_arm_set_twedel_scr_el3() [optional] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +:: + + Argument : void + Return : uint32_t + +This function is used in v8.6+ systems to set the WFE trap delay value in +SCR_EL3. If this function returns TWED_DISABLED or is left unimplemented, this +feature is not enabled. The only hook provided is to set the TWED fields in +SCR_EL3, there are similar fields in HCR_EL2, SCTLR_EL2, and SCTLR_EL1 to adjust +the WFE trap delays in lower ELs and these fields should be set by the +appropriate EL2 or EL1 code depending on the platform configuration. + #define : PLAT_PERCPU_BAKERY_LOCK_SIZE [optional] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h index 81e0f27..92e6737 100644 --- a/include/arch/aarch64/arch.h +++ b/include/arch/aarch64/arch.h @@ -226,6 +226,12 @@ #define ID_AA64MMFR0_EL1_TGRAN16_SUPPORTED ULL(0x1) #define ID_AA64MMFR0_EL1_TGRAN16_NOT_SUPPORTED ULL(0x0) +/* ID_AA64MMFR1_EL1 definitions */ +#define ID_AA64MMFR1_EL1_TWED_SHIFT U(32) +#define ID_AA64MMFR1_EL1_TWED_MASK ULL(0xf) +#define ID_AA64MMFR1_EL1_TWED_SUPPORTED ULL(0x1) +#define ID_AA64MMFR1_EL1_TWED_NOT_SUPPORTED ULL(0x0) + /* ID_AA64MMFR2_EL1 definitions */ #define ID_AA64MMFR2_EL1 S3_0_C0_C7_2 @@ -312,6 +318,9 @@ /* SCR definitions */ #define SCR_RES1_BITS ((U(1) << 4) | (U(1) << 5)) +#define SCR_TWEDEL_SHIFT U(30) +#define SCR_TWEDEL_MASK ULL(0xf) +#define SCR_TWEDEn_BIT (UL(1) << 29) #define SCR_ATA_BIT (U(1) << 26) #define SCR_FIEN_BIT (U(1) << 21) #define SCR_EEL2_BIT (U(1) << 18) diff --git a/include/arch/aarch64/arch_features.h b/include/arch/aarch64/arch_features.h index 9513e97..49d827d 100644 --- a/include/arch/aarch64/arch_features.h +++ b/include/arch/aarch64/arch_features.h @@ -58,4 +58,10 @@ ID_AA64PFR0_SEL2_MASK) == 1ULL; } +static inline bool is_armv8_6_twed_present(void) +{ + return (((read_id_aa64mmfr1_el1() >> ID_AA64MMFR1_EL1_TWED_SHIFT) & + ID_AA64MMFR1_EL1_TWED_MASK) == ID_AA64MMFR1_EL1_TWED_SUPPORTED); +} + #endif /* ARCH_FEATURES_H */ diff --git a/include/arch/aarch64/arch_helpers.h b/include/arch/aarch64/arch_helpers.h index 9cd1ae5..09059ca 100644 --- a/include/arch/aarch64/arch_helpers.h +++ b/include/arch/aarch64/arch_helpers.h @@ -358,6 +358,7 @@ DEFINE_SYSREG_READ_FUNC(midr_el1) DEFINE_SYSREG_READ_FUNC(mpidr_el1) DEFINE_SYSREG_READ_FUNC(id_aa64mmfr0_el1) +DEFINE_SYSREG_READ_FUNC(id_aa64mmfr1_el1) DEFINE_SYSREG_RW_FUNCS(scr_el3) DEFINE_SYSREG_RW_FUNCS(hcr_el2) diff --git a/include/lib/extensions/twed.h b/include/lib/extensions/twed.h new file mode 100644 index 0000000..eac4aa3 --- /dev/null +++ b/include/lib/extensions/twed.h @@ -0,0 +1,16 @@ +/* + * Copyright (c) 2020, Arm Limited. All rights reserved. + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#ifndef TWED_H +#define TWED_H + +#include + +#define TWED_DISABLED U(0xFFFFFFFF) + +uint32_t plat_arm_set_twedel_scr_el3(void); + +#endif /* TWEDE_H */ diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c index 0314a85..64a2d7b 100644 --- a/lib/el3_runtime/aarch64/context_mgmt.c +++ b/lib/el3_runtime/aarch64/context_mgmt.c @@ -22,6 +22,7 @@ #include #include #include +#include #include @@ -229,6 +230,24 @@ sctlr_elx |= SCTLR_IESB_BIT; #endif + /* Enable WFE trap delay in SCR_EL3 if supported and configured */ + if (is_armv8_6_twed_present()) { + uint32_t delay = plat_arm_set_twedel_scr_el3(); + + if (delay != TWED_DISABLED) { + /* Make sure delay value fits */ + assert((delay & ~SCR_TWEDEL_MASK) == 0U); + + /* Set delay in SCR_EL3 */ + scr_el3 &= ~(SCR_TWEDEL_MASK << SCR_TWEDEL_SHIFT); + scr_el3 |= ((delay & SCR_TWEDEL_MASK) + << SCR_TWEDEL_SHIFT); + + /* Enable WFE delay */ + scr_el3 |= SCR_TWEDEn_BIT; + } + } + /* * Store the initialised SCTLR_EL1 value in the cpu_context - SCTLR_EL2 * and other EL2 registers are set up by cm_prepare_ns_entry() as they diff --git a/plat/common/aarch64/plat_common.c b/plat/common/aarch64/plat_common.c index 63871d9..b8a4d01 100644 --- a/plat/common/aarch64/plat_common.c +++ b/plat/common/aarch64/plat_common.c @@ -11,6 +11,7 @@ #if RAS_EXTENSION #include #endif +#include #include #include @@ -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 @@ #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; +}