feat(fpmr): disable FPMR trap
This patch enables support of FEAT_FPMR by enabling access
to FPMR register. It achieves it by setting the EnFPM bit of
SCR_EL3. This feature is currently enabled for NS world only.
Reference:
https://developer.arm.com/documentation/109697/2024_09/
Feature-descriptions/The-Armv9-5-architecture-extension?lang=en
Change-Id: I580c409b9b22f8ead0737502280fb9093a3d5dd2
Signed-off-by: Arvind Ram Prakash <arvind.ramprakash@arm.com>
diff --git a/Makefile b/Makefile
index 384c1e4..2b6857b 100644
--- a/Makefile
+++ b/Makefile
@@ -951,8 +951,21 @@
ifeq (${ENABLE_FEAT_RNG_TRAP},1)
$(error "ENABLE_FEAT_RNG_TRAP cannot be used with ARCH=aarch32")
endif
+
+ ifneq (${ENABLE_FEAT_FPMR},0)
+ $(error "ENABLE_FEAT_FPMR cannot be used with ARCH=aarch32")
+ endif
endif #(ARCH=aarch32)
+ifneq (${ENABLE_FEAT_FPMR},0)
+ ifeq (${ENABLE_FEAT_FGT},0)
+ $(error "ENABLE_FEAT_FPMR requires ENABLE_FEAT_FGT")
+ endif
+ ifeq (${ENABLE_FEAT_HCX},0)
+ $(error "ENABLE_FEAT_FPMR requires ENABLE_FEAT_HCX")
+ endif
+endif #(ENABLE_FEAT_FPMR)
+
ifneq (${ENABLE_SME_FOR_NS},0)
ifeq (${ENABLE_SVE_FOR_NS},0)
$(error "ENABLE_SME_FOR_NS requires ENABLE_SVE_FOR_NS")
@@ -1264,6 +1277,7 @@
ENABLE_FEAT_ECV \
ENABLE_FEAT_FGT \
ENABLE_FEAT_FGT2 \
+ ENABLE_FEAT_FPMR \
ENABLE_FEAT_HCX \
ENABLE_FEAT_LS64_ACCDATA \
ENABLE_FEAT_MTE2 \
@@ -1425,6 +1439,7 @@
ENABLE_MPMM_FCONF \
ENABLE_FEAT_FGT \
ENABLE_FEAT_FGT2 \
+ ENABLE_FEAT_FPMR \
ENABLE_FEAT_ECV \
ENABLE_FEAT_AMUv1p1 \
ENABLE_FEAT_SEL2 \
diff --git a/bl31/bl31.mk b/bl31/bl31.mk
index 336ad2b..2f9dc65 100644
--- a/bl31/bl31.mk
+++ b/bl31/bl31.mk
@@ -150,6 +150,10 @@
BL31_SOURCES += lib/extensions/trf/aarch64/trf.c
endif
+ifneq (${ENABLE_FEAT_FPMR},0)
+BL31_SOURCES += lib/extensions/fpmr/fpmr.c
+endif
+
ifeq (${WORKAROUND_CVE_2017_5715},1)
BL31_SOURCES += lib/cpus/aarch64/wa_cve_2017_5715_bpiall.S \
lib/cpus/aarch64/wa_cve_2017_5715_mmu.S
diff --git a/common/feat_detect.c b/common/feat_detect.c
index 8c03ab8..0f6be9f 100644
--- a/common/feat_detect.c
+++ b/common/feat_detect.c
@@ -280,6 +280,12 @@
ID_AA64MMFR3_EL1_D128_MASK);
}
+static unsigned int read_feat_fpmr_id_field(void)
+{
+ return ISOLATE_FIELD(read_id_aa64pfr2_el1(), ID_AA64PFR2_EL1_FPMR_SHIFT,
+ ID_AA64PFR2_EL1_FPMR_MASK);
+}
+
/***********************************************************************************
* TF-A supports many Arm architectural features starting from arch version
* (8.0 till 8.7+). These features are mostly enabled through build flags. This
@@ -405,6 +411,8 @@
"SME", 1, 2);
check_feature(ENABLE_SME2_FOR_NS, read_feat_sme_id_field(),
"SME2", 2, 2);
+ check_feature(ENABLE_FEAT_FPMR, read_feat_fpmr_id_field(),
+ "FPMR", 1, 1);
/* v9.3 features */
check_feature(ENABLE_FEAT_D128, read_feat_d128_id_field(),
diff --git a/docs/getting_started/build-options.rst b/docs/getting_started/build-options.rst
index 7d067c6..bd11d68 100644
--- a/docs/getting_started/build-options.rst
+++ b/docs/getting_started/build-options.rst
@@ -351,6 +351,12 @@
This flag can take the values 0 to 2, to align with the ``ENABLE_FEAT``
mechanism. Default value is ``0``.
+- ``ENABLE_FEAT_FPMR``: Numerical value to enable support for Floating Point
+ Mode Register feature, allowing access to the FPMR register. FPMR register
+ controls the behaviors of FP8 instructions. It is an optional architectural
+ feature from v9.2 and upwards. This flag can take value of 0 to 2, to align
+ with the ``FEATURE_DETECTION`` mechanism. Default value is ``0``.
+
- ``ENABLE_FEAT_FGT``: Numeric value to enable support for FGT (Fine Grain Traps)
feature allowing for access to the HDFGRTR_EL2 (Hypervisor Debug Fine-Grained
Read Trap Register) during EL2 to EL3 context save/restore operations.
diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index 737d07a..3a7e2eb 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -465,6 +465,11 @@
#define ID_AA64PFR2_EL1_MTEFAR_SHIFT U(8)
#define ID_AA64PFR2_EL1_MTEFAR_MASK ULL(0xf)
+#define ID_AA64PFR2_EL1_FPMR_SHIFT U(32)
+#define ID_AA64PFR2_EL1_FPMR_MASK ULL(0xf)
+
+#define FPMR_IMPLEMENTED ULL(0x1)
+
#define VDISR_EL2 S3_4_C12_C1_1
#define VSESR_EL2 S3_4_C5_C2_3
@@ -605,6 +610,7 @@
#define SCR_NSE_SHIFT U(62)
#define SCR_FGTEN2_BIT (UL(1) << 59)
#define SCR_NSE_BIT (ULL(1) << SCR_NSE_SHIFT)
+#define SCR_EnFPM_BIT (ULL(1) << 50)
#define SCR_GPF_BIT (UL(1) << 48)
#define SCR_D128En_BIT (UL(1) << 47)
#define SCR_TWEDEL_SHIFT U(30)
@@ -1522,6 +1528,11 @@
******************************************************************************/
#define CLUSTERPWRDN_EL1 S3_0_c15_c3_6
+/*******************************************************************************
+ * FEAT_FPMR - Floating point Mode Register
+ ******************************************************************************/
+#define FPMR S3_3_C4_C4_2
+
/* CLUSTERPWRDN_EL1 register definitions */
#define DSU_CLUSTER_PWR_OFF 0
#define DSU_CLUSTER_PWR_ON 1
diff --git a/include/arch/aarch64/arch_features.h b/include/arch/aarch64/arch_features.h
index 59188da..8bdc13c 100644
--- a/include/arch/aarch64/arch_features.h
+++ b/include/arch/aarch64/arch_features.h
@@ -142,6 +142,8 @@
* +----------------------------+
* | FEAT_LS64_ACCDATA |
* +----------------------------+
+ * | FEAT_FPMR |
+ * +----------------------------+
*/
__attribute__((always_inline))
@@ -284,6 +286,12 @@
ID_AA64MMFR3_EL1_D128_MASK, D128_IMPLEMENTED,
ENABLE_FEAT_D128)
+/* FEAT_FPMR */
+CREATE_FEATURE_FUNCS(feat_fpmr, id_aa64pfr2_el1, ID_AA64PFR2_EL1_FPMR_SHIFT,
+ ID_AA64PFR2_EL1_FPMR_MASK, FPMR_IMPLEMENTED,
+ ENABLE_FEAT_FPMR)
+
+
__attribute__((always_inline))
static inline bool is_feat_sxpie_supported(void)
{
diff --git a/include/arch/aarch64/arch_helpers.h b/include/arch/aarch64/arch_helpers.h
index 119c428..3f3f14d 100644
--- a/include/arch/aarch64/arch_helpers.h
+++ b/include/arch/aarch64/arch_helpers.h
@@ -718,6 +718,8 @@
DEFINE_RENAME_SYSREG_RW_FUNCS(gptbr_el3, GPTBR_EL3)
DEFINE_RENAME_SYSREG_RW_FUNCS(gpccr_el3, GPCCR_EL3)
+DEFINE_RENAME_SYSREG_RW_FUNCS(fpmr, FPMR)
+
#define IS_IN_EL(x) \
(GET_EL(read_CurrentEl()) == MODE_EL##x)
diff --git a/include/lib/extensions/fpmr.h b/include/lib/extensions/fpmr.h
new file mode 100644
index 0000000..bc3ee9e
--- /dev/null
+++ b/include/lib/extensions/fpmr.h
@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2024, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef FPMR_H
+#define FPMR_H
+
+#include <context.h>
+
+#if ENABLE_FEAT_FPMR
+void fpmr_enable_per_world(per_world_context_t *per_world_ctx);
+#else
+static inline void fpmr_enable_per_world(per_world_context_t *per_world_ctx)
+{
+}
+#endif /* ENABLE_FEAT_FPMR */
+
+#endif /* FPMR_H */
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 4ae1306..f963ed1 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -28,6 +28,7 @@
#include <lib/extensions/brbe.h>
#include <lib/extensions/debug_v8p9.h>
#include <lib/extensions/fgt2.h>
+#include <lib/extensions/fpmr.h>
#include <lib/extensions/mpam.h>
#include <lib/extensions/pmuv3.h>
#include <lib/extensions/sme.h>
@@ -291,6 +292,13 @@
scr_el3 |= SCR_D128En_BIT;
}
+ if (is_feat_fpmr_supported()) {
+ /* Set the EnFPM bit in SCR_EL3 to enable access to FPMR
+ * register.
+ */
+ scr_el3 |= SCR_EnFPM_BIT;
+ }
+
write_ctx_reg(state, CTX_SCR_EL3, scr_el3);
/* Initialize EL2 context registers */
@@ -714,6 +722,10 @@
if (is_feat_mpam_supported()) {
mpam_enable_per_world(&per_world_context[CPU_CONTEXT_NS]);
}
+
+ if (is_feat_fpmr_supported()) {
+ fpmr_enable_per_world(&per_world_context[CPU_CONTEXT_NS]);
+ }
}
#endif /* IMAGE_BL31 */
diff --git a/lib/extensions/fpmr/fpmr.c b/lib/extensions/fpmr/fpmr.c
new file mode 100644
index 0000000..8e37e7a
--- /dev/null
+++ b/lib/extensions/fpmr/fpmr.c
@@ -0,0 +1,20 @@
+/*
+ * Copyright (c) 2024, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <arch_features.h>
+#include <arch_helpers.h>
+#include <lib/extensions/fpmr.h>
+
+void fpmr_enable_per_world(per_world_context_t *per_world_ctx)
+{
+ u_register_t reg;
+
+ /* Disable Floating point Trap in CPTR_EL3. */
+ reg = per_world_ctx->ctx_cptr_el3;
+ reg &= ~TFP_BIT;
+ per_world_ctx->ctx_cptr_el3 = reg;
+}
diff --git a/make_helpers/arch_features.mk b/make_helpers/arch_features.mk
index 57609d5..a1db0b8 100644
--- a/make_helpers/arch_features.mk
+++ b/make_helpers/arch_features.mk
@@ -408,6 +408,9 @@
# if FEAT_BRBE is implemented.
ENABLE_BRBE_FOR_NS ?= 0
+# Flag to enable Floating point exception Mode Register Feature (FEAT_FPMR)
+ENABLE_FEAT_FPMR ?= 0
+
#----
# 9.3
#----
diff --git a/plat/arm/board/fvp/platform.mk b/plat/arm/board/fvp/platform.mk
index 1340a65..3b638e4 100644
--- a/plat/arm/board/fvp/platform.mk
+++ b/plat/arm/board/fvp/platform.mk
@@ -57,6 +57,7 @@
ENABLE_BRBE_FOR_NS := 2
ENABLE_TRBE_FOR_NS := 2
ENABLE_FEAT_D128 := 2
+ ENABLE_FEAT_FPMR := 2
endif
ENABLE_SYS_REG_TRACE_FOR_NS := 2