lib: sbi: implement SBI FWFT extension

The SBI FWFT extension defines a set of function that can be called
to control the configuration of some platform features (misaligned
trap delegation, etc). This patch implements sbi_fwft_set() and
sbi_fwft_get() as defined in the specification [1].

Link: https://lists.riscv.org/g/tech-prs/message/924
Signed-off-by: Clément Léger <cleger@rivosinc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

diff --git a/lib/sbi/Kconfig b/lib/sbi/Kconfig
index cc8e0318cb07400b1633a8b035f74acc06786483..6cf54ce4d385e4098f72d57cfc2db90c51ffbf00 100644 (file)
--- a/lib/sbi/Kconfig
+++ b/lib/sbi/Kconfig
@@ -38,6 +38,10 @@ config SBI_ECALL_CPPC
        bool "CPPC extension"
        default y
 
+config SBI_ECALL_FWFT
+       bool "Firmware Feature extension"
+       default y
+
 config SBI_ECALL_LEGACY
        bool "SBI v0.1 legacy extensions"
        default y

diff --git a/lib/sbi/objects.mk b/lib/sbi/objects.mk
index 221e72cdfb7bf773ebb846bb874b6c2fe95997d5..211abad60fcad1f71e90ebdf95f0ab9cfbd2b4f7 100644 (file)
--- a/lib/sbi/objects.mk
+++ b/lib/sbi/objects.mk
@@ -46,6 +46,9 @@ libsbi-objs-$(CONFIG_SBI_ECALL_DBCN) += sbi_ecall_dbcn.o
 carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_CPPC) += ecall_cppc
 libsbi-objs-$(CONFIG_SBI_ECALL_CPPC) += sbi_ecall_cppc.o
 
+carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_FWFT) += ecall_fwft
+libsbi-objs-$(CONFIG_SBI_ECALL_FWFT) += sbi_ecall_fwft.o
+
 carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_LEGACY) += ecall_legacy
 libsbi-objs-$(CONFIG_SBI_ECALL_LEGACY) += sbi_ecall_legacy.o
 

diff --git a/lib/sbi/sbi_ecall_fwft.c b/lib/sbi/sbi_ecall_fwft.c
new file mode 100644 (file)
index 0000000..267cbab
--- /dev/null
+++ b/lib/sbi/sbi_ecall_fwft.c
@@ -0,0 +1,49 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2024 Rivos Inc.
+ *
+ * Authors:
+ *   Clément Léger <cleger@rivosinc.com>
+ */
+
+#include <sbi/sbi_ecall.h>
+#include <sbi/sbi_ecall_interface.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_fwft.h>
+#include <sbi/sbi_trap.h>
+
+static int sbi_ecall_fwft_handler(unsigned long extid, unsigned long funcid,
+                                struct sbi_trap_regs *regs,
+                                struct sbi_ecall_return *out)
+{
+       int ret = 0;
+
+       switch (funcid) {
+       case SBI_EXT_FWFT_SET:
+               ret = sbi_fwft_set(regs->a0, regs->a1, regs->a2);
+               break;
+       case SBI_EXT_FWFT_GET:
+               ret = sbi_fwft_get(regs->a0, &out->value);
+               break;
+       default:
+               ret = SBI_ENOTSUPP;
+               break;
+       }
+
+       return ret;
+}
+
+struct sbi_ecall_extension ecall_fwft;
+
+static int sbi_ecall_fwft_register_extensions(void)
+{
+       return sbi_ecall_register_extension(&ecall_fwft);
+}
+
+struct sbi_ecall_extension ecall_fwft = {
+       .extid_start = SBI_EXT_FWFT,
+       .extid_end = SBI_EXT_FWFT,
+       .register_extensions = sbi_ecall_fwft_register_extensions,
+       .handle = sbi_ecall_fwft_handler,
+};