Add a small driver to request double trap enabling as well as registering a SSE handler for double trap. This will also be used by KVM SBI FWFT extension support to detect if it is possible to enable double trap in VS-mode. Signed-off-by: Clément Léger <cleger@xxxxxxxxxxxx> --- arch/riscv/include/asm/sbi.h | 1 + drivers/firmware/Kconfig | 7 +++ drivers/firmware/Makefile | 1 + drivers/firmware/riscv_dbltrp.c | 95 +++++++++++++++++++++++++++++++++ include/linux/riscv_dbltrp.h | 19 +++++++ 5 files changed, 123 insertions(+) create mode 100644 drivers/firmware/riscv_dbltrp.c create mode 100644 include/linux/riscv_dbltrp.h diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h index 744aa1796c92..9cd4ca66487c 100644 --- a/arch/riscv/include/asm/sbi.h +++ b/arch/riscv/include/asm/sbi.h @@ -314,6 +314,7 @@ enum sbi_sse_attr_id { #define SBI_SSE_ATTR_INTERRUPTED_FLAGS_SPIE (1 << 2) #define SBI_SSE_EVENT_LOCAL_RAS 0x00000000 +#define SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP 0x00000001 #define SBI_SSE_EVENT_GLOBAL_RAS 0x00008000 #define SBI_SSE_EVENT_LOCAL_PMU 0x00010000 #define SBI_SSE_EVENT_LOCAL_SOFTWARE 0xffff0000 diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig index 59f611288807..a037f6e89942 100644 --- a/drivers/firmware/Kconfig +++ b/drivers/firmware/Kconfig @@ -197,6 +197,13 @@ config RISCV_SSE_TEST Select if you want to enable SSE extension testing at boot time. This will run a series of test which verifies SSE sanity. +config RISCV_DBLTRP + bool "Enable Double trap handling" + depends on RISCV_SSE && RISCV_SBI + default n + help + Select if you want to enable SSE double trap handler. + config SYSFB bool select BOOT_VESA_SUPPORT diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile index fb7b0c08c56d..ad67a1738c0f 100644 --- a/drivers/firmware/Makefile +++ b/drivers/firmware/Makefile @@ -18,6 +18,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o obj-$(CONFIG_FW_CFG_SYSFS) += qemu_fw_cfg.o obj-$(CONFIG_RISCV_SSE) += riscv_sse.o obj-$(CONFIG_RISCV_SSE_TEST) += riscv_sse_test.o +obj-$(CONFIG_RISCV_DBLTRP) += riscv_dbltrp.o obj-$(CONFIG_SYSFB) += sysfb.o obj-$(CONFIG_SYSFB_SIMPLEFB) += sysfb_simplefb.o obj-$(CONFIG_TI_SCI_PROTOCOL) += ti_sci.o diff --git a/drivers/firmware/riscv_dbltrp.c b/drivers/firmware/riscv_dbltrp.c new file mode 100644 index 000000000000..72f9a067e87a --- /dev/null +++ b/drivers/firmware/riscv_dbltrp.c @@ -0,0 +1,95 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2023 Rivos Inc. + */ + +#define pr_fmt(fmt) "riscv-dbltrp: " fmt + +#include <linux/cpu.h> +#include <linux/init.h> +#include <linux/riscv_dbltrp.h> +#include <linux/riscv_sse.h> + +#include <asm/sbi.h> + +static bool double_trap_enabled; + +static int riscv_sse_dbltrp_handle(uint32_t evt, void *arg, + struct pt_regs *regs) +{ + __show_regs(regs); + panic("Double trap !\n"); + + return 0; +} + +struct cpu_dbltrp_data { + int error; +}; + +static void +sbi_cpu_enable_double_trap(void *data) +{ + struct sbiret ret; + struct cpu_dbltrp_data *cdd = data; + + ret = sbi_ecall(SBI_EXT_FWFT, SBI_EXT_FWFT_SET, + SBI_FWFT_DOUBLE_TRAP_ENABLE, 1, 0, 0, 0, 0); + + if (ret.error) { + cdd->error = 1; + pr_err("Failed to enable double trap on cpu %d\n", smp_processor_id()); + } +} + +static int sbi_enable_double_trap(void) +{ + struct cpu_dbltrp_data cdd = {0}; + + on_each_cpu(sbi_cpu_enable_double_trap, &cdd, 1); + if (cdd.error) + return -1; + + double_trap_enabled = true; + + return 0; +} + +bool riscv_double_trap_enabled(void) +{ + return double_trap_enabled; +} +EXPORT_SYMBOL(riscv_double_trap_enabled); + +static int __init riscv_dbltrp(void) +{ + struct sse_event *evt; + + if (!riscv_has_extension_unlikely(RISCV_ISA_EXT_SSDBLTRP)) { + pr_err("Ssdbltrp extension not available\n"); + return 1; + } + + if (!sbi_probe_extension(SBI_EXT_FWFT)) { + pr_err("Can not enable double trap, SBI_EXT_FWFT is not available\n"); + return 1; + } + + if (sbi_enable_double_trap()) { + pr_err("Failed to enable double trap on all cpus\n"); + return 1; + } + + evt = sse_event_register(SBI_SSE_EVENT_LOCAL_DOUBLE_TRAP, 0, + riscv_sse_dbltrp_handle, NULL); + if (IS_ERR(evt)) { + pr_err("SSE double trap register failed\n"); + return PTR_ERR(evt); + } + + sse_event_enable(evt); + pr_info("Double trap handling registered\n"); + + return 0; +} +device_initcall(riscv_dbltrp); diff --git a/include/linux/riscv_dbltrp.h b/include/linux/riscv_dbltrp.h new file mode 100644 index 000000000000..6de4f43fae6b --- /dev/null +++ b/include/linux/riscv_dbltrp.h @@ -0,0 +1,19 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2023 Rivos Inc. + */ + +#ifndef __LINUX_RISCV_DBLTRP_H +#define __LINUX_RISCV_DBLTRP_H + +#if defined(CONFIG_RISCV_DBLTRP) +bool riscv_double_trap_enabled(void); +#else + +static inline bool riscv_double_trap_enabled(void) +{ + return false; +} +#endif + +#endif /* __LINUX_RISCV_DBLTRP_H */ -- 2.43.0