If CSRs like seed are readable by S-mode, may not be determinable by S-mode. For safe driver probing allow to resume via a longjmp after an exception.
Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com --- v2: new patch --- arch/riscv/lib/interrupts.c | 13 +++++++++++++ include/interrupt.h | 22 ++++++++++++++++++++++ 2 files changed, 35 insertions(+) create mode 100644 include/interrupt.h
diff --git a/arch/riscv/lib/interrupts.c b/arch/riscv/lib/interrupts.c index 02dbcfd423..a26ccc721f 100644 --- a/arch/riscv/lib/interrupts.c +++ b/arch/riscv/lib/interrupts.c @@ -12,6 +12,7 @@ #include <linux/compat.h> #include <efi_loader.h> #include <hang.h> +#include <interrupt.h> #include <irq_func.h> #include <asm/global_data.h> #include <asm/ptrace.h> @@ -21,6 +22,13 @@
DECLARE_GLOBAL_DATA_PTR;
+static struct resume_data *resume; + +void set_resume(struct resume_data *data) +{ + resume = data; +} + static void show_efi_loaded_images(uintptr_t epc) { efi_print_image_infos((void *)epc); @@ -105,6 +113,11 @@ static void _exit_trap(ulong code, ulong epc, ulong tval, struct pt_regs *regs) "Store/AMO page fault", };
+ if (resume) { + resume->code = code; + longjmp(resume->jump, 1); + } + if (code < ARRAY_SIZE(exception_code)) printf("Unhandled exception: %s\n", exception_code[code]); else diff --git a/include/interrupt.h b/include/interrupt.h new file mode 100644 index 0000000000..1baa60bcf2 --- /dev/null +++ b/include/interrupt.h @@ -0,0 +1,22 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ + +#include <asm/setjmp.h> + +/** + * struct resume_data - data for resume after interrupt + */ +struct resume_data { + /** @jump: longjmp buffer */ + jmp_buf jump; + /** @code: exception code */ + ulong code; +}; + +/** + * set_resume() - set longjmp buffer for resuming after interrupt + * + * When resuming the exception code will be returned in @data->code. + * + * @data: pointer to structure with longjmp address + */ +void set_resume(struct resume_data *data);