From ee55ff803b383e03d0855661d3416aa1763e54f9 Mon Sep 17 00:00:00 2001 From: Guo Ren Date: Thu, 17 Dec 2020 16:01:45 +0000 Subject: [PATCH] riscv: Add support for function error injection Inspired by the commit 42d038c4fb00 ("arm64: Add support for function error injection"), this patch supports function error injection for riscv. This patch mainly support two functions: one is regs_set_return_value() which is used to overwrite the return value; the another function is override_function_with_return() which is to override the probed function returning and jump to its caller. Test log: cd /sys/kernel/debug/fail_function echo sys_clone > inject echo 100 > probability echo 1 > interval ls / [ 313.176875] FAULT_INJECTION: forcing a failure. [ 313.176875] name fail_function, interval 1, probability 100, space 0, times 1 [ 313.184357] CPU: 0 PID: 87 Comm: sh Not tainted 5.8.0-rc5-00007-g6a758cc #117 [ 313.187616] Call Trace: [ 313.189100] [] walk_stackframe+0x0/0xc2 [ 313.191626] [] show_stack+0x40/0x4c [ 313.193927] [] dump_stack+0x7c/0x96 [ 313.194795] [] should_fail+0x140/0x142 [ 313.195923] [] fei_kprobe_handler+0x2c/0x5a [ 313.197687] [] kprobe_breakpoint_handler+0xb4/0x18a [ 313.200054] [] do_trap_break+0x36/0xca [ 313.202147] [] ret_from_exception+0x0/0xc [ 313.204556] [] ret_from_syscall+0x0/0x2 -sh: can't fork: Invalid argument Signed-off-by: Guo Ren Reviewed-by: Masami Hiramatsu Cc: Palmer Dabbelt Cc: Paul Walmsley Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/ptrace.h | 6 ++++++ arch/riscv/lib/Makefile | 2 ++ arch/riscv/lib/error-inject.c | 10 ++++++++++ 4 files changed, 19 insertions(+) create mode 100644 arch/riscv/lib/error-inject.c diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 7b5bb48055e7..18d293f84318 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -67,6 +67,7 @@ config RISCV select HAVE_DEBUG_KMEMLEAK select HAVE_DMA_CONTIGUOUS if MMU select HAVE_EBPF_JIT if MMU + select HAVE_FUNCTION_ERROR_INJECTION select HAVE_FUTEX_CMPXCHG if FUTEX select HAVE_GCC_PLUGINS select HAVE_GENERIC_VDSO if MMU && 64BIT diff --git a/arch/riscv/include/asm/ptrace.h b/arch/riscv/include/asm/ptrace.h index 23372bbcfde8..cb4abb639e8d 100644 --- a/arch/riscv/include/asm/ptrace.h +++ b/arch/riscv/include/asm/ptrace.h @@ -109,6 +109,12 @@ static inline unsigned long regs_return_value(struct pt_regs *regs) return regs->a0; } +static inline void regs_set_return_value(struct pt_regs *regs, + unsigned long val) +{ + regs->a0 = val; +} + extern int regs_query_register_offset(const char *name); extern unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, unsigned int n); diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile index ac6171e9c19e..25d5c9664e57 100644 --- a/arch/riscv/lib/Makefile +++ b/arch/riscv/lib/Makefile @@ -5,3 +5,5 @@ lib-y += memset.o lib-y += memmove.o lib-$(CONFIG_MMU) += uaccess.o lib-$(CONFIG_64BIT) += tishift.o + +obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o diff --git a/arch/riscv/lib/error-inject.c b/arch/riscv/lib/error-inject.c new file mode 100644 index 000000000000..d667ade2bc41 --- /dev/null +++ b/arch/riscv/lib/error-inject.c @@ -0,0 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include +#include + +void override_function_with_return(struct pt_regs *regs) +{ + instruction_pointer_set(regs, regs->ra); +} +NOKPROBE_SYMBOL(override_function_with_return);