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riscv: Add support for function error injection

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Inspired by the commit 42d038c4fb ("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] [<ffffffe0002036b6>] walk_stackframe+0x0/0xc2
[  313.191626] [<ffffffe00020395c>] show_stack+0x40/0x4c
[  313.193927] [<ffffffe000556c60>] dump_stack+0x7c/0x96
[  313.194795] [<ffffffe0005522e8>] should_fail+0x140/0x142
[  313.195923] [<ffffffe000299ffc>] fei_kprobe_handler+0x2c/0x5a
[  313.197687] [<ffffffe0009e2ec4>] kprobe_breakpoint_handler+0xb4/0x18a
[  313.200054] [<ffffffe00020357e>] do_trap_break+0x36/0xca
[  313.202147] [<ffffffe000201bca>] ret_from_exception+0x0/0xc
[  313.204556] [<ffffffe000201bbc>] ret_from_syscall+0x0/0x2
-sh: can't fork: Invalid argument

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
This commit is contained in:
Guo Ren 2020-12-17 16:01:45 +00:00 committed by Palmer Dabbelt
parent 74784081aa
commit ee55ff803b
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
4 changed files with 19 additions and 0 deletions
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1
arch/riscv/Kconfig
View File

@ -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

6
arch/riscv/include/asm/ptrace.h
View File

@ -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);

2
arch/riscv/lib/Makefile
View File

@ -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

10
arch/riscv/lib/error-inject.c Normal file
View File

@ -0,0 +1,10 @@
// SPDX-License-Identifier: GPL-2.0
#include <linux/error-injection.h>
#include <linux/kprobes.h>
void override_function_with_return(struct pt_regs *regs)
{
instruction_pointer_set(regs, regs->ra);
}
NOKPROBE_SYMBOL(override_function_with_return);