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authorTiezhu Yang <yangtiezhu@loongson.cn>2023-05-01 12:19:52 +0300
committerHuacai Chen <chenhuacai@loongson.cn>2023-05-01 12:19:52 +0300
commit8b5ee2c66d5c4c1312fd193d4138e6963160ba43 (patch)
treeee327696a53f8044b20325adc0f586aa671dea71
parentd4c937c2a57bbba24790be6fe7a791456f5fbb60 (diff)
downloadlinux-8b5ee2c66d5c4c1312fd193d4138e6963160ba43.tar.xz
LoongArch: Add support for function error injection
Inspired by the commit 42d038c4fb00f ("arm64: Add support for function error injection") and the commit ee55ff803b383 ("riscv: Add support for function error injection"), this patch supports function error injection for LoongArch. Mainly implement two functions: (1) regs_set_return_value() which is used to overwrite the return value, (2) override_function_with_return() which is used to override the probed function returning and jump to its caller. Here is a simple test under CONFIG_FUNCTION_ERROR_INJECTION and CONFIG_FAIL_FUNCTION: # echo sys_clone > /sys/kernel/debug/fail_function/inject # echo 100 > /sys/kernel/debug/fail_function/probability # dmesg bash: fork: Invalid argument # dmesg ... FAULT_INJECTION: forcing a failure. name fail_function, interval 1, probability 100, space 0, times 1 ... Call Trace: [<90000000002238f4>] show_stack+0x5c/0x180 [<90000000012e384c>] dump_stack_lvl+0x60/0x88 [<9000000000b1879c>] should_fail_ex+0x1b0/0x1f4 [<900000000032ead4>] fei_kprobe_handler+0x28/0x6c [<9000000000230970>] kprobe_breakpoint_handler+0xf0/0x118 [<90000000012e3e60>] do_bp+0x2c4/0x358 [<9000000002241924>] exception_handlers+0x1924/0x10000 [<900000000023b7d0>] sys_clone+0x0/0x4 [<90000000012e4744>] do_syscall+0x7c/0x94 [<9000000000221e44>] handle_syscall+0xc4/0x160 Tested-by: Hengqi Chen <hengqi.chen@gmail.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
-rw-r--r--arch/loongarch/Kconfig1
-rw-r--r--arch/loongarch/include/asm/ptrace.h5
-rw-r--r--arch/loongarch/lib/Makefile2
-rw-r--r--arch/loongarch/lib/error-inject.c10
4 files changed, 18 insertions, 0 deletions
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 3e5d6acbf240..629a6dac33e1 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -100,6 +100,7 @@ config LOONGARCH
select HAVE_FAST_GUP
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_ARG_ACCESS_API
+ select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_FUNCTION_TRACER
select HAVE_GENERIC_VDSO
diff --git a/arch/loongarch/include/asm/ptrace.h b/arch/loongarch/include/asm/ptrace.h
index d761db943335..35f0958163ac 100644
--- a/arch/loongarch/include/asm/ptrace.h
+++ b/arch/loongarch/include/asm/ptrace.h
@@ -154,6 +154,11 @@ static inline long regs_return_value(struct pt_regs *regs)
return regs->regs[4];
}
+static inline void regs_set_return_value(struct pt_regs *regs, unsigned long val)
+{
+ regs->regs[4] = val;
+}
+
#define instruction_pointer(regs) ((regs)->csr_era)
#define profile_pc(regs) instruction_pointer(regs)
diff --git a/arch/loongarch/lib/Makefile b/arch/loongarch/lib/Makefile
index 271ed45f51bb..d60d4e096cfa 100644
--- a/arch/loongarch/lib/Makefile
+++ b/arch/loongarch/lib/Makefile
@@ -5,3 +5,5 @@
lib-y += delay.o memset.o memcpy.o memmove.o \
clear_user.o copy_user.o csum.o dump_tlb.o unaligned.o
+
+obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/loongarch/lib/error-inject.c b/arch/loongarch/lib/error-inject.c
new file mode 100644
index 000000000000..afc9e1c7c973
--- /dev/null
+++ b/arch/loongarch/lib/error-inject.c
@@ -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->regs[1]);
+}
+NOKPROBE_SYMBOL(override_function_with_return);