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authorGuo Ren <guoren@linux.alibaba.com>2020-07-28 16:30:46 +0000
committerGuo Ren <guoren@linux.alibaba.com>2020-07-31 01:52:07 +0000
commit71e193d7cbcfc988c3802e15261bd807171adb6b (patch)
treeb339e8d97c2a6094ac17bc85ea306bff7edb983f
parenta5447fb9b32eb33b2f0f09a63e4852b46af5b056 (diff)
csky: 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 csky. 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 / [ 108.644163] FAULT_INJECTION: forcing a failure. [ 108.644163] name fail_function, interval 1, probability 100, space 0, times 1 [ 108.647799] CPU: 0 PID: 104 Comm: sh Not tainted 5.8.0-rc5+ #46 [ 108.648384] Call Trace: [ 108.649339] [<8005eed4>] walk_stackframe+0x0/0xf0 [ 108.649679] [<8005f16a>] show_stack+0x32/0x5c [ 108.649927] [<8040f9d2>] dump_stack+0x6e/0x9c [ 108.650271] [<80406f7e>] should_fail+0x15e/0x1ac [ 108.650720] [<80118ba8>] fei_kprobe_handler+0x28/0x5c [ 108.651519] [<80754110>] kprobe_breakpoint_handler+0x144/0x1cc [ 108.652289] [<8005d6da>] trap_c+0x8e/0x110 [ 108.652816] [<8005ce8c>] csky_trap+0x5c/0x70 -sh: can't fork: Invalid argument Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Cc: Arnd Bergmann <arnd@arndb.de>
-rw-r--r--arch/csky/Kconfig1
-rw-r--r--arch/csky/include/asm/ptrace.h6
-rw-r--r--arch/csky/lib/Makefile1
-rw-r--r--arch/csky/lib/error-inject.c10
4 files changed, 18 insertions, 0 deletions
diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index 822362d0598e..c51f64c14391 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -45,6 +45,7 @@ config CSKY
select HAVE_DYNAMIC_FTRACE_WITH_REGS
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
+ select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZO
diff --git a/arch/csky/include/asm/ptrace.h b/arch/csky/include/asm/ptrace.h
index bcfb7070e48d..82da5e08558d 100644
--- a/arch/csky/include/asm/ptrace.h
+++ b/arch/csky/include/asm/ptrace.h
@@ -52,6 +52,12 @@ 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;
+}
+
/* Valid only for Kernel mode traps. */
static inline unsigned long kernel_stack_pointer(struct pt_regs *regs)
{
diff --git a/arch/csky/lib/Makefile b/arch/csky/lib/Makefile
index 078e2d5f32e1..7fbdbb2c4d12 100644
--- a/arch/csky/lib/Makefile
+++ b/arch/csky/lib/Makefile
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0-only
lib-y := usercopy.o delay.o
+obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/csky/lib/error-inject.c b/arch/csky/lib/error-inject.c
new file mode 100644
index 000000000000..c15fb36fe067
--- /dev/null
+++ b/arch/csky/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->lr);
+}
+NOKPROBE_SYMBOL(override_function_with_return);