ARM: 9279/1: support function error injection

aaa4dd1b · Wang Kefeng <[email protected]> · 2022-12-04 04:46:40 +01:00

This enables HAVE_FUNCTION_ERROR_INJECTION by adding necessary
regs_set_return_value() and override_function_with_return().

Simply tested according to Documentation/fault-injection/fault-injection.rst.

Signed-off-by: Kefeng Wang <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>

Commit: aaa4dd1b47f5ff5ef477fec5dcc6c397b457f1c2
Parents: ba290d4f

Changes

4 files changed · +17 −0

File	Status	Add	Del	Content
arch/arm/Kconfig	modified	+1	−0	View file
arch/arm/include/asm/ptrace.h	modified	+4	−0	View file
arch/arm/lib/Makefile	modified	+2	−0	View file
arch/arm/lib/error-inject.c	added	+10	−0	View file

arch/arm/Kconfig

View file

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b342753..981bbfa 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -97,6 +97,7 @@ config ARM
 	select HAVE_EXIT_THREAD
 	select HAVE_FAST_GUP if ARM_LPAE
 	select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
+	select HAVE_FUNCTION_ERROR_INJECTION
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER if !XIP_KERNEL
 	select HAVE_GCC_PLUGINS

arch/arm/include/asm/ptrace.h

View file

diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index 1408a6a..483b8dd 100644
--- a/arch/arm/include/asm/ptrace.h
+++ b/arch/arm/include/asm/ptrace.h
@@ -163,6 +163,10 @@ static inline unsigned long user_stack_pointer(struct pt_regs *regs)
 		((current_stack_pointer | (THREAD_SIZE - 1)) - 7) - 1;	\
 })
 
+static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
+{
+	regs->ARM_r0 = rc;
+}
 
 /*
  * Update ITSTATE after normal execution of an IT block instruction.

arch/arm/lib/Makefile

View file

diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 42fb75c..650404b 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -44,3 +44,5 @@ ifeq ($(CONFIG_KERNEL_MODE_NEON),y)
   CFLAGS_xor-neon.o		+= $(NEON_FLAGS)
   obj-$(CONFIG_XOR_BLOCKS)	+= xor-neon.o
 endif
+
+obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o

arch/arm/lib/error-inject.c

View file

diff --git a/arch/arm/lib/error-inject.c b/arch/arm/lib/error-inject.c
new file mode 100644
index 0000000..5a5b405
--- /dev/null
+++ b/arch/arm/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->ARM_lr);
+}
+NOKPROBE_SYMBOL(override_function_with_return);