ARM: 9279/1: support function error injection

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 <wangkefeng.wang@huawei.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index b3427536731d67aa12364ab772821adb9682b05d..981bbfa62b7dea873f39232471e3075550d0c477 100644 (file)
--- 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

diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h
index 1408a6a15d0e03c81225c0f143f85011e8b0162f..483b8ddfcb82cdb89d3c26ed6da8259f426b1cd5 100644 (file)
--- 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.

diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
index 42fb75c06647f8c76f90204ebd41c444a2381b63..650404be6768a0f7cd1aa8a06af32f3d472f3a22 100644 (file)
--- 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

diff --git a/arch/arm/lib/error-inject.c b/arch/arm/lib/error-inject.c
new file mode 100644 (file)
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);