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authorLeo Yan <leo.yan@linaro.org>2019-08-06 18:00:14 +0800
committerWill Deacon <will@kernel.org>2019-08-07 13:53:09 +0100
commit42d038c4fb00f1ec1a4c4616784da4561385b628 (patch)
treec8c5335e01986c073ae56ca1df94eeed5c13fe1e /arch
parent45880f7b7b19e043ce0aaa4cb7d05369425c82fa (diff)
downloadlinux-42d038c4fb00f1ec1a4c4616784da4561385b628.tar.bz2
arm64: Add support for function error injection
Inspired by the commit 7cd01b08d35f ("powerpc: Add support for function error injection"), this patch supports function error injection for Arm64. 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. Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Leo Yan <leo.yan@linaro.org> Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/Kconfig1
-rw-r--r--arch/arm64/include/asm/ptrace.h5
-rw-r--r--arch/arm64/lib/Makefile2
-rw-r--r--arch/arm64/lib/error-inject.c18
4 files changed, 26 insertions, 0 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3adcec05b1f6..b15803afb2a0 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -148,6 +148,7 @@ config ARM64
select HAVE_FAST_GUP
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_FUNCTION_TRACER
+ select HAVE_FUNCTION_ERROR_INJECTION
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_GCC_PLUGINS
select HAVE_HW_BREAKPOINT if PERF_EVENTS
diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index 1dcf63a9ac1f..fbebb411ae20 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -301,6 +301,11 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
return regs->regs[0];
}
+static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc)
+{
+ regs->regs[0] = rc;
+}
+
/**
* regs_get_kernel_argument() - get Nth function argument in kernel
* @regs: pt_regs of that context
diff --git a/arch/arm64/lib/Makefile b/arch/arm64/lib/Makefile
index 33c2a4abda04..f182ccb0438e 100644
--- a/arch/arm64/lib/Makefile
+++ b/arch/arm64/lib/Makefile
@@ -33,3 +33,5 @@ UBSAN_SANITIZE_atomic_ll_sc.o := n
lib-$(CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE) += uaccess_flushcache.o
obj-$(CONFIG_CRC32) += crc32.o
+
+obj-$(CONFIG_FUNCTION_ERROR_INJECTION) += error-inject.o
diff --git a/arch/arm64/lib/error-inject.c b/arch/arm64/lib/error-inject.c
new file mode 100644
index 000000000000..ed15021da3ed
--- /dev/null
+++ b/arch/arm64/lib/error-inject.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/error-injection.h>
+#include <linux/kprobes.h>
+
+void override_function_with_return(struct pt_regs *regs)
+{
+ /*
+ * 'regs' represents the state on entry of a predefined function in
+ * the kernel/module and which is captured on a kprobe.
+ *
+ * When kprobe returns back from exception it will override the end
+ * of probed function and directly return to the predefined
+ * function's caller.
+ */
+ instruction_pointer_set(regs, procedure_link_pointer(regs));
+}
+NOKPROBE_SYMBOL(override_function_with_return);