Commit 42d038c4 authored by Leo Yan's avatar Leo Yan Committed by Will Deacon
Browse files

arm64: Add support for function error injection 



Inspired by the commit 7cd01b08 ("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: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarLeo Yan <leo.yan@linaro.org>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 45880f7b

arch/arm64/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/include/asm/ptrace.h

+5 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/lib/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/arm64/lib/error-inject.c

0 → 100644
+18 −0
Original line number Diff line number Diff line 
// 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);

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