| Message ID | 20190716111301.1855-3-leo.yan@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | arm/arm64: Add support for function error injection | expand |
Hi Russell, On Tue, Jul 16, 2019 at 07:13:01PM +0800, Leo Yan wrote: > This patch implement regs_set_return_value() and > override_function_with_return() to support function error injection > for arm. > > In the exception flow, we can update pt_regs::ARM_pc with > pt_regs::ARM_lr so that can override the probed function return. Gentle ping. > Signed-off-by: Leo Yan <leo.yan@linaro.org> > --- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/error-injection.h | 13 +++++++++++++ > arch/arm/include/asm/ptrace.h | 5 +++++ > arch/arm/lib/Makefile | 2 ++ > arch/arm/lib/error-inject.c | 19 +++++++++++++++++++ > 5 files changed, 40 insertions(+) > create mode 100644 arch/arm/include/asm/error-injection.h > create mode 100644 arch/arm/lib/error-inject.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index 8869742a85df..f7932a5e29ea 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -74,6 +74,7 @@ config ARM > select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU > select HAVE_EXIT_THREAD > select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL > + select HAVE_FUNCTION_ERROR_INJECTION if !THUMB2_KERNEL > select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG > select HAVE_FUNCTION_TRACER if !XIP_KERNEL > select HAVE_GCC_PLUGINS > diff --git a/arch/arm/include/asm/error-injection.h b/arch/arm/include/asm/error-injection.h > new file mode 100644 > index 000000000000..da057e8ed224 > --- /dev/null > +++ b/arch/arm/include/asm/error-injection.h > @@ -0,0 +1,13 @@ > +/* SPDX-License-Identifier: GPL-2.0+ */ > + > +#ifndef __ASM_ERROR_INJECTION_H_ > +#define __ASM_ERROR_INJECTION_H_ > + > +#include <linux/compiler.h> > +#include <linux/linkage.h> > +#include <asm/ptrace.h> > +#include <asm-generic/error-injection.h> > + > +void override_function_with_return(struct pt_regs *regs); > + > +#endif /* __ASM_ERROR_INJECTION_H_ */ > diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h > index 91d6b7856be4..3b41f37b361a 100644 > --- a/arch/arm/include/asm/ptrace.h > +++ b/arch/arm/include/asm/ptrace.h > @@ -89,6 +89,11 @@ static inline long regs_return_value(struct pt_regs *regs) > return regs->ARM_r0; > } > > +static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) > +{ > + regs->ARM_r0 = rc; > +} > + > #define instruction_pointer(regs) (regs)->ARM_pc > > #ifdef CONFIG_THUMB2_KERNEL > diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile > index 0bff0176db2c..d3d7430ecd76 100644 > --- a/arch/arm/lib/Makefile > +++ b/arch/arm/lib/Makefile > @@ -43,3 +43,5 @@ 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 > index 000000000000..96319d017114 > --- /dev/null > +++ b/arch/arm/lib/error-inject.c > @@ -0,0 +1,19 @@ > +// 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. > + * > + * 'regs->ARM_lr' contains the the link register for the probed > + * function and assign it to 'regs->ARM_pc', so when kprobe returns > + * back from exception it will override the end of probed function > + * and drirectly return to the predefined function's caller. > + */ > + regs->ARM_pc = regs->ARM_lr; > +} > +NOKPROBE_SYMBOL(override_function_with_return); > -- > 2.17.1 >
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 8869742a85df..f7932a5e29ea 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -74,6 +74,7 @@ config ARM select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU select HAVE_EXIT_THREAD select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL + select HAVE_FUNCTION_ERROR_INJECTION if !THUMB2_KERNEL select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG select HAVE_FUNCTION_TRACER if !XIP_KERNEL select HAVE_GCC_PLUGINS diff --git a/arch/arm/include/asm/error-injection.h b/arch/arm/include/asm/error-injection.h new file mode 100644 index 000000000000..da057e8ed224 --- /dev/null +++ b/arch/arm/include/asm/error-injection.h @@ -0,0 +1,13 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +#ifndef __ASM_ERROR_INJECTION_H_ +#define __ASM_ERROR_INJECTION_H_ + +#include <linux/compiler.h> +#include <linux/linkage.h> +#include <asm/ptrace.h> +#include <asm-generic/error-injection.h> + +void override_function_with_return(struct pt_regs *regs); + +#endif /* __ASM_ERROR_INJECTION_H_ */ diff --git a/arch/arm/include/asm/ptrace.h b/arch/arm/include/asm/ptrace.h index 91d6b7856be4..3b41f37b361a 100644 --- a/arch/arm/include/asm/ptrace.h +++ b/arch/arm/include/asm/ptrace.h @@ -89,6 +89,11 @@ static inline long regs_return_value(struct pt_regs *regs) return regs->ARM_r0; } +static inline void regs_set_return_value(struct pt_regs *regs, unsigned long rc) +{ + regs->ARM_r0 = rc; +} + #define instruction_pointer(regs) (regs)->ARM_pc #ifdef CONFIG_THUMB2_KERNEL diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile index 0bff0176db2c..d3d7430ecd76 100644 --- a/arch/arm/lib/Makefile +++ b/arch/arm/lib/Makefile @@ -43,3 +43,5 @@ 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 index 000000000000..96319d017114 --- /dev/null +++ b/arch/arm/lib/error-inject.c @@ -0,0 +1,19 @@ +// 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. + * + * 'regs->ARM_lr' contains the the link register for the probed + * function and assign it to 'regs->ARM_pc', so when kprobe returns + * back from exception it will override the end of probed function + * and drirectly return to the predefined function's caller. + */ + regs->ARM_pc = regs->ARM_lr; +} +NOKPROBE_SYMBOL(override_function_with_return);
This patch implement regs_set_return_value() and override_function_with_return() to support function error injection for arm. In the exception flow, we can update pt_regs::ARM_pc with pt_regs::ARM_lr so that can override the probed function return. Signed-off-by: Leo Yan <leo.yan@linaro.org> --- arch/arm/Kconfig | 1 + arch/arm/include/asm/error-injection.h | 13 +++++++++++++ arch/arm/include/asm/ptrace.h | 5 +++++ arch/arm/lib/Makefile | 2 ++ arch/arm/lib/error-inject.c | 19 +++++++++++++++++++ 5 files changed, 40 insertions(+) create mode 100644 arch/arm/include/asm/error-injection.h create mode 100644 arch/arm/lib/error-inject.c -- 2.17.1