[1/2] arm64: Add support for function error injection
diff mbox series

Message ID 20190716111301.1855-2-leo.yan@linaro.org
State New
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Series
  • arm/arm64: Add support for function error injection
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Commit Message

Leo Yan July 16, 2019, 11:13 a.m. UTC
This patch implement regs_set_return_value() and
override_function_with_return() to support function error injection
for arm64.

In the exception flow, arm64's general register x30 contains the value
for the link register; so we can just update pt_regs::pc with it rather
than redirecting execution to a dummy function that returns.

This patch is heavily inspired by the commit 7cd01b08d35f ("powerpc:
Add support for function error injection").

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 arch/arm64/Kconfig                       |  1 +
 arch/arm64/include/asm/error-injection.h | 13 +++++++++++++
 arch/arm64/include/asm/ptrace.h          |  5 +++++
 arch/arm64/lib/Makefile                  |  2 ++
 arch/arm64/lib/error-inject.c            | 19 +++++++++++++++++++
 5 files changed, 40 insertions(+)
 create mode 100644 arch/arm64/include/asm/error-injection.h
 create mode 100644 arch/arm64/lib/error-inject.c

Comments

Leo Yan July 25, 2019, 1:42 a.m. UTC | #1
On Tue, Jul 16, 2019 at 07:13:00PM +0800, Leo Yan wrote:
> This patch implement regs_set_return_value() and
> override_function_with_return() to support function error injection
> for arm64.
> 
> In the exception flow, arm64's general register x30 contains the value
> for the link register; so we can just update pt_regs::pc with it rather
> than redirecting execution to a dummy function that returns.
> 
> This patch is heavily inspired by the commit 7cd01b08d35f ("powerpc:
> Add support for function error injection").
> 
> Signed-off-by: Leo Yan <leo.yan@linaro.org>

Catalin, Will:  Gentle ping ...

> ---
>  arch/arm64/Kconfig                       |  1 +
>  arch/arm64/include/asm/error-injection.h | 13 +++++++++++++
>  arch/arm64/include/asm/ptrace.h          |  5 +++++
>  arch/arm64/lib/Makefile                  |  2 ++
>  arch/arm64/lib/error-inject.c            | 19 +++++++++++++++++++
>  5 files changed, 40 insertions(+)
>  create mode 100644 arch/arm64/include/asm/error-injection.h
>  create mode 100644 arch/arm64/lib/error-inject.c
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 697ea0510729..a6d9e622977d 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -142,6 +142,7 @@ config ARM64
>  	select HAVE_EFFICIENT_UNALIGNED_ACCESS
>  	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/error-injection.h b/arch/arm64/include/asm/error-injection.h
> new file mode 100644
> index 000000000000..da057e8ed224
> --- /dev/null
> +++ b/arch/arm64/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/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
> index dad858b6adc6..3aafbbe218a2 100644
> --- a/arch/arm64/include/asm/ptrace.h
> +++ b/arch/arm64/include/asm/ptrace.h
> @@ -294,6 +294,11 @@ 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..35661c2de4b0
> --- /dev/null
> +++ b/arch/arm64/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->regs[30]' contains the the link register for the probed
> +	 * function and assign it to 'regs->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->pc = regs->regs[30];
> +}
> +NOKPROBE_SYMBOL(override_function_with_return);
> -- 
> 2.17.1
>
Will Deacon July 31, 2019, 4:08 p.m. UTC | #2
On Tue, Jul 16, 2019 at 07:13:00PM +0800, Leo Yan wrote:
> This patch implement regs_set_return_value() and
> override_function_with_return() to support function error injection
> for arm64.
> 
> In the exception flow, arm64's general register x30 contains the value
> for the link register; so we can just update pt_regs::pc with it rather
> than redirecting execution to a dummy function that returns.
> 
> This patch is heavily inspired by the commit 7cd01b08d35f ("powerpc:
> Add support for function error injection").
> 
> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
>  arch/arm64/Kconfig                       |  1 +
>  arch/arm64/include/asm/error-injection.h | 13 +++++++++++++
>  arch/arm64/include/asm/ptrace.h          |  5 +++++
>  arch/arm64/lib/Makefile                  |  2 ++
>  arch/arm64/lib/error-inject.c            | 19 +++++++++++++++++++
>  5 files changed, 40 insertions(+)
>  create mode 100644 arch/arm64/include/asm/error-injection.h
>  create mode 100644 arch/arm64/lib/error-inject.c
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 697ea0510729..a6d9e622977d 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -142,6 +142,7 @@ config ARM64
>  	select HAVE_EFFICIENT_UNALIGNED_ACCESS
>  	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/error-injection.h b/arch/arm64/include/asm/error-injection.h
> new file mode 100644
> index 000000000000..da057e8ed224
> --- /dev/null
> +++ b/arch/arm64/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_ */

Why isn't this prototype in the asm-generic header? Seems weird to have to
duplicate it for each architecture.

> diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
> index dad858b6adc6..3aafbbe218a2 100644
> --- a/arch/arm64/include/asm/ptrace.h
> +++ b/arch/arm64/include/asm/ptrace.h
> @@ -294,6 +294,11 @@ 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..35661c2de4b0
> --- /dev/null
> +++ b/arch/arm64/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->regs[30]' contains the the link register for the probed

extra "the"

> +	 * function and assign it to 'regs->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.

directly

> +	 */
> +	regs->pc = regs->regs[30];

I suppose we could be all fancy and do:

	instruction_pointer_set(regs, procedure_link_pointer(regs));

How about that?

Will
Leo Yan July 31, 2019, 4:58 p.m. UTC | #3
Hi Will,

Thanks for reviewing.

On Wed, Jul 31, 2019 at 05:08:37PM +0100, Will Deacon wrote:
> On Tue, Jul 16, 2019 at 07:13:00PM +0800, Leo Yan wrote:
> > This patch implement regs_set_return_value() and
> > override_function_with_return() to support function error injection
> > for arm64.
> > 
> > In the exception flow, arm64's general register x30 contains the value
> > for the link register; so we can just update pt_regs::pc with it rather
> > than redirecting execution to a dummy function that returns.
> > 
> > This patch is heavily inspired by the commit 7cd01b08d35f ("powerpc:
> > Add support for function error injection").
> > 
> > Signed-off-by: Leo Yan <leo.yan@linaro.org>
> > ---
> >  arch/arm64/Kconfig                       |  1 +
> >  arch/arm64/include/asm/error-injection.h | 13 +++++++++++++
> >  arch/arm64/include/asm/ptrace.h          |  5 +++++
> >  arch/arm64/lib/Makefile                  |  2 ++
> >  arch/arm64/lib/error-inject.c            | 19 +++++++++++++++++++
> >  5 files changed, 40 insertions(+)
> >  create mode 100644 arch/arm64/include/asm/error-injection.h
> >  create mode 100644 arch/arm64/lib/error-inject.c
> > 
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 697ea0510729..a6d9e622977d 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -142,6 +142,7 @@ config ARM64
> >  	select HAVE_EFFICIENT_UNALIGNED_ACCESS
> >  	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/error-injection.h b/arch/arm64/include/asm/error-injection.h
> > new file mode 100644
> > index 000000000000..da057e8ed224
> > --- /dev/null
> > +++ b/arch/arm64/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_ */
> 
> Why isn't this prototype in the asm-generic header? Seems weird to have to
> duplicate it for each architecture.

Yeah.  When I spin for new version patches, will try to refactor in
the asm-generic header.

> > diff --git a/arch/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
> > index dad858b6adc6..3aafbbe218a2 100644
> > --- a/arch/arm64/include/asm/ptrace.h
> > +++ b/arch/arm64/include/asm/ptrace.h
> > @@ -294,6 +294,11 @@ 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..35661c2de4b0
> > --- /dev/null
> > +++ b/arch/arm64/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->regs[30]' contains the the link register for the probed
> 
> extra "the"

Will fix.

> > +	 * function and assign it to 'regs->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.
> 
> directly

Will fix.

> > +	 */
> > +	regs->pc = regs->regs[30];
> 
> I suppose we could be all fancy and do:
> 
> 	instruction_pointer_set(regs, procedure_link_pointer(regs));
> 
> How about that?

Ah, good point.  Will change to use the common APIs.

Thanks,
Leo Yan

Patch
diff mbox series

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 697ea0510729..a6d9e622977d 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -142,6 +142,7 @@  config ARM64
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
 	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/error-injection.h b/arch/arm64/include/asm/error-injection.h
new file mode 100644
index 000000000000..da057e8ed224
--- /dev/null
+++ b/arch/arm64/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/arm64/include/asm/ptrace.h b/arch/arm64/include/asm/ptrace.h
index dad858b6adc6..3aafbbe218a2 100644
--- a/arch/arm64/include/asm/ptrace.h
+++ b/arch/arm64/include/asm/ptrace.h
@@ -294,6 +294,11 @@  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..35661c2de4b0
--- /dev/null
+++ b/arch/arm64/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->regs[30]' contains the the link register for the probed
+	 * function and assign it to 'regs->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->pc = regs->regs[30];
+}
+NOKPROBE_SYMBOL(override_function_with_return);