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* [PATCH 0/2] arm/arm64: Add support for function error injection
@ 2019-07-16 11:12 Leo Yan
  2019-07-16 11:13 ` [PATCH 1/2] arm64: " Leo Yan
                   ` (2 more replies)
  0 siblings, 3 replies; 9+ messages in thread
From: Leo Yan @ 2019-07-16 11:12 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
	Yonghong Song, Arnd Bergmann, linux-arm-kernel, linux-kernel,
	netdev, bpf, Masami Hiramatsu, Justin He
  Cc: Leo Yan

This small patch set is to add support for function error injection;
this can be used to eanble more advanced debugging feature, e.g.
CONFIG_BPF_KPROBE_OVERRIDE.

I only tested the first patch on arm64 platform Juno-r2 with below
steps; the second patch is for arm arch, but I absent the platform
for the testing so only pass compilation.

- Enable kernel configuration:
  CONFIG_BPF_KPROBE_OVERRIDE
  CONFIG_BTRFS_FS
  CONFIG_BPF_EVENTS=y
  CONFIG_KPROBES=y
  CONFIG_KPROBE_EVENTS=y
  CONFIG_BPF_KPROBE_OVERRIDE=y
- Build samples/bpf on Juno-r2 board with Debian rootFS:
  # cd $kernel
  # make headers_install
  # make samples/bpf/ LLC=llc-7 CLANG=clang-7
- Run the sample tracex7:
  # ./tracex7 /dev/sdb1
  [ 1975.211781] BTRFS error (device (efault)): open_ctree failed
  mount: /mnt/linux-kernel/linux-cs-dev/samples/bpf/tmpmnt: mount(2) system call failed: Cannot allocate memory.


Leo Yan (2):
  arm64: Add support for function error injection
  arm: Add support for function error injection

 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 +++++++++++++++++++
 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 +++++++++++++++++++
 10 files changed, 80 insertions(+)
 create mode 100644 arch/arm/include/asm/error-injection.h
 create mode 100644 arch/arm/lib/error-inject.c
 create mode 100644 arch/arm64/include/asm/error-injection.h
 create mode 100644 arch/arm64/lib/error-inject.c

-- 
2.17.1


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^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH 1/2] arm64: Add support for function error injection
  2019-07-16 11:12 [PATCH 0/2] arm/arm64: Add support for function error injection Leo Yan
@ 2019-07-16 11:13 ` " Leo Yan
  2019-07-25  1:42   ` Leo Yan
  2019-07-31 16:08   ` Will Deacon
  2019-07-16 11:13 ` [PATCH 2/2] arm: " Leo Yan
  2019-07-17  7:52 ` [PATCH 0/2] arm/arm64: " Masami Hiramatsu
  2 siblings, 2 replies; 9+ messages in thread
From: Leo Yan @ 2019-07-16 11:13 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
	Yonghong Song, Arnd Bergmann, linux-arm-kernel, linux-kernel,
	netdev, bpf, Masami Hiramatsu, Justin He
  Cc: Leo Yan

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_ */
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


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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 9+ messages in thread

* [PATCH 2/2] arm: Add support for function error injection
  2019-07-16 11:12 [PATCH 0/2] arm/arm64: Add support for function error injection Leo Yan
  2019-07-16 11:13 ` [PATCH 1/2] arm64: " Leo Yan
@ 2019-07-16 11:13 ` " Leo Yan
  2019-07-25  1:48   ` Leo Yan
  2019-07-17  7:52 ` [PATCH 0/2] arm/arm64: " Masami Hiramatsu
  2 siblings, 1 reply; 9+ messages in thread
From: Leo Yan @ 2019-07-16 11:13 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
	Yonghong Song, Arnd Bergmann, linux-arm-kernel, linux-kernel,
	netdev, bpf, Masami Hiramatsu, Justin He
  Cc: Leo Yan

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

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


_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 0/2] arm/arm64: Add support for function error injection
  2019-07-16 11:12 [PATCH 0/2] arm/arm64: Add support for function error injection Leo Yan
  2019-07-16 11:13 ` [PATCH 1/2] arm64: " Leo Yan
  2019-07-16 11:13 ` [PATCH 2/2] arm: " Leo Yan
@ 2019-07-17  7:52 ` " Masami Hiramatsu
  2019-07-17  8:14   ` Leo Yan
  2 siblings, 1 reply; 9+ messages in thread
From: Masami Hiramatsu @ 2019-07-17  7:52 UTC (permalink / raw)
  To: Leo Yan
  Cc: Song Liu, linux-kernel, Arnd Bergmann, Daniel Borkmann,
	Catalin Marinas, Alexei Starovoitov, Russell King, netdev,
	Oleg Nesterov, Yonghong Song, bpf, Will Deacon, Martin KaFai Lau,
	linux-arm-kernel, Justin He

On Tue, 16 Jul 2019 19:12:59 +0800
Leo Yan <leo.yan@linaro.org> wrote:

> This small patch set is to add support for function error injection;
> this can be used to eanble more advanced debugging feature, e.g.
> CONFIG_BPF_KPROBE_OVERRIDE.
> 
> I only tested the first patch on arm64 platform Juno-r2 with below
> steps; the second patch is for arm arch, but I absent the platform
> for the testing so only pass compilation.
> 
> - Enable kernel configuration:
>   CONFIG_BPF_KPROBE_OVERRIDE
>   CONFIG_BTRFS_FS
>   CONFIG_BPF_EVENTS=y
>   CONFIG_KPROBES=y
>   CONFIG_KPROBE_EVENTS=y
>   CONFIG_BPF_KPROBE_OVERRIDE=y
> - Build samples/bpf on Juno-r2 board with Debian rootFS:
>   # cd $kernel
>   # make headers_install
>   # make samples/bpf/ LLC=llc-7 CLANG=clang-7
> - Run the sample tracex7:
>   # ./tracex7 /dev/sdb1
>   [ 1975.211781] BTRFS error (device (efault)): open_ctree failed
>   mount: /mnt/linux-kernel/linux-cs-dev/samples/bpf/tmpmnt: mount(2) system call failed: Cannot allocate memory.

This series looks good to me from the view point of override usage :)

Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>

For this series.

Thank you,

> 
> 
> Leo Yan (2):
>   arm64: Add support for function error injection
>   arm: Add support for function error injection
> 
>  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 +++++++++++++++++++
>  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 +++++++++++++++++++
>  10 files changed, 80 insertions(+)
>  create mode 100644 arch/arm/include/asm/error-injection.h
>  create mode 100644 arch/arm/lib/error-inject.c
>  create mode 100644 arch/arm64/include/asm/error-injection.h
>  create mode 100644 arch/arm64/lib/error-inject.c
> 
> -- 
> 2.17.1
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 0/2] arm/arm64: Add support for function error injection
  2019-07-17  7:52 ` [PATCH 0/2] arm/arm64: " Masami Hiramatsu
@ 2019-07-17  8:14   ` Leo Yan
  0 siblings, 0 replies; 9+ messages in thread
From: Leo Yan @ 2019-07-17  8:14 UTC (permalink / raw)
  To: Masami Hiramatsu
  Cc: Song Liu, linux-kernel, Arnd Bergmann, Daniel Borkmann,
	Catalin Marinas, Alexei Starovoitov, Russell King, netdev,
	Oleg Nesterov, Yonghong Song, bpf, Will Deacon, Martin KaFai Lau,
	linux-arm-kernel, Justin He

On Wed, Jul 17, 2019 at 04:52:22PM +0900, Masami Hiramatsu wrote:
> On Tue, 16 Jul 2019 19:12:59 +0800
> Leo Yan <leo.yan@linaro.org> wrote:
> 
> > This small patch set is to add support for function error injection;
> > this can be used to eanble more advanced debugging feature, e.g.
> > CONFIG_BPF_KPROBE_OVERRIDE.
> > 
> > I only tested the first patch on arm64 platform Juno-r2 with below
> > steps; the second patch is for arm arch, but I absent the platform
> > for the testing so only pass compilation.
> > 
> > - Enable kernel configuration:
> >   CONFIG_BPF_KPROBE_OVERRIDE
> >   CONFIG_BTRFS_FS
> >   CONFIG_BPF_EVENTS=y
> >   CONFIG_KPROBES=y
> >   CONFIG_KPROBE_EVENTS=y
> >   CONFIG_BPF_KPROBE_OVERRIDE=y
> > - Build samples/bpf on Juno-r2 board with Debian rootFS:
> >   # cd $kernel
> >   # make headers_install
> >   # make samples/bpf/ LLC=llc-7 CLANG=clang-7
> > - Run the sample tracex7:
> >   # ./tracex7 /dev/sdb1
> >   [ 1975.211781] BTRFS error (device (efault)): open_ctree failed
> >   mount: /mnt/linux-kernel/linux-cs-dev/samples/bpf/tmpmnt: mount(2) system call failed: Cannot allocate memory.
> 
> This series looks good to me from the view point of override usage :)
> 
> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
> 
> For this series.
> 
> Thank you,

Thank you for reviewing, Masami.

> > 
> > 
> > Leo Yan (2):
> >   arm64: Add support for function error injection
> >   arm: Add support for function error injection
> > 
> >  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 +++++++++++++++++++
> >  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 +++++++++++++++++++
> >  10 files changed, 80 insertions(+)
> >  create mode 100644 arch/arm/include/asm/error-injection.h
> >  create mode 100644 arch/arm/lib/error-inject.c
> >  create mode 100644 arch/arm64/include/asm/error-injection.h
> >  create mode 100644 arch/arm64/lib/error-inject.c
> > 
> > -- 
> > 2.17.1
> > 
> 
> 
> -- 
> Masami Hiramatsu <mhiramat@kernel.org>

_______________________________________________
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 1/2] arm64: Add support for function error injection
  2019-07-16 11:13 ` [PATCH 1/2] arm64: " Leo Yan
@ 2019-07-25  1:42   ` Leo Yan
  2019-07-31 16:08   ` Will Deacon
  1 sibling, 0 replies; 9+ messages in thread
From: Leo Yan @ 2019-07-25  1:42 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
	Yonghong Song, Arnd Bergmann, linux-arm-kernel, linux-kernel,
	netdev, bpf, Masami Hiramatsu, Justin He

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
> 

_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 2/2] arm: Add support for function error injection
  2019-07-16 11:13 ` [PATCH 2/2] arm: " Leo Yan
@ 2019-07-25  1:48   ` Leo Yan
  0 siblings, 0 replies; 9+ messages in thread
From: Leo Yan @ 2019-07-25  1:48 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Alexei Starovoitov, Daniel Borkmann, Martin KaFai Lau, Song Liu,
	Yonghong Song, Arnd Bergmann, linux-arm-kernel, linux-kernel,
	netdev, bpf, Masami Hiramatsu, Justin He

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
> 

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 1/2] arm64: Add support for function error injection
  2019-07-16 11:13 ` [PATCH 1/2] arm64: " Leo Yan
  2019-07-25  1:42   ` Leo Yan
@ 2019-07-31 16:08   ` Will Deacon
  2019-07-31 16:58     ` Leo Yan
  1 sibling, 1 reply; 9+ messages in thread
From: Will Deacon @ 2019-07-31 16:08 UTC (permalink / raw)
  To: Leo Yan
  Cc: Song Liu, linux-kernel, Arnd Bergmann, Daniel Borkmann,
	Catalin Marinas, Alexei Starovoitov, Russell King, netdev,
	Masami Hiramatsu, Oleg Nesterov, Yonghong Song, bpf,
	Martin KaFai Lau, linux-arm-kernel, Justin He

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

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 9+ messages in thread

* Re: [PATCH 1/2] arm64: Add support for function error injection
  2019-07-31 16:08   ` Will Deacon
@ 2019-07-31 16:58     ` Leo Yan
  0 siblings, 0 replies; 9+ messages in thread
From: Leo Yan @ 2019-07-31 16:58 UTC (permalink / raw)
  To: Will Deacon
  Cc: Song Liu, linux-kernel, Arnd Bergmann, Daniel Borkmann,
	Catalin Marinas, Alexei Starovoitov, Russell King, netdev,
	Masami Hiramatsu, Oleg Nesterov, Yonghong Song, bpf,
	Martin KaFai Lau, linux-arm-kernel, Justin He

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

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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, back to index

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-07-16 11:12 [PATCH 0/2] arm/arm64: Add support for function error injection Leo Yan
2019-07-16 11:13 ` [PATCH 1/2] arm64: " Leo Yan
2019-07-25  1:42   ` Leo Yan
2019-07-31 16:08   ` Will Deacon
2019-07-31 16:58     ` Leo Yan
2019-07-16 11:13 ` [PATCH 2/2] arm: " Leo Yan
2019-07-25  1:48   ` Leo Yan
2019-07-17  7:52 ` [PATCH 0/2] arm/arm64: " Masami Hiramatsu
2019-07-17  8:14   ` Leo Yan

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