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* [PATCH v2 0/3] arm/arm64: Add support for function error injection
@ 2019-08-06 10:00 Leo Yan
  2019-08-06 10:00 ` [PATCH v2 1/3] error-injection: Consolidate override function definition Leo Yan
                   ` (4 more replies)
  0 siblings, 5 replies; 11+ messages in thread
From: Leo Yan @ 2019-08-06 10:00 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu
  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.

The patch 01/03 is to consolidate the function definition which can be
suared cross architectures, patches 02,03/03 are used for enabling
function error injection on arm64 and arm architecture respectively.

I tested on arm64 platform Juno-r2 and one of my laptop with x86
architecture with below steps; I don't test for Arm architecture 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 with Debian rootFS:
  # cd $kernel
  # make headers_install
  # make samples/bpf/ LLC=llc-7 CLANG=clang-7

- Run the sample tracex7:
  # dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1
  # DEVICE=$(losetup --show -f testfile.img)
  # mkfs.btrfs -f $DEVICE
  # ./tracex7 testfile.img
  [ 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.

Changes from v1:
* Consolidated the function definition into asm-generic header (Will);
* Used APIs to access pt_regs elements (Will);
* Fixed typos in the comments (Will).


Leo Yan (3):
  error-injection: Consolidate override function definition
  arm64: Add support for function error injection
  arm: Add support for function error injection

 arch/arm/Kconfig                           |  1 +
 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/ptrace.h            |  5 +++++
 arch/arm64/lib/Makefile                    |  2 ++
 arch/arm64/lib/error-inject.c              | 18 ++++++++++++++++++
 arch/powerpc/include/asm/error-injection.h | 13 -------------
 arch/x86/include/asm/error-injection.h     | 13 -------------
 include/asm-generic/error-injection.h      |  6 ++++++
 include/linux/error-injection.h            |  6 +++---
 12 files changed, 62 insertions(+), 29 deletions(-)
 create mode 100644 arch/arm/lib/error-inject.c
 create mode 100644 arch/arm64/lib/error-inject.c
 delete mode 100644 arch/powerpc/include/asm/error-injection.h
 delete mode 100644 arch/x86/include/asm/error-injection.h

-- 
2.17.1


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v2 1/3] error-injection: Consolidate override function definition
  2019-08-06 10:00 [PATCH v2 0/3] arm/arm64: Add support for function error injection Leo Yan
@ 2019-08-06 10:00 ` Leo Yan
  2019-08-06 10:00 ` [PATCH v2 2/3] arm64: Add support for function error injection Leo Yan
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 11+ messages in thread
From: Leo Yan @ 2019-08-06 10:00 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu
  Cc: Leo Yan

The function override_function_with_return() is defined separately for
each architecture and every architecture's definition is almost same
with each other.  E.g. x86 and powerpc both define function in its own
asm/error-injection.h header and override_function_with_return() has
the same definition, the only difference is that x86 defines an extra
function just_return_func() but it is specific for x86 and is only used
by x86's override_function_with_return(), so don't need to export this
function.

This patch consolidates override_function_with_return() definition into
asm-generic/error-injection.h header, thus all architectures can use the
common definition.  As result, the architecture specific headers are
removed; the include/linux/error-injection.h header also changes to
include asm-generic/error-injection.h header rather than architecture
header, furthermore, it includes linux/compiler.h for successful
compilation.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 arch/powerpc/include/asm/error-injection.h | 13 -------------
 arch/x86/include/asm/error-injection.h     | 13 -------------
 include/asm-generic/error-injection.h      |  6 ++++++
 include/linux/error-injection.h            |  6 +++---
 4 files changed, 9 insertions(+), 29 deletions(-)
 delete mode 100644 arch/powerpc/include/asm/error-injection.h
 delete mode 100644 arch/x86/include/asm/error-injection.h

diff --git a/arch/powerpc/include/asm/error-injection.h b/arch/powerpc/include/asm/error-injection.h
deleted file mode 100644
index 62fd24739852..000000000000
--- a/arch/powerpc/include/asm/error-injection.h
+++ /dev/null
@@ -1,13 +0,0 @@
-/* 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/x86/include/asm/error-injection.h b/arch/x86/include/asm/error-injection.h
deleted file mode 100644
index 47b7a1296245..000000000000
--- a/arch/x86/include/asm/error-injection.h
+++ /dev/null
@@ -1,13 +0,0 @@
-/* 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>
-
-asmlinkage void just_return_func(void);
-void override_function_with_return(struct pt_regs *regs);
-
-#endif /* _ASM_ERROR_INJECTION_H */
diff --git a/include/asm-generic/error-injection.h b/include/asm-generic/error-injection.h
index 95a159a4137f..80ca61058dd2 100644
--- a/include/asm-generic/error-injection.h
+++ b/include/asm-generic/error-injection.h
@@ -16,6 +16,8 @@ struct error_injection_entry {
 	int		etype;
 };
 
+struct pt_regs;
+
 #ifdef CONFIG_FUNCTION_ERROR_INJECTION
 /*
  * Whitelist ganerating macro. Specify functions which can be
@@ -28,8 +30,12 @@ static struct error_injection_entry __used				\
 		.addr = (unsigned long)fname,				\
 		.etype = EI_ETYPE_##_etype,				\
 	};
+
+void override_function_with_return(struct pt_regs *regs);
 #else
 #define ALLOW_ERROR_INJECTION(fname, _etype)
+
+static inline void override_function_with_return(struct pt_regs *regs) { }
 #endif
 #endif
 
diff --git a/include/linux/error-injection.h b/include/linux/error-injection.h
index 280c61ecbf20..635a95caf29f 100644
--- a/include/linux/error-injection.h
+++ b/include/linux/error-injection.h
@@ -2,16 +2,16 @@
 #ifndef _LINUX_ERROR_INJECTION_H
 #define _LINUX_ERROR_INJECTION_H
 
-#ifdef CONFIG_FUNCTION_ERROR_INJECTION
+#include <linux/compiler.h>
+#include <asm-generic/error-injection.h>
 
-#include <asm/error-injection.h>
+#ifdef CONFIG_FUNCTION_ERROR_INJECTION
 
 extern bool within_error_injection_list(unsigned long addr);
 extern int get_injectable_error_type(unsigned long addr);
 
 #else /* !CONFIG_FUNCTION_ERROR_INJECTION */
 
-#include <asm-generic/error-injection.h>
 static inline bool within_error_injection_list(unsigned long addr)
 {
 	return false;
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* [PATCH v2 2/3] arm64: Add support for function error injection
  2019-08-06 10:00 [PATCH v2 0/3] arm/arm64: Add support for function error injection Leo Yan
  2019-08-06 10:00 ` [PATCH v2 1/3] error-injection: Consolidate override function definition Leo Yan
@ 2019-08-06 10:00 ` Leo Yan
  2019-08-06 10:00 ` [PATCH v2 3/3] arm: " Leo Yan
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 11+ messages in thread
From: Leo Yan @ 2019-08-06 10:00 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu
  Cc: Leo Yan

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.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 arch/arm64/Kconfig              |  1 +
 arch/arm64/include/asm/ptrace.h |  5 +++++
 arch/arm64/lib/Makefile         |  2 ++
 arch/arm64/lib/error-inject.c   | 18 ++++++++++++++++++
 4 files changed, 26 insertions(+)
 create mode 100644 arch/arm64/lib/error-inject.c

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 b1dd039023ef..891b9995cb4b 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);
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* [PATCH v2 3/3] arm: Add support for function error injection
  2019-08-06 10:00 [PATCH v2 0/3] arm/arm64: Add support for function error injection Leo Yan
  2019-08-06 10:00 ` [PATCH v2 1/3] error-injection: Consolidate override function definition Leo Yan
  2019-08-06 10:00 ` [PATCH v2 2/3] arm64: Add support for function error injection Leo Yan
@ 2019-08-06 10:00 ` Leo Yan
  2019-08-19  9:18   ` Leo Yan
  2019-08-07  0:08 ` [PATCH v2 0/3] arm/arm64: " Masami Hiramatsu
  2019-08-07 16:07 ` Will Deacon
  4 siblings, 1 reply; 11+ messages in thread
From: Leo Yan @ 2019-08-06 10:00 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu
  Cc: Leo Yan

This patch implements arm specific functions regs_set_return_value() and
override_function_with_return() to support function error injection.

In the exception flow, it updates pt_regs::ARM_pc with pt_regs::ARM_lr
so can override the probed function return.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
---
 arch/arm/Kconfig              |  1 +
 arch/arm/include/asm/ptrace.h |  5 +++++
 arch/arm/lib/Makefile         |  2 ++
 arch/arm/lib/error-inject.c   | 19 +++++++++++++++++++
 4 files changed, 27 insertions(+)
 create mode 100644 arch/arm/lib/error-inject.c

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 33b00579beff..2d3d44a037f6 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -77,6 +77,7 @@ config ARM
 	select HAVE_EXIT_THREAD
 	select HAVE_FAST_GUP if ARM_LPAE
 	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/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 b25c54585048..8f56484a7156 100644
--- a/arch/arm/lib/Makefile
+++ b/arch/arm/lib/Makefile
@@ -42,3 +42,5 @@ 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..2d696dc94893
--- /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, 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, regs->ARM_lr);
+}
+NOKPROBE_SYMBOL(override_function_with_return);
-- 
2.17.1


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 0/3] arm/arm64: Add support for function error injection
  2019-08-06 10:00 [PATCH v2 0/3] arm/arm64: Add support for function error injection Leo Yan
                   ` (2 preceding siblings ...)
  2019-08-06 10:00 ` [PATCH v2 3/3] arm: " Leo Yan
@ 2019-08-07  0:08 ` Masami Hiramatsu
  2019-08-07  1:31   ` Leo Yan
  2019-08-07 16:07 ` Will Deacon
  4 siblings, 1 reply; 11+ messages in thread
From: Masami Hiramatsu @ 2019-08-07  0:08 UTC (permalink / raw)
  To: Leo Yan
  Cc: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux

On Tue,  6 Aug 2019 18:00:12 +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.
> 
> The patch 01/03 is to consolidate the function definition which can be
> suared cross architectures, patches 02,03/03 are used for enabling
> function error injection on arm64 and arm architecture respectively.
> 
> I tested on arm64 platform Juno-r2 and one of my laptop with x86
> architecture with below steps; I don't test for Arm architecture 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 with Debian rootFS:
>   # cd $kernel
>   # make headers_install
>   # make samples/bpf/ LLC=llc-7 CLANG=clang-7
> 
> - Run the sample tracex7:
>   # dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1
>   # DEVICE=$(losetup --show -f testfile.img)
>   # mkfs.btrfs -f $DEVICE
>   # ./tracex7 testfile.img
>   [ 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.
> 
> Changes from v1:
> * Consolidated the function definition into asm-generic header (Will);
> * Used APIs to access pt_regs elements (Will);
> * Fixed typos in the comments (Will).

This looks good to me.

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

Thank you!

> 
> 
> Leo Yan (3):
>   error-injection: Consolidate override function definition
>   arm64: Add support for function error injection
>   arm: Add support for function error injection
> 
>  arch/arm/Kconfig                           |  1 +
>  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/ptrace.h            |  5 +++++
>  arch/arm64/lib/Makefile                    |  2 ++
>  arch/arm64/lib/error-inject.c              | 18 ++++++++++++++++++
>  arch/powerpc/include/asm/error-injection.h | 13 -------------
>  arch/x86/include/asm/error-injection.h     | 13 -------------
>  include/asm-generic/error-injection.h      |  6 ++++++
>  include/linux/error-injection.h            |  6 +++---
>  12 files changed, 62 insertions(+), 29 deletions(-)
>  create mode 100644 arch/arm/lib/error-inject.c
>  create mode 100644 arch/arm64/lib/error-inject.c
>  delete mode 100644 arch/powerpc/include/asm/error-injection.h
>  delete mode 100644 arch/x86/include/asm/error-injection.h
> 
> -- 
> 2.17.1
> 


-- 
Masami Hiramatsu <mhiramat@kernel.org>

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 0/3] arm/arm64: Add support for function error injection
  2019-08-07  0:08 ` [PATCH v2 0/3] arm/arm64: " Masami Hiramatsu
@ 2019-08-07  1:31   ` Leo Yan
  0 siblings, 0 replies; 11+ messages in thread
From: Leo Yan @ 2019-08-07  1:31 UTC (permalink / raw)
  To: Masami Hiramatsu
  Cc: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux

On Wed, Aug 07, 2019 at 09:08:11AM +0900, Masami Hiramatsu wrote:
> On Tue,  6 Aug 2019 18:00:12 +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.
> > 
> > The patch 01/03 is to consolidate the function definition which can be
> > suared cross architectures, patches 02,03/03 are used for enabling
> > function error injection on arm64 and arm architecture respectively.
> > 
> > I tested on arm64 platform Juno-r2 and one of my laptop with x86
> > architecture with below steps; I don't test for Arm architecture 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 with Debian rootFS:
> >   # cd $kernel
> >   # make headers_install
> >   # make samples/bpf/ LLC=llc-7 CLANG=clang-7
> > 
> > - Run the sample tracex7:
> >   # dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1
> >   # DEVICE=$(losetup --show -f testfile.img)
> >   # mkfs.btrfs -f $DEVICE
> >   # ./tracex7 testfile.img
> >   [ 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.
> > 
> > Changes from v1:
> > * Consolidated the function definition into asm-generic header (Will);
> > * Used APIs to access pt_regs elements (Will);
> > * Fixed typos in the comments (Will).
> 
> This looks good to me.
> 
> Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
> 
> Thank you!

Thanks a lot for reviewing, Masami.

Leo.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 0/3] arm/arm64: Add support for function error injection
  2019-08-06 10:00 [PATCH v2 0/3] arm/arm64: Add support for function error injection Leo Yan
                   ` (3 preceding siblings ...)
  2019-08-07  0:08 ` [PATCH v2 0/3] arm/arm64: " Masami Hiramatsu
@ 2019-08-07 16:07 ` Will Deacon
  2019-08-08  9:09   ` Leo Yan
  4 siblings, 1 reply; 11+ messages in thread
From: Will Deacon @ 2019-08-07 16:07 UTC (permalink / raw)
  To: Leo Yan
  Cc: Russell King, Oleg Nesterov, Catalin Marinas,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu

On Tue, Aug 06, 2019 at 06:00:12PM +0800, Leo Yan 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.
> 
> The patch 01/03 is to consolidate the function definition which can be
> suared cross architectures, patches 02,03/03 are used for enabling
> function error injection on arm64 and arm architecture respectively.
> 
> I tested on arm64 platform Juno-r2 and one of my laptop with x86
> architecture with below steps; I don't test for Arm architecture so
> only pass compilation.

Thanks. I've queued the first two patches up here:

https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=for-next/error-injection

Will

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 0/3] arm/arm64: Add support for function error injection
  2019-08-07 16:07 ` Will Deacon
@ 2019-08-08  9:09   ` Leo Yan
  0 siblings, 0 replies; 11+ messages in thread
From: Leo Yan @ 2019-08-08  9:09 UTC (permalink / raw)
  To: Will Deacon
  Cc: Russell King, Oleg Nesterov, Catalin Marinas,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu

On Wed, Aug 07, 2019 at 05:07:03PM +0100, Will Deacon wrote:
> On Tue, Aug 06, 2019 at 06:00:12PM +0800, Leo Yan 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.
> > 
> > The patch 01/03 is to consolidate the function definition which can be
> > suared cross architectures, patches 02,03/03 are used for enabling
> > function error injection on arm64 and arm architecture respectively.
> > 
> > I tested on arm64 platform Juno-r2 and one of my laptop with x86
> > architecture with below steps; I don't test for Arm architecture so
> > only pass compilation.
> 
> Thanks. I've queued the first two patches up here:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/log/?h=for-next/error-injection

Thank you, Will.

Leo.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 3/3] arm: Add support for function error injection
  2019-08-06 10:00 ` [PATCH v2 3/3] arm: " Leo Yan
@ 2019-08-19  9:18   ` Leo Yan
  2019-08-29  6:57     ` Russell King - ARM Linux admin
  0 siblings, 1 reply; 11+ messages in thread
From: Leo Yan @ 2019-08-19  9:18 UTC (permalink / raw)
  To: Russell King, Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu

Hi Russell,

On Tue, Aug 06, 2019 at 06:00:15PM +0800, Leo Yan wrote:
> This patch implements arm specific functions regs_set_return_value() and
> override_function_with_return() to support function error injection.
> 
> In the exception flow, it updates pt_regs::ARM_pc with pt_regs::ARM_lr
> so can override the probed function return.

Gentle ping ...  Could you review this patch?

Thanks,
Leo.

> Signed-off-by: Leo Yan <leo.yan@linaro.org>
> ---
>  arch/arm/Kconfig              |  1 +
>  arch/arm/include/asm/ptrace.h |  5 +++++
>  arch/arm/lib/Makefile         |  2 ++
>  arch/arm/lib/error-inject.c   | 19 +++++++++++++++++++
>  4 files changed, 27 insertions(+)
>  create mode 100644 arch/arm/lib/error-inject.c
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 33b00579beff..2d3d44a037f6 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -77,6 +77,7 @@ config ARM
>  	select HAVE_EXIT_THREAD
>  	select HAVE_FAST_GUP if ARM_LPAE
>  	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/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 b25c54585048..8f56484a7156 100644
> --- a/arch/arm/lib/Makefile
> +++ b/arch/arm/lib/Makefile
> @@ -42,3 +42,5 @@ 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..2d696dc94893
> --- /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, 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, regs->ARM_lr);
> +}
> +NOKPROBE_SYMBOL(override_function_with_return);
> -- 
> 2.17.1
> 

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 3/3] arm: Add support for function error injection
  2019-08-19  9:18   ` Leo Yan
@ 2019-08-29  6:57     ` Russell King - ARM Linux admin
  2019-08-29  7:23       ` Leo Yan
  0 siblings, 1 reply; 11+ messages in thread
From: Russell King - ARM Linux admin @ 2019-08-29  6:57 UTC (permalink / raw)
  To: Leo Yan
  Cc: Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu

I'm sorry, I can't apply this, it produces loads of:

include/linux/error-injection.h:7:10: fatal error: asm/error-injection.h: No such file or directory

Since your patch 1 has been merged by the ARM64 people, I can't take
it until next cycle.

On Mon, Aug 19, 2019 at 05:18:08PM +0800, Leo Yan wrote:
> Hi Russell,
> 
> On Tue, Aug 06, 2019 at 06:00:15PM +0800, Leo Yan wrote:
> > This patch implements arm specific functions regs_set_return_value() and
> > override_function_with_return() to support function error injection.
> > 
> > In the exception flow, it updates pt_regs::ARM_pc with pt_regs::ARM_lr
> > so can override the probed function return.
> 
> Gentle ping ...  Could you review this patch?
> 
> Thanks,
> Leo.
> 
> > Signed-off-by: Leo Yan <leo.yan@linaro.org>
> > ---
> >  arch/arm/Kconfig              |  1 +
> >  arch/arm/include/asm/ptrace.h |  5 +++++
> >  arch/arm/lib/Makefile         |  2 ++
> >  arch/arm/lib/error-inject.c   | 19 +++++++++++++++++++
> >  4 files changed, 27 insertions(+)
> >  create mode 100644 arch/arm/lib/error-inject.c
> > 
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 33b00579beff..2d3d44a037f6 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -77,6 +77,7 @@ config ARM
> >  	select HAVE_EXIT_THREAD
> >  	select HAVE_FAST_GUP if ARM_LPAE
> >  	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/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 b25c54585048..8f56484a7156 100644
> > --- a/arch/arm/lib/Makefile
> > +++ b/arch/arm/lib/Makefile
> > @@ -42,3 +42,5 @@ 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..2d696dc94893
> > --- /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, 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, regs->ARM_lr);
> > +}
> > +NOKPROBE_SYMBOL(override_function_with_return);
> > -- 
> > 2.17.1
> > 
> 

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
According to speedtest.net: 11.9Mbps down 500kbps up

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v2 3/3] arm: Add support for function error injection
  2019-08-29  6:57     ` Russell King - ARM Linux admin
@ 2019-08-29  7:23       ` Leo Yan
  0 siblings, 0 replies; 11+ messages in thread
From: Leo Yan @ 2019-08-29  7:23 UTC (permalink / raw)
  To: Russell King - ARM Linux admin
  Cc: Oleg Nesterov, Catalin Marinas, Will Deacon,
	Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
	Thomas Gleixner, Ingo Molnar, Borislav Petkov, H. Peter Anvin,
	x86, Arnd Bergmann, Alexei Starovoitov, Daniel Borkmann,
	Martin KaFai Lau, Song Liu, Yonghong Song, Naveen N. Rao,
	linux-arm-kernel, linux-kernel, linuxppc-dev, linux-arch, netdev,
	bpf, clang-built-linux, Masami Hiramatsu

Hi Russell,

On Thu, Aug 29, 2019 at 07:57:29AM +0100, Russell King - ARM Linux admin wrote:
> I'm sorry, I can't apply this, it produces loads of:
> 
> include/linux/error-injection.h:7:10: fatal error: asm/error-injection.h: No such file or directory
> 
> Since your patch 1 has been merged by the ARM64 people, I can't take
> it until next cycle.

For this case, do you want me to resend this patch in next merge
window?  Or you have picked up this patch but will send PR in next
cycle?

Thanks,
Leo Yan

> On Mon, Aug 19, 2019 at 05:18:08PM +0800, Leo Yan wrote:
> > Hi Russell,
> > 
> > On Tue, Aug 06, 2019 at 06:00:15PM +0800, Leo Yan wrote:
> > > This patch implements arm specific functions regs_set_return_value() and
> > > override_function_with_return() to support function error injection.
> > > 
> > > In the exception flow, it updates pt_regs::ARM_pc with pt_regs::ARM_lr
> > > so can override the probed function return.
> > 
> > Gentle ping ...  Could you review this patch?
> > 
> > Thanks,
> > Leo.
> > 
> > > Signed-off-by: Leo Yan <leo.yan@linaro.org>
> > > ---
> > >  arch/arm/Kconfig              |  1 +
> > >  arch/arm/include/asm/ptrace.h |  5 +++++
> > >  arch/arm/lib/Makefile         |  2 ++
> > >  arch/arm/lib/error-inject.c   | 19 +++++++++++++++++++
> > >  4 files changed, 27 insertions(+)
> > >  create mode 100644 arch/arm/lib/error-inject.c
> > > 
> > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > > index 33b00579beff..2d3d44a037f6 100644
> > > --- a/arch/arm/Kconfig
> > > +++ b/arch/arm/Kconfig
> > > @@ -77,6 +77,7 @@ config ARM
> > >  	select HAVE_EXIT_THREAD
> > >  	select HAVE_FAST_GUP if ARM_LPAE
> > >  	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/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 b25c54585048..8f56484a7156 100644
> > > --- a/arch/arm/lib/Makefile
> > > +++ b/arch/arm/lib/Makefile
> > > @@ -42,3 +42,5 @@ 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..2d696dc94893
> > > --- /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, 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, regs->ARM_lr);
> > > +}
> > > +NOKPROBE_SYMBOL(override_function_with_return);
> > > -- 
> > > 2.17.1
> > > 
> > 
> 
> -- 
> RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
> FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up
> According to speedtest.net: 11.9Mbps down 500kbps up

^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2019-08-29  7:24 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-08-06 10:00 [PATCH v2 0/3] arm/arm64: Add support for function error injection Leo Yan
2019-08-06 10:00 ` [PATCH v2 1/3] error-injection: Consolidate override function definition Leo Yan
2019-08-06 10:00 ` [PATCH v2 2/3] arm64: Add support for function error injection Leo Yan
2019-08-06 10:00 ` [PATCH v2 3/3] arm: " Leo Yan
2019-08-19  9:18   ` Leo Yan
2019-08-29  6:57     ` Russell King - ARM Linux admin
2019-08-29  7:23       ` Leo Yan
2019-08-07  0:08 ` [PATCH v2 0/3] arm/arm64: " Masami Hiramatsu
2019-08-07  1:31   ` Leo Yan
2019-08-07 16:07 ` Will Deacon
2019-08-08  9:09   ` Leo Yan

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