From: "Madhavan T. Venkataraman" <[email protected]>
- Create arch/arm64/include/asm/livepatch.h and define
klp_arch_set_pc() and klp_get_ftrace_location() which
are required for livepatch.
- Define TIF_PATCH_PENDING in arch/arm64/include/asm/thread_info.h
for livepatch.
- Check TIF_PATCH_PENDING in do_notify_resume() to patch the
current task for livepatch.
Signed-off-by: Suraj Jitindar Singh <[email protected]>
Signed-off-by: Madhavan T. Venkataraman <[email protected]>
---
arch/arm64/include/asm/livepatch.h | 42 ++++++++++++++++++++++++++++
arch/arm64/include/asm/thread_info.h | 4 ++-
arch/arm64/kernel/signal.c | 4 +++
3 files changed, 49 insertions(+), 1 deletion(-)
create mode 100644 arch/arm64/include/asm/livepatch.h
diff --git a/arch/arm64/include/asm/livepatch.h b/arch/arm64/include/asm/livepatch.h
new file mode 100644
index 000000000000..72d7cd86f158
--- /dev/null
+++ b/arch/arm64/include/asm/livepatch.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: GPL-2.0
+ *
+ * livepatch.h - arm64-specific Kernel Live Patching Core
+ */
+#ifndef _ASM_ARM64_LIVEPATCH_H
+#define _ASM_ARM64_LIVEPATCH_H
+
+#include <linux/ftrace.h>
+
+static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
+{
+ struct pt_regs *regs = ftrace_get_regs(fregs);
+
+ regs->pc = ip;
+}
+
+/*
+ * klp_get_ftrace_location is expected to return the address of the BL to the
+ * relevant ftrace handler in the callsite. The location of this can vary based
+ * on several compilation options.
+ * CONFIG_DYNAMIC_FTRACE_WITH_REGS
+ * - Inserts 2 nops on function entry the second of which is the BL
+ * referenced above. (See ftrace_init_nop() for the callsite sequence)
+ * (this is required by livepatch and must be selected)
+ * CONFIG_ARM64_BTI_KERNEL:
+ * - Inserts a hint #0x22 on function entry if the function is called
+ * indirectly (to satisfy BTI requirements), which is inserted before
+ * the two nops from above.
+ */
+#define klp_get_ftrace_location klp_get_ftrace_location
+static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
+{
+ unsigned long addr = faddr + AARCH64_INSN_SIZE;
+
+#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)
+ addr = ftrace_location_range(addr, addr + AARCH64_INSN_SIZE);
+#endif
+
+ return addr;
+}
+
+#endif /* _ASM_ARM64_LIVEPATCH_H */
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index e1317b7c4525..a1d8999dbdcc 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -68,6 +68,7 @@ int arch_dup_task_struct(struct task_struct *dst,
#define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */
#define TIF_MTE_ASYNC_FAULT 5 /* MTE Asynchronous Tag Check Fault */
#define TIF_NOTIFY_SIGNAL 6 /* signal notifications exist */
+#define TIF_PATCH_PENDING 7 /* pending live patching update */
#define TIF_SYSCALL_TRACE 8 /* syscall trace active */
#define TIF_SYSCALL_AUDIT 9 /* syscall auditing */
#define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */
@@ -98,11 +99,12 @@ int arch_dup_task_struct(struct task_struct *dst,
#define _TIF_SVE (1 << TIF_SVE)
#define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT)
#define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
+#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING)
#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
_TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
_TIF_UPROBE | _TIF_MTE_ASYNC_FAULT | \
- _TIF_NOTIFY_SIGNAL)
+ _TIF_NOTIFY_SIGNAL | _TIF_PATCH_PENDING)
#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 4a4122ef6f39..cbec9597349f 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -17,6 +17,7 @@
#include <linux/sizes.h>
#include <linux/string.h>
#include <linux/resume_user_mode.h>
+#include <linux/livepatch.h>
#include <linux/ratelimit.h>
#include <linux/syscalls.h>
@@ -938,6 +939,9 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
(void __user *)NULL, current);
}
+ if (thread_flags & _TIF_PATCH_PENDING)
+ klp_update_patch_state(current);
+
if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
do_signal(regs);
--
2.25.1
Hi,
sorry for the late reply...
On Mon, 23 May 2022, [email protected] wrote:
> From: "Madhavan T. Venkataraman" <[email protected]>
>
> - Create arch/arm64/include/asm/livepatch.h and define
> klp_arch_set_pc() and klp_get_ftrace_location() which
> are required for livepatch.
>
> - Define TIF_PATCH_PENDING in arch/arm64/include/asm/thread_info.h
> for livepatch.
>
> - Check TIF_PATCH_PENDING in do_notify_resume() to patch the
> current task for livepatch.
>
> Signed-off-by: Suraj Jitindar Singh <[email protected]>
> Signed-off-by: Madhavan T. Venkataraman <[email protected]>
> ---
> arch/arm64/include/asm/livepatch.h | 42 ++++++++++++++++++++++++++++
> arch/arm64/include/asm/thread_info.h | 4 ++-
> arch/arm64/kernel/signal.c | 4 +++
> 3 files changed, 49 insertions(+), 1 deletion(-)
> create mode 100644 arch/arm64/include/asm/livepatch.h
>
> diff --git a/arch/arm64/include/asm/livepatch.h b/arch/arm64/include/asm/livepatch.h
> new file mode 100644
> index 000000000000..72d7cd86f158
> --- /dev/null
> +++ b/arch/arm64/include/asm/livepatch.h
> @@ -0,0 +1,42 @@
> +/* SPDX-License-Identifier: GPL-2.0
> + *
> + * livepatch.h - arm64-specific Kernel Live Patching Core
> + */
> +#ifndef _ASM_ARM64_LIVEPATCH_H
> +#define _ASM_ARM64_LIVEPATCH_H
> +
> +#include <linux/ftrace.h>
> +
> +static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
> +{
> + struct pt_regs *regs = ftrace_get_regs(fregs);
> +
> + regs->pc = ip;
> +}
kernel/livepatch/ does not use klp_arch_set_pc() anymore. It was replaced
by ftrace_instruction_pointer_set() and
CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS.
> +/*
> + * klp_get_ftrace_location is expected to return the address of the BL to the
> + * relevant ftrace handler in the callsite. The location of this can vary based
> + * on several compilation options.
> + * CONFIG_DYNAMIC_FTRACE_WITH_REGS
> + * - Inserts 2 nops on function entry the second of which is the BL
> + * referenced above. (See ftrace_init_nop() for the callsite sequence)
> + * (this is required by livepatch and must be selected)
> + * CONFIG_ARM64_BTI_KERNEL:
> + * - Inserts a hint #0x22 on function entry if the function is called
> + * indirectly (to satisfy BTI requirements), which is inserted before
> + * the two nops from above.
> + */
> +#define klp_get_ftrace_location klp_get_ftrace_location
> +static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
> +{
> + unsigned long addr = faddr + AARCH64_INSN_SIZE;
> +
> +#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)
> + addr = ftrace_location_range(addr, addr + AARCH64_INSN_SIZE);
> +#endif
> +
> + return addr;
> +}
This is not needed either. peterz improved the ftrace code and livepatch
now uses ftrace_location() which gives the proper location directly.
> diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
> index e1317b7c4525..a1d8999dbdcc 100644
> --- a/arch/arm64/include/asm/thread_info.h
> +++ b/arch/arm64/include/asm/thread_info.h
> @@ -68,6 +68,7 @@ int arch_dup_task_struct(struct task_struct *dst,
> #define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */
> #define TIF_MTE_ASYNC_FAULT 5 /* MTE Asynchronous Tag Check Fault */
> #define TIF_NOTIFY_SIGNAL 6 /* signal notifications exist */
> +#define TIF_PATCH_PENDING 7 /* pending live patching update */
> #define TIF_SYSCALL_TRACE 8 /* syscall trace active */
> #define TIF_SYSCALL_AUDIT 9 /* syscall auditing */
> #define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */
> @@ -98,11 +99,12 @@ int arch_dup_task_struct(struct task_struct *dst,
> #define _TIF_SVE (1 << TIF_SVE)
> #define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT)
> #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
> +#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING)
>
> #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
> _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
> _TIF_UPROBE | _TIF_MTE_ASYNC_FAULT | \
> - _TIF_NOTIFY_SIGNAL)
> + _TIF_NOTIFY_SIGNAL | _TIF_PATCH_PENDING)
>
> #define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
> _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
> diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
> index 4a4122ef6f39..cbec9597349f 100644
> --- a/arch/arm64/kernel/signal.c
> +++ b/arch/arm64/kernel/signal.c
> @@ -17,6 +17,7 @@
> #include <linux/sizes.h>
> #include <linux/string.h>
> #include <linux/resume_user_mode.h>
> +#include <linux/livepatch.h>
> #include <linux/ratelimit.h>
> #include <linux/syscalls.h>
>
> @@ -938,6 +939,9 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
> (void __user *)NULL, current);
> }
>
> + if (thread_flags & _TIF_PATCH_PENDING)
> + klp_update_patch_state(current);
> +
> if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
> do_signal(regs);
The rest should be fine.
Regards
Miroslav
Thanks for the review.
On 7/1/22 09:16, Miroslav Benes wrote:
> Hi,
>
> sorry for the late reply...
>
> On Mon, 23 May 2022, [email protected] wrote:
>
>> From: "Madhavan T. Venkataraman" <[email protected]>
>>
>> - Create arch/arm64/include/asm/livepatch.h and define
>> klp_arch_set_pc() and klp_get_ftrace_location() which
>> are required for livepatch.
>>
>> - Define TIF_PATCH_PENDING in arch/arm64/include/asm/thread_info.h
>> for livepatch.
>>
>> - Check TIF_PATCH_PENDING in do_notify_resume() to patch the
>> current task for livepatch.
>>
>> Signed-off-by: Suraj Jitindar Singh <[email protected]>
>> Signed-off-by: Madhavan T. Venkataraman <[email protected]>
>> ---
>> arch/arm64/include/asm/livepatch.h | 42 ++++++++++++++++++++++++++++
>> arch/arm64/include/asm/thread_info.h | 4 ++-
>> arch/arm64/kernel/signal.c | 4 +++
>> 3 files changed, 49 insertions(+), 1 deletion(-)
>> create mode 100644 arch/arm64/include/asm/livepatch.h
>>
>> diff --git a/arch/arm64/include/asm/livepatch.h b/arch/arm64/include/asm/livepatch.h
>> new file mode 100644
>> index 000000000000..72d7cd86f158
>> --- /dev/null
>> +++ b/arch/arm64/include/asm/livepatch.h
>> @@ -0,0 +1,42 @@
>> +/* SPDX-License-Identifier: GPL-2.0
>> + *
>> + * livepatch.h - arm64-specific Kernel Live Patching Core
>> + */
>> +#ifndef _ASM_ARM64_LIVEPATCH_H
>> +#define _ASM_ARM64_LIVEPATCH_H
>> +
>> +#include <linux/ftrace.h>
>> +
>> +static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip)
>> +{
>> + struct pt_regs *regs = ftrace_get_regs(fregs);
>> +
>> + regs->pc = ip;
>> +}
>
> kernel/livepatch/ does not use klp_arch_set_pc() anymore. It was replaced
> by ftrace_instruction_pointer_set() and
> CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS.
>
OK. I will address this in the next version.
Thanks for pointing it out.
>> +/*
>> + * klp_get_ftrace_location is expected to return the address of the BL to the
>> + * relevant ftrace handler in the callsite. The location of this can vary based
>> + * on several compilation options.
>> + * CONFIG_DYNAMIC_FTRACE_WITH_REGS
>> + * - Inserts 2 nops on function entry the second of which is the BL
>> + * referenced above. (See ftrace_init_nop() for the callsite sequence)
>> + * (this is required by livepatch and must be selected)
>> + * CONFIG_ARM64_BTI_KERNEL:
>> + * - Inserts a hint #0x22 on function entry if the function is called
>> + * indirectly (to satisfy BTI requirements), which is inserted before
>> + * the two nops from above.
>> + */
>> +#define klp_get_ftrace_location klp_get_ftrace_location
>> +static inline unsigned long klp_get_ftrace_location(unsigned long faddr)
>> +{
>> + unsigned long addr = faddr + AARCH64_INSN_SIZE;
>> +
>> +#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)
>> + addr = ftrace_location_range(addr, addr + AARCH64_INSN_SIZE);
>> +#endif
>> +
>> + return addr;
>> +}
>
> This is not needed either. peterz improved the ftrace code and livepatch
> now uses ftrace_location() which gives the proper location directly.
>
OK. I will remove this in the next version.
>> diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
>> index e1317b7c4525..a1d8999dbdcc 100644
>> --- a/arch/arm64/include/asm/thread_info.h
>> +++ b/arch/arm64/include/asm/thread_info.h
>> @@ -68,6 +68,7 @@ int arch_dup_task_struct(struct task_struct *dst,
>> #define TIF_UPROBE 4 /* uprobe breakpoint or singlestep */
>> #define TIF_MTE_ASYNC_FAULT 5 /* MTE Asynchronous Tag Check Fault */
>> #define TIF_NOTIFY_SIGNAL 6 /* signal notifications exist */
>> +#define TIF_PATCH_PENDING 7 /* pending live patching update */
>> #define TIF_SYSCALL_TRACE 8 /* syscall trace active */
>> #define TIF_SYSCALL_AUDIT 9 /* syscall auditing */
>> #define TIF_SYSCALL_TRACEPOINT 10 /* syscall tracepoint for ftrace */
>> @@ -98,11 +99,12 @@ int arch_dup_task_struct(struct task_struct *dst,
>> #define _TIF_SVE (1 << TIF_SVE)
>> #define _TIF_MTE_ASYNC_FAULT (1 << TIF_MTE_ASYNC_FAULT)
>> #define _TIF_NOTIFY_SIGNAL (1 << TIF_NOTIFY_SIGNAL)
>> +#define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING)
>>
>> #define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
>> _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE | \
>> _TIF_UPROBE | _TIF_MTE_ASYNC_FAULT | \
>> - _TIF_NOTIFY_SIGNAL)
>> + _TIF_NOTIFY_SIGNAL | _TIF_PATCH_PENDING)
>>
>> #define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
>> _TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP | \
>> diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
>> index 4a4122ef6f39..cbec9597349f 100644
>> --- a/arch/arm64/kernel/signal.c
>> +++ b/arch/arm64/kernel/signal.c
>> @@ -17,6 +17,7 @@
>> #include <linux/sizes.h>
>> #include <linux/string.h>
>> #include <linux/resume_user_mode.h>
>> +#include <linux/livepatch.h>
>> #include <linux/ratelimit.h>
>> #include <linux/syscalls.h>
>>
>> @@ -938,6 +939,9 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_flags)
>> (void __user *)NULL, current);
>> }
>>
>> + if (thread_flags & _TIF_PATCH_PENDING)
>> + klp_update_patch_state(current);
>> +
>> if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
>> do_signal(regs);
>
> The rest should be fine.
>
Thanks!
Madhavan