From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
To: Miroslav Benes <mbenes@suse.cz>
Cc: jpoimboe@redhat.com, peterz@infradead.org,
chenzhongjin@huawei.com, mark.rutland@arm.com,
broonie@kernel.org, nobuta.keiya@fujitsu.com,
sjitindarsingh@gmail.com, catalin.marinas@arm.com,
will@kernel.org, jamorris@linux.microsoft.com,
linux-arm-kernel@lists.infradead.org,
live-patching@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v2 19/20] arm64: Miscellaneous changes required for enabling livepatch
Date: Fri, 1 Jul 2022 14:53:30 -0500 [thread overview]
Message-ID: <884d1d23-84ee-38ad-2bff-40b2d046fbf2@linux.microsoft.com> (raw)
In-Reply-To: <alpine.LSU.2.21.2207011609360.23331@pobox.suse.cz>
Thanks for the review.
On 7/1/22 09:16, Miroslav Benes wrote:
> Hi,
>
> sorry for the late reply...
>
> On Mon, 23 May 2022, madvenka@linux.microsoft.com wrote:
>
>> From: "Madhavan T. Venkataraman" <madvenka@linux.microsoft.com>
>>
>> - 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 <sjitindarsingh@gmail.com>
>> Signed-off-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
>> ---
>> 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
next prev parent reply other threads:[~2022-07-01 19:53 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <e81e773678f88f7c2ff7480e2eb096973ec198db>
2022-05-24 0:16 ` [RFC PATCH v2 00/20] arm64: livepatch: Use ORC for dynamic frame pointer validation madvenka
2022-05-24 0:16 ` [RFC PATCH v2 01/20] objtool: Reorganize CFI code madvenka
2022-05-24 0:16 ` [RFC PATCH v2 02/20] objtool: Reorganize instruction-related code madvenka
2022-05-24 0:16 ` [RFC PATCH v2 03/20] objtool: Move decode_instructions() to a separate file madvenka
2022-05-24 0:16 ` [RFC PATCH v2 04/20] objtool: Reorganize Unwind hint code madvenka
2022-05-24 0:16 ` [RFC PATCH v2 05/20] objtool: Reorganize ORC types madvenka
2022-05-24 14:27 ` Chen Zhongjin
2022-05-29 15:36 ` Madhavan T. Venkataraman
2022-05-24 0:16 ` [RFC PATCH v2 06/20] objtool: Reorganize ORC code madvenka
2022-05-24 0:16 ` [RFC PATCH v2 07/20] objtool: Reorganize ORC kernel code madvenka
2022-05-24 0:16 ` [RFC PATCH v2 08/20] objtool: arm64: Implement decoder for FP validation madvenka
2022-05-24 0:16 ` [RFC PATCH v2 09/20] objtool: arm64: Implement command to invoke the decoder madvenka
2022-05-24 14:09 ` Mark Brown
2022-05-29 14:49 ` Madhavan T. Venkataraman
2022-05-30 7:51 ` Peter Zijlstra
2022-06-01 22:45 ` Madhavan T. Venkataraman
2022-06-07 18:13 ` Madhavan T. Venkataraman
2022-05-24 0:16 ` [RFC PATCH v2 10/20] objtool: arm64: Compute destinations for call and jump instructions madvenka
2022-05-24 0:16 ` [RFC PATCH v2 11/20] objtool: arm64: Walk instructions and compute CFI for each instruction madvenka
2022-05-24 13:45 ` Chen Zhongjin
2022-05-29 15:18 ` Madhavan T. Venkataraman
2022-05-30 1:44 ` Chen Zhongjin
2022-05-24 0:16 ` [RFC PATCH v2 12/20] objtool: arm64: Generate ORC data from CFI for object files madvenka
2022-05-24 0:16 ` [RFC PATCH v2 13/20] objtool: arm64: Dump ORC data present in " madvenka
2022-05-24 0:16 ` [RFC PATCH v2 14/20] objtool: arm64: Add unwind hint support madvenka
2022-05-24 0:16 ` [RFC PATCH v2 15/20] arm64: Add unwind hints to specific points in code madvenka
2022-05-24 0:16 ` [RFC PATCH v2 16/20] arm64: Add kernel and module support for ORC madvenka
2022-05-24 0:16 ` [RFC PATCH v2 17/20] arm64: Build the kernel with ORC information madvenka
2022-05-24 0:16 ` [RFC PATCH v2 18/20] arm64: unwinder: Add a reliability check in the unwinder based on ORC madvenka
2022-05-24 0:16 ` [RFC PATCH v2 19/20] arm64: Miscellaneous changes required for enabling livepatch madvenka
2022-07-01 14:16 ` Miroslav Benes
2022-07-01 19:53 ` Madhavan T. Venkataraman [this message]
2022-05-24 0:16 ` [RFC PATCH v2 20/20] arm64: Enable livepatch for ARM64 madvenka
2022-05-24 14:24 ` [RFC PATCH v2 00/20] arm64: livepatch: Use ORC for dynamic frame pointer validation Chen Zhongjin
2022-05-29 15:30 ` Madhavan T. Venkataraman
2022-06-15 12:18 ` Ivan T. Ivanov
2022-06-15 13:37 ` Mark Rutland
2022-06-15 14:18 ` Ivan T. Ivanov
2022-06-15 20:50 ` Madhavan T. Venkataraman
2022-06-15 20:47 ` Madhavan T. Venkataraman
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