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From: Will Deacon <will@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	rostedt@goodmis.org, mhiramat@kernel.org, bristot@redhat.com,
	jbaron@akamai.com, torvalds@linux-foundation.org,
	tglx@linutronix.de, mingo@kernel.org, namit@vmware.com,
	hpa@zytor.com, luto@kernel.org, ard.biesheuvel@linaro.org,
	jpoimboe@redhat.com, jeyu@kernel.org,
	alexei.starovoitov@gmail.com, rabin@rab.in,
	Mark Rutland <mark.rutland@arm.com>,
	james.morse@arm.com
Subject: Re: [PATCH -v5 13/17] arm/ftrace: Use __patch_text_real()
Date: Mon, 11 Nov 2019 16:47:03 +0000	[thread overview]
Message-ID: <20191111164703.GA11521@willie-the-truck> (raw)
In-Reply-To: <20191111132458.220458362@infradead.org>

On Mon, Nov 11, 2019 at 02:13:05PM +0100, Peter Zijlstra wrote:
> Instead of flipping text protection, use the patch_text infrastructure
> that uses a fixmap alias where required.
> 
> This removes the last user of set_all_modules_text_*().
> 
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> Cc: ard.biesheuvel@linaro.org
> Cc: rabin@rab.in
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: james.morse@arm.com
> ---
>  arch/arm/kernel/ftrace.c |   16 ++++++++--------
>  1 file changed, 8 insertions(+), 8 deletions(-)
> 
> --- a/arch/arm/kernel/ftrace.c
> +++ b/arch/arm/kernel/ftrace.c
> @@ -22,6 +22,7 @@
>  #include <asm/ftrace.h>
>  #include <asm/insn.h>
>  #include <asm/set_memory.h>
> +#include <asm/patch.h>
>  
>  #ifdef CONFIG_THUMB2_KERNEL
>  #define	NOP		0xf85deb04	/* pop.w {lr} */
> @@ -31,13 +32,15 @@
>  
>  #ifdef CONFIG_DYNAMIC_FTRACE
>  
> +static int patch_text_remap = 0;
> +
>  static int __ftrace_modify_code(void *data)
>  {
>  	int *command = data;
>  
> -	set_kernel_text_rw();
> +	patch_text_remap++;
>  	ftrace_modify_all_code(*command);
> -	set_kernel_text_ro();
> +	patch_text_remap--;
>  
>  	return 0;
>  }
> @@ -59,13 +62,13 @@ static unsigned long adjust_address(stru
>  
>  int ftrace_arch_code_modify_prepare(void)
>  {
> -	set_all_modules_text_rw();
> +	patch_text_remap++;
>  	return 0;
>  }
>  
>  int ftrace_arch_code_modify_post_process(void)
>  {
> -	set_all_modules_text_ro();
> +	patch_text_remap--;
>  	/* Make sure any TLB misses during machine stop are cleared. */
>  	flush_tlb_all();
>  	return 0;
> @@ -97,10 +100,7 @@ static int ftrace_modify_code(unsigned l
>  			return -EINVAL;
>  	}
>  
> -	if (probe_kernel_write((void *)pc, &new, MCOUNT_INSN_SIZE))
> -		return -EPERM;
> -
> -	flush_icache_range(pc, pc + MCOUNT_INSN_SIZE);
> +	__patch_text_real((void *)pc, new, patch_text_remap);

I'd still prefer to pass 'true' unconditionally here, since I don't think
this is a hot path.

Will

  reply	other threads:[~2019-11-11 16:47 UTC|newest]

Thread overview: 106+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-11 13:12 [PATCH -v5 00/17] Rewrite x86/ftrace to use text_poke (and more) Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 01/17] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 02/17] x86/alternatives: Update int3_emulate_push() comment Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 03/17] x86/alternatives,jump_label: Provide better text_poke() batching interface Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] x86/alternatives, jump_label: " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 04/17] x86/alternatives: Add and use text_gen_insn() helper Peter Zijlstra
2019-11-12 17:10   ` Steven Rostedt
2019-11-12 22:25     ` Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 05/17] x86/ftrace: Use text_poke() Peter Zijlstra
2019-11-12 18:25   ` Steven Rostedt
2019-11-12 22:24     ` Peter Zijlstra
2019-11-12 22:48       ` Steven Rostedt
2019-11-13  9:01         ` Peter Zijlstra
2019-11-13 14:27           ` Steven Rostedt
2019-11-14 13:18             ` Peter Zijlstra
2019-11-14 13:56               ` Steven Rostedt
2019-11-14 14:05                 ` Peter Zijlstra
2019-11-13  8:53       ` Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-11-16 20:46     ` Borislav Petkov
2019-11-18 17:35       ` [PATCH] x86/ftrace: Mark ftrace_modify_code_direct() __ref Borislav Petkov
2019-11-18 17:52         ` Steven Rostedt
2019-11-19  9:55       ` [tip: core/kprobes] " tip-bot2 for Borislav Petkov
2019-12-04  8:33       ` tip-bot2 for Borislav Petkov
2019-12-04  8:33   ` [tip: core/kprobes] x86/ftrace: Use text_poke() tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 06/17] x86/mm: Remove set_kernel_text_r[ow]() Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:12 ` [PATCH -v5 07/17] x86/alternative: Add text_opcode_size() Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 08/17] x86/ftrace: Use text_gen_insn() Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 09/17] x86/alternative: Remove text_poke_loc::len Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 10/17] x86/alternative: Shrink text_poke_loc Peter Zijlstra
2019-11-15  9:43   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 11/17] x86/kprobes: Convert to text-patching.h Peter Zijlstra
2019-11-19 16:56   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 12/17] x86/kprobes: Fix ordering Peter Zijlstra
2019-11-13 14:31   ` Paul E. McKenney
2019-11-13 15:42   ` Mathieu Desnoyers
2019-11-14 13:53     ` Peter Zijlstra
2019-11-14 15:06       ` Mathieu Desnoyers
2019-11-14 15:13         ` Paul E. McKenney
2019-11-14 15:22           ` Mathieu Desnoyers
2019-11-14 15:28             ` Peter Zijlstra
2019-11-14 15:30               ` Mathieu Desnoyers
2019-11-14 15:42                 ` Peter Zijlstra
2019-11-14 15:58                   ` Peter Zijlstra
2019-11-19 16:56   ` [tip: core/kprobes] x86/kprobes: Fix ordering while text-patching tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 13/17] arm/ftrace: Use __patch_text_real() Peter Zijlstra
2019-11-11 16:47   ` Will Deacon [this message]
2019-11-11 17:19     ` Peter Zijlstra
2019-11-11 17:25       ` Peter Zijlstra
2019-11-12 11:29         ` Will Deacon
2019-11-13  9:26           ` [PATCH -v5mkII 13/17] arm/ftrace: Use __patch_text() Peter Zijlstra
2019-11-19 16:56             ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33             ` tip-bot2 for Peter Zijlstra
2020-01-22 21:26               ` Dmitry Osipenko
2020-02-07 10:17                 ` Peter Zijlstra
2020-02-07 10:26                   ` Peter Zijlstra
2020-02-07 11:27                 ` Peter Zijlstra
2020-02-07 16:47                   ` Dmitry Osipenko
2020-01-08 12:22             ` [PATCH -v5mkII 13/17] " Arnd Bergmann
2020-01-08 14:16               ` Steven Rostedt
2020-01-08 14:22                 ` Arnd Bergmann
2019-11-11 13:13 ` [PATCH -v5 14/17] module: Remove set_all_modules_text_*() Peter Zijlstra
2019-11-19 16:56   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 15/17] ftrace: Rework event_create_dir() Peter Zijlstra
2019-11-14 14:07   ` Steven Rostedt
2019-11-19 16:56   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 16/17] x86/kprobe: Add comments to arch_{,un}optimize_kprobes() Peter Zijlstra
2019-11-19 16:56   ` [tip: core/kprobes] " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 13:13 ` [PATCH -v5 17/17] x86/alternative: Use INT3_INSN_SIZE Peter Zijlstra
2019-11-19 16:56   ` [tip: core/kprobes] x86/alternatives: " tip-bot2 for Peter Zijlstra
2019-12-04  8:33   ` tip-bot2 for Peter Zijlstra
2019-11-11 19:47 ` [PATCH -v5 00/17] Rewrite x86/ftrace to use text_poke (and more) Alexei Starovoitov
2019-11-11 20:39   ` Peter Zijlstra
2019-11-11 20:42   ` Peter Zijlstra
2019-11-11 20:56     ` Alexei Starovoitov
2019-11-12 18:26 ` Steven Rostedt
2019-11-25  3:55 ` Masami Hiramatsu
2019-11-25  6:47   ` Masami Hiramatsu
2019-11-25 17:32   ` Steven Rostedt
2019-11-26  0:11     ` Masami Hiramatsu
2019-11-26  8:58       ` Masami Hiramatsu
2019-11-26  9:58         ` Masami Hiramatsu
2019-11-26 23:48           ` Masami Hiramatsu
     [not found]             ` <CAADnVQK4twuXzFhD-qLHmCVK0n1h-GDENQLu+4PVV3Hp++R6kQ@mail.gmail.com>
2019-11-27  4:32               ` Alexei Starovoitov
2019-11-27  5:01                 ` Alexei Starovoitov
2019-11-27  6:41                 ` Masami Hiramatsu

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