From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <srostedt@redhat.com>
Subject: Re: [PATCH 2/5] ftrace, x86: make kernel text writable only for conversions
Date: Fri, 20 Feb 2009 18:30:35 +0100 [thread overview]
Message-ID: <20090220173035.GI24538@elte.hu> (raw)
In-Reply-To: <20090220164045.827841413@goodmis.org>
* Steven Rostedt <rostedt@goodmis.org> wrote:
> diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
> index b55b4a7..5564cf3 100644
> --- a/arch/x86/include/asm/ftrace.h
> +++ b/arch/x86/include/asm/ftrace.h
> @@ -80,4 +80,14 @@ extern void return_to_handler(void);
> #endif /* __ASSEMBLY__ */
> #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
>
> +#ifndef __ASSEMBLY__
> +#ifdef CONFIG_DEBUG_RODATA
> +void set_kernel_text_rw(void);
> +void set_kernel_text_ro(void);
> +#else
> +static inline void set_kernel_text_rw(void) { }
> +static inline void set_kernel_text_ro(void) { }
> +#endif
> +#endif /* __ASSEMBLY__ */
The proper place for this is where the other pagetable attribute
functions reside: arch/x86/include/asm/cacheflush.h.
> +/* used by ftrace */
> +void set_kernel_text_rw(void)
> +{
> + unsigned long start = PFN_ALIGN(_text);
> + unsigned long size = PFN_ALIGN(_etext) - start;
> +
> + printk(KERN_INFO "Set kernel text: %lx - %lx for read write\n",
> + start, start+size);
> +
> + set_pages_rw(virt_to_page(start), size >> PAGE_SHIFT);
Wont this be executed by every suspend/resume cycle? I'm not
sure we want a KERN_INFO printout every time.
> +/* used by ftrace */
> +void set_kernel_text_rw(void)
i'd leave out the 'used by ftrace' bit - more uses might arise.
How does kprobes get around readonly pages, it uses these APIs
too, right?
Ingo
next prev parent reply other threads:[~2009-02-20 17:30 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-20 16:38 [git pull] updates for tip Steven Rostedt
2009-02-20 16:38 ` [PATCH 1/5] ftrace: allow archs to preform pre and post process for code modification Steven Rostedt
2009-02-20 17:25 ` Ingo Molnar
2009-02-20 17:32 ` Steven Rostedt
2009-02-20 16:38 ` [PATCH 2/5] ftrace, x86: make kernel text writable only for conversions Steven Rostedt
2009-02-20 17:30 ` Ingo Molnar [this message]
2009-02-20 17:52 ` Steven Rostedt
2009-02-20 17:55 ` Ingo Molnar
2009-02-20 18:00 ` Steven Rostedt
2009-02-20 16:38 ` [PATCH 3/5] ftrace: immediately stop code modification if failure is detected Steven Rostedt
2009-02-20 16:38 ` [PATCH 4/5] ftrace: break out modify loop immediately on detection of error Steven Rostedt
2009-02-20 17:33 ` Ingo Molnar
2009-02-20 17:54 ` Steven Rostedt
2009-02-20 16:38 ` [PATCH 5/5] ftrace, x86: do not depend on system state for kernel text info Steven Rostedt
2009-02-20 17:34 ` Ingo Molnar
2009-02-20 17:54 ` Steven Rostedt
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