From: pageexec@freemail.hu
To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Date: Tue, 13 Nov 2007 22:54:18 +0200
MIME-Version: 1.0
Subject: Re: [patch 06/11] Text Edit Lock - Alternative code for x86
Reply-to: pageexec@freemail.hu
CC: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       Andi Kleen <andi@firstfloor.org>
Message-ID: <473A2B1A.16967.38D5698D@pageexec.freemail.hu>
In-reply-to: <20071113184719.506949138@polymtl.ca>
References: <20071113184627.667866257@polymtl.ca>, <20071113184719.506949138@polymtl.ca>
Content-type: text/plain; charset=US-ASCII
Content-transfer-encoding: 7BIT
Content-description: Mail message body
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1221
Lines: 43

On 13 Nov 2007 at 13:46, Mathieu Desnoyers wrote:

> +void *text_poke_early(void *addr, const void *opcode, size_t len)
> +{
> +	memcpy(addr, opcode, len);
> +	text_sync(addr, len);
> +	return addr;
> +}

why do you need this function (vs. using text_poke throughout)?

> +#define kernel_wp_save(cr0)					\
> +	do {							\
> +		preempt_disable();				\
> +		cr0 = read_cr0();				\
> +		if (cpu_data(smp_processor_id()).wp_works_ok)	\

why do you need this test? if cr0.wp is ineffective, then it doesn't
matter whether it's on or off (in fact, at least the intel manual
says that 386s would not even let you change its value, they'll
silently ignore attempts of setting the wp bit).

> +			write_cr0(cr0 & ~X86_CR0_WP);		\
> +	} while (0)
> +
> +#define kernel_wp_restore(cr0)					\
> +	do {							\
> +		if (cpu_data(smp_processor_id()).wp_works_ok)	\

ditto...

> +			write_cr0(cr0);				\
> +		preempt_enable();				\
> +	} while (0)
>  
>  #endif /* _I386_ALTERNATIVE_H */


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/