From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Michael Ellerman <mpe@ellerman.id.au>,
Scott Wood <oss@buserror.net>, Paul Mackerras <paulus@samba.org>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 3/3] powerpc/mm: Implement CONFIG_DEBUG_RODATA on PPC32
Date: Fri, 21 Apr 2017 13:32:10 +0000 [thread overview]
Message-ID: <1492781365.w4t118903f.astroid@naverao1-tp.none> (raw)
In-Reply-To: <97d45054364142af48b8767f9f9e115504d7568b.1492778567.git.christophe.leroy@c-s .fr>
Excerpts from Christophe Leroy's message of April 21, 2017 18:32:
> This patch implements CONFIG_DEBUG_RODATA on PPC32.
>
> As for CONFIG_DEBUG_PAGEALLOC, it deactivates BAT and LTLB mappings
> in order to allow page protection setup at the level of each page.
>
> As BAT/LTLB mappings are deactivated, their might be performance
> impact. For this reason, we keep it OFF by default.
>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[snip]
> diff --git a/arch/powerpc/kernel/ftrace.c
> b/arch/powerpc/kernel/ftrace.c
> index 32509de6ce4c..06d2ac53f471 100644
> --- a/arch/powerpc/kernel/ftrace.c
> +++ b/arch/powerpc/kernel/ftrace.c
> @@ -46,6 +46,7 @@ static int
> ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
> {
> unsigned int replaced;
> + int err;
>
> /*
> * Note:
> @@ -67,10 +68,11 @@ ftrace_modify_code(unsigned long ip, unsigned int old, unsigned int new)
> }
>
> /* replace the text with the new text */
> - if (patch_instruction((unsigned int *)ip, new))
> - return -EPERM;
> + set_kernel_text_rw(ip);
> + err = patch_instruction((unsigned int *)ip, new);
> + set_kernel_text_ro(ip);
Is there a reason to not put those inside patch_instruction()?
- Naveen
next prev parent reply other threads:[~2017-04-21 13:33 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-21 13:02 [PATCH v2 0/3] powerpc/mm: Fix kernel protection and implement CONFIG_DEBUG_RODATA on PPC32 Christophe Leroy
2017-04-21 13:02 ` [PATCH v2 1/3] powerpc/mm: Ensure change_page_attr() doesn't invalidate pinned TLBs Christophe Leroy
2017-04-21 13:02 ` [PATCH v2 2/3] powerpc/mm: Fix kernel RAM protection after freeing unused memory on PPC32 Christophe Leroy
2017-04-21 13:02 ` [PATCH v2 3/3] powerpc/mm: Implement CONFIG_DEBUG_RODATA " Christophe Leroy
[not found] ` <97d45054364142af48b8767f9f9e115504d7568b.1492778567.git.christophe.leroy@c-s .fr>
2017-04-21 13:32 ` Naveen N. Rao [this message]
2017-04-22 6:08 ` Michael Ellerman
2017-04-22 6:58 ` christophe leroy
2017-04-23 10:26 ` Michael Ellerman
2017-04-24 14:31 ` Christophe LEROY
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