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Wed, 7 Aug 2019 11:22:16 +0800 Subject: Re: [PATCH v4 09/10] powerpc/fsl_booke/kaslr: support nokaslr cmdline parameter To: Christophe Leroy , , , , , , , , References: <20190805064335.19156-1-yanaijie@huawei.com> <20190805064335.19156-10-yanaijie@huawei.com> From: Jason Yan Message-ID: <3a83c812-ac14-3e89-241e-eeade105d23e@huawei.com> Date: Wed, 7 Aug 2019 11:22:14 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.177.96.203] X-CFilter-Loop: Reflected X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wangkefeng.wang@huawei.com, linux-kernel@vger.kernel.org, jingxiangfeng@huawei.com, zhaohongjiang@huawei.com, thunder.leizhen@huawei.com, fanchengyang@huawei.com, yebin10@huawei.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On 2019/8/6 15:59, Christophe Leroy wrote: > > > Le 05/08/2019 à 08:43, Jason Yan a écrit : >> One may want to disable kaslr when boot, so provide a cmdline parameter >> 'nokaslr' to support this. >> >> Signed-off-by: Jason Yan >> Cc: Diana Craciun >> Cc: Michael Ellerman >> Cc: Christophe Leroy >> Cc: Benjamin Herrenschmidt >> Cc: Paul Mackerras >> Cc: Nicholas Piggin >> Cc: Kees Cook >> Reviewed-by: Diana Craciun >> Tested-by: Diana Craciun > > Reviewed-by: Christophe Leroy > > Tiny comment below. > >> --- >>   arch/powerpc/kernel/kaslr_booke.c | 14 ++++++++++++++ >>   1 file changed, 14 insertions(+) >> >> diff --git a/arch/powerpc/kernel/kaslr_booke.c >> b/arch/powerpc/kernel/kaslr_booke.c >> index 4b3f19a663fc..7c3cb41e7122 100644 >> --- a/arch/powerpc/kernel/kaslr_booke.c >> +++ b/arch/powerpc/kernel/kaslr_booke.c >> @@ -361,6 +361,18 @@ static unsigned long __init >> kaslr_choose_location(void *dt_ptr, phys_addr_t size >>       return kaslr_offset; >>   } >> +static inline __init bool kaslr_disabled(void) >> +{ >> +    char *str; >> + >> +    str = strstr(boot_command_line, "nokaslr"); >> +    if ((str == boot_command_line) || >> +        (str > boot_command_line && *(str - 1) == ' ')) >> +        return true; > > I don't think additional () are needed for the left part 'str == > boot_command_line' > Agree. >> + >> +    return false; >> +} >> + >>   /* >>    * To see if we need to relocate the kernel to a random offset >>    * void *dt_ptr - address of the device tree >> @@ -376,6 +388,8 @@ notrace void __init kaslr_early_init(void *dt_ptr, >> phys_addr_t size) >>       kernel_sz = (unsigned long)_end - KERNELBASE; >>       kaslr_get_cmdline(dt_ptr); >> +    if (kaslr_disabled()) >> +        return; >>       offset = kaslr_choose_location(dt_ptr, size, kernel_sz); >> > > . >