linux-kernel - Re: [PATCH 3/3] jz4740

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <16211aea-cd48-2d68-7ba9-d81b126d81cf@samsung.com>
Date:   Fri, 21 Jun 2019 13:32:16 +0200
From:   Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:     Christoph Hellwig <hch@....de>
Cc:     Manuel Lauss <manuel.lauss@...il.com>, linux-mips@...r.kernel.org,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] jz4740_fb: fix DMA API abuse


Hi,

On 6/7/19 2:21 PM, Bartlomiej Zolnierkiewicz wrote:
> 
> On 5/9/19 7:38 PM, Christoph Hellwig wrote:
>> Virtual addresses return from dma(m)_alloc_coherent are opaque in what
>> backs then, and drivers must not poke into them.  Switch the driver
>> to use the generic DMA API mmap helper to avoid these problems.
> Change itself looks fine but the patch description doesn't match what
> the patch is actually doing (there is no conversion to DMA API helper
> because the driver is already using it). Please correct it. Thank you.

I've just removed the "Switch the driver.." sentence myself from
the patch description and applied the change, thanks!

>> Signed-off-by: Christoph Hellwig <hch@....de>
>> ---
>>  drivers/video/fbdev/jz4740_fb.c | 7 -------
>>  1 file changed, 7 deletions(-)
>> diff --git a/drivers/video/fbdev/jz4740_fb.c b/drivers/video/fbdev/jz4740_fb.c
>> index b57df83fdbd3..b95cdfa9e0a1 100644
>> --- a/drivers/video/fbdev/jz4740_fb.c
>> +++ b/drivers/video/fbdev/jz4740_fb.c
>> @@ -466,7 +466,6 @@ static int jzfb_alloc_devmem(struct jzfb *jzfb)
>>  {
>>  	int max_videosize = 0;
>>  	struct fb_videomode *mode = jzfb->pdata->modes;
>> -	void *page;
>>  	int i;
>>  
>>  	for (i = 0; i < jzfb->pdata->num_modes; ++mode, ++i) {
>> @@ -491,12 +490,6 @@ static int jzfb_alloc_devmem(struct jzfb *jzfb)
>>  	if (!jzfb->vidmem)
>>  		goto err_free_framedesc;
>>  
>> -	for (page = jzfb->vidmem;
>> -		 page < jzfb->vidmem + PAGE_ALIGN(jzfb->vidmem_size);
>> -		 page += PAGE_SIZE) {
>> -		SetPageReserved(virt_to_page(page));
>> -	}
>> -
>>  	jzfb->framedesc->next = jzfb->framedesc_phys;
>>  	jzfb->framedesc->addr = jzfb->vidmem_phys;
>>  	jzfb->framedesc->id = 0xdeafbead;
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics