On 10/30/2016 02:59 AM, Keerthy wrote:
On Saturday 29 October 2016 11:19 PM, Marek Vasut wrote:
On 10/29/2016 07:47 PM, Tom Rini wrote:
On Sat, Oct 29, 2016 at 07:44:34PM +0200, Marek Vasut wrote:
On 10/29/2016 07:41 PM, Tom Rini wrote:
On Sat, Oct 29, 2016 at 03:19:10PM +0530, Keerthy wrote:
While we setup the mmu initially we mark set_section_dcache with DCACHE_OFF flag. In case of non-LPAE mode the DCACHE_OFF macro is rightly defined with TTB_SECT_XN_MASK set so as to mark all the 4GB XN. In case of LPAE mode XN(Execute-never) bit is not set with DCACHE_OFF. Hence XN bit is not set by default for DCACHE_OFF which keeps all the regions execute okay and this leads to random speculative fetches in random memory regions which was eventually caught by kernel omap-l3-noc driver.
Fix this to mark the regions as XN by default.
Signed-off-by: Keerthy j-keerthy@ti.com Reviewed-by: Alexander Graf agraf@suse.de
Reviewed-by: Tom Rini trini@konsulko.com
Isn't this patch exactly undoing the following one ?
commit 8890c2fbe6ed4c5ca9a61f21e846a55f8f2c38fc Author: Marek Vasut <> Date: Tue Dec 29 19:44:02 2015 +0100
arm: Remove S bit from MMU section entry Restore the old behavior of the MMU section entries configuration, which is without the S-bit.Is it? I guess perhaps you and Keerthy need to chat then as there's some other problem they're addressing.
Ummmm, wait a second, I think this one adds XN bit and the previous one removed S bit. I think I was wrong, but please double-check this. I recall we had some odd cache issues on V7 back then.
Marek,
First and foremost if we git blame on the file: arch/arm/include/asm/system.h
your commit: 8890c2fbe6ed4c5ca9a61f21e846a55f8f2c38fc
arm: Remove S bit from MMU section entry
It is removing S bit under #elif defined(CONFIG_CPU_V7)
I am adding the missing XN bit under: #ifdef CONFIG_ARMV7_LPAE
So we are dealing with different modes.
In a nutshell your patch removes S bit from MMU section entry for non-LPAE cases for ARMV7 and mine adds XN bit for LPAE cases.
Hope this clears out the confusion.
Yeah, it does, thanks.