On Tue, May 08, 2012 at 03:01:57PM +0100, Shilimkar, Santosh wrote: > From b906ef372f0e2dfa7e1fbc3c87406b1c303d8975 Mon Sep 17 00:00:00 2001 > From: R Sricharan <r.sricharan@xxxxxx> > Date: Mon, 7 May 2012 15:11:58 +0530 > Subject: [PATCH] ARM: decompressor: Fix mmu mapping for non-DRAM address > space. > > ARM decompressor code setups entire 4GB address space pages. > Out of the 4GB, about 256MB are setup with normal memory attributes > for needed DRAM and the rest of the address space as Strongly ordered. > > But since all the sections are mapped in DOMAIN0(Manager), processor > like Cortex-A15, can speculatively prefetch from non-DRAM read sensitive > areas even in the presence of XN(Non-executable). This is because XN > attribute is ignored when domain is Manager. > > This can lead to accesses to non-accessible address regions leading > to various interconnect violations. The issue is observed on OMAP5. > > This patch tries to fix the issue by ensuring that all regions > are marked as a client domain so that XN attribute is effective. > > Signed-off-by: R Sricharan <r.sricharan@xxxxxx> > Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx> > Cc: Russell King <linux@xxxxxxxxxxxxxxxx> > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > --- > arch/arm/boot/compressed/head.S | 10 ++++++++-- > 1 files changed, 8 insertions(+), 2 deletions(-) > > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index dc7e8ce..a2602b8 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -578,10 +578,12 @@ __setup_mmu: sub r3, r4, #16384 @ Page directory size > mov r9, r0, lsr #18 > mov r9, r9, lsl #18 @ start of RAM > add r10, r9, #0x10000000 @ a reasonable RAM size > - mov r1, #0x12 > + mov r1, #0x02 @ Default executable section I think it is simpler if you leave the original code here (with XN) > orr r1, r1, #3 << 10 > add r2, r3, #16384 > 1: cmp r1, r9 @ if virt > start of RAM > + orrlo r1, r1, #0x10 @ Mark XN for non DRAM > + bichs r1, r1, #0x10 @ clear XN for DRAM and just do the bichs above. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
