On 06/04, Nicolas Pitre wrote: > > The LC0 area should be considered read-only as it may be located in > flash. > > Here's what I came with instead: > > From: Nicolas Pitre <nicolas.pitre@xxxxxxxxxx> > Date: Tue, 4 Jun 2013 17:01:30 -0400 > Subject: [PATCH] ARM: zImage: don't overwrite ourself with a page table > > When zImage is loaded into RAM at a low address but TEXT_OFFSET > is set higher, we risk overwriting ourself with the page table > needed to turn on the cache as it is located relative to the relocation > address. Let's defer the cache setup after relocation in that case. > > Signed-off-by: Nicolas Pitre <nico@xxxxxxxxxx> Reported-by: Stephen Boyd <sboyd@xxxxxxxxxxxxx> Tested-by: Stephen Boyd <sboyd@xxxxxxxxxxxxx> This one passes testing on my two platforms with and without the 2Mb reservation at the beginning of ram. Seems like a good enough compromise for me. > > diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S > index 9a94f344df..aa909393f2 100644 > --- a/arch/arm/boot/compressed/head.S > +++ b/arch/arm/boot/compressed/head.S > @@ -182,7 +182,19 @@ not_angel: > ldr r4, =zreladdr > #endif > > - bl cache_on > + /* > + * Set up a page table only if it won't overwrite ourself. > + * That means r4 < pc && r4 - 16k page directory > &_end. > + * Given that r4 > &_en is most unfrequent, we add a rough /s/_en/_end/ > + * additional 1MB of room for a possible appended DTB. > + */ > + mov r0, pc > + cmp r0, r4 > + ldrcc r0, LC0+32 > + addcc r0, r0, pc > + cmpcc r4, r0 > + orrcc r4, r4, #1 @ remember we skipped cache_on > + blcs cache_on > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
