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authorRussell King <rmk+kernel@arm.linux.org.uk>2012-01-29 18:55:21 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-02-02 21:37:41 +0400
commit97f1040982d7935716e9a45a26ccd5cc8fe92f8c (patch)
tree158cd337307a4a4e09a3fb5110f29ab0136bef6c /arch
parent3c424f359898aff48c3d5bed608ac706f8a528c3 (diff)
downloadlinux-97f1040982d7935716e9a45a26ccd5cc8fe92f8c.tar.xz
Revert "ARM: 7304/1: ioremap: fix boundary check when reusing static mapping"
This reverts commit 3c424f359898aff48c3d5bed608ac706f8a528c3. Joachim Eastwood reports: | "ARM: 7304/1: ioremap: fix boundary check when reusing static mapping" | Commit: 3c424f359898aff48c3d5bed608ac706f8a528c3 in Linus master | | Breaks booting on my custom AT91RM9200 board. | There isn't any error messages or anything that indicates what goes | wrong it just stops after; Uncompressing Linux... done, booting the | kernel. | | Reverting it makes my board boot again. and further debugging reveals: ioremap: pfn=fffff phys=fffff000 offset=400 size=1000 ioremap: area c3ffdfc0: phys_addr=200000 pfn=200 size=4000 ioremap: found: addr fef74000 => fed73000 => fed73400 Clearly, an area for pfn 0x200, 16K can't ever satisfy a request for pfn 0xfffff. This happens because the changed if statement becomes: if (0x00200 > 0xfffff || 0xfffff000 + 0x400 + 0x1000-1 > 0x00200000 + 0x4000-1) and therefore: if (0x00200 > 0xfffff || 0x000003ff > 0x00203fff) The if condition fails, and so we _believe_ that the SRAM mapping fits our request. Clearly that's totally bogus. Moreover, the original premise of the 'fix' patch was wrong: | The condition checking boundaries of the requested and existing | mappings didn't take in-page offset into consideration though, | which lead to obscure and hard to debug problems when requested | mapping crossed end of the static one. as the code immediately above this loop does: size = PAGE_ALIGN(offset + size); so 'size' already contains the requested offset into the page. So, revert the broken 'fix'. Acked-by: Nicolas Pitre <nico@linaro.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/mm/ioremap.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index ba159370fa5f..80632e8d7538 100644
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -225,8 +225,7 @@ void __iomem * __arm_ioremap_pfn_caller(unsigned long pfn,
if ((area->flags & VM_ARM_MTYPE_MASK) != VM_ARM_MTYPE(mtype))
continue;
if (__phys_to_pfn(area->phys_addr) > pfn ||
- __pfn_to_phys(pfn) + offset + size-1 >
- area->phys_addr + area->size-1)
+ __pfn_to_phys(pfn) + size-1 > area->phys_addr + area->size-1)
continue;
/* we can drop the lock here as we know *area is static */
read_unlock(&vmlist_lock);