This reverts commit 3c424f3598.
Joachim Eastwood reports:
| "ARM: 7304/1: ioremap: fix boundary check when reusing static mapping"
| Commit: 3c424f3598 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>
97f1040982