Helge Deller 48d27cb229 parisc: fix usage of 32bit PTE page table entries on 32bit kernels ... This patch fixes a long outstanding bug on 32bit parisc linux kernels which prevented us from using 32bit PTE table entries (instead of 64bit entries of which 32bit were unused). The problem was caused by this assembler statement in the L2_ptep macro in arch/parisc/kernel/entry.S:447: EXTR \va,31-ASM_PGDIR_SHIFT,ASM_BITS_PER_PGD,\index which expanded to extrw,u r8,9,11,r1 and which has undefined behavior since the length value (11) extends beyond the leftmost bit (11-1 > 9). Interestingly PA2.0 processors seem to don't care and just zero-extend the value, while PA1.1 processors don't. Fix this problem by detecting an address space overflow with ASM_BITS_PER_PGD and adjusting it accordingly. To prevent such problems in the future, some compile time sanity checks in arch/parisc/mm/init.c were added. Since the page table now only consumes half of it's old size, we can use the freed memory to harmonize 32- and 64bit kernels and let both map 16MB for the initial page table. Signed-off-by: Helge Deller <deller@gmx.de> Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>		2009-03-31 02:51:33 +00:00
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asm	parisc: fix usage of 32bit PTE page table entries on 32bit kernels	2009-03-31 02:51:33 +00:00