From: Steve Capper Date: Tue, 28 May 2013 12:35:51 +0000 (+0100) Subject: ARM64: mm: Move PTE_PROT_NONE bit. X-Git-Tag: omap-for-v3.11/fixes-for-merge-window~40^2^2~3 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=59911ca4325dc7bd95e05c988fef3593b694e62c;p=pandora-kernel.git ARM64: mm: Move PTE_PROT_NONE bit. Under ARM64, PTEs can be broadly categorised as follows: - Present and valid: Bit #0 is set. The PTE is valid and memory access to the region may fault. - Present and invalid: Bit #0 is clear and bit #1 is set. Represents present memory with PROT_NONE protection. The PTE is an invalid entry, and the user fault handler will raise a SIGSEGV. - Not present (file or swap): Bits #0 and #1 are clear. Memory represented has been paged out. The PTE is an invalid entry, and the fault handler will try and re-populate the memory where necessary. Huge PTEs are block descriptors that have bit #1 clear. If we wish to represent PROT_NONE huge PTEs we then run into a problem as there is no way to distinguish between regular and huge PTEs if we set bit #1. To resolve this ambiguity this patch moves PTE_PROT_NONE from bit #1 to bit #2 and moves PTE_FILE from bit #2 to bit #3. The number of swap/file bits is reduced by 1 as a consequence, leaving 60 bits for file and swap entries. Signed-off-by: Steve Capper Acked-by: Catalin Marinas --- Reading git-diff-tree failed