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path: root/arch/powerpc/mm/40x_mmu.c
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2008-11-13powerpc/40x: Limit allocable DRAM during early mappingGrant Erickson
If the size of DRAM is not an exact power of two, we may not have covered DRAM in its entirety with large 16 and 4 MiB pages. If that is the case, we can get non-recoverable page faults when doing the final PTE mappings for the non-large page PTEs. Consequently, we restrict the top end of DRAM currently allocable by updating '__initial_memory_limit_addr' so that calls to the LMB to allocate PTEs for "tail" coverage with normal-sized pages (or other reasons) do not attempt to allocate outside the allowed range. Signed-off-by: Grant Erickson <gerickson@nuovations.com> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
2008-04-17[POWERPC] Remove and replace uses of PPC_MEMSTART with memstart_addrKumar Gala
A number of users of PPC_MEMSTART (40x, ppc_mmu_32) can just always use 0 as we don't support booting these kernels at non-zero physical addresses since their exception vectors must be at 0 (or 0xfffx_xxxx). For the sub-arches that support relocatable interrupt vectors (book-e), it's reasonable to have memory start at a non-zero physical address. For those cases use the variable memstart_addr instead of the #define PPC_MEMSTART since the only uses of PPC_MEMSTART are for initialization and in the future we can set memstart_addr at runtime to have a relocatable kernel. Signed-off-by: Kumar Gala <galak@kernel.crashing.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-11-01[POWERPC] ppc405 Fix arithmatic rollover bug when memory size under 16MGrant Likely
mmu_mapin_ram() loops over total_lowmem to setup page tables. However, if total_lowmem is less that 16M, the subtraction rolls over and results in a number just under 4G (because total_lowmem is an unsigned value). This patch rejigs the loop from countup to countdown to eliminate the bug. Special thanks to Magnus Hjorth who wrote the original patch to fix this bug. This patch improves on his by making the loop code simpler (which also eliminates the possibility of another rollover at the high end) and also applies the change to arch/powerpc. Signed-off-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
2007-08-20[POWERPC] 40x MMUJosh Boyer
Add MMU definitions for 40x platforms. Also fixes two warnings in 40x_mmu.c. Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com> Acked-by: David Gibson <david@gibson.dropbear.id.au>
2007-08-20[POWERPC] Rename 4xx paths to 40xJosh Boyer
4xx is a bit of a misnomer for certain things, as they really apply to PowerPC 40x only. Rename some of the files to clean this up. Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com> Acked-by: David Gibson <david@gibson.dropbear.id.au>