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ARM: 8980/1: Allow either FLATMEM or SPARSEMEM on the multiplatform build

ARMv7 chips with LPAE can often benefit from SPARSEMEM, as portions of system memory can be located deep in the 36-bit address space. Allow FLATMEM or SPARSEMEM to be selectable at compile time; FLATMEM remains the default. This is based on Kevin's "[PATCH 3/3] ARM: Allow either FLATMEM or SPARSEMEM on the multi-v7 build" from [1] and shamelessly rips off his commit message text above. As Arnd pointed out at [2] there doesn't seem to be any reason to tie this specifically to ARMv7, so this has been changed to apply to all multiplatform kernels. The addition of this option does not change the defaults and a build with any defconfig will behave the same way as previously. The only effect this change has is to enable user to change "Memory model" selection in interactive kernel configuration (menuconfig, xconfig etc). [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-September/286837.html [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2014-October/298950.html [ rppt: added ARCH_SELECT_MEMORY_MODEL and updated the changelog ]

Gregory Fong committed 6 years ago

Commit fb597f21 parent 98f3f7e1 file · +10 −1Browse files

Unified · Split

arch/arm/Kconfig+10−1
@@ -312,6 +312,9 @@ choice · 311 unmodified lines
312312 config ARCH_MULTIPLATFORM
313313 bool "Allow multiple platforms to be selected"
314314 depends on MMU
315+ select ARCH_FLATMEM_ENABLE
316+ select ARCH_SPARSEMEM_ENABLE
317+ select ARCH_SELECT_MEMORY_MODEL
315318 select ARM_HAS_SG_CHAIN
316319 select ARM_PATCH_PHYS_VIRT
317320 select AUTO_ZRELADDR
@@ -1515,9 +1518,15 @@ config OABI_COMPAT · 1197 unmodified lines
15151518 config ARCH_HAS_HOLES_MEMORYMODEL
15161519 bool
15171520
1521+config ARCH_SELECT_MEMORY_MODEL
1522+ bool
1523+
1524+config ARCH_FLATMEM_ENABLE
1525+ bool
1526+
15181527 config ARCH_SPARSEMEM_ENABLE
15191528 bool
1520− select SPARSEMEM_STATIC
1529+ select SPARSEMEM_STATIC if SPARSEMEM
15211530
15221531 config HAVE_ARCH_PFN_VALID
15231532 def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM