d024d369b8
ARC processors are known for its configurability and one of those configurable things is MMU page size which might be set to any power of two from 4 KiB to 16 MiB, though in the Linux kernel we only support 4, 8 and 16 KiB due to practical considerations. And the most used setting is 8 KiB thus GNU LD assumes maximum page size is 8 KiB by default and while this works for smaller pages (it's OK to align segments by larger value it will be still peoperly aligned) this breaks execution of user-space apps on HW with larger pages because Elf sections might very well span across allocated pages and thus make executable broken. Simplest example: ------------------------------------>8----------------------------------- $ arc-linux-gcc test.c $ arc-linux-readelf --segments a.out Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align ... LOAD 0x000000 0x00010000 0x00010000 0x003e8 0x003e8 R E 0x2000 <-- See LOAD 0x001f24 0x00013f24 0x00013f24 0x000f0 0x0010c RW 0x2000 ------------------------------------>8----------------------------------- Fortunately we may override default page size settings with "max-page-size" linker option this way: ------------------------------------>8----------------------------------- $ arc-linux-gcc test.c -Wl,-z,max-page-size=16384 $ arc-linux-readelf --segments a.out Elf file type is EXEC (Executable file) Entry point 0x102c4 There are 8 program headers, starting at offset 52 Program Headers: Type Offset VirtAddr PhysAddr FileSiz MemSiz Flg Align ... LOAD 0x000000 0x00010000 0x00010000 0x003e8 0x003e8 R E 0x4000 <-- See LOAD 0x001f24 0x00015f24 0x00015f24 0x000f0 0x0010c RW 0x4000 ------------------------------------>8----------------------------------- Which we implement with that change. Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> [yann.morin.1998@free.fr: fix comment: s/8196/8192/] Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
15 lines
371 B
Plaintext
15 lines
371 B
Plaintext
ifeq ($(BR2_arc),y)
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# -matomic is always required when the ARC core has the atomic extensions
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ifeq ($(BR2_ARC_ATOMIC_EXT),y)
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ARCH_TOOLCHAIN_WRAPPER_OPTS = -matomic
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endif
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# By default MAXPAGESIZE for ARC is 8192 so for larger MMU pages
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# it needs to be overridden.
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ifeq ($(BR2_ARC_PAGE_SIZE_16K),y)
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ARCH_TOOLCHAIN_WRAPPER_OPTS += -Wl,-z,max-page-size=16384
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endif
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endif
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