Messages in this thread | | | From | Andreas Larsson <> | Subject | sparc32: boot fails with > 256 MB memory after switch to NO_BOOTMEM | Date | Wed, 27 Jan 2021 16:03:00 +0100 |
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Commit cca079ef8ac29a7c02192d2bad2ffe4c0c5ffdd0 makes sparc32 use memblocks instead of the previous bootmem solution. Unfortunately, due to this:
#define PAGE_OFFSET 0xf0000000 #define __va(x) ((void *)((unsigned long) (x) - phys_base + PAGE_OFFSET)) #define phys_to_virt __va
it makes physical addresses >= 0x10000000 past phys_base wrap around the 32-bit memory space when converted to virtual addresses, e.g. in memblock_alloc_try_nid. Physical memory exactly 0x10000000 past phys_base is returned as an unintended NULL pointer, leading to a panic in my boot when percpu memory allocation fails due to it.
Unfortunately I have had 256 MB memory or less in a lot of my testing, so this old one has slipped by me.
Does anyone has any ideas or pointers on how to resolve this?
Example follows where I have 512 MB memory at 0x40000000:
----->%>%>%>%----- memblock_add: [0x40000000-0x5fffafff] bootmem_init+0x1f8/0x210 319MB HIGHMEM available. memblock_reserve: [0x40000000-0x40e71fff] bootmem_init+0x178/0x210 memblock_add: [0x40000000-0x40e71fff] bootmem_init+0x188/0x210 memblock_alloc_try_nid: 5242880 bytes align=0x40000 nid=-1 from=0x00000000 max_addr=0x00000000 srmmu_nocache_init+0x20/0x25c memblock_reserve: [0x40e80000-0x4137ffff] memblock_alloc_range_nid+0xcc/0x178 memblock_alloc_try_nid: 2560 bytes align=0x20 nid=-1 from=0x00000000 max_addr=0x00000000 srmmu_nocache_init+0x94/0x25c memblock_reserve: [0x40e72000-0x40e729ff] memblock_alloc_range_nid+0xcc/0x178 memblock_alloc_try_nid: 4096 bytes align=0x20 nid=-1 from=0x00000000 max_addr=0x00000000 sparc_context_init+0x1c/0xe4 memblock_reserve: [0x40e72a00-0x40e739ff] memblock_alloc_range_nid+0xcc/0x178 Zone ranges: DMA [mem 0x0000000040000000-0x000000004bffffff] Normal empty HighMem [mem 0x000000004c000000-0x000000005fffafff] Movable zone start for each node Early memory node ranges node 0: [mem 0x0000000040000000-0x000000005fffafff] Initmem setup node 0 [mem 0x0000000040000000-0x000000005fffafff] ----->%>%>%>%-----
then much much later memblock_alloc_internal gets 0x50000000 from memblock_alloc_range_nid and returns a NULL pointer as result of phys_to_virt.
----->%>%>%>%----- memblock_alloc_try_nid: 40960 bytes align=0x1000 nid=-1 from=0x4fffffff max_addr=0x00000000 pcpu_dfl_fc_alloc+0x28/0x40 memblock_reserve: [0x50000000-0x50009fff] memblock_alloc_range_nid+0xcc/0x178 memblock_free: [0x40e7e000-0x40e7efff] pcpu_free_alloc_info+0x1c/0x30 memblock_free: [0x40e7f000-0x40e7ffff] pcpu_embed_first_chunk+0x194/0x3b8 Kernel panic - not syncing: Failed to initialize percpu areas. CPU: 0 PID: 0 Comm: swapper Not tainted 5.11.0-rc3-00040-gbc4547251e1-dirty #28 ----->%>%>%>%-----
Adding mem=256M to the command line solves the panic problem but makes the extra memory not be available for normal allocation later on either.
The two first memblock_add calls (seen in the first first set of outputs) with overlapping address ranges that is done in bootmem_init also looks a bit worrying, but removing the second one does not affect this problem.
-- Best regards,
Andreas Larsson Cobham Gaisler
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