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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2019-11-28 10:59:22 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-11-29 14:41:15 +0300 |
| commit | 2807273f5e88ed086d7d5d838fdee71e11e5085f (patch) | |
| tree | 261a16a92820ab0e061967629b7ced4eec76f795 | |
| parent | 6f090192f8225f52ba95d08785989688cb768cca (diff) | |
| download | linux-2807273f5e88ed086d7d5d838fdee71e11e5085f.tar.xz | |
powerpc/fixmap: fix crash with HIGHMEM
Commit f2bb86937d86 ("powerpc/fixmap: don't clear fixmap area in
paging_init()") removed the clearing of fixmap area in order to
avoid clearing fixmapped areas set earlier.
However unlike all other users of fixmap which use __set_fixmap(),
HIGHMEM functions directly use __set_pte_at(). This means
the page table must pre-exist, otherwise the following crash
can be encoutered due to the lack of entry in the PGD.
Oops: Kernel access of bad area, sig: 11 [#1]
BE PAGE_SIZE=4K MMU=Hash PowerMac
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0+ #2528
NIP: c0144ce8 LR: c0144ccc CTR: 00000080
REGS: ef0b5aa0 TRAP: 0300 Not tainted (5.4.0+)
MSR: 00009032 <EE,ME,IR,DR,RI> CR: 44282842 XER: 00000000
DAR: fffdf000 DSISR: 42000000
GPR00: c0144ccc ef0b5b58 ef0b0000 fffdf000 fffdf000 00000000 c0000f7c 00000000
GPR08: c0833000 fffdf000 00000000 ef1c53c9 24042842 00000000 00000000 00000000
GPR16: 00000000 00000000 ef7e7358 effe8160 00000000 c08a9660 c0851644 00000004
GPR24: c08c70a8 00002dc2 00000000 00000001 00000201 effe8160 effe8160 00000000
NIP [c0144ce8] prep_new_page+0x138/0x178
LR [c0144ccc] prep_new_page+0x11c/0x178
Call Trace:
[ef0b5b58] [c0144ccc] prep_new_page+0x11c/0x178 (unreliable)
[ef0b5b88] [c0147218] get_page_from_freelist+0x1fc/0xd88
[ef0b5c38] [c0148328] __alloc_pages_nodemask+0xd4/0xbb4
[ef0b5cf8] [c0142ba8] __vmalloc_node_range+0x1b4/0x2e0
[ef0b5d38] [c0142dd0] vzalloc+0x48/0x58
[ef0b5d58] [c0301c8c] check_partition+0x58/0x244
[ef0b5d78] [c02ffe80] blk_add_partitions+0x44/0x2cc
[ef0b5db8] [c01a32d8] bdev_disk_changed+0x68/0xfc
[ef0b5de8] [c01a4494] __blkdev_get+0x290/0x460
[ef0b5e28] [c02fdd40] __device_add_disk+0x480/0x4d8
[ef0b5e68] [c0810688] brd_init+0xc0/0x188
[ef0b5e88] [c0005194] do_one_initcall+0x40/0x19c
[ef0b5ee8] [c07dd4dc] kernel_init_freeable+0x164/0x230
[ef0b5f28] [c0005408] kernel_init+0x18/0x10c
[ef0b5f38] [c0014274] ret_from_kernel_thread+0x14/0x1c
Partially revert that commit to still clear the fixmap area dedicated
to HIGHMEM.
Fixes: f2bb86937d86 ("powerpc/fixmap: don't clear fixmap area in paging_init()")
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/d42fa9747df5afa41e67b08e374c98d3b40529c9.1574927918.git.christophe.leroy@c-s.fr
| -rw-r--r-- | arch/powerpc/mm/mem.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c index bf0c54b1f161..b5835a71f10f 100644 --- a/arch/powerpc/mm/mem.c +++ b/arch/powerpc/mm/mem.c @@ -238,6 +238,12 @@ void __init paging_init(void) phys_addr_t top_of_ram = memblock_end_of_DRAM(); #ifdef CONFIG_HIGHMEM + unsigned long v = __fix_to_virt(FIX_KMAP_END); + unsigned long end = __fix_to_virt(FIX_KMAP_BEGIN); + + for (; v < end; v += PAGE_SIZE) + map_kernel_page(v, 0, __pgprot(0)); /* XXX gross */ + map_kernel_page(PKMAP_BASE, 0, __pgprot(0)); /* XXX gross */ pkmap_page_table = virt_to_kpte(PKMAP_BASE); |