diff options
authorChristophe Leroy <christophe.leroy@c-s.fr>2019-11-28 07:59:22 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2019-11-29 22:41:15 +1100
commit2807273f5e88ed086d7d5d838fdee71e11e5085f (patch)
parentx86/efi: remove unused variables (diff)
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
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();
+ 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);