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authorJia He <justin.he@arm.com>2019-08-07 12:58:51 +0800
committerCatalin Marinas <catalin.marinas@arm.com>2019-08-08 18:38:20 +0100
commit30e235389faadb9e3d918887b1f126155d7d761d (patch)
tree00e6b4e2fe87f7edd0f2ed98acf1b802d721ae7f /arch
parente21a712a9685488f5ce80495b37b9fdbe96c230d (diff)
download96b-common-30e235389faadb9e3d918887b1f126155d7d761d.tar.gz
arm64: mm: add missing PTE_SPECIAL in pte_mkdevmap on arm64
Without this patch, the MAP_SYNC test case will cause a print_bad_pte warning on arm64 as follows: [ 25.542693] BUG: Bad page map in process mapdax333 pte:2e8000448800f53 pmd:41ff5f003 [ 25.546360] page:ffff7e0010220000 refcount:1 mapcount:-1 mapping:ffff8003e29c7440 index:0x0 [ 25.550281] ext4_dax_aops [ 25.550282] name:"__aaabbbcccddd__" [ 25.551553] flags: 0x3ffff0000001002(referenced|reserved) [ 25.555802] raw: 03ffff0000001002 ffff8003dfffa908 0000000000000000 ffff8003e29c7440 [ 25.559446] raw: 0000000000000000 0000000000000000 00000001fffffffe 0000000000000000 [ 25.563075] page dumped because: bad pte [ 25.564938] addr:0000ffffbe05b000 vm_flags:208000fb anon_vma:0000000000000000 mapping:ffff8003e29c7440 index:0 [ 25.574272] file:__aaabbbcccddd__ fault:ext4_dax_fault mmmmap:ext4_file_mmap readpage:0x0 [ 25.578799] CPU: 1 PID: 1180 Comm: mapdax333 Not tainted 5.2.0+ #21 [ 25.581702] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 25.585624] Call trace: [ 25.587008] dump_backtrace+0x0/0x178 [ 25.588799] show_stack+0x24/0x30 [ 25.590328] dump_stack+0xa8/0xcc [ 25.591901] print_bad_pte+0x18c/0x218 [ 25.593628] unmap_page_range+0x778/0xc00 [ 25.595506] unmap_single_vma+0x94/0xe8 [ 25.597304] unmap_vmas+0x90/0x108 [ 25.598901] unmap_region+0xc0/0x128 [ 25.600566] __do_munmap+0x284/0x3f0 [ 25.602245] __vm_munmap+0x78/0xe0 [ 25.603820] __arm64_sys_munmap+0x34/0x48 [ 25.605709] el0_svc_common.constprop.0+0x78/0x168 [ 25.607956] el0_svc_handler+0x34/0x90 [ 25.609698] el0_svc+0x8/0xc [...] The root cause is in _vm_normal_page, without the PTE_SPECIAL bit, the return value will be incorrectly set to pfn_to_page(pfn) instead of NULL. Besides, this patch also rewrite the pmd_mkdevmap to avoid setting PTE_SPECIAL for pmd The MAP_SYNC test case is as follows(Provided by Yibo Cai) $#include <stdio.h> $#include <string.h> $#include <unistd.h> $#include <sys/file.h> $#include <sys/mman.h> $#ifndef MAP_SYNC $#define MAP_SYNC 0x80000 $#endif /* mount -o dax /dev/pmem0 /mnt */ $#define F "/mnt/__aaabbbcccddd__" int main(void) { int fd; char buf[4096]; void *addr; if ((fd = open(F, O_CREAT|O_TRUNC|O_RDWR, 0644)) < 0) { perror("open1"); return 1; } if (write(fd, buf, 4096) != 4096) { perror("lseek"); return 1; } addr = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_SYNC, fd, 0); if (addr == MAP_FAILED) { perror("mmap"); printf("did you mount with '-o dax'?\n"); return 1; } memset(addr, 0x55, 4096); if (munmap(addr, 4096) == -1) { perror("munmap"); return 1; } close(fd); return 0; } Fixes: 73b20c84d42d ("arm64: mm: implement pte_devmap support") Reported-by: Yibo Cai <Yibo.Cai@arm.com> Acked-by: Will Deacon <will@kernel.org> Acked-by: Robin Murphy <Robin.Murphy@arm.com> Signed-off-by: Jia He <justin.he@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/pgtable.h7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 5fdcfe237338..e09760ece844 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -209,7 +209,7 @@ static inline pmd_t pmd_mkcont(pmd_t pmd)
static inline pte_t pte_mkdevmap(pte_t pte)
{
- return set_pte_bit(pte, __pgprot(PTE_DEVMAP));
+ return set_pte_bit(pte, __pgprot(PTE_DEVMAP | PTE_SPECIAL));
}
static inline void set_pte(pte_t *ptep, pte_t pte)
@@ -396,7 +396,10 @@ static inline int pmd_protnone(pmd_t pmd)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
#define pmd_devmap(pmd) pte_devmap(pmd_pte(pmd))
#endif
-#define pmd_mkdevmap(pmd) pte_pmd(pte_mkdevmap(pmd_pte(pmd)))
+static inline pmd_t pmd_mkdevmap(pmd_t pmd)
+{
+ return pte_pmd(set_pte_bit(pmd_pte(pmd), __pgprot(PTE_DEVMAP)));
+}
#define __pmd_to_phys(pmd) __pte_to_phys(pmd_pte(pmd))
#define __phys_to_pmd_val(phys) __phys_to_pte_val(phys)