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Do not sync vmalloc/ioremap mappings on x86-64 kernels.

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Hopefully now without the bugs!
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'x86-mm-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 mm updates from Ingo Molnar:
 "Do not sync vmalloc/ioremap mappings on x86-64 kernels.

  Hopefully now without the bugs!"

* tag 'x86-mm-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm/64: Update comment in preallocate_vmalloc_pages()
  x86/mm/64: Do not sync vmalloc/ioremap mappings
This commit is contained in:
Linus Torvalds 2020-10-12 15:02:38 -07:00
parent b85cac5745 7a27ef5e83
commit c1b4ec85ee
2 changed files with 10 additions and 12 deletions
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2
arch/x86/include/asm/pgtable_64_types.h
View file

@ -159,6 +159,4 @@ extern unsigned int ptrs_per_p4d;
#define PGD_KERNEL_START ((PAGE_SIZE / 2) / sizeof(pgd_t))
#define ARCH_PAGE_TABLE_SYNC_MASK (pgtable_l5_enabled() ? PGTBL_PGD_MODIFIED : PGTBL_P4D_MODIFIED)
#endif /* _ASM_X86_PGTABLE_64_DEFS_H */

20
arch/x86/mm/init_64.c
View file

@ -217,11 +217,6 @@ static void sync_global_pgds(unsigned long start, unsigned long end)
sync_global_pgds_l4(start, end);
}
void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
{
sync_global_pgds(start, end);
}
/*
* NOTE: This function is marked __ref because it calls __init function
* (alloc_bootmem_pages). It's safe to do it ONLY when after_bootmem == 0.
@ -1257,14 +1252,19 @@ static void __init preallocate_vmalloc_pages(void)
if (!p4d)
goto failed;
/*
* With 5-level paging the P4D level is not folded. So the PGDs
* are now populated and there is no need to walk down to the
* PUD level.
*/
if (pgtable_l5_enabled())
continue;
/*
* The goal here is to allocate all possibly required
* hardware page tables pointed to by the top hardware
* level.
*
* On 4-level systems, the P4D layer is folded away and
* the above code does no preallocation. Below, go down
* to the pud _software_ level to ensure the second
* hardware level is allocated on 4-level systems too.
*/
lvl = "pud";
pud = pud_alloc(&init_mm, p4d, addr);
if (!pud)