Messages in this thread | | | From | Ard Biesheuvel <> | Date | Tue, 20 Jul 2021 14:33:04 +0200 | Subject | Re: [PATCH] Revert "mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge" |
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On Sat, 17 Jul 2021 at 18:06, Jonathan Marek <jonathan@marek.ca> wrote: > > c742199a breaks arm64 for some configs because it stubs out functions which > should not have been stubbed out. > > With 4K pages and ARM64_VA_BITS_39=y, the kernel crashes early on unmapped > 1G pages in the linear map caused by pud_set_huge() in alloc_init_pud() > being stubbed out. Reverting c742199a fixes the crash. > > Fixes: c742199a ("mm/pgtable: add stubs for {pmd/pub}_{set/clear}_huge") > Signed-off-by: Jonathan Marek <jonathan@marek.ca>
(replying here because some cc'ees were dropped from Christophe's reply and the thread that followed it - unfortunately, lore does not seem to have captured any of that discussion either)
Acked-by: Ard Biesheuvel <ardb@kernel.org>
> --- > arch/arm64/mm/mmu.c | 20 ++++++++------------ > arch/x86/mm/pgtable.c | 34 +++++++++++++++------------------- > include/linux/pgtable.h | 26 +------------------------- > 3 files changed, 24 insertions(+), 56 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index d745865084488..9ff0de1b2b93c 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -1339,7 +1339,6 @@ void *__init fixmap_remap_fdt(phys_addr_t dt_phys, int *size, pgprot_t prot) > return dt_virt; > } > > -#if CONFIG_PGTABLE_LEVELS > 3 > int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) > { > pud_t new_pud = pfn_pud(__phys_to_pfn(phys), mk_pud_sect_prot(prot)); > @@ -1354,16 +1353,6 @@ int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot) > return 1; > } > > -int pud_clear_huge(pud_t *pudp) > -{ > - if (!pud_sect(READ_ONCE(*pudp))) > - return 0; > - pud_clear(pudp); > - return 1; > -} > -#endif > - > -#if CONFIG_PGTABLE_LEVELS > 2 > int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) > { > pmd_t new_pmd = pfn_pmd(__phys_to_pfn(phys), mk_pmd_sect_prot(prot)); > @@ -1378,6 +1367,14 @@ int pmd_set_huge(pmd_t *pmdp, phys_addr_t phys, pgprot_t prot) > return 1; > } > > +int pud_clear_huge(pud_t *pudp) > +{ > + if (!pud_sect(READ_ONCE(*pudp))) > + return 0; > + pud_clear(pudp); > + return 1; > +} > + > int pmd_clear_huge(pmd_t *pmdp) > { > if (!pmd_sect(READ_ONCE(*pmdp))) > @@ -1385,7 +1382,6 @@ int pmd_clear_huge(pmd_t *pmdp) > pmd_clear(pmdp); > return 1; > } > -#endif > > int pmd_free_pte_page(pmd_t *pmdp, unsigned long addr) > { > diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c > index 3364fe62b9037..3481b35cb4ec7 100644 > --- a/arch/x86/mm/pgtable.c > +++ b/arch/x86/mm/pgtable.c > @@ -682,7 +682,6 @@ int p4d_clear_huge(p4d_t *p4d) > } > #endif > > -#if CONFIG_PGTABLE_LEVELS > 3 > /** > * pud_set_huge - setup kernel PUD mapping > * > @@ -721,23 +720,6 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot) > return 1; > } > > -/** > - * pud_clear_huge - clear kernel PUD mapping when it is set > - * > - * Returns 1 on success and 0 on failure (no PUD map is found). > - */ > -int pud_clear_huge(pud_t *pud) > -{ > - if (pud_large(*pud)) { > - pud_clear(pud); > - return 1; > - } > - > - return 0; > -} > -#endif > - > -#if CONFIG_PGTABLE_LEVELS > 2 > /** > * pmd_set_huge - setup kernel PMD mapping > * > @@ -768,6 +750,21 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot) > return 1; > } > > +/** > + * pud_clear_huge - clear kernel PUD mapping when it is set > + * > + * Returns 1 on success and 0 on failure (no PUD map is found). > + */ > +int pud_clear_huge(pud_t *pud) > +{ > + if (pud_large(*pud)) { > + pud_clear(pud); > + return 1; > + } > + > + return 0; > +} > + > /** > * pmd_clear_huge - clear kernel PMD mapping when it is set > * > @@ -782,7 +779,6 @@ int pmd_clear_huge(pmd_t *pmd) > > return 0; > } > -#endif > > #ifdef CONFIG_X86_64 > /** > diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h > index d147480cdefc7..e24d2c992b112 100644 > --- a/include/linux/pgtable.h > +++ b/include/linux/pgtable.h > @@ -1397,34 +1397,10 @@ static inline int p4d_clear_huge(p4d_t *p4d) > } > #endif /* !__PAGETABLE_P4D_FOLDED */ > > -#ifndef __PAGETABLE_PUD_FOLDED > int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot); > -int pud_clear_huge(pud_t *pud); > -#else > -static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot) > -{ > - return 0; > -} > -static inline int pud_clear_huge(pud_t *pud) > -{ > - return 0; > -} > -#endif /* !__PAGETABLE_PUD_FOLDED */ > - > -#ifndef __PAGETABLE_PMD_FOLDED > int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot); > +int pud_clear_huge(pud_t *pud); > int pmd_clear_huge(pmd_t *pmd); > -#else > -static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot) > -{ > - return 0; > -} > -static inline int pmd_clear_huge(pmd_t *pmd) > -{ > - return 0; > -} > -#endif /* !__PAGETABLE_PMD_FOLDED */ > - > int p4d_free_pud_page(p4d_t *p4d, unsigned long addr); > int pud_free_pmd_page(pud_t *pud, unsigned long addr); > int pmd_free_pte_page(pmd_t *pmd, unsigned long addr); > -- > 2.26.1 >
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