Messages in this thread | | | Date | Fri, 18 Nov 2022 11:10:16 +0000 | From | Mark Rutland <> | Subject | Re: [PATCH] arm64/mm: Drop redundant BUG_ON(!pgtable_alloc) |
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On Fri, Nov 18, 2022 at 11:01:02AM +0530, Anshuman Khandual wrote: > __create_pgd_mapping_locked() expects a page allocator used while mapping a > virtual range. This page allocator function propagates down the call chain, > while building intermediate levels in the page table. Passed page allocator > is a necessary ingredient required to build the page table but its presence > can be asserted just once in the very beginning rather than in all the down > stream functions. This consolidates BUG_ON(!pgtable_alloc) checks just in a > single place i.e __create_pgd_mapping_locked(). > > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Will Deacon <will@kernel.org> > Cc: Mark Rutland <mark.rutland@arm.com> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: linux-arm-kernel@lists.infradead.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
I don't have strong feelings either way, so FWIW:
Acked-by: Mark Rutland <mark.rutland@arm.com>
Thanks, Mark.
> --- > This applies on v6.1-rc5 > > arch/arm64/mm/mmu.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 5a19950e7289..97ca82001089 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -207,7 +207,6 @@ static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr, > > if (flags & NO_EXEC_MAPPINGS) > pmdval |= PMD_TABLE_PXN; > - BUG_ON(!pgtable_alloc); > pte_phys = pgtable_alloc(PAGE_SHIFT); > __pmd_populate(pmdp, pte_phys, pmdval); > pmd = READ_ONCE(*pmdp); > @@ -285,7 +284,6 @@ static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr, > > if (flags & NO_EXEC_MAPPINGS) > pudval |= PUD_TABLE_PXN; > - BUG_ON(!pgtable_alloc); > pmd_phys = pgtable_alloc(PMD_SHIFT); > __pud_populate(pudp, pmd_phys, pudval); > pud = READ_ONCE(*pudp); > @@ -324,7 +322,6 @@ static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end, > > if (flags & NO_EXEC_MAPPINGS) > p4dval |= P4D_TABLE_PXN; > - BUG_ON(!pgtable_alloc); > pud_phys = pgtable_alloc(PUD_SHIFT); > __p4d_populate(p4dp, pud_phys, p4dval); > p4d = READ_ONCE(*p4dp); > @@ -383,6 +380,7 @@ static void __create_pgd_mapping_locked(pgd_t *pgdir, phys_addr_t phys, > phys &= PAGE_MASK; > addr = virt & PAGE_MASK; > end = PAGE_ALIGN(virt + size); > + BUG_ON(!pgtable_alloc); > > do { > next = pgd_addr_end(addr, end); > -- > 2.25.1 >
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