Messages in this thread | | | Date | Fri, 8 Jan 2016 12:00:08 +0000 | From | Catalin Marinas <> | Subject | Re: [PATCH v2 04/13] arm64: decouple early fixmap init from linear mapping |
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On Wed, Dec 30, 2015 at 04:26:03PM +0100, Ard Biesheuvel wrote: > @@ -583,33 +555,42 @@ void __init early_fixmap_init(void) > unsigned long addr = FIXADDR_START; > > pgd = pgd_offset_k(addr); > - pgd_populate(&init_mm, pgd, bm_pud); > - pud = pud_offset(pgd, addr); > - pud_populate(&init_mm, pud, bm_pmd); > - pmd = pmd_offset(pud, addr); > - pmd_populate_kernel(&init_mm, pmd, bm_pte); > +#if CONFIG_PGTABLE_LEVELS > 3 > + if (pgd_none(*pgd)) { > + static pud_t bm_pud[PTRS_PER_PUD] __pgdir; > + > + pgd_populate(&init_mm, pgd, bm_pud); > + memblock_reserve(__pa(bm_pud), sizeof(bm_pud)); > + } > + pud = (pud_t *)__phys_to_kimg(pud_offset_phys(pgd, addr)); > +#else > + pud = (pud_t *)pgd; > +#endif > +#if CONFIG_PGTABLE_LEVELS > 2 > + if (pud_none(*pud)) { > + static pmd_t bm_pmd[PTRS_PER_PMD] __pgdir; > + > + pud_populate(&init_mm, pud, bm_pmd); > + memblock_reserve(__pa(bm_pmd), sizeof(bm_pmd)); > + } > + pmd = (pmd_t *)__phys_to_kimg(pmd_offset_phys(pud, addr)); > +#else > + pmd = (pmd_t *)pud; > +#endif > + if (pmd_none(*pmd)) { > + static pte_t bm_pte[PTRS_PER_PTE] __pgdir; > + > + pmd_populate_kernel(&init_mm, pmd, bm_pte); > + memblock_reserve(__pa(bm_pte), sizeof(bm_pte)); > + } > + __fixmap_pte = (pte_t *)__phys_to_kimg(pmd_page_paddr(*pmd));
I haven't tried but could you not avoid the #if and just rely on the pud_none() etc. definitions to be 0 and the compiler+linker optimising the irrelevant code out?
-- Catalin
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