Messages in this thread | | | Date | Fri, 8 Jan 2016 13:05:14 +0100 | Subject | Re: [PATCH v2 04/13] arm64: decouple early fixmap init from linear mapping | From | Ard Biesheuvel <> |
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On 8 January 2016 at 13:00, Catalin Marinas <catalin.marinas@arm.com> wrote: > 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? >
I tried but it requires some tinkering so I gave up. I can have another go based on the latest version (which will look a bit different)
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