Messages in this thread | | | Date | Fri, 03 Apr 2020 08:17:02 -0700 (PDT) | Subject | Re: [RFC PATCH 1/7] riscv: Get rid of compile time logic with MAX_EARLY_MAPPING_SIZE | From | Palmer Dabbelt <> |
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On Sun, 22 Mar 2020 04:00:22 PDT (-0700), alex@ghiti.fr wrote: > There is no need to compare at compile time MAX_EARLY_MAPPING_SIZE value > with PGDIR_SIZE since MAX_EARLY_MAPPING_SIZE is set to 128MB which is less > than PGDIR_SIZE that is equal to 1GB: that allows to simplify early_pmd > definition. > > Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> > --- > arch/riscv/mm/init.c | 16 ++++------------ > 1 file changed, 4 insertions(+), 12 deletions(-) > > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c > index 238bd0033c3f..18bbb426848e 100644 > --- a/arch/riscv/mm/init.c > +++ b/arch/riscv/mm/init.c > @@ -247,13 +247,7 @@ static void __init create_pte_mapping(pte_t *ptep, > > pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss; > pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss; > - > -#if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE > -#define NUM_EARLY_PMDS 1UL > -#else > -#define NUM_EARLY_PMDS (1UL + MAX_EARLY_MAPPING_SIZE / PGDIR_SIZE) > -#endif > -pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata __aligned(PAGE_SIZE); > +pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE); > > static pmd_t *__init get_pmd_virt(phys_addr_t pa) > { > @@ -267,14 +261,12 @@ static pmd_t *__init get_pmd_virt(phys_addr_t pa) > > static phys_addr_t __init alloc_pmd(uintptr_t va) > { > - uintptr_t pmd_num; > - > if (mmu_enabled) > return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE); > > - pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT; > - BUG_ON(pmd_num >= NUM_EARLY_PMDS); > - return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD]; > + BUG_ON((va - PAGE_OFFSET) >> PGDIR_SHIFT); > + > + return (uintptr_t)early_pmd; > } > > static void __init create_pmd_mapping(pmd_t *pmdp,
My specific worry here was that allyesconfig kernels are quite large, and that dropping the code to handle large kernels would make it even harder to boot them. That said, I can't actually get one to boot so I'm happy to just push that off until later and drop the code we can't practically use.
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Thanks!
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