From e8a62cc26ddf53a3c6ba2a8d33036cf7b84f3923 Mon Sep 17 00:00:00 2001 From: Alexandre Ghiti Date: Mon, 6 Dec 2021 11:46:51 +0100 Subject: riscv: Implement sv48 support By adding a new 4th level of page table, give the possibility to 64bit kernel to address 2^48 bytes of virtual address: in practice, that offers 128TB of virtual address space to userspace and allows up to 64TB of physical memory. If the underlying hardware does not support sv48, we will automatically fallback to a standard 3-level page table by folding the new PUD level into PGDIR level. In order to detect HW capabilities at runtime, we use SATP feature that ignores writes with an unsupported mode. Signed-off-by: Alexandre Ghiti Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/pgalloc.h | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) (limited to 'arch/riscv/include/asm/pgalloc.h') diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h index 0af6933a7100..11823004b87a 100644 --- a/arch/riscv/include/asm/pgalloc.h +++ b/arch/riscv/include/asm/pgalloc.h @@ -11,6 +11,8 @@ #include #ifdef CONFIG_MMU +#define __HAVE_ARCH_PUD_ALLOC_ONE +#define __HAVE_ARCH_PUD_FREE #include static inline void pmd_populate_kernel(struct mm_struct *mm, @@ -36,6 +38,44 @@ static inline void pud_populate(struct mm_struct *mm, pud_t *pud, pmd_t *pmd) set_pud(pud, __pud((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE)); } + +static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4d, pud_t *pud) +{ + if (pgtable_l4_enabled) { + unsigned long pfn = virt_to_pfn(pud); + + set_p4d(p4d, __p4d((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE)); + } +} + +static inline void p4d_populate_safe(struct mm_struct *mm, p4d_t *p4d, + pud_t *pud) +{ + if (pgtable_l4_enabled) { + unsigned long pfn = virt_to_pfn(pud); + + set_p4d_safe(p4d, + __p4d((pfn << _PAGE_PFN_SHIFT) | _PAGE_TABLE)); + } +} + +#define pud_alloc_one pud_alloc_one +static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr) +{ + if (pgtable_l4_enabled) + return __pud_alloc_one(mm, addr); + + return NULL; +} + +#define pud_free pud_free +static inline void pud_free(struct mm_struct *mm, pud_t *pud) +{ + if (pgtable_l4_enabled) + __pud_free(mm, pud); +} + +#define __pud_free_tlb(tlb, pud, addr) pud_free((tlb)->mm, pud) #endif /* __PAGETABLE_PMD_FOLDED */ static inline pgd_t *pgd_alloc(struct mm_struct *mm) -- cgit