From: Will Deacon <will.deacon@xxxxxxx> Subject: lib/ioremap: ensure phys_addr actually corresponds to a physical address The current ioremap() code uses a phys_addr variable at each level of page table, which is confusingly offset by subtracting the base virtual address being mapped so that adding the current virtual address back on when iterating through the page table entries gives back the corresponding physical address. This is fairly confusing and results in all users of phys_addr having to add the current virtual address back on. Instead, this patch just updates phys_addr when iterating over the page table entries, ensuring that it's always up-to-date and doesn't require explicit offsetting. Link: http://lkml.kernel.org/r/1544120495-17438-5-git-send-email-will.deacon@xxxxxxx Signed-off-by: Will Deacon <will.deacon@xxxxxxx> Tested-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> Reviewed-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> Cc: Chintan Pandya <cpandya@xxxxxxxxxxxxxx> Cc: Toshi Kani <toshi.kani@xxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- --- a/lib/ioremap.c~lib-ioremap-ensure-phys_addr-actually-corresponds-to-a-physical-address +++ a/lib/ioremap.c @@ -101,19 +101,18 @@ static inline int ioremap_pmd_range(pud_ pmd_t *pmd; unsigned long next; - phys_addr -= addr; pmd = pmd_alloc(&init_mm, pud, addr); if (!pmd) return -ENOMEM; do { next = pmd_addr_end(addr, end); - if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr + addr, prot)) + if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr, prot)) continue; - if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot)) + if (ioremap_pte_range(pmd, addr, next, phys_addr, prot)) return -ENOMEM; - } while (pmd++, addr = next, addr != end); + } while (pmd++, phys_addr += (next - addr), addr = next, addr != end); return 0; } @@ -142,19 +141,18 @@ static inline int ioremap_pud_range(p4d_ pud_t *pud; unsigned long next; - phys_addr -= addr; pud = pud_alloc(&init_mm, p4d, addr); if (!pud) return -ENOMEM; do { next = pud_addr_end(addr, end); - if (ioremap_try_huge_pud(pud, addr, next, phys_addr + addr, prot)) + if (ioremap_try_huge_pud(pud, addr, next, phys_addr, prot)) continue; - if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot)) + if (ioremap_pmd_range(pud, addr, next, phys_addr, prot)) return -ENOMEM; - } while (pud++, addr = next, addr != end); + } while (pud++, phys_addr += (next - addr), addr = next, addr != end); return 0; } @@ -164,7 +162,6 @@ static inline int ioremap_p4d_range(pgd_ p4d_t *p4d; unsigned long next; - phys_addr -= addr; p4d = p4d_alloc(&init_mm, pgd, addr); if (!p4d) return -ENOMEM; @@ -173,14 +170,14 @@ static inline int ioremap_p4d_range(pgd_ if (ioremap_p4d_enabled() && ((next - addr) == P4D_SIZE) && - IS_ALIGNED(phys_addr + addr, P4D_SIZE)) { - if (p4d_set_huge(p4d, phys_addr + addr, prot)) + IS_ALIGNED(phys_addr, P4D_SIZE)) { + if (p4d_set_huge(p4d, phys_addr, prot)) continue; } - if (ioremap_pud_range(p4d, addr, next, phys_addr + addr, prot)) + if (ioremap_pud_range(p4d, addr, next, phys_addr, prot)) return -ENOMEM; - } while (p4d++, addr = next, addr != end); + } while (p4d++, phys_addr += (next - addr), addr = next, addr != end); return 0; } @@ -196,14 +193,13 @@ int ioremap_page_range(unsigned long add BUG_ON(addr >= end); start = addr; - phys_addr -= addr; pgd = pgd_offset_k(addr); do { next = pgd_addr_end(addr, end); - err = ioremap_p4d_range(pgd, addr, next, phys_addr+addr, prot); + err = ioremap_p4d_range(pgd, addr, next, phys_addr, prot); if (err) break; - } while (pgd++, addr = next, addr != end); + } while (pgd++, phys_addr += (next - addr), addr = next, addr != end); flush_cache_vmap(start, end); _
