From: Will Deacon will.deacon@arm.com
mainline inclusion from mainline-v5.0-rc1 commit 36ddc5a78c878e9b10c323d2fe88b0dae2f487eb category: feature bugzilla: NA CVE: NA
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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@arm.c... Signed-off-by: Will Deacon will.deacon@arm.com Tested-by: Sean Christopherson sean.j.christopherson@intel.com Reviewed-by: Sean Christopherson sean.j.christopherson@intel.com Cc: Chintan Pandya cpandya@codeaurora.org Cc: Toshi Kani toshi.kani@hpe.com Cc: Thomas Gleixner tglx@linutronix.de Cc: Michal Hocko mhocko@suse.com Cc: Sean Christopherson sean.j.christopherson@intel.com Cc: "H. Peter Anvin" hpa@zytor.com Cc: Ingo Molnar mingo@elte.hu Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Rui Xiang rui.xiang@huawei.com Reviewed-by: Ding Tianhong dingtianhong@huawei.com Reviewed-by: Zefan Li lizefan@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- lib/ioremap.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-)
diff --git a/lib/ioremap.c b/lib/ioremap.c index 6c72764af19c..10d7c5485c39 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -101,19 +101,18 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, 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_t *p4d, unsigned long addr, 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_t *pgd, unsigned long addr, 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_t *pgd, unsigned long addr,
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 addr, 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);