diff options
| -rw-r--r-- | arch/arm/mm/ioremap.c | 167 | ||||
| -rw-r--r-- | include/asm-arm/memory.h | 5 | ||||
| -rw-r--r-- | include/asm-arm/mmu.h | 1 | ||||
| -rw-r--r-- | include/asm-arm/mmu_context.h | 12 |
4 files changed, 180 insertions, 5 deletions
diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c index 7691cfdba56..6aa13d59c85 100644 --- a/arch/arm/mm/ioremap.c +++ b/arch/arm/mm/ioremap.c @@ -27,7 +27,16 @@ #include <asm/cacheflush.h> #include <asm/io.h> +#include <asm/mmu_context.h> +#include <asm/pgalloc.h> #include <asm/tlbflush.h> +#include <asm/sizes.h> + +/* + * Used by ioremap() and iounmap() code to mark section-mapped I/O regions + * in vm_struct->flags field. + */ +#define VM_ARM_SECTION_MAPPING 0x80000000 static inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, @@ -113,10 +122,120 @@ remap_area_pages(unsigned long start, unsigned long pfn, dir++; } while (address && (address < end)); - flush_cache_vmap(start, end); return err; } + +void __check_kvm_seq(struct mm_struct *mm) +{ + unsigned int seq; + + do { + seq = init_mm.context.kvm_seq; + memcpy(pgd_offset(mm, VMALLOC_START), + pgd_offset_k(VMALLOC_START), + sizeof(pgd_t) * (pgd_index(VMALLOC_END) - + pgd_index(VMALLOC_START))); + mm->context.kvm_seq = seq; + } while (seq != init_mm.context.kvm_seq); +} + +#ifndef CONFIG_SMP +/* + * Section support is unsafe on SMP - If you iounmap and ioremap a region, + * the other CPUs will not see this change until their next context switch. + * Meanwhile, (eg) if an interrupt comes in on one of those other CPUs + * which requires the new ioremap'd region to be referenced, the CPU will + * reference the _old_ region. + * + * Note that get_vm_area() allocates a guard 4K page, so we need to mask + * the size back to 1MB aligned or we will overflow in the loop below. + */ +static void unmap_area_sections(unsigned long virt, unsigned long size) +{ + unsigned long addr = virt, end = virt + (size & ~SZ_1M); + pgd_t *pgd; + + flush_cache_vunmap(addr, end); + pgd = pgd_offset_k(addr); + do { + pmd_t pmd, *pmdp = pmd_offset(pgd, addr); + + pmd = *pmdp; + if (!pmd_none(pmd)) { + /* + * Clear the PMD from the page table, and + * increment the kvm sequence so others + * notice this change. + * + * Note: this is still racy on SMP machines. + */ + pmd_clear(pmdp); + init_mm.context.kvm_seq++; + + /* + * Free the page table, if there was one. + */ + if ((pmd_val(pmd) & PMD_TYPE_MASK) == PMD_TYPE_TABLE) + pte_free_kernel(pmd_page_kernel(pmd)); + } + + addr += PGDIR_SIZE; + pgd++; + } while (addr < end); + + /* + * Ensure that the active_mm is up to date - we want to + * catch any use-after-iounmap cases. + */ + if (current->active_mm->context.kvm_seq != init_mm.context.kvm_seq) + __check_kvm_seq(current->active_mm); + + flush_tlb_kernel_range(virt, end); +} + +static int +remap_area_sections(unsigned long virt, unsigned long pfn, + unsigned long size, unsigned long flags) +{ + unsigned long prot, addr = virt, end = virt + size; + pgd_t *pgd; + + /* + * Remove and free any PTE-based mapping, and + * sync the current kernel mapping. + */ + unmap_area_sections(virt, size); + + prot = PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_DOMAIN(DOMAIN_IO) | + (flags & (L_PTE_CACHEABLE | L_PTE_BUFFERABLE)); + + /* + * ARMv6 and above need XN set to prevent speculative prefetches + * hitting IO. + */ + if (cpu_architecture() >= CPU_ARCH_ARMv6) + prot |= PMD_SECT_XN; + + pgd = pgd_offset_k(addr); + do { + pmd_t *pmd = pmd_offset(pgd, addr); + + pmd[0] = __pmd(__pfn_to_phys(pfn) | prot); + pfn += SZ_1M >> PAGE_SHIFT; + pmd[1] = __pmd(__pfn_to_phys(pfn) | prot); + pfn += SZ_1M >> PAGE_SHIFT; + flush_pmd_entry(pmd); + + addr += PGDIR_SIZE; + pgd++; + } while (addr < end); + + return 0; +} +#endif + + /* * Remap an arbitrary physical address space into the kernel virtual * address space. Needed when the kernel wants to access high addresses @@ -133,6 +252,7 @@ void __iomem * __ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, unsigned long flags) { + int err; unsigned long addr; struct vm_struct * area; @@ -140,11 +260,22 @@ __ioremap_pfn(unsigned long pfn, unsigned long offset, size_t size, if (!area) return NULL; addr = (unsigned long)area->addr; - if (remap_area_pages(addr, pfn, size, flags)) { + +#ifndef CONFIG_SMP + if (!((__pfn_to_phys(pfn) | size | addr) & ~PMD_MASK)) { + area->flags |= VM_ARM_SECTION_MAPPING; + err = remap_area_sections(addr, pfn, size, flags); + } else +#endif + err = remap_area_pages(addr, pfn, size, flags); + + if (err) { vunmap((void *)addr); return NULL; } - return (void __iomem *) (offset + (char *)addr); + + flush_cache_vmap(addr, addr + size); + return (void __iomem *) (offset + addr); } EXPORT_SYMBOL(__ioremap_pfn); @@ -173,6 +304,34 @@ EXPORT_SYMBOL(__ioremap); void __iounmap(void __iomem *addr) { - vunmap((void *)(PAGE_MASK & (unsigned long)addr)); + struct vm_struct **p, *tmp; + unsigned int section_mapping = 0; + + addr = (void __iomem *)(PAGE_MASK & (unsigned long)addr); + + /* + * If this is a section based mapping we need to handle it + * specially as the VM subysystem does not know how to handle + * such a beast. We need the lock here b/c we need to clear + * all the mappings before the area can be reclaimed + * by someone else. + */ + write_lock(&vmlist_lock); + for (p = &vmlist ; (tmp = *p) ; p = &tmp->next) { + if((tmp->flags & VM_IOREMAP) && (tmp->addr == addr)) { + if (tmp->flags & VM_ARM_SECTION_MAPPING) { + *p = tmp->next; + unmap_area_sections((unsigned long)tmp->addr, + tmp->size); + kfree(tmp); + section_mapping = 1; + } + break; + } + } + write_unlock(&vmlist_lock); + + if (!section_mapping) + vunmap(addr); } EXPORT_SYMBOL(__iounmap); diff --git a/include/asm-arm/memory.h b/include/asm-arm/memory.h index 94f973b704f..176a4fb0498 100644 --- a/include/asm-arm/memory.h +++ b/include/asm-arm/memory.h @@ -68,6 +68,11 @@ */ #define XIP_VIRT_ADDR(physaddr) (MODULE_START + ((physaddr) & 0x000fffff)) +/* + * Allow 2MB-aligned ioremap pages + */ +#define IOREMAP_MAX_ORDER 21 + #else /* CONFIG_MMU */ /* diff --git a/include/asm-arm/mmu.h b/include/asm-arm/mmu.h index 23dde52e094..fe2a23b5627 100644 --- a/include/asm-arm/mmu.h +++ b/include/asm-arm/mmu.h @@ -7,6 +7,7 @@ typedef struct { #if __LINUX_ARM_ARCH__ >= 6 unsigned int id; #endif + unsigned int kvm_seq; } mm_context_t; #if __LINUX_ARM_ARCH__ >= 6 diff --git a/include/asm-arm/mmu_context.h b/include/asm-arm/mmu_context.h index 9fadb01e030..d1a65b1edca 100644 --- a/include/asm-arm/mmu_context.h +++ b/include/asm-arm/mmu_context.h @@ -17,6 +17,8 @@ #include <asm/cacheflush.h> #include <asm/proc-fns.h> +void __check_kvm_seq(struct mm_struct *mm); + #if __LINUX_ARM_ARCH__ >= 6 /* @@ -45,13 +47,21 @@ static inline void check_context(struct mm_struct *mm) { if (unlikely((mm->context.id ^ cpu_last_asid) >> ASID_BITS)) __new_context(mm); + + if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) + __check_kvm_seq(mm); } #define init_new_context(tsk,mm) (__init_new_context(tsk,mm),0) #else -#define check_context(mm) do { } while (0) +static inline void check_context(struct mm_struct *mm) +{ + if (unlikely(mm->context.kvm_seq != init_mm.context.kvm_seq)) + __check_kvm_seq(mm); +} + #define init_new_context(tsk,mm) 0 #endif |