diff options
| -rw-r--r-- | arch/x86/mm/pat.c | 128 | ||||
| -rw-r--r-- | drivers/char/mem.c | 35 |
2 files changed, 152 insertions, 11 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 64cc0c18233..1489aafbfa7 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -11,6 +11,7 @@ #include <linux/kernel.h> #include <linux/gfp.h> #include <linux/fs.h> +#include <linux/bootmem.h> #include <asm/msr.h> #include <asm/tlbflush.h> @@ -21,6 +22,7 @@ #include <asm/cacheflush.h> #include <asm/fcntl.h> #include <asm/mtrr.h> +#include <asm/io.h> int pat_wc_enabled = 1; @@ -190,6 +192,21 @@ static int pat_x_mtrr_type(u64 start, u64 end, unsigned long prot, return 0; } +/* + * req_type typically has one of the: + * - _PAGE_CACHE_WB + * - _PAGE_CACHE_WC + * - _PAGE_CACHE_UC_MINUS + * - _PAGE_CACHE_UC + * + * req_type will have a special case value '-1', when requester want to inherit + * the memory type from mtrr (if WB), existing PAT, defaulting to UC_MINUS. + * + * If ret_type is NULL, function will return an error if it cannot reserve the + * region with req_type. If ret_type is non-null, function will return + * available type in ret_type in case of no error. In case of any error + * it will return a negative return value. + */ int reserve_memtype(u64 start, u64 end, unsigned long req_type, unsigned long *ret_type) { @@ -200,9 +217,14 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type, /* Only track when pat_wc_enabled */ if (!pat_wc_enabled) { - if (ret_type) - *ret_type = req_type; - + /* This is identical to page table setting without PAT */ + if (ret_type) { + if (req_type == -1) { + *ret_type = _PAGE_CACHE_WB; + } else { + *ret_type = req_type; + } + } return 0; } @@ -214,8 +236,29 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type, return 0; } - req_type &= _PAGE_CACHE_MASK; - err = pat_x_mtrr_type(start, end, req_type, &actual_type); + if (req_type == -1) { + /* + * Special case where caller wants to inherit from mtrr or + * existing pat mapping, defaulting to UC_MINUS in case of + * no match. + */ + u8 mtrr_type = mtrr_type_lookup(start, end); + if (mtrr_type == 0xFE) { /* MTRR match error */ + err = -1; + } + + if (mtrr_type == MTRR_TYPE_WRBACK) { + req_type = _PAGE_CACHE_WB; + actual_type = _PAGE_CACHE_WB; + } else { + req_type = _PAGE_CACHE_UC_MINUS; + actual_type = _PAGE_CACHE_UC_MINUS; + } + } else { + req_type &= _PAGE_CACHE_MASK; + err = pat_x_mtrr_type(start, end, req_type, &actual_type); + } + if (err) { if (ret_type) *ret_type = actual_type; @@ -420,7 +463,14 @@ int free_memtype(u64 start, u64 end) } -/* /dev/mem interface. Use the previous mapping */ +/* + * /dev/mem mmap interface. The memtype used for mapping varies: + * - Use UC for mappings with O_SYNC flag + * - Without O_SYNC flag, if there is any conflict in reserve_memtype, + * inherit the memtype from existing mapping. + * - Else use UC_MINUS memtype (for backward compatibility with existing + * X drivers. + */ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot) { @@ -430,10 +480,13 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, unsigned long size, pgprot_t *vma_prot) { + u64 offset = ((u64) pfn) << PAGE_SHIFT; + unsigned long flags = _PAGE_CACHE_UC_MINUS; + unsigned long ret_flags; + int retval; if (file->f_flags & O_SYNC) { - *vma_prot = pgprot_noncached(*vma_prot); - return 1; + flags = _PAGE_CACHE_UC; } #ifdef CONFIG_X86_32 @@ -451,10 +504,65 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) || test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability)) && (pfn << PAGE_SHIFT) >= __pa(high_memory)) { - *vma_prot = pgprot_noncached(*vma_prot); - return 1; + flags = _PAGE_CACHE_UC; } #endif + /* + * With O_SYNC, we can only take UC mapping. Fail if we cannot. + * Without O_SYNC, we want to get + * - WB for WB-able memory and no other conflicting mappings + * - UC_MINUS for non-WB-able memory with no other conflicting mappings + * - Inherit from confliting mappings otherwise + */ + if (flags != _PAGE_CACHE_UC_MINUS) { + retval = reserve_memtype(offset, offset + size, flags, NULL); + } else { + retval = reserve_memtype(offset, offset + size, -1, &ret_flags); + } + + if (retval < 0) + return 0; + + flags = ret_flags; + + if (pfn <= max_pfn_mapped && + ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) { + free_memtype(offset, offset + size); + printk(KERN_DEBUG + "%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n", + current->comm, current->pid, + cattr_name(flags), + offset, offset + size); + return 0; + } + + *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) | + flags); return 1; } + +void map_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot) +{ + u64 addr = (u64)pfn << PAGE_SHIFT; + unsigned long flags; + unsigned long want_flags = (pgprot_val(vma_prot) & _PAGE_CACHE_MASK); + + reserve_memtype(addr, addr + size, want_flags, &flags); + if (flags != want_flags) { + printk(KERN_DEBUG + "%s:%d /dev/mem expected mapping type %s for %Lx-%Lx, got %s\n", + current->comm, current->pid, + cattr_name(want_flags), + addr, addr + size, + cattr_name(flags)); + } +} + +void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot) +{ + u64 addr = (u64)pfn << PAGE_SHIFT; + + free_memtype(addr, addr + size); +} + diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 56b2fb4fbc9..e83623ead44 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -300,6 +300,35 @@ static inline int private_mapping_ok(struct vm_area_struct *vma) } #endif +void __attribute__((weak)) +map_devmem(unsigned long pfn, unsigned long len, pgprot_t prot) +{ + /* nothing. architectures can override. */ +} + +void __attribute__((weak)) +unmap_devmem(unsigned long pfn, unsigned long len, pgprot_t prot) +{ + /* nothing. architectures can override. */ +} + +static void mmap_mem_open(struct vm_area_struct *vma) +{ + map_devmem(vma->vm_pgoff, vma->vm_end - vma->vm_start, + vma->vm_page_prot); +} + +static void mmap_mem_close(struct vm_area_struct *vma) +{ + unmap_devmem(vma->vm_pgoff, vma->vm_end - vma->vm_start, + vma->vm_page_prot); +} + +static struct vm_operations_struct mmap_mem_ops = { + .open = mmap_mem_open, + .close = mmap_mem_close +}; + static int mmap_mem(struct file * file, struct vm_area_struct * vma) { size_t size = vma->vm_end - vma->vm_start; @@ -321,13 +350,17 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma) size, vma->vm_page_prot); + vma->vm_ops = &mmap_mem_ops; + /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */ if (remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff, size, - vma->vm_page_prot)) + vma->vm_page_prot)) { + unmap_devmem(vma->vm_pgoff, size, vma->vm_page_prot); return -EAGAIN; + } return 0; } |