diff options
Diffstat (limited to 'arch/x86/mm/pat.c')
| -rw-r--r-- | arch/x86/mm/pat.c | 268 |
1 files changed, 229 insertions, 39 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index d4585077977..738fd0f2495 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -7,22 +7,24 @@ * Loosely based on earlier PAT patchset from Eric Biederman and Andi Kleen. */ -#include <linux/mm.h> +#include <linux/seq_file.h> +#include <linux/bootmem.h> +#include <linux/debugfs.h> #include <linux/kernel.h> #include <linux/gfp.h> +#include <linux/mm.h> #include <linux/fs.h> -#include <linux/bootmem.h> -#include <asm/msr.h> -#include <asm/tlbflush.h> +#include <asm/cacheflush.h> #include <asm/processor.h> -#include <asm/page.h> +#include <asm/tlbflush.h> #include <asm/pgtable.h> -#include <asm/pat.h> -#include <asm/e820.h> -#include <asm/cacheflush.h> #include <asm/fcntl.h> +#include <asm/e820.h> #include <asm/mtrr.h> +#include <asm/page.h> +#include <asm/msr.h> +#include <asm/pat.h> #include <asm/io.h> #ifdef CONFIG_X86_PAT @@ -44,6 +46,7 @@ early_param("nopat", nopat); static int debug_enable; + static int __init pat_debug_setup(char *str) { debug_enable = 1; @@ -143,14 +146,14 @@ static char *cattr_name(unsigned long flags) */ struct memtype { - u64 start; - u64 end; - unsigned long type; - struct list_head nd; + u64 start; + u64 end; + unsigned long type; + struct list_head nd; }; static LIST_HEAD(memtype_list); -static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */ +static DEFINE_SPINLOCK(memtype_lock); /* protects memtype list */ /* * Does intersection of PAT memory type and MTRR memory type and returns @@ -178,8 +181,8 @@ static unsigned long pat_x_mtrr_type(u64 start, u64 end, unsigned long req_type) return req_type; } -static int chk_conflict(struct memtype *new, struct memtype *entry, - unsigned long *type) +static int +chk_conflict(struct memtype *new, struct memtype *entry, unsigned long *type) { if (new->type != entry->type) { if (type) { @@ -205,6 +208,69 @@ static int chk_conflict(struct memtype *new, struct memtype *entry, return -EBUSY; } +static struct memtype *cached_entry; +static u64 cached_start; + +/* + * For RAM pages, mark the pages as non WB memory type using + * PageNonWB (PG_arch_1). We allow only one set_memory_uc() or + * set_memory_wc() on a RAM page at a time before marking it as WB again. + * This is ok, because only one driver will be owning the page and + * doing set_memory_*() calls. + * + * For now, we use PageNonWB to track that the RAM page is being mapped + * as non WB. In future, we will have to use one more flag + * (or some other mechanism in page_struct) to distinguish between + * UC and WC mapping. + */ +static int reserve_ram_pages_type(u64 start, u64 end, unsigned long req_type, + unsigned long *new_type) +{ + struct page *page; + u64 pfn, end_pfn; + + for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) { + page = pfn_to_page(pfn); + if (page_mapped(page) || PageNonWB(page)) + goto out; + + SetPageNonWB(page); + } + return 0; + +out: + end_pfn = pfn; + for (pfn = (start >> PAGE_SHIFT); pfn < end_pfn; ++pfn) { + page = pfn_to_page(pfn); + ClearPageNonWB(page); + } + + return -EINVAL; +} + +static int free_ram_pages_type(u64 start, u64 end) +{ + struct page *page; + u64 pfn, end_pfn; + + for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) { + page = pfn_to_page(pfn); + if (page_mapped(page) || !PageNonWB(page)) + goto out; + + ClearPageNonWB(page); + } + return 0; + +out: + end_pfn = pfn; + for (pfn = (start >> PAGE_SHIFT); pfn < end_pfn; ++pfn) { + page = pfn_to_page(pfn); + SetPageNonWB(page); + } + return -EINVAL; +} + /* * req_type typically has one of the: * - _PAGE_CACHE_WB @@ -221,14 +287,15 @@ static int chk_conflict(struct memtype *new, struct memtype *entry, * it will return a negative return value. */ int reserve_memtype(u64 start, u64 end, unsigned long req_type, - unsigned long *new_type) + unsigned long *new_type) { struct memtype *new, *entry; unsigned long actual_type; struct list_head *where; + int is_range_ram; int err = 0; - BUG_ON(start >= end); /* end is exclusive */ + BUG_ON(start >= end); /* end is exclusive */ if (!pat_enabled) { /* This is identical to page table setting without PAT */ @@ -261,28 +328,41 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type, actual_type = _PAGE_CACHE_WB; else actual_type = _PAGE_CACHE_UC_MINUS; - } else + } else { actual_type = pat_x_mtrr_type(start, end, req_type & _PAGE_CACHE_MASK); + } + + is_range_ram = pagerange_is_ram(start, end); + if (is_range_ram == 1) + return reserve_ram_pages_type(start, end, req_type, new_type); + else if (is_range_ram < 0) + return -EINVAL; new = kmalloc(sizeof(struct memtype), GFP_KERNEL); if (!new) return -ENOMEM; - new->start = start; - new->end = end; - new->type = actual_type; + new->start = start; + new->end = end; + new->type = actual_type; if (new_type) *new_type = actual_type; spin_lock(&memtype_lock); + if (cached_entry && start >= cached_start) + entry = cached_entry; + else + entry = list_entry(&memtype_list, struct memtype, nd); + /* Search for existing mapping that overlaps the current range */ where = NULL; - list_for_each_entry(entry, &memtype_list, nd) { + list_for_each_entry_continue(entry, &memtype_list, nd) { if (end <= entry->start) { where = entry->nd.prev; + cached_entry = list_entry(where, struct memtype, nd); break; } else if (start <= entry->start) { /* end > entry->start */ err = chk_conflict(new, entry, new_type); @@ -290,6 +370,8 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type, dprintk("Overlap at 0x%Lx-0x%Lx\n", entry->start, entry->end); where = entry->nd.prev; + cached_entry = list_entry(where, + struct memtype, nd); } break; } else if (start < entry->end) { /* start > entry->start */ @@ -297,7 +379,20 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type, if (!err) { dprintk("Overlap at 0x%Lx-0x%Lx\n", entry->start, entry->end); - where = &entry->nd; + cached_entry = list_entry(entry->nd.prev, + struct memtype, nd); + + /* + * Move to right position in the linked + * list to add this new entry + */ + list_for_each_entry_continue(entry, + &memtype_list, nd) { + if (start <= entry->start) { + where = entry->nd.prev; + break; + } + } } break; } @@ -309,9 +404,12 @@ int reserve_memtype(u64 start, u64 end, unsigned long req_type, start, end, cattr_name(new->type), cattr_name(req_type)); kfree(new); spin_unlock(&memtype_lock); + return err; } + cached_start = start; + if (where) list_add(&new->nd, where); else @@ -330,6 +428,7 @@ int free_memtype(u64 start, u64 end) { struct memtype *entry; int err = -EINVAL; + int is_range_ram; if (!pat_enabled) return 0; @@ -338,9 +437,18 @@ int free_memtype(u64 start, u64 end) if (is_ISA_range(start, end - 1)) return 0; + is_range_ram = pagerange_is_ram(start, end); + if (is_range_ram == 1) + return free_ram_pages_type(start, end); + else if (is_range_ram < 0) + return -EINVAL; + spin_lock(&memtype_lock); list_for_each_entry(entry, &memtype_list, nd) { if (entry->start == start && entry->end == end) { + if (cached_entry == entry || cached_start == start) + cached_entry = NULL; + list_del(&entry->nd); kfree(entry); err = 0; @@ -355,26 +463,19 @@ int free_memtype(u64 start, u64 end) } dprintk("free_memtype request 0x%Lx-0x%Lx\n", start, end); + return err; } -/* - * /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) { return vma_prot; } -#ifdef CONFIG_NONPROMISC_DEVMEM -/* This check is done in drivers/char/mem.c in case of NONPROMISC_DEVMEM*/ +#ifdef CONFIG_STRICT_DEVMEM +/* This check is done in drivers/char/mem.c in case of STRICT_DEVMEM*/ static inline int range_is_allowed(unsigned long pfn, unsigned long size) { return 1; @@ -398,20 +499,20 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size) } return 1; } -#endif /* CONFIG_NONPROMISC_DEVMEM */ +#endif /* CONFIG_STRICT_DEVMEM */ 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 flags = -1; int retval; if (!range_is_allowed(pfn, size)) return 0; if (file->f_flags & O_SYNC) { - flags = _PAGE_CACHE_UC; + flags = _PAGE_CACHE_UC_MINUS; } #ifdef CONFIG_X86_32 @@ -434,13 +535,14 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, #endif /* - * With O_SYNC, we can only take UC mapping. Fail if we cannot. + * With O_SYNC, we can only take UC_MINUS 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) { + if (flags != -1) { retval = reserve_memtype(offset, offset + size, flags, NULL); } else { retval = reserve_memtype(offset, offset + size, -1, &flags); @@ -468,9 +570,9 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, void map_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot) { + unsigned long want_flags = (pgprot_val(vma_prot) & _PAGE_CACHE_MASK); 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) { @@ -489,3 +591,91 @@ void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot) free_memtype(addr, addr + size); } + +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT) + +/* get Nth element of the linked list */ +static struct memtype *memtype_get_idx(loff_t pos) +{ + struct memtype *list_node, *print_entry; + int i = 1; + + print_entry = kmalloc(sizeof(struct memtype), GFP_KERNEL); + if (!print_entry) + return NULL; + + spin_lock(&memtype_lock); + list_for_each_entry(list_node, &memtype_list, nd) { + if (pos == i) { + *print_entry = *list_node; + spin_unlock(&memtype_lock); + return print_entry; + } + ++i; + } + spin_unlock(&memtype_lock); + kfree(print_entry); + + return NULL; +} + +static void *memtype_seq_start(struct seq_file *seq, loff_t *pos) +{ + if (*pos == 0) { + ++*pos; + seq_printf(seq, "PAT memtype list:\n"); + } + + return memtype_get_idx(*pos); +} + +static void *memtype_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + ++*pos; + return memtype_get_idx(*pos); +} + +static void memtype_seq_stop(struct seq_file *seq, void *v) +{ +} + +static int memtype_seq_show(struct seq_file *seq, void *v) +{ + struct memtype *print_entry = (struct memtype *)v; + + seq_printf(seq, "%s @ 0x%Lx-0x%Lx\n", cattr_name(print_entry->type), + print_entry->start, print_entry->end); + kfree(print_entry); + + return 0; +} + +static struct seq_operations memtype_seq_ops = { + .start = memtype_seq_start, + .next = memtype_seq_next, + .stop = memtype_seq_stop, + .show = memtype_seq_show, +}; + +static int memtype_seq_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &memtype_seq_ops); +} + +static const struct file_operations memtype_fops = { + .open = memtype_seq_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + +static int __init pat_memtype_list_init(void) +{ + debugfs_create_file("pat_memtype_list", S_IRUSR, arch_debugfs_dir, + NULL, &memtype_fops); + return 0; +} + +late_initcall(pat_memtype_list_init); + +#endif /* CONFIG_DEBUG_FS && CONFIG_X86_PAT */ |