/* * Handle caching attributes in page tables (PAT) * * Authors: Venkatesh Pallipadi * Suresh B Siddha * * Loosely based on earlier PAT patchset from Eric Biederman and Andi Kleen. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "pat_internal.h" #include "mm_internal.h" #undef pr_fmt #define pr_fmt(fmt) "" fmt static bool __read_mostly boot_cpu_done; static bool __read_mostly pat_disabled = !IS_ENABLED(CONFIG_X86_PAT); static bool __read_mostly pat_initialized; static bool __read_mostly init_cm_done; void pat_disable(const char *reason) { if (pat_disabled) return; if (boot_cpu_done) { WARN_ONCE(1, "x86/PAT: PAT cannot be disabled after initialization\n"); return; } pat_disabled = true; pr_info("x86/PAT: %s\n", reason); } static int __init nopat(char *str) { pat_disable("PAT support disabled."); return 0; } early_param("nopat", nopat); bool pat_enabled(void) { return pat_initialized; } EXPORT_SYMBOL_GPL(pat_enabled); int pat_debug_enable; static int __init pat_debug_setup(char *str) { pat_debug_enable = 1; return 0; } __setup("debugpat", pat_debug_setup); #ifdef CONFIG_X86_PAT /* * X86 PAT uses page flags arch_1 and uncached together to keep track of * memory type of pages that have backing page struct. * * X86 PAT supports 4 different memory types: * - _PAGE_CACHE_MODE_WB * - _PAGE_CACHE_MODE_WC * - _PAGE_CACHE_MODE_UC_MINUS * - _PAGE_CACHE_MODE_WT * * _PAGE_CACHE_MODE_WB is the default type. */ #define _PGMT_WB 0 #define _PGMT_WC (1UL << PG_arch_1) #define _PGMT_UC_MINUS (1UL << PG_uncached) #define _PGMT_WT (1UL << PG_uncached | 1UL << PG_arch_1) #define _PGMT_MASK (1UL << PG_uncached | 1UL << PG_arch_1) #define _PGMT_CLEAR_MASK (~_PGMT_MASK) static inline enum page_cache_mode get_page_memtype(struct page *pg) { unsigned long pg_flags = pg->flags & _PGMT_MASK; if (pg_flags == _PGMT_WB) return _PAGE_CACHE_MODE_WB; else if (pg_flags == _PGMT_WC) return _PAGE_CACHE_MODE_WC; else if (pg_flags == _PGMT_UC_MINUS) return _PAGE_CACHE_MODE_UC_MINUS; else return _PAGE_CACHE_MODE_WT; } static inline void set_page_memtype(struct page *pg, enum page_cache_mode memtype) { unsigned long memtype_flags; unsigned long old_flags; unsigned long new_flags; switch (memtype) { case _PAGE_CACHE_MODE_WC: memtype_flags = _PGMT_WC; break; case _PAGE_CACHE_MODE_UC_MINUS: memtype_flags = _PGMT_UC_MINUS; break; case _PAGE_CACHE_MODE_WT: memtype_flags = _PGMT_WT; break; case _PAGE_CACHE_MODE_WB: default: memtype_flags = _PGMT_WB; break; } do { old_flags = pg->flags; new_flags = (old_flags & _PGMT_CLEAR_MASK) | memtype_flags; } while (cmpxchg(&pg->flags, old_flags, new_flags) != old_flags); } #else static inline enum page_cache_mode get_page_memtype(struct page *pg) { return -1; } static inline void set_page_memtype(struct page *pg, enum page_cache_mode memtype) { } #endif enum { PAT_UC = 0, /* uncached */ PAT_WC = 1, /* Write combining */ PAT_WT = 4, /* Write Through */ PAT_WP = 5, /* Write Protected */ PAT_WB = 6, /* Write Back (default) */ PAT_UC_MINUS = 7, /* UC, but can be overridden by MTRR */ }; #define CM(c) (_PAGE_CACHE_MODE_ ## c) static enum page_cache_mode pat_get_cache_mode(unsigned pat_val, char *msg) { enum page_cache_mode cache; char *cache_mode; switch (pat_val) { case PAT_UC: cache = CM(UC); cache_mode = "UC "; break; case PAT_WC: cache = CM(WC); cache_mode = "WC "; break; case PAT_WT: cache = CM(WT); cache_mode = "WT "; break; case PAT_WP: cache = CM(WP); cache_mode = "WP "; break; case PAT_WB: cache = CM(WB); cache_mode = "WB "; break; case PAT_UC_MINUS: cache = CM(UC_MINUS); cache_mode = "UC- "; break; default: cache = CM(WB); cache_mode = "WB "; break; } memcpy(msg, cache_mode, 4); return cache; } #undef CM /* * Update the cache mode to pgprot translation tables according to PAT * configuration. * Using lower indices is preferred, so we start with highest index. */ static void __init_cache_modes(u64 pat) { enum page_cache_mode cache; char pat_msg[33]; int i; pat_msg[32] = 0; for (i = 7; i >= 0; i--) { cache = pat_get_cache_mode((pat >> (i * 8)) & 7, pat_msg + 4 * i); update_cache_mode_entry(i, cache); } pr_info("x86/PAT: Configuration [0-7]: %s\n", pat_msg); init_cm_done = true; } #define PAT(x, y) ((u64)PAT_ ## y << ((x)*8)) static void pat_bsp_init(u64 pat) { u64 tmp_pat; if (!boot_cpu_has(X86_FEATURE_PAT)) { pat_disable("PAT not supported by CPU."); return; } rdmsrl(MSR_IA32_CR_PAT, tmp_pat); if (!tmp_pat) { pat_disable("PAT MSR is 0, disabled."); return; } wrmsrl(MSR_IA32_CR_PAT, pat); pat_initialized = true; __init_cache_modes(pat); } static void pat_ap_init(u64 pat) { if (!boot_cpu_has(X86_FEATURE_PAT)) { /* * If this happens we are on a secondary CPU, but switched to * PAT on the boot CPU. We have no way to undo PAT. */ panic("x86/PAT: PAT enabled, but not supported by secondary CPU\n"); } wrmsrl(MSR_IA32_CR_PAT, pat); } void init_cache_modes(void) { u64 pat = 0; if (init_cm_done) return; if (boot_cpu_has(X86_FEATURE_PAT)) { /* * CPU supports PAT. Set PAT table to be consistent with * PAT MSR. This case supports "nopat" boot option, and * virtual machine environments which support PAT without * MTRRs. In specific, Xen has unique setup to PAT MSR. * * If PAT MSR returns 0, it is considered invalid and emulates * as No PAT. */ rdmsrl(MSR_IA32_CR_PAT, pat); } if (!pat) { /* * No PAT. Emulate the PAT table that corresponds to the two * cache bits, PWT (Write Through) and PCD (Cache Disable). * This setup is also the same as the BIOS default setup. * * PTE encoding: * * PCD * |PWT PAT * || slot * 00 0 WB : _PAGE_CACHE_MODE_WB * 01 1 WT : _PAGE_CACHE_MODE_WT * 10 2 UC-: _PAGE_CACHE_MODE_UC_MINUS * 11 3 UC : _PAGE_CACHE_MODE_UC * * NOTE: When WC or WP is used, it is redirected to UC- per * the default setup in __cachemode2pte_tbl[]. */ pat = PAT(0, WB) | PAT(1, WT) | PAT(2, UC_MINUS) | PAT(3, UC) | PAT(4, WB) | PAT(5, WT) | PAT(6, UC_MINUS) | PAT(7, UC); } __init_cache_modes(pat); } /** * pat_init - Initialize PAT MSR and PAT table * * This function initializes PAT MSR and PAT table with an OS-defined value * to enable additional cache attributes, WC, WT and WP. * * This function must be called on all CPUs using the specific sequence of * operations defined in Intel SDM. mtrr_rendezvous_handler() provides this * procedure for PAT. */ void pat_init(void) { u64 pat; struct cpuinfo_x86 *c = &boot_cpu_data; if (pat_disabled) return; if ((c->x86_vendor == X86_VENDOR_INTEL) && (((c->x86 == 0x6) && (c->x86_model <= 0xd)) || ((c->x86 == 0xf) && (c->x86_model <= 0x6)))) { /* * PAT support with the lower four entries. Intel Pentium 2, * 3, M, and 4 are affected by PAT errata, which makes the * upper four entries unusable. To be on the safe side, we don't * use those. * * PTE encoding: * PAT * |PCD * ||PWT PAT * ||| slot * 000 0 WB : _PAGE_CACHE_MODE_WB * 001 1 WC : _PAGE_CACHE_MODE_WC * 010 2 UC-: _PAGE_CACHE_MODE_UC_MINUS * 011 3 UC : _PAGE_CACHE_MODE_UC * PAT bit unused * * NOTE: When WT or WP is used, it is redirected to UC- per * the default setup in __cachemode2pte_tbl[]. */ pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) | PAT(4, WB) | PAT(5, WC) | PAT(6, UC_MINUS) | PAT(7, UC); } else { /* * Full PAT support. We put WT in slot 7 to improve * robustness in the presence of errata that might cause * the high PAT bit to be ignored. This way, a buggy slot 7 * access will hit slot 3, and slot 3 is UC, so at worst * we lose performance without causing a correctness issue. * Pentium 4 erratum N46 is an example for such an erratum, * although we try not to use PAT at all on affected CPUs. * * PTE encoding: * PAT * |PCD * ||PWT PAT * ||| slot * 000 0 WB : _PAGE_CACHE_MODE_WB * 001 1 WC : _PAGE_CACHE_MODE_WC * 010 2 UC-: _PAGE_CACHE_MODE_UC_MINUS * 011 3 UC : _PAGE_CACHE_MODE_UC * 100 4 WB : Reserved * 101 5 WP : _PAGE_CACHE_MODE_WP * 110 6 UC-: Reserved * 111 7 WT : _PAGE_CACHE_MODE_WT * * The reserved slots are unused, but mapped to their * corresponding types in the presence of PAT errata. */ pat = PAT(0, WB) | PAT(1, WC) | PAT(2, UC_MINUS) | PAT(3, UC) | PAT(4, WB) | PAT(5, WP) | PAT(6, UC_MINUS) | PAT(7, WT); } if (!boot_cpu_done) { pat_bsp_init(pat); boot_cpu_done = true; } else { pat_ap_init(pat); } } #undef PAT static DEFINE_SPINLOCK(memtype_lock); /* protects memtype accesses */ /* * Does intersection of PAT memory type and MTRR memory type and returns * the resulting memory type as PAT understands it. * (Type in pat and mtrr will not have same value) * The intersection is based on "Effective Memory Type" tables in IA-32 * SDM vol 3a */ static unsigned long pat_x_mtrr_type(u64 start, u64 end, enum page_cache_mode req_type) { /* * Look for MTRR hint to get the effective type in case where PAT * request is for WB. */ if (req_type == _PAGE_CACHE_MODE_WB) { u8 mtrr_type, uniform; mtrr_type = mtrr_type_lookup(start, end, &uniform); if (mtrr_type != MTRR_TYPE_WRBACK) return _PAGE_CACHE_MODE_UC_MINUS; return _PAGE_CACHE_MODE_WB; } return req_type; } struct pagerange_state { unsigned long cur_pfn; int ram; int not_ram; }; static int pagerange_is_ram_callback(unsigned long initial_pfn, unsigned long total_nr_pages, void *arg) { struct pagerange_state *state = arg; state->not_ram |= initial_pfn > state->cur_pfn; state->ram |= total_nr_pages > 0; state->cur_pfn = initial_pfn + total_nr_pages; return state->ram && state->not_ram; } static int pat_pagerange_is_ram(resource_size_t start, resource_size_t end) { int ret = 0; unsigned long start_pfn = start >> PAGE_SHIFT; unsigned long end_pfn = (end + PAGE_SIZE - 1) >> PAGE_SHIFT; struct pagerange_state state = {start_pfn, 0, 0}; /* * For legacy reasons, physical address range in the legacy ISA * region is tracked as non-RAM. This will allow users of * /dev/mem to map portions of legacy ISA region, even when * some of those portions are listed(or not even listed) with * different e820 types(RAM/reserved/..) */ if (start_pfn < ISA_END_ADDRESS >> PAGE_SHIFT) start_pfn = ISA_END_ADDRESS >> PAGE_SHIFT; if (start_pfn < end_pfn) { ret = walk_system_ram_range(start_pfn, end_pfn - start_pfn, &state, pagerange_is_ram_callback); } return (ret > 0) ? -1 : (state.ram ? 1 : 0); } /* * For RAM pages, we use page flags to mark the pages with appropriate type. * The page flags are limited to four types, WB (default), WC, WT and UC-. * WP request fails with -EINVAL, and UC gets redirected to UC-. Setting * a new memory type is only allowed for a page mapped with the default WB * type. * * Here we do two passes: * - Find the memtype of all the pages in the range, look for any conflicts. * - In case of no conflicts, set the new memtype for pages in the range. */ static int reserve_ram_pages_type(u64 start, u64 end, enum page_cache_mode req_type, enum page_cache_mode *new_type) { struct page *page; u64 pfn; if (req_type == _PAGE_CACHE_MODE_WP) { if (new_type) *new_type = _PAGE_CACHE_MODE_UC_MINUS; return -EINVAL; } if (req_type == _PAGE_CACHE_MODE_UC) { /* We do not support strong UC */ WARN_ON_ONCE(1); req_type = _PAGE_CACHE_MODE_UC_MINUS; } for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) { enum page_cache_mode type; page = pfn_to_page(pfn); type = get_page_memtype(page); if (type != _PAGE_CACHE_MODE_WB) { pr_info("x86/PAT: reserve_ram_pages_type failed [mem %#010Lx-%#010Lx], track 0x%x, req 0x%x\n", start, end - 1, type, req_type); if (new_type) *new_type = type; return -EBUSY; } } if (new_type) *new_type = req_type; for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) { page = pfn_to_page(pfn); set_page_memtype(page, req_type); } return 0; } static int free_ram_pages_type(u64 start, u64 end) { struct page *page; u64 pfn; for (pfn = (start >> PAGE_SHIFT); pfn < (end >> PAGE_SHIFT); ++pfn) { page = pfn_to_page(pfn); set_page_memtype(page, _PAGE_CACHE_MODE_WB); } return 0; } /* * req_type typically has one of the: * - _PAGE_CACHE_MODE_WB * - _PAGE_CACHE_MODE_WC * - _PAGE_CACHE_MODE_UC_MINUS * - _PAGE_CACHE_MODE_UC * - _PAGE_CACHE_MODE_WT * * If new_type is NULL, function will return an error if it cannot reserve the * region with req_type. If new_type is non-NULL, function will return * available type in new_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, enum page_cache_mode req_type, enum page_cache_mode *new_type) { struct memtype *new; enum page_cache_mode actual_type; int is_range_ram; int err = 0; BUG_ON(start >= end); /* end is exclusive */ if (!pat_enabled()) { /* This is identical to page table setting without PAT */ if (new_type) *new_type = req_type; return 0; } /* Low ISA region is always mapped WB in page table. No need to track */ if (x86_platform.is_untracked_pat_range(start, end)) { if (new_type) *new_type = _PAGE_CACHE_MODE_WB; return 0; } /* * Call mtrr_lookup to get the type hint. This is an * optimization for /dev/mem mmap'ers into WB memory (BIOS * tools and ACPI tools). Use WB request for WB memory and use * UC_MINUS otherwise. */ actual_type = pat_x_mtrr_type(start, end, req_type); if (new_type) *new_type = actual_type; is_range_ram = pat_pagerange_is_ram(start, end); if (is_range_ram == 1) { err = reserve_ram_pages_type(start, end, req_type, new_type); return err; } else if (is_range_ram < 0) { return -EINVAL; } new = kzalloc(sizeof(struct memtype), GFP_KERNEL); if (!new) return -ENOMEM; new->start = start; new->end = end; new->type = actual_type; spin_lock(&memtype_lock); err = rbt_memtype_check_insert(new, new_type); if (err) { pr_info("x86/PAT: reserve_memtype failed [mem %#010Lx-%#010Lx], track %s, req %s\n", start, end - 1, cattr_name(new->type), cattr_name(req_type)); kfree(new); spin_unlock(&memtype_lock); return err; } spin_unlock(&memtype_lock); dprintk("reserve_memtype added [mem %#010Lx-%#010Lx], track %s, req %s, ret %s\n", start, end - 1, cattr_name(new->type), cattr_name(req_type), new_type ? cattr_name(*new_type) : "-"); return err; } int free_memtype(u64 start, u64 end) { int err = -EINVAL; int is_range_ram; struct memtype *entry; if (!pat_enabled()) return 0; /* Low ISA region is always mapped WB. No need to track */ if (x86_platform.is_untracked_pat_range(start, end)) return 0; is_range_ram = pat_pagerange_is_ram(start, end); if (is_range_ram == 1) { err = free_ram_pages_type(start, end); return err; } else if (is_range_ram < 0) { return -EINVAL; } spin_lock(&memtype_lock); entry = rbt_memtype_erase(start, end); spin_unlock(&memtype_lock); if (IS_ERR(entry)) { pr_info("x86/PAT: %s:%d freeing invalid memtype [mem %#010Lx-%#010Lx]\n", current->comm, current->pid, start, end - 1); return -EINVAL; } kfree(entry); dprintk("free_memtype request [mem %#010Lx-%#010Lx]\n", start, end - 1); return 0; } /** * lookup_memtype - Looksup the memory type for a physical address * @paddr: physical address of which memory type needs to be looked up * * Only to be called when PAT is enabled * * Returns _PAGE_CACHE_MODE_WB, _PAGE_CACHE_MODE_WC, _PAGE_CACHE_MODE_UC_MINUS * or _PAGE_CACHE_MODE_WT. */ static enum page_cache_mode lookup_memtype(u64 paddr) { enum page_cache_mode rettype = _PAGE_CACHE_MODE_WB; struct memtype *entry; if (x86_platform.is_untracked_pat_range(paddr, paddr + PAGE_SIZE)) return rettype; if (pat_pagerange_is_ram(paddr, paddr + PAGE_SIZE)) { struct page *page; page = pfn_to_page(paddr >> PAGE_SHIFT); return get_page_memtype(page); } spin_lock(&memtype_lock); entry = rbt_memtype_lookup(paddr); if (entry != NULL) rettype = entry->type; else rettype = _PAGE_CACHE_MODE_UC_MINUS; spin_unlock(&memtype_lock); return rettype; } /** * pat_pfn_immune_to_uc_mtrr - Check whether the PAT memory type * of @pfn cannot be overridden by UC MTRR memory type. * * Only to be called when PAT is enabled. * * Returns true, if the PAT memory type of @pfn is UC, UC-, or WC. * Returns false in other cases. */ bool pat_pfn_immune_to_uc_mtrr(unsigned long pfn) { enum page_cache_mode cm = lookup_memtype(PFN_PHYS(pfn)); return cm == _PAGE_CACHE_MODE_UC || cm == _PAGE_CACHE_MODE_UC_MINUS || cm == _PAGE_CACHE_MODE_WC; } EXPORT_SYMBOL_GPL(pat_pfn_immune_to_uc_mtrr); /** * io_reserve_memtype - Request a memory type mapping for a region of memory * @start: start (physical address) of the region * @end: end (physical address) of the region * @type: A pointer to memtype, with requested type. On success, requested * or any other compatible type that was available for the region is returned * * On success, returns 0 * On failure, returns non-zero */ int io_reserve_memtype(resource_size_t start, resource_size_t end, enum page_cache_mode *type) { resource_size_t size = end - start; enum page_cache_mode req_type = *type; enum page_cache_mode new_type; int ret; WARN_ON_ONCE(iomem_map_sanity_check(start, size)); ret = reserve_memtype(start, end, req_type, &new_type); if (ret) goto out_err; if (!is_new_memtype_allowed(start, size, req_type, new_type)) goto out_free; if (kernel_map_sync_memtype(start, size, new_type) < 0) goto out_free; *type = new_type; return 0; out_free: free_memtype(start, end); ret = -EBUSY; out_err: return ret; } /** * io_free_memtype - Release a memory type mapping for a region of memory * @start: start (physical address) of the region * @end: end (physical address) of the region */ void io_free_memtype(resource_size_t start, resource_size_t end) { free_memtype(start, end); } int arch_io_reserve_memtype_wc(resource_size_t start, resource_size_t size) { enum page_cache_mode type = _PAGE_CACHE_MODE_WC; return io_reserve_memtype(start, start + size, &type); } EXPORT_SYMBOL(arch_io_reserve_memtype_wc); void arch_io_free_memtype_wc(resource_size_t start, resource_size_t size) { io_free_memtype(start, start + size); } EXPORT_SYMBOL(arch_io_free_memtype_wc); pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot) { if (!phys_mem_access_encrypted(pfn << PAGE_SHIFT, size)) vma_prot = pgprot_decrypted(vma_prot); return vma_prot; } #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; } #else /* This check is needed to avoid cache aliasing when PAT is enabled */ static inline int range_is_allowed(unsigned long pfn, unsigned long size) { u64 from = ((u64)pfn) << PAGE_SHIFT; u64 to = from + size; u64 cursor = from; if (!pat_enabled()) return 1; while (cursor < to) { if (!devmem_is_allowed(pfn)) return 0; cursor += PAGE_SIZE; pfn++; } return 1; } #endif /* CONFIG_STRICT_DEVMEM */ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, unsigned long size, pgprot_t *vma_prot) { enum page_cache_mode pcm = _PAGE_CACHE_MODE_WB; if (!range_is_allowed(pfn, size)) return 0; if (file->f_flags & O_DSYNC) pcm = _PAGE_CACHE_MODE_UC_MINUS; *vma_prot = __pgprot((pgprot_val(*vma_prot) & ~_PAGE_CACHE_MASK) | cachemode2protval(pcm)); return 1; } /* * Change the memory type for the physial address range in kernel identity * mapping space if that range is a part of identity map. */ int kernel_map_sync_memtype(u64 base, unsigned long size, enum page_cache_mode pcm) { unsigned long id_sz; if (base > __pa(high_memory-1)) return 0; /* * some areas in the middle of the kernel identity range * are not mapped, like the PCI space. */ if (!page_is_ram(base >> PAGE_SHIFT)) return 0; id_sz = (__pa(high_memory-1) <= base + size) ? __pa(high_memory) - base : size; if (ioremap_change_attr((unsigned long)__va(base), id_sz, pcm) < 0) { pr_info("x86/PAT: %s:%d ioremap_change_attr failed %s for [mem %#010Lx-%#010Lx]\n", current->comm, current->pid, cattr_name(pcm), base, (unsigned long long)(base + size-1)); return -EINVAL; } return 0; } /* * Internal interface to reserve a range of physical memory with prot. * Reserved non RAM regions only and after successful reserve_memtype, * this func also keeps identity mapping (if any) in sync with this new prot. */ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot, int strict_prot) { int is_ram = 0; int ret; enum page_cache_mode want_pcm = pgprot2cachemode(*vma_prot); enum page_cache_mode pcm = want_pcm; is_ram = pat_pagerange_is_ram(paddr, paddr + size); /* * reserve_pfn_range() for RAM pages. We do not refcount to keep * track of number of mappings of RAM pages. We can assert that * the type requested matches the type of first page in the range. */ if (is_ram) { if (!pat_enabled()) return 0; pcm = lookup_memtype(paddr); if (want_pcm != pcm) { pr_warn("x86/PAT: %s:%d map pfn RAM range req %s for [mem %#010Lx-%#010Lx], got %s\n", current->comm, current->pid, cattr_name(want_pcm), (unsigned long long)paddr, (unsigned long long)(paddr + size - 1), cattr_name(pcm)); *vma_prot = __pgprot((pgprot_val(*vma_prot) & (~_PAGE_CACHE_MASK)) | cachemode2protval(pcm)); } return 0; } ret = reserve_memtype(paddr, paddr + size, want_pcm, &pcm); if (ret) return ret; if (pcm != want_pcm) { if (strict_prot || !is_new_memtype_allowed(paddr, size, want_pcm, pcm)) { free_memtype(paddr, paddr + size); pr_err("x86/PAT: %s:%d map pfn expected mapping type %s for [mem %#010Lx-%#010Lx], got %s\n", current->comm, current->pid, cattr_name(want_pcm), (unsigned long long)paddr, (unsigned long long)(paddr + size - 1), cattr_name(pcm)); return -EINVAL; } /* * We allow returning different type than the one requested in * non strict case. */ *vma_prot = __pgprot((pgprot_val(*vma_prot) & (~_PAGE_CACHE_MASK)) | cachemode2protval(pcm)); } if (kernel_map_sync_memtype(paddr, size, pcm) < 0) { free_memtype(paddr, paddr + size); return -EINVAL; } return 0; } /* * Internal interface to free a range of physical memory. * Frees non RAM regions only. */ static void free_pfn_range(u64 paddr, unsigned long size) { int is_ram; is_ram = pat_pagerange_is_ram(paddr, paddr + size); if (is_ram == 0) free_memtype(paddr, paddr + size); } /* * track_pfn_copy is called when vma that is covering the pfnmap gets * copied through copy_page_range(). * * If the vma has a linear pfn mapping for the entire range, we get the prot * from pte and reserve the entire vma range with single reserve_pfn_range call. */ int track_pfn_copy(struct vm_area_struct *vma) { resource_size_t paddr; unsigned long prot; unsigned long vma_size = vma->vm_end - vma->vm_start; pgprot_t pgprot; if (vma->vm_flags & VM_PAT) { /* * reserve the whole chunk covered by vma. We need the * starting address and protection from pte. */ if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) { WARN_ON_ONCE(1); return -EINVAL; } pgprot = __pgprot(prot); return reserve_pfn_range(paddr, vma_size, &pgprot, 1); } return 0; } /* * prot is passed in as a parameter for the new mapping. If the vma has * a linear pfn mapping for the entire range, or no vma is provided, * reserve the entire pfn + size range with single reserve_pfn_range * call. */ int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot, unsigned long pfn, unsigned long addr, unsigned long size) { resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT; enum page_cache_mode pcm; /* reserve the whole chunk starting from paddr */ if (!vma || (addr == vma->vm_start && size == (vma->vm_end - vma->vm_start))) { int ret; ret = reserve_pfn_range(paddr, size, prot, 0); if (ret == 0 && vma) vma->vm_flags |= VM_PAT; return ret; } if (!pat_enabled()) return 0; /* * For anything smaller than the vma size we set prot based on the * lookup. */ pcm = lookup_memtype(paddr); /* Check memtype for the remaining pages */ while (size > PAGE_SIZE) { size -= PAGE_SIZE; paddr += PAGE_SIZE; if (pcm != lookup_memtype(paddr)) return -EINVAL; } *prot = __pgprot((pgprot_val(*prot) & (~_PAGE_CACHE_MASK)) | cachemode2protval(pcm)); return 0; } void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, pfn_t pfn) { enum page_cache_mode pcm; if (!pat_enabled()) return; /* Set prot based on lookup */ pcm = lookup_memtype(pfn_t_to_phys(pfn)); *prot = __pgprot((pgprot_val(*prot) & (~_PAGE_CACHE_MASK)) | cachemode2protval(pcm)); } /* * untrack_pfn is called while unmapping a pfnmap for a region. * untrack can be called for a specific region indicated by pfn and size or * can be for the entire vma (in which case pfn, size are zero). */ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, unsigned long size) { resource_size_t paddr; unsigned long prot; if (vma && !(vma->vm_flags & VM_PAT)) return; /* free the chunk starting from pfn or the whole chunk */ paddr = (resource_size_t)pfn << PAGE_SHIFT; if (!paddr && !size) { if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) { WARN_ON_ONCE(1); return; } size = vma->vm_end - vma->vm_start; } free_pfn_range(paddr, size); if (vma) vma->vm_flags &= ~VM_PAT; } /* * untrack_pfn_moved is called, while mremapping a pfnmap for a new region, * with the old vma after its pfnmap page table has been removed. The new * vma has a new pfnmap to the same pfn & cache type with VM_PAT set. */ void untrack_pfn_moved(struct vm_area_struct *vma) { vma->vm_flags &= ~VM_PAT; } pgprot_t pgprot_writecombine(pgprot_t prot) { return __pgprot(pgprot_val(prot) | cachemode2protval(_PAGE_CACHE_MODE_WC)); } EXPORT_SYMBOL_GPL(pgprot_writecombine); pgprot_t pgprot_writethrough(pgprot_t prot) { return __pgprot(pgprot_val(prot) | cachemode2protval(_PAGE_CACHE_MODE_WT)); } EXPORT_SYMBOL_GPL(pgprot_writethrough); #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT) static struct memtype *memtype_get_idx(loff_t pos) { struct memtype *print_entry; int ret; print_entry = kzalloc(sizeof(struct memtype), GFP_KERNEL); if (!print_entry) return NULL; spin_lock(&memtype_lock); ret = rbt_memtype_copy_nth_element(print_entry, pos); spin_unlock(&memtype_lock); if (!ret) { return print_entry; } else { kfree(print_entry); return NULL; } } static void *memtype_seq_start(struct seq_file *seq, loff_t *pos) { if (*pos == 0) { ++*pos; seq_puts(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 const 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) { if (pat_enabled()) { 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 */