1 files changed, 236 insertions, 0 deletions

diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index eb1bf000d12e..541bcc944a5b 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -596,6 +596,242 @@ void unmap_devmem(unsigned long pfn, unsigned long size, pgprot_t vma_prot)
         free_memtype(addr, addr + size);
 }
 
+/*
+ * 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 is_ram = 0;
+        int id_sz, ret;
+        unsigned long flags;
+        unsigned long want_flags = (pgprot_val(vma_prot) & _PAGE_CACHE_MASK);
+
+        is_ram = pagerange_is_ram(paddr, paddr + size);
+
+        if (is_ram != 0) {
+                /*
+                 * For mapping RAM pages, drivers need to call
+                 * set_memory_[uc|wc|wb] directly, for reserve and free, before
+                 * setting up the PTE.
+                 */
+                WARN_ON_ONCE(1);
+                return 0;
+        }
+
+        ret = reserve_memtype(paddr, paddr + size, want_flags, &flags);
+        if (ret)
+                return ret;
+
+        if (flags != want_flags) {
+                free_memtype(paddr, paddr + size);
+                printk(KERN_ERR
+                "%s:%d map pfn expected mapping type %s for %Lx-%Lx, got %s\n",
+                        current->comm, current->pid,
+                        cattr_name(want_flags),
+                        (unsigned long long)paddr,
+                        (unsigned long long)(paddr + size),
+                        cattr_name(flags));
+                return -EINVAL;
+        }
+
+        /* Need to keep identity mapping in sync */
+        if (paddr >= __pa(high_memory))
+                return 0;
+
+        id_sz = (__pa(high_memory) < paddr + size) ?
+                                __pa(high_memory) - paddr :
+                                size;
+
+        if (ioremap_change_attr((unsigned long)__va(paddr), id_sz, flags) < 0) {
+                free_memtype(paddr, paddr + size);
+                printk(KERN_ERR
+                        "%s:%d reserve_pfn_range ioremap_change_attr failed %s "
+                        "for %Lx-%Lx\n",
+                        current->comm, current->pid,
+                        cattr_name(flags),
+                        (unsigned long long)paddr,
+                        (unsigned long long)(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 = pagerange_is_ram(paddr, paddr + size);
+        if (is_ram == 0)
+                free_memtype(paddr, paddr + size);
+}
+
+/*
+ * track_pfn_vma_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.
+ * Otherwise, we reserve the entire vma range, my ging through the PTEs page
+ * by page to get physical address and protection.
+ */
+int track_pfn_vma_copy(struct vm_area_struct *vma)
+{
+        int retval = 0;
+        unsigned long i, j;
+        u64 paddr;
+        unsigned long prot;
+        unsigned long vma_start = vma->vm_start;
+        unsigned long vma_end = vma->vm_end;
+        unsigned long vma_size = vma_end - vma_start;
+
+        if (!pat_enabled)
+                return 0;
+
+        if (is_linear_pfn_mapping(vma)) {
+                /*
+                 * reserve the whole chunk covered by vma. We need the
+                 * starting address and protection from pte.
+                 */
+                if (follow_phys(vma, vma_start, 0, &prot, &paddr)) {
+                        WARN_ON_ONCE(1);
+                        return -EINVAL;
+                }
+                return reserve_pfn_range(paddr, vma_size, __pgprot(prot));
+        }
+
+        /* reserve entire vma page by page, using pfn and prot from pte */
+        for (i = 0; i < vma_size; i += PAGE_SIZE) {
+                if (follow_phys(vma, vma_start + i, 0, &prot, &paddr))
+                        continue;
+
+                retval = reserve_pfn_range(paddr, PAGE_SIZE, __pgprot(prot));
+                if (retval)
+                        goto cleanup_ret;
+        }
+        return 0;
+
+cleanup_ret:
+        /* Reserve error: Cleanup partial reservation and return error */
+        for (j = 0; j < i; j += PAGE_SIZE) {
+                if (follow_phys(vma, vma_start + j, 0, &prot, &paddr))
+                        continue;
+
+                free_pfn_range(paddr, PAGE_SIZE);
+        }
+
+        return retval;
+}
+
+/*
+ * track_pfn_vma_new is called when a _new_ pfn mapping is being established
+ * for physical range indicated by pfn and size.
+ *
+ * prot is passed in as a parameter for the new mapping. If the vma has a
+ * linear pfn mapping for the entire range reserve the entire vma range with
+ * single reserve_pfn_range call.
+ * Otherwise, we look t the pfn and size and reserve only the specified range
+ * page by page.
+ *
+ * Note that this function can be called with caller trying to map only a
+ * subrange/page inside the vma.
+ */
+int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t prot,
+                        unsigned long pfn, unsigned long size)
+{
+        int retval = 0;
+        unsigned long i, j;
+        u64 base_paddr;
+        u64 paddr;
+        unsigned long vma_start = vma->vm_start;
+        unsigned long vma_end = vma->vm_end;
+        unsigned long vma_size = vma_end - vma_start;
+
+        if (!pat_enabled)
+                return 0;
+
+        if (is_linear_pfn_mapping(vma)) {
+                /* reserve the whole chunk starting from vm_pgoff */
+                paddr = (u64)vma->vm_pgoff << PAGE_SHIFT;
+                return reserve_pfn_range(paddr, vma_size, prot);
+        }
+
+        /* reserve page by page using pfn and size */
+        base_paddr = (u64)pfn << PAGE_SHIFT;
+        for (i = 0; i < size; i += PAGE_SIZE) {
+                paddr = base_paddr + i;
+                retval = reserve_pfn_range(paddr, PAGE_SIZE, prot);
+                if (retval)
+                        goto cleanup_ret;
+        }
+        return 0;
+
+cleanup_ret:
+        /* Reserve error: Cleanup partial reservation and return error */
+        for (j = 0; j < i; j += PAGE_SIZE) {
+                paddr = base_paddr + j;
+                free_pfn_range(paddr, PAGE_SIZE);
+        }
+
+        return retval;
+}
+
+/*
+ * untrack_pfn_vma 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 size can be zero).
+ */
+void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
+                        unsigned long size)
+{
+        unsigned long i;
+        u64 paddr;
+        unsigned long prot;
+        unsigned long vma_start = vma->vm_start;
+        unsigned long vma_end = vma->vm_end;
+        unsigned long vma_size = vma_end - vma_start;
+
+        if (!pat_enabled)
+                return;
+
+        if (is_linear_pfn_mapping(vma)) {
+                /* free the whole chunk starting from vm_pgoff */
+                paddr = (u64)vma->vm_pgoff << PAGE_SHIFT;
+                free_pfn_range(paddr, vma_size);
+                return;
+        }
+
+        if (size != 0 && size != vma_size) {
+                /* free page by page, using pfn and size */
+                paddr = (u64)pfn << PAGE_SHIFT;
+                for (i = 0; i < size; i += PAGE_SIZE) {
+                        paddr = paddr + i;
+                        free_pfn_range(paddr, PAGE_SIZE);
+                }
+        } else {
+                /* free entire vma, page by page, using the pfn from pte */
+                for (i = 0; i < vma_size; i += PAGE_SIZE) {
+                        if (follow_phys(vma, vma_start + i, 0, &prot, &paddr))
+                                continue;
+
+                        free_pfn_range(paddr, PAGE_SIZE);
+                }
+        }
+}
+
+pgprot_t pgprot_writecombine(pgprot_t prot)
+{
+        if (pat_enabled)
+                return __pgprot(pgprot_val(prot) | _PAGE_CACHE_WC);
+        else
+                return pgprot_noncached(prot);
+}
+
 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_PAT)
 
 /* get Nth element of the linked list */