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-rw-r--r--arch/riscv/mm/pageattr.c439
1 files changed, 439 insertions, 0 deletions
diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
new file mode 100644
index 0000000000..01398fee5c
--- /dev/null
+++ b/arch/riscv/mm/pageattr.c
@@ -0,0 +1,439 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2019 SiFive
+ */
+
+#include <linux/pagewalk.h>
+#include <linux/pgtable.h>
+#include <linux/vmalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/bitops.h>
+#include <asm/set_memory.h>
+
+struct pageattr_masks {
+ pgprot_t set_mask;
+ pgprot_t clear_mask;
+};
+
+static unsigned long set_pageattr_masks(unsigned long val, struct mm_walk *walk)
+{
+ struct pageattr_masks *masks = walk->private;
+ unsigned long new_val = val;
+
+ new_val &= ~(pgprot_val(masks->clear_mask));
+ new_val |= (pgprot_val(masks->set_mask));
+
+ return new_val;
+}
+
+static int pageattr_p4d_entry(p4d_t *p4d, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
+{
+ p4d_t val = READ_ONCE(*p4d);
+
+ if (p4d_leaf(val)) {
+ val = __p4d(set_pageattr_masks(p4d_val(val), walk));
+ set_p4d(p4d, val);
+ }
+
+ return 0;
+}
+
+static int pageattr_pud_entry(pud_t *pud, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
+{
+ pud_t val = READ_ONCE(*pud);
+
+ if (pud_leaf(val)) {
+ val = __pud(set_pageattr_masks(pud_val(val), walk));
+ set_pud(pud, val);
+ }
+
+ return 0;
+}
+
+static int pageattr_pmd_entry(pmd_t *pmd, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
+{
+ pmd_t val = READ_ONCE(*pmd);
+
+ if (pmd_leaf(val)) {
+ val = __pmd(set_pageattr_masks(pmd_val(val), walk));
+ set_pmd(pmd, val);
+ }
+
+ return 0;
+}
+
+static int pageattr_pte_entry(pte_t *pte, unsigned long addr,
+ unsigned long next, struct mm_walk *walk)
+{
+ pte_t val = READ_ONCE(*pte);
+
+ val = __pte(set_pageattr_masks(pte_val(val), walk));
+ set_pte(pte, val);
+
+ return 0;
+}
+
+static int pageattr_pte_hole(unsigned long addr, unsigned long next,
+ int depth, struct mm_walk *walk)
+{
+ /* Nothing to do here */
+ return 0;
+}
+
+static const struct mm_walk_ops pageattr_ops = {
+ .p4d_entry = pageattr_p4d_entry,
+ .pud_entry = pageattr_pud_entry,
+ .pmd_entry = pageattr_pmd_entry,
+ .pte_entry = pageattr_pte_entry,
+ .pte_hole = pageattr_pte_hole,
+ .walk_lock = PGWALK_RDLOCK,
+};
+
+#ifdef CONFIG_64BIT
+static int __split_linear_mapping_pmd(pud_t *pudp,
+ unsigned long vaddr, unsigned long end)
+{
+ pmd_t *pmdp;
+ unsigned long next;
+
+ pmdp = pmd_offset(pudp, vaddr);
+
+ do {
+ next = pmd_addr_end(vaddr, end);
+
+ if (next - vaddr >= PMD_SIZE &&
+ vaddr <= (vaddr & PMD_MASK) && end >= next)
+ continue;
+
+ if (pmd_leaf(*pmdp)) {
+ struct page *pte_page;
+ unsigned long pfn = _pmd_pfn(*pmdp);
+ pgprot_t prot = __pgprot(pmd_val(*pmdp) & ~_PAGE_PFN_MASK);
+ pte_t *ptep_new;
+ int i;
+
+ pte_page = alloc_page(GFP_KERNEL);
+ if (!pte_page)
+ return -ENOMEM;
+
+ ptep_new = (pte_t *)page_address(pte_page);
+ for (i = 0; i < PTRS_PER_PTE; ++i, ++ptep_new)
+ set_pte(ptep_new, pfn_pte(pfn + i, prot));
+
+ smp_wmb();
+
+ set_pmd(pmdp, pfn_pmd(page_to_pfn(pte_page), PAGE_TABLE));
+ }
+ } while (pmdp++, vaddr = next, vaddr != end);
+
+ return 0;
+}
+
+static int __split_linear_mapping_pud(p4d_t *p4dp,
+ unsigned long vaddr, unsigned long end)
+{
+ pud_t *pudp;
+ unsigned long next;
+ int ret;
+
+ pudp = pud_offset(p4dp, vaddr);
+
+ do {
+ next = pud_addr_end(vaddr, end);
+
+ if (next - vaddr >= PUD_SIZE &&
+ vaddr <= (vaddr & PUD_MASK) && end >= next)
+ continue;
+
+ if (pud_leaf(*pudp)) {
+ struct page *pmd_page;
+ unsigned long pfn = _pud_pfn(*pudp);
+ pgprot_t prot = __pgprot(pud_val(*pudp) & ~_PAGE_PFN_MASK);
+ pmd_t *pmdp_new;
+ int i;
+
+ pmd_page = alloc_page(GFP_KERNEL);
+ if (!pmd_page)
+ return -ENOMEM;
+
+ pmdp_new = (pmd_t *)page_address(pmd_page);
+ for (i = 0; i < PTRS_PER_PMD; ++i, ++pmdp_new)
+ set_pmd(pmdp_new,
+ pfn_pmd(pfn + ((i * PMD_SIZE) >> PAGE_SHIFT), prot));
+
+ smp_wmb();
+
+ set_pud(pudp, pfn_pud(page_to_pfn(pmd_page), PAGE_TABLE));
+ }
+
+ ret = __split_linear_mapping_pmd(pudp, vaddr, next);
+ if (ret)
+ return ret;
+ } while (pudp++, vaddr = next, vaddr != end);
+
+ return 0;
+}
+
+static int __split_linear_mapping_p4d(pgd_t *pgdp,
+ unsigned long vaddr, unsigned long end)
+{
+ p4d_t *p4dp;
+ unsigned long next;
+ int ret;
+
+ p4dp = p4d_offset(pgdp, vaddr);
+
+ do {
+ next = p4d_addr_end(vaddr, end);
+
+ /*
+ * If [vaddr; end] contains [vaddr & P4D_MASK; next], we don't
+ * need to split, we'll change the protections on the whole P4D.
+ */
+ if (next - vaddr >= P4D_SIZE &&
+ vaddr <= (vaddr & P4D_MASK) && end >= next)
+ continue;
+
+ if (p4d_leaf(*p4dp)) {
+ struct page *pud_page;
+ unsigned long pfn = _p4d_pfn(*p4dp);
+ pgprot_t prot = __pgprot(p4d_val(*p4dp) & ~_PAGE_PFN_MASK);
+ pud_t *pudp_new;
+ int i;
+
+ pud_page = alloc_page(GFP_KERNEL);
+ if (!pud_page)
+ return -ENOMEM;
+
+ /*
+ * Fill the pud level with leaf puds that have the same
+ * protections as the leaf p4d.
+ */
+ pudp_new = (pud_t *)page_address(pud_page);
+ for (i = 0; i < PTRS_PER_PUD; ++i, ++pudp_new)
+ set_pud(pudp_new,
+ pfn_pud(pfn + ((i * PUD_SIZE) >> PAGE_SHIFT), prot));
+
+ /*
+ * Make sure the pud filling is not reordered with the
+ * p4d store which could result in seeing a partially
+ * filled pud level.
+ */
+ smp_wmb();
+
+ set_p4d(p4dp, pfn_p4d(page_to_pfn(pud_page), PAGE_TABLE));
+ }
+
+ ret = __split_linear_mapping_pud(p4dp, vaddr, next);
+ if (ret)
+ return ret;
+ } while (p4dp++, vaddr = next, vaddr != end);
+
+ return 0;
+}
+
+static int __split_linear_mapping_pgd(pgd_t *pgdp,
+ unsigned long vaddr,
+ unsigned long end)
+{
+ unsigned long next;
+ int ret;
+
+ do {
+ next = pgd_addr_end(vaddr, end);
+ /* We never use PGD mappings for the linear mapping */
+ ret = __split_linear_mapping_p4d(pgdp, vaddr, next);
+ if (ret)
+ return ret;
+ } while (pgdp++, vaddr = next, vaddr != end);
+
+ return 0;
+}
+
+static int split_linear_mapping(unsigned long start, unsigned long end)
+{
+ return __split_linear_mapping_pgd(pgd_offset_k(start), start, end);
+}
+#endif /* CONFIG_64BIT */
+
+static int __set_memory(unsigned long addr, int numpages, pgprot_t set_mask,
+ pgprot_t clear_mask)
+{
+ int ret;
+ unsigned long start = addr;
+ unsigned long end = start + PAGE_SIZE * numpages;
+ unsigned long __maybe_unused lm_start;
+ unsigned long __maybe_unused lm_end;
+ struct pageattr_masks masks = {
+ .set_mask = set_mask,
+ .clear_mask = clear_mask
+ };
+
+ if (!numpages)
+ return 0;
+
+ mmap_write_lock(&init_mm);
+
+#ifdef CONFIG_64BIT
+ /*
+ * We are about to change the permissions of a kernel mapping, we must
+ * apply the same changes to its linear mapping alias, which may imply
+ * splitting a huge mapping.
+ */
+
+ if (is_vmalloc_or_module_addr((void *)start)) {
+ struct vm_struct *area = NULL;
+ int i, page_start;
+
+ area = find_vm_area((void *)start);
+ page_start = (start - (unsigned long)area->addr) >> PAGE_SHIFT;
+
+ for (i = page_start; i < page_start + numpages; ++i) {
+ lm_start = (unsigned long)page_address(area->pages[i]);
+ lm_end = lm_start + PAGE_SIZE;
+
+ ret = split_linear_mapping(lm_start, lm_end);
+ if (ret)
+ goto unlock;
+
+ ret = walk_page_range_novma(&init_mm, lm_start, lm_end,
+ &pageattr_ops, NULL, &masks);
+ if (ret)
+ goto unlock;
+ }
+ } else if (is_kernel_mapping(start) || is_linear_mapping(start)) {
+ if (is_kernel_mapping(start)) {
+ lm_start = (unsigned long)lm_alias(start);
+ lm_end = (unsigned long)lm_alias(end);
+ } else {
+ lm_start = start;
+ lm_end = end;
+ }
+
+ ret = split_linear_mapping(lm_start, lm_end);
+ if (ret)
+ goto unlock;
+
+ ret = walk_page_range_novma(&init_mm, lm_start, lm_end,
+ &pageattr_ops, NULL, &masks);
+ if (ret)
+ goto unlock;
+ }
+
+ ret = walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL,
+ &masks);
+
+unlock:
+ mmap_write_unlock(&init_mm);
+
+ /*
+ * We can't use flush_tlb_kernel_range() here as we may have split a
+ * hugepage that is larger than that, so let's flush everything.
+ */
+ flush_tlb_all();
+#else
+ ret = walk_page_range_novma(&init_mm, start, end, &pageattr_ops, NULL,
+ &masks);
+
+ mmap_write_unlock(&init_mm);
+
+ flush_tlb_kernel_range(start, end);
+#endif
+
+ return ret;
+}
+
+int set_memory_rw_nx(unsigned long addr, int numpages)
+{
+ return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE),
+ __pgprot(_PAGE_EXEC));
+}
+
+int set_memory_ro(unsigned long addr, int numpages)
+{
+ return __set_memory(addr, numpages, __pgprot(_PAGE_READ),
+ __pgprot(_PAGE_WRITE));
+}
+
+int set_memory_rw(unsigned long addr, int numpages)
+{
+ return __set_memory(addr, numpages, __pgprot(_PAGE_READ | _PAGE_WRITE),
+ __pgprot(0));
+}
+
+int set_memory_x(unsigned long addr, int numpages)
+{
+ return __set_memory(addr, numpages, __pgprot(_PAGE_EXEC), __pgprot(0));
+}
+
+int set_memory_nx(unsigned long addr, int numpages)
+{
+ return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
+}
+
+int set_direct_map_invalid_noflush(struct page *page)
+{
+ return __set_memory((unsigned long)page_address(page), 1,
+ __pgprot(0), __pgprot(_PAGE_PRESENT));
+}
+
+int set_direct_map_default_noflush(struct page *page)
+{
+ return __set_memory((unsigned long)page_address(page), 1,
+ PAGE_KERNEL, __pgprot(_PAGE_EXEC));
+}
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+void __kernel_map_pages(struct page *page, int numpages, int enable)
+{
+ if (!debug_pagealloc_enabled())
+ return;
+
+ if (enable)
+ __set_memory((unsigned long)page_address(page), numpages,
+ __pgprot(_PAGE_PRESENT), __pgprot(0));
+ else
+ __set_memory((unsigned long)page_address(page), numpages,
+ __pgprot(0), __pgprot(_PAGE_PRESENT));
+}
+#endif
+
+bool kernel_page_present(struct page *page)
+{
+ unsigned long addr = (unsigned long)page_address(page);
+ pgd_t *pgd;
+ pud_t *pud;
+ p4d_t *p4d;
+ pmd_t *pmd;
+ pte_t *pte;
+
+ pgd = pgd_offset_k(addr);
+ if (!pgd_present(*pgd))
+ return false;
+ if (pgd_leaf(*pgd))
+ return true;
+
+ p4d = p4d_offset(pgd, addr);
+ if (!p4d_present(*p4d))
+ return false;
+ if (p4d_leaf(*p4d))
+ return true;
+
+ pud = pud_offset(p4d, addr);
+ if (!pud_present(*pud))
+ return false;
+ if (pud_leaf(*pud))
+ return true;
+
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd))
+ return false;
+ if (pmd_leaf(*pmd))
+ return true;
+
+ pte = pte_offset_kernel(pmd, addr);
+ return pte_present(*pte);
+}