arm64/mm: wire up CONFIG_ARCH_HAS_SET_DIRECT_MAP

Wire up the special helper functions to manipulate aliases of vmalloc
regions in the linear map.

Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 22f8e6b..61b4a2d 100644 (file)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -26,6 +26,7 @@ config ARM64
        select ARCH_HAS_MEMBARRIER_SYNC_CORE
        select ARCH_HAS_PTE_SPECIAL
        select ARCH_HAS_SETUP_DMA_OPS
+       select ARCH_HAS_SET_DIRECT_MAP
        select ARCH_HAS_SET_MEMORY
        select ARCH_HAS_STRICT_KERNEL_RWX
        select ARCH_HAS_STRICT_MODULE_RWX

diff --git a/arch/arm64/include/asm/cacheflush.h b/arch/arm64/include/asm/cacheflush.h
index 1984421..b9ee551 100644 (file)
--- a/arch/arm64/include/asm/cacheflush.h
+++ b/arch/arm64/include/asm/cacheflush.h
@@ -187,4 +187,7 @@ static inline void flush_cache_vunmap(unsigned long start, unsigned long end)
 
 int set_memory_valid(unsigned long addr, int numpages, int enable);
 
+int set_direct_map_invalid_noflush(struct page *page);
+int set_direct_map_default_noflush(struct page *page);
+
 #endif

diff --git a/arch/arm64/mm/pageattr.c b/arch/arm64/mm/pageattr.c
index 6cd645e..9c6b903 100644 (file)
--- a/arch/arm64/mm/pageattr.c
+++ b/arch/arm64/mm/pageattr.c
@@ -159,17 +159,48 @@ int set_memory_valid(unsigned long addr, int numpages, int enable)
                                        __pgprot(PTE_VALID));
 }
 
-#ifdef CONFIG_DEBUG_PAGEALLOC
+int set_direct_map_invalid_noflush(struct page *page)
+{
+       struct page_change_data data = {
+               .set_mask = __pgprot(0),
+               .clear_mask = __pgprot(PTE_VALID),
+       };
+
+       if (!rodata_full)
+               return 0;
+
+       return apply_to_page_range(&init_mm,
+                                  (unsigned long)page_address(page),
+                                  PAGE_SIZE, change_page_range, &data);
+}
+
+int set_direct_map_default_noflush(struct page *page)
+{
+       struct page_change_data data = {
+               .set_mask = __pgprot(PTE_VALID | PTE_WRITE),
+               .clear_mask = __pgprot(PTE_RDONLY),
+       };
+
+       if (!rodata_full)
+               return 0;
+
+       return apply_to_page_range(&init_mm,
+                                  (unsigned long)page_address(page),
+                                  PAGE_SIZE, change_page_range, &data);
+}
+
 void __kernel_map_pages(struct page *page, int numpages, int enable)
 {
+       if (!debug_pagealloc_enabled() && !rodata_full)
+               return;
+
        set_memory_valid((unsigned long)page_address(page), numpages, enable);
 }
-#ifdef CONFIG_HIBERNATION
+
 /*
- * When built with CONFIG_DEBUG_PAGEALLOC and CONFIG_HIBERNATION, this function
- * is used to determine if a linear map page has been marked as not-valid by
- * CONFIG_DEBUG_PAGEALLOC. Walk the page table and check the PTE_VALID bit.
- * This is based on kern_addr_valid(), which almost does what we need.
+ * This function is used to determine if a linear map page has been marked as
+ * not-valid. Walk the page table and check the PTE_VALID bit. This is based
+ * on kern_addr_valid(), which almost does what we need.
  *
  * Because this is only called on the kernel linear map,  p?d_sect() implies
  * p?d_present(). When debug_pagealloc is enabled, sections mappings are
@@ -183,6 +214,9 @@ bool kernel_page_present(struct page *page)
        pte_t *ptep;
        unsigned long addr = (unsigned long)page_address(page);
 
+       if (!debug_pagealloc_enabled() && !rodata_full)
+               return true;
+
        pgdp = pgd_offset_k(addr);
        if (pgd_none(READ_ONCE(*pgdp)))
                return false;
@@ -204,5 +238,3 @@ bool kernel_page_present(struct page *page)
        ptep = pte_offset_kernel(pmdp, addr);
        return pte_valid(READ_ONCE(*ptep));
 }
-#endif /* CONFIG_HIBERNATION */
-#endif /* CONFIG_DEBUG_PAGEALLOC */

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 7350a12..6bd7b51 100644 (file)
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2128,17 +2128,6 @@ static void vm_remove_mappings(struct vm_struct *area, int deallocate_pages)
        int flush_reset = area->flags & VM_FLUSH_RESET_PERMS;
        int i;
 
-       /*
-        * The below block can be removed when all architectures that have
-        * direct map permissions also have set_direct_map_() implementations.
-        * This is concerned with resetting the direct map any an vm alias with
-        * execute permissions, without leaving a RW+X window.
-        */
-       if (flush_reset && !IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
-               set_memory_nx(addr, area->nr_pages);
-               set_memory_rw(addr, area->nr_pages);
-       }
-
        remove_vm_area(area->addr);
 
        /* If this is not VM_FLUSH_RESET_PERMS memory, no need for the below. */