arm64: Clean up the default pgprot setting

The primary aim of this patchset is to remove the pgprot_default and
prot_sect_default global variables and rely strictly on predefined
values. The original goal was to be able to run SMP kernels on UP
hardware by not setting the Shareability bit. However, it is unlikely to
see UP ARMv8 hardware and even if we do, the Shareability bit is no
longer assumed to disable cacheable accesses.

A side effect is that the device mappings now have the Shareability
attribute set. The hardware, however, should ignore it since Device
accesses are always Outer Shareable.

Following the removal of the two global variables, there is some PROT_*
macro reshuffling and cleanup, including the __PAGE_* macros (replaced
by PAGE_*).

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Will Deacon <will.deacon@arm.com>

5 files changed, 50 insertions, 95 deletions

diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index a1bef78f0303..e0ecdcf6632d 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -230,19 +230,11 @@ extern void __iomem *__ioremap(phys_addr_t phys_addr, size_t size, pgprot_t prot
 extern void __iounmap(volatile void __iomem *addr);
 extern void __iomem *ioremap_cache(phys_addr_t phys_addr, size_t size);
 
-#define PROT_DEFAULT            (PTE_TYPE_PAGE | PTE_AF | PTE_DIRTY)
-#define PROT_DEVICE_nGnRE       (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRE))
-#define PROT_NORMAL_NC          (PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL_NC))
-#define PROT_NORMAL             (PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
-
 #define ioremap(addr, size)             __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE))
 #define ioremap_nocache(addr, size)     __ioremap((addr), (size), __pgprot(PROT_DEVICE_nGnRE))
 #define ioremap_wc(addr, size)          __ioremap((addr), (size), __pgprot(PROT_NORMAL_NC))
 #define iounmap                         __iounmap
 
-#define PROT_SECT_DEFAULT       (PMD_TYPE_SECT | PMD_SECT_AF)
-#define PROT_SECT_DEVICE_nGnRE  (PROT_SECT_DEFAULT | PTE_PXN | PTE_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
-
 #define ARCH_HAS_IOREMAP_WC
 #include <asm-generic/iomap.h>
 
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index e50bb3cbd8f2..752348dbb4f3 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -52,67 +52,60 @@ extern void __pgd_error(const char *file, int line, unsigned long val);
 #endif
 #define pgd_ERROR(pgd)          __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
 
-/*
- * The pgprot_* and protection_map entries will be fixed up at runtime to
- * include the cachable and bufferable bits based on memory policy, as well as
- * any architecture dependent bits like global/ASID and SMP shared mapping
- * bits.
- */
-#define _PAGE_DEFAULT           PTE_TYPE_PAGE | PTE_AF
+#ifdef CONFIG_SMP
+#define PROT_DEFAULT            (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
+#define PROT_SECT_DEFAULT       (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
+#else
+#define PROT_DEFAULT            (PTE_TYPE_PAGE | PTE_AF)
+#define PROT_SECT_DEFAULT       (PMD_TYPE_SECT | PMD_SECT_AF)
+#endif
 
-extern pgprot_t pgprot_default;
+#define PROT_DEVICE_nGnRE       (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRE))
+#define PROT_NORMAL_NC          (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL_NC))
+#define PROT_NORMAL             (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL))
 
-#define __pgprot_modify(prot,mask,bits) \
-        __pgprot((pgprot_val(prot) & ~(mask)) | (bits))
+#define PROT_SECT_DEVICE_nGnRE  (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
+#define PROT_SECT_NORMAL        (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
+#define PROT_SECT_NORMAL_EXEC   (PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
 
-#define _MOD_PROT(p, b)         __pgprot_modify(p, 0, b)
+#define _PAGE_DEFAULT           (PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
 
-#define PAGE_NONE               __pgprot_modify(pgprot_default, PTE_TYPE_MASK, PTE_PROT_NONE | PTE_PXN | PTE_UXN)
-#define PAGE_SHARED             _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
-#define PAGE_SHARED_EXEC        _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN | PTE_WRITE)
-#define PAGE_COPY               _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
-#define PAGE_COPY_EXEC          _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN)
-#define PAGE_READONLY           _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
-#define PAGE_READONLY_EXEC      _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN)
-#define PAGE_KERNEL             _MOD_PROT(pgprot_default, PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE)
-#define PAGE_KERNEL_EXEC        _MOD_PROT(pgprot_default, PTE_UXN | PTE_DIRTY | PTE_WRITE)
+#define PAGE_KERNEL             __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE)
+#define PAGE_KERNEL_EXEC        __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE)
 
-#define PAGE_HYP                _MOD_PROT(pgprot_default, PTE_HYP)
+#define PAGE_HYP                __pgprot(_PAGE_DEFAULT | PTE_HYP)
 #define PAGE_HYP_DEVICE         __pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
 
-#define PAGE_S2                 __pgprot_modify(pgprot_default, PTE_S2_MEMATTR_MASK, PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
+#define PAGE_S2                 __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
 #define PAGE_S2_DEVICE          __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDWR | PTE_UXN)
 
-#define __PAGE_NONE             __pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE | PTE_PXN | PTE_UXN)
-#define __PAGE_SHARED           __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
-#define __PAGE_SHARED_EXEC      __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_WRITE)
-#define __PAGE_COPY             __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
-#define __PAGE_COPY_EXEC        __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
-#define __PAGE_READONLY         __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
-#define __PAGE_READONLY_EXEC    __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
-#define __PAGE_EXECONLY         __pgprot(_PAGE_DEFAULT | PTE_NG | PTE_PXN)
-
-#endif /* __ASSEMBLY__ */
-
-#define __P000  __PAGE_NONE
-#define __P001  __PAGE_READONLY
-#define __P010  __PAGE_COPY
-#define __P011  __PAGE_COPY
-#define __P100  __PAGE_EXECONLY
-#define __P101  __PAGE_READONLY_EXEC
-#define __P110  __PAGE_COPY_EXEC
-#define __P111  __PAGE_COPY_EXEC
-
-#define __S000  __PAGE_NONE
-#define __S001  __PAGE_READONLY
-#define __S010  __PAGE_SHARED
-#define __S011  __PAGE_SHARED
-#define __S100  __PAGE_EXECONLY
-#define __S101  __PAGE_READONLY_EXEC
-#define __S110  __PAGE_SHARED_EXEC
-#define __S111  __PAGE_SHARED_EXEC
+#define PAGE_NONE               __pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE | PTE_PXN | PTE_UXN)
+#define PAGE_SHARED             __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
+#define PAGE_SHARED_EXEC        __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_WRITE)
+#define PAGE_COPY               __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
+#define PAGE_COPY_EXEC          __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
+#define PAGE_READONLY           __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
+#define PAGE_READONLY_EXEC      __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
+#define PAGE_EXECONLY           __pgprot(_PAGE_DEFAULT | PTE_NG | PTE_PXN)
+
+#define __P000  PAGE_NONE
+#define __P001  PAGE_READONLY
+#define __P010  PAGE_COPY
+#define __P011  PAGE_COPY
+#define __P100  PAGE_EXECONLY
+#define __P101  PAGE_READONLY_EXEC
+#define __P110  PAGE_COPY_EXEC
+#define __P111  PAGE_COPY_EXEC
+
+#define __S000  PAGE_NONE
+#define __S001  PAGE_READONLY
+#define __S010  PAGE_SHARED
+#define __S011  PAGE_SHARED
+#define __S100  PAGE_EXECONLY
+#define __S101  PAGE_READONLY_EXEC
+#define __S110  PAGE_SHARED_EXEC
+#define __S111  PAGE_SHARED_EXEC
 
-#ifndef __ASSEMBLY__
 /*
  * ZERO_PAGE is a global shared page that is always zero: used
  * for zero-mapped memory areas etc..
@@ -274,6 +267,9 @@ static inline int has_transparent_hugepage(void)
         return 1;
 }
 
+#define __pgprot_modify(prot,mask,bits) \
+        __pgprot((pgprot_val(prot) & ~(mask)) | (bits))
+
 /*
  * Mark the prot value as uncacheable and unbufferable.
  */
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 5b9e046d580e..7450c5802c3f 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -376,7 +376,6 @@ void __init setup_arch(char **cmdline_p)
 
         *cmdline_p = boot_command_line;
 
-        init_mem_pgprot();
         early_ioremap_init();
 
         parse_early_param();
diff --git a/arch/arm64/mm/dma-mapping.c b/arch/arm64/mm/dma-mapping.c
index c851eb44dc50..4164c5ace9f8 100644
--- a/arch/arm64/mm/dma-mapping.c
+++ b/arch/arm64/mm/dma-mapping.c
@@ -115,7 +115,7 @@ static void *__dma_alloc_noncoherent(struct device *dev, size_t size,
         for (i = 0; i < (size >> PAGE_SHIFT); i++)
                 map[i] = page + i;
         coherent_ptr = vmap(map, size >> PAGE_SHIFT, VM_MAP,
-                            __get_dma_pgprot(attrs, pgprot_default, false));
+                            __get_dma_pgprot(attrs, __pgprot(PROT_NORMAL_NC), false));
         kfree(map);
         if (!coherent_ptr)
                 goto no_map;
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 0a472c41a67f..2c0e1dda8163 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -43,11 +43,6 @@
 struct page *empty_zero_page;
 EXPORT_SYMBOL(empty_zero_page);
 
-pgprot_t pgprot_default;
-EXPORT_SYMBOL(pgprot_default);
-
-static pmdval_t prot_sect_kernel;
-
 struct cachepolicy {
         const char      policy[16];
         u64             mair;
@@ -122,33 +117,6 @@ static int __init early_cachepolicy(char *p)
 }
 early_param("cachepolicy", early_cachepolicy);
 
-/*
- * Adjust the PMD section entries according to the CPU in use.
- */
-void __init init_mem_pgprot(void)
-{
-        pteval_t default_pgprot;
-        int i;
-
-        default_pgprot = PTE_ATTRINDX(MT_NORMAL);
-        prot_sect_kernel = PMD_TYPE_SECT | PMD_SECT_AF | PMD_ATTRINDX(MT_NORMAL);
-
-#ifdef CONFIG_SMP
-        /*
-         * Mark memory with the "shared" attribute for SMP systems
-         */
-        default_pgprot |= PTE_SHARED;
-        prot_sect_kernel |= PMD_SECT_S;
-#endif
-
-        for (i = 0; i < 16; i++) {
-                unsigned long v = pgprot_val(protection_map[i]);
-                protection_map[i] = __pgprot(v | default_pgprot);
-        }
-
-        pgprot_default = __pgprot(PTE_TYPE_PAGE | PTE_AF | default_pgprot);
-}
-
 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
                               unsigned long size, pgprot_t vma_prot)
 {
@@ -205,7 +173,7 @@ static void __init alloc_init_pmd(pud_t *pud, unsigned long addr,
                 /* try section mapping first */
                 if (((addr | next | phys) & ~SECTION_MASK) == 0) {
                         pmd_t old_pmd =*pmd;
-                        set_pmd(pmd, __pmd(phys | prot_sect_kernel));
+                        set_pmd(pmd, __pmd(phys | PROT_SECT_NORMAL_EXEC));
                         /*
                          * Check for previous table entries created during
                          * boot (__create_page_tables) and flush them.
@@ -417,7 +385,7 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
                         if (!p)
                                 return -ENOMEM;
 
-                        set_pmd(pmd, __pmd(__pa(p) | prot_sect_kernel));
+                        set_pmd(pmd, __pmd(__pa(p) | PROT_SECT_NORMAL));
                 } else
                         vmemmap_verify((pte_t *)pmd, node, addr, next);
         } while (addr = next, addr != end);