[v2 PATCH 1/2] powerpc32: adds handling of _PAGE_RO
From: Christophe Leroy
Date: Wed Dec 17 2014 - 04:15:25 EST
Some powerpc like the 8xx don't have a RW bit in PTE bits but a RO (Read Only) bit.
This patch implements the handling of a _PAGE_RO flag to be used in place of _PAGE_RW
Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
---
v2 is a complete rework compared to v1
arch/powerpc/include/asm/pgtable-ppc32.h | 11 ++++++-----
arch/powerpc/include/asm/pgtable.h | 10 +++++++---
arch/powerpc/include/asm/pte-common.h | 27 ++++++++++++++++++---------
arch/powerpc/mm/gup.c | 2 ++
arch/powerpc/mm/mem.c | 2 +-
arch/powerpc/mm/pgtable_32.c | 24 ++++++++++++++++++++----
6 files changed, 54 insertions(+), 22 deletions(-)
diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h
index 543bb8e..64ed9e1 100644
--- a/arch/powerpc/include/asm/pgtable-ppc32.h
+++ b/arch/powerpc/include/asm/pgtable-ppc32.h
@@ -125,7 +125,7 @@ extern int icache_44x_need_flush;
#ifndef __ASSEMBLY__
#define pte_clear(mm, addr, ptep) \
- do { pte_update(ptep, ~_PAGE_HASHPTE, 0); } while (0)
+ do { pte_update(ptep, ~_PAGE_HASHPTE, _PAGE_RO); } while (0)
#define pmd_none(pmd) (!pmd_val(pmd))
#define pmd_bad(pmd) (pmd_val(pmd) & _PMD_BAD)
@@ -268,14 +268,14 @@ static inline int __ptep_test_and_clear_young(unsigned int context, unsigned lon
static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
- return __pte(pte_update(ptep, ~_PAGE_HASHPTE, 0));
+ return __pte(pte_update(ptep, ~_PAGE_HASHPTE, _PAGE_RO));
}
#define __HAVE_ARCH_PTEP_SET_WRPROTECT
static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addr,
pte_t *ptep)
{
- pte_update(ptep, (_PAGE_RW | _PAGE_HWWRITE), 0);
+ pte_update(ptep, (_PAGE_RW | _PAGE_HWWRITE), _PAGE_RO);
}
static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
unsigned long addr, pte_t *ptep)
@@ -287,8 +287,9 @@ static inline void huge_ptep_set_wrprotect(struct mm_struct *mm,
static inline void __ptep_set_access_flags(pte_t *ptep, pte_t entry)
{
unsigned long bits = pte_val(entry) &
- (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_EXEC);
- pte_update(ptep, 0, bits);
+ (_PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_RW | _PAGE_RO |
+ _PAGE_EXEC);
+ pte_update(ptep, _PAGE_RO, bits);
}
#define __HAVE_ARCH_PTE_SAME
diff --git a/arch/powerpc/include/asm/pgtable.h b/arch/powerpc/include/asm/pgtable.h
index 316f9a5..88f65fd 100644
--- a/arch/powerpc/include/asm/pgtable.h
+++ b/arch/powerpc/include/asm/pgtable.h
@@ -30,12 +30,14 @@ struct mm_struct;
#include <asm/tlbflush.h>
/* Generic accessors to PTE bits */
-static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_RW; }
+static inline int pte_write(pte_t pte)
+{ return (pte_val(pte) & (_PAGE_RW | _PAGE_RO)) != _PAGE_RO; }
static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_DIRTY; }
static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; }
static inline int pte_file(pte_t pte) { return pte_val(pte) & _PAGE_FILE; }
static inline int pte_special(pte_t pte) { return pte_val(pte) & _PAGE_SPECIAL; }
-static inline int pte_none(pte_t pte) { return (pte_val(pte) & ~_PTE_NONE_MASK) == 0; }
+static inline int pte_none(pte_t pte)
+{ return (pte_val(pte) & ~_PTE_NONE_MASK) == _PAGE_RO; }
static inline pgprot_t pte_pgprot(pte_t pte) { return __pgprot(pte_val(pte) & PAGE_PROT_BITS); }
#ifdef CONFIG_NUMA_BALANCING
@@ -115,12 +117,14 @@ static inline unsigned long pte_pfn(pte_t pte) {
/* Generic modifiers for PTE bits */
static inline pte_t pte_wrprotect(pte_t pte) {
- pte_val(pte) &= ~(_PAGE_RW | _PAGE_HWWRITE); return pte; }
+ pte_val(pte) &= ~(_PAGE_RW | _PAGE_HWWRITE);
+ pte_val(pte) |= _PAGE_RO; return pte; }
static inline pte_t pte_mkclean(pte_t pte) {
pte_val(pte) &= ~(_PAGE_DIRTY | _PAGE_HWWRITE); return pte; }
static inline pte_t pte_mkold(pte_t pte) {
pte_val(pte) &= ~_PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkwrite(pte_t pte) {
+ pte_val(pte) &= ~_PAGE_RO;
pte_val(pte) |= _PAGE_RW; return pte; }
static inline pte_t pte_mkdirty(pte_t pte) {
pte_val(pte) |= _PAGE_DIRTY; return pte; }
diff --git a/arch/powerpc/include/asm/pte-common.h b/arch/powerpc/include/asm/pte-common.h
index e040c35..7ed79b8 100644
--- a/arch/powerpc/include/asm/pte-common.h
+++ b/arch/powerpc/include/asm/pte-common.h
@@ -34,6 +34,12 @@
#ifndef _PAGE_PSIZE
#define _PAGE_PSIZE 0
#endif
+/* _PAGE_RO and _PAGE_RW shall not be defined at the same time */
+#ifndef _PAGE_RO
+#define _PAGE_RO 0
+#else
+#define _PAGE_RW 0
+#endif
#ifndef _PMD_PRESENT_MASK
#define _PMD_PRESENT_MASK _PMD_PRESENT
#endif
@@ -42,10 +48,10 @@
#define PMD_PAGE_SIZE(pmd) bad_call_to_PMD_PAGE_SIZE()
#endif
#ifndef _PAGE_KERNEL_RO
-#define _PAGE_KERNEL_RO 0
+#define _PAGE_KERNEL_RO (_PAGE_RO)
#endif
#ifndef _PAGE_KERNEL_ROX
-#define _PAGE_KERNEL_ROX (_PAGE_EXEC)
+#define _PAGE_KERNEL_ROX (_PAGE_EXEC | _PAGE_RO)
#endif
#ifndef _PAGE_KERNEL_RW
#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW | _PAGE_HWWRITE)
@@ -95,7 +101,7 @@ extern unsigned long bad_call_to_PMD_PAGE_SIZE(void);
/* Mask of bits returned by pte_pgprot() */
#define PAGE_PROT_BITS (_PAGE_GUARDED | _PAGE_COHERENT | _PAGE_NO_CACHE | \
_PAGE_WRITETHRU | _PAGE_ENDIAN | _PAGE_4K_PFN | \
- _PAGE_USER | _PAGE_ACCESSED | \
+ _PAGE_USER | _PAGE_ACCESSED | _PAGE_RO | \
_PAGE_RW | _PAGE_HWWRITE | _PAGE_DIRTY | _PAGE_EXEC)
#ifdef CONFIG_NUMA_BALANCING
@@ -126,13 +132,16 @@ extern unsigned long bad_call_to_PMD_PAGE_SIZE(void);
*
* Note due to the way vm flags are laid out, the bits are XWR
*/
-#define PAGE_NONE __pgprot(_PAGE_BASE)
+#define PAGE_NONE __pgprot(_PAGE_BASE | _PAGE_RO)
#define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW)
-#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC)
-#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER)
-#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
-#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER)
-#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC)
+#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | \
+ _PAGE_EXEC)
+#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RO)
+#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RO | \
+ _PAGE_EXEC)
+#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RO)
+#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RO | \
+ _PAGE_EXEC)
#define __P000 PAGE_NONE
#define __P001 PAGE_READONLY
diff --git a/arch/powerpc/mm/gup.c b/arch/powerpc/mm/gup.c
index d874668..fa287fc 100644
--- a/arch/powerpc/mm/gup.c
+++ b/arch/powerpc/mm/gup.c
@@ -30,6 +30,8 @@ static noinline int gup_pte_range(pmd_t pmd, unsigned long addr,
result = _PAGE_PRESENT|_PAGE_USER;
if (write)
result |= _PAGE_RW;
+ else
+ result |= _PAGE_RO;
mask = result | _PAGE_SPECIAL;
ptep = pte_offset_kernel(&pmd, addr);
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 8ebaac7..3a74ee6 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -329,7 +329,7 @@ void __init paging_init(void)
unsigned long end = __fix_to_virt(FIX_HOLE);
for (; v < end; v += PAGE_SIZE)
- map_page(v, 0, 0); /* XXX gross */
+ map_page(v, 0, _PAGE_RO); /* XXX gross */
#endif
#ifdef CONFIG_HIGHMEM
diff --git a/arch/powerpc/mm/pgtable_32.c b/arch/powerpc/mm/pgtable_32.c
index a349089..e1e30bb 100644
--- a/arch/powerpc/mm/pgtable_32.c
+++ b/arch/powerpc/mm/pgtable_32.c
@@ -96,6 +96,18 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd)
#endif
}
+static inline void pte_alloc_clear(pte_t *pte)
+{
+#if _PAGE_RO == 0
+ clear_page(pte);
+#else
+ int i;
+
+ for (i = 0; i < PTRS_PER_PTE; i++)
+ pte[i] = __pte(_PAGE_RO);
+#endif
+}
+
__init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
{
pte_t *pte;
@@ -103,11 +115,12 @@ __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long add
extern void *early_get_page(void);
if (mem_init_done) {
- pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO);
+ pte = (pte_t *)__get_free_page(GFP_KERNEL|__GFP_REPEAT);
+ pte_alloc_clear(pte);
} else {
pte = (pte_t *)early_get_page();
if (pte)
- clear_page(pte);
+ pte_alloc_clear(pte);
}
return pte;
}
@@ -115,12 +128,15 @@ __init_refok pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long add
pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)
{
struct page *ptepage;
+ pte_t *pte;
- gfp_t flags = GFP_KERNEL | __GFP_REPEAT | __GFP_ZERO;
+ gfp_t flags = GFP_KERNEL | __GFP_REPEAT;
ptepage = alloc_pages(flags, 0);
if (!ptepage)
return NULL;
+ pte = (pte_t *)pfn_to_kaddr(page_to_pfn(ptepage));
+ pte_alloc_clear(pte);
if (!pgtable_page_ctor(ptepage)) {
__free_page(ptepage);
return NULL;
@@ -148,7 +164,7 @@ void __iomem *
ioremap_prot(phys_addr_t addr, unsigned long size, unsigned long flags)
{
/* writeable implies dirty for kernel addresses */
- if (flags & _PAGE_RW)
+ if ((flags & (_PAGE_RW | _PAGE_RO)) != _PAGE_RO)
flags |= _PAGE_DIRTY | _PAGE_HWWRITE;
/* we don't want to let _PAGE_USER and _PAGE_EXEC leak out */
--
2.1.0
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