@@ -518,6 +518,16 @@ static inline pte_t pte_mkuser(pte_t pte)
return __pte(pte_val(pte) | _PAGE_USER);
}
+static inline pte_t pte_mkpresent(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_PRESENT);
+}
+
+static inline pte_t pte_mkabsent(pte_t pte)
+{
+ return __pte(pte_val(pte) & ~_PAGE_PRESENT);
+}
+
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
@@ -724,6 +724,16 @@ static inline pte_t pte_mkuser(pte_t pte)
return __pte_raw(pte_raw(pte) & cpu_to_be64(~_PAGE_PRIVILEGED));
}
+static inline pte_t pte_mkpresent(pte_t pte)
+{
+ return __pte_raw(pte_raw(pte) | cpu_to_be64(_PAGE_PRESENT));
+}
+
+static inline pte_t pte_mkabsent(pte_t pte)
+{
+ return __pte_raw(pte_raw(pte) & cpu_to_be64(~_PAGE_PRESENT));
+}
+
/*
* This is potentially called with a pmd as the argument, in which case it's not
* safe to check _PAGE_DEVMAP unless we also confirm that _PAGE_PTE is set.
@@ -166,6 +166,16 @@ static inline pte_t pte_mkuser(pte_t pte)
}
#endif
+static inline pte_t pte_mkpresent(pte_t pte)
+{
+ return __pte(pte_val(pte) | _PAGE_PRESENT);
+}
+
+static inline pte_t pte_mkabsent(pte_t pte)
+{
+ return __pte(pte_val(pte) & ~_PAGE_PRESENT);
+}
+
static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot));
@@ -6,6 +6,8 @@
#define SET_MEMORY_RW 1
#define SET_MEMORY_NX 2
#define SET_MEMORY_X 3
+#define SET_MEMORY_NP 4
+#define SET_MEMORY_P 5
int change_memory_attr(unsigned long addr, int numpages, long action);
@@ -29,6 +31,14 @@ static inline int set_memory_x(unsigned long addr, int numpages)
return change_memory_attr(addr, numpages, SET_MEMORY_X);
}
-int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot);
+static inline int set_memory_np(unsigned long addr, int numpages)
+{
+ return change_memory_attr(addr, numpages, SET_MEMORY_NP);
+}
+
+static inline int set_memory_p(unsigned long addr, int numpages)
+{
+ return change_memory_attr(addr, numpages, SET_MEMORY_P);
+}
#endif
@@ -48,6 +48,12 @@ static int change_page_attr(pte_t *ptep, unsigned long addr, void *data)
case SET_MEMORY_X:
pte = pte_mkexec(pte);
break;
+ case SET_MEMORY_NP:
+ pte = pte_mkabsent(pte);
+ break;
+ case SET_MEMORY_P:
+ pte = pte_mkpresent(pte);
+ break;
default:
WARN_ON_ONCE(1);
break;
@@ -96,36 +102,3 @@ int change_memory_attr(unsigned long addr, int numpages, long action)
return apply_to_existing_page_range(&init_mm, start, size,
change_page_attr, (void *)action);
}
-
-/*
- * Set the attributes of a page:
- *
- * This function is used by PPC32 at the end of init to set final kernel memory
- * protection. It includes changing the maping of the page it is executing from
- * and data pages it is using.
- */
-static int set_page_attr(pte_t *ptep, unsigned long addr, void *data)
-{
- pgprot_t prot = __pgprot((unsigned long)data);
-
- spin_lock(&init_mm.page_table_lock);
-
- set_pte_at(&init_mm, addr, ptep, pte_modify(*ptep, prot));
- flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
-
- spin_unlock(&init_mm.page_table_lock);
-
- return 0;
-}
-
-int set_memory_attr(unsigned long addr, int numpages, pgprot_t prot)
-{
- unsigned long start = ALIGN_DOWN(addr, PAGE_SIZE);
- unsigned long sz = numpages * PAGE_SIZE;
-
- if (numpages <= 0)
- return 0;
-
- return apply_to_existing_page_range(&init_mm, start, sz, set_page_attr,
- (void *)pgprot_val(prot));
-}
@@ -135,10 +135,12 @@ void mark_initmem_nx(void)
unsigned long numpages = PFN_UP((unsigned long)_einittext) -
PFN_DOWN((unsigned long)_sinittext);
- if (v_block_mapped((unsigned long)_sinittext))
+ if (v_block_mapped((unsigned long)_sinittext)) {
mmu_mark_initmem_nx();
- else
- set_memory_attr((unsigned long)_sinittext, numpages, PAGE_KERNEL);
+ } else {
+ set_memory_nx((unsigned long)_sinittext, numpages);
+ set_memory_rw((unsigned long)_sinittext, numpages);
+ }
}
#ifdef CONFIG_STRICT_KERNEL_RWX
@@ -152,18 +154,14 @@ void mark_rodata_ro(void)
return;
}
- numpages = PFN_UP((unsigned long)_etext) -
- PFN_DOWN((unsigned long)_stext);
-
- set_memory_attr((unsigned long)_stext, numpages, PAGE_KERNEL_ROX);
/*
- * mark .rodata as read only. Use __init_begin rather than __end_rodata
- * to cover NOTES and EXCEPTION_TABLE.
+ * mark .text and .rodata as read only. Use __init_begin rather than
+ * __end_rodata to cover NOTES and EXCEPTION_TABLE.
*/
numpages = PFN_UP((unsigned long)__init_begin) -
- PFN_DOWN((unsigned long)__start_rodata);
+ PFN_DOWN((unsigned long)_stext);
- set_memory_attr((unsigned long)__start_rodata, numpages, PAGE_KERNEL_RO);
+ set_memory_ro((unsigned long)_stext, numpages);
// mark_initmem_nx() should have already run by now
ptdump_check_wx();
@@ -179,8 +177,8 @@ void __kernel_map_pages(struct page *page, int numpages, int enable)
return;
if (enable)
- set_memory_attr(addr, numpages, PAGE_KERNEL);
+ set_memory_p(addr, numpages);
else
- set_memory_attr(addr, numpages, __pgprot(0));
+ set_memory_np(addr, numpages);
}
#endif /* CONFIG_DEBUG_PAGEALLOC */
set_memory_attr() was implemented by commit 4d1755b6a762 ("powerpc/mm: implement set_memory_attr()") because the set_memory_xx() couldn't be used at that time to modify memory "on the fly" as explained it the commit. But set_memory_attr() uses set_pte_at() which leads to warnings when CONFIG_DEBUG_VM is selected, because set_pte_at() is unexpected for updating existing page table entries. The check could be bypassed by using __set_pte_at() instead, as it was the case before commit c988cfd38e48 ("powerpc/32: use set_memory_attr()") but since commit 9f7853d7609d ("powerpc/mm: Fix set_memory_*() against concurrent accesses") it is now possible to use set_memory_xx() functions to update page table entries "on the fly" because the update is now atomic. For DEBUG_PAGEALLOC we need to clear and set back _PAGE_PRESENT. Add set_memory_np() and set_memory_p() for that. Replace all uses of set_memory_attr() by the relevant set_memory_xx() and remove set_memory_attr(). Reported-by: Maxime Bizon <mbizon@freebox.fr> Fixes: c988cfd38e48 ("powerpc/32: use set_memory_attr()") Cc: stable@vger.kernel.org Depends-on: 9f7853d7609d ("powerpc/mm: Fix set_memory_*() against concurrent accesses") Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu> --- arch/powerpc/include/asm/book3s/32/pgtable.h | 10 +++++ arch/powerpc/include/asm/book3s/64/pgtable.h | 10 +++++ arch/powerpc/include/asm/nohash/pgtable.h | 10 +++++ arch/powerpc/include/asm/set_memory.h | 12 +++++- arch/powerpc/mm/pageattr.c | 39 +++----------------- arch/powerpc/mm/pgtable_32.c | 24 ++++++------ 6 files changed, 58 insertions(+), 47 deletions(-)