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authorDavid Gibson <david@gibson.dropbear.id.au>2005-12-09 14:20:52 +1100
committerPaul Mackerras <paulus@samba.org>2005-12-09 16:30:48 +1100
commitcbf52afdc0eb88492cf7808cc4b4f58a46f1b1ad (patch)
tree89910c9d9a054f0bf64670757a3715e19fcc62b2 /arch/powerpc
parentdabcafd3f363bacd6b89f537af27dc79128e4806 (diff)
[PATCH] powerpc: Add missing icache flushes for hugepages
On most powerpc CPUs, the dcache and icache are not coherent so between writing and executing a page, the caches must be flushed. Userspace programs assume pages given to them by the kernel are icache clean, so we must do this flush between the kernel clearing a page and it being mapped into userspace for execute. We were not doing this for hugepages, this patch corrects the situation. We use the same lazy mechanism as we use for normal pages, delaying the flush until userspace actually attempts to execute from the page in question. Tested on G5. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc')
-rw-r--r--arch/powerpc/mm/hash_utils_64.c2
-rw-r--r--arch/powerpc/mm/hugetlbpage.c35
2 files changed, 35 insertions, 2 deletions
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 706e8a63ced..a33583f3b0e 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -601,7 +601,7 @@ int hash_page(unsigned long ea, unsigned long access, unsigned long trap)
/* Handle hugepage regions */
if (unlikely(in_hugepage_area(mm->context, ea))) {
DBG_LOW(" -> huge page !\n");
- return hash_huge_page(mm, access, ea, vsid, local);
+ return hash_huge_page(mm, access, ea, vsid, local, trap);
}
/* Get PTE and page size from page tables */
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 8bce515dc32..97512b89e7b 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -639,8 +639,36 @@ unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
return -ENOMEM;
}
+/*
+ * Called by asm hashtable.S for doing lazy icache flush
+ */
+static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
+ pte_t pte, int trap)
+{
+ struct page *page;
+ int i;
+
+ if (!pfn_valid(pte_pfn(pte)))
+ return rflags;
+
+ page = pte_page(pte);
+
+ /* page is dirty */
+ if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
+ if (trap == 0x400) {
+ for (i = 0; i < (HPAGE_SIZE / PAGE_SIZE); i++)
+ __flush_dcache_icache(page_address(page+i));
+ set_bit(PG_arch_1, &page->flags);
+ } else {
+ rflags |= HPTE_R_N;
+ }
+ }
+ return rflags;
+}
+
int hash_huge_page(struct mm_struct *mm, unsigned long access,
- unsigned long ea, unsigned long vsid, int local)
+ unsigned long ea, unsigned long vsid, int local,
+ unsigned long trap)
{
pte_t *ptep;
unsigned long old_pte, new_pte;
@@ -691,6 +719,11 @@ int hash_huge_page(struct mm_struct *mm, unsigned long access,
rflags = 0x2 | (!(new_pte & _PAGE_RW));
/* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
+ if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
+ /* No CPU has hugepages but lacks no execute, so we
+ * don't need to worry about that case */
+ rflags = hash_huge_page_do_lazy_icache(rflags, __pte(old_pte),
+ trap);
/* Check if pte already has an hpte (case 2) */
if (unlikely(old_pte & _PAGE_HASHPTE)) {