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authorHelge Deller <deller@gmx.de>2015-11-22 00:07:06 +0100
committerHelge Deller <deller@gmx.de>2015-11-22 12:23:10 +0100
commit736d2169338a50c8814efc186b5423aee43b0c68 (patch)
tree69165c38eafe94a26675eae70e4f09bae4863fa4 /arch/parisc/mm/hugetlbpage.c
parentparisc: Use long branch to do_syscall_trace_exit (diff)
downloadlinux-dev-736d2169338a50c8814efc186b5423aee43b0c68.tar.xz
linux-dev-736d2169338a50c8814efc186b5423aee43b0c68.zip
parisc: Add Huge Page and HUGETLBFS support
This patch adds huge page support to allow userspace to allocate huge pages and to use hugetlbfs filesystem on 32- and 64-bit Linux kernels. A later patch will add kernel support to map kernel text and data on huge pages. The only requirement is, that the kernel needs to be compiled for a PA8X00 CPU (PA2.0 architecture). Older PA1.X CPUs do not support variable page sizes. 64bit Kernels are compiled for PA2.0 by default. Technically on parisc multiple physical huge pages may be needed to emulate standard 2MB huge pages. Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to '')
-rw-r--r--arch/parisc/mm/hugetlbpage.c161
1 files changed, 161 insertions, 0 deletions
diff --git a/arch/parisc/mm/hugetlbpage.c b/arch/parisc/mm/hugetlbpage.c
new file mode 100644
index 000000000000..f6fdc77a72bd
--- /dev/null
+++ b/arch/parisc/mm/hugetlbpage.c
@@ -0,0 +1,161 @@
+/*
+ * PARISC64 Huge TLB page support.
+ *
+ * This parisc implementation is heavily based on the SPARC and x86 code.
+ *
+ * Copyright (C) 2015 Helge Deller <deller@gmx.de>
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/pagemap.h>
+#include <linux/sysctl.h>
+
+#include <asm/mman.h>
+#include <asm/pgalloc.h>
+#include <asm/tlb.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+#include <asm/mmu_context.h>
+
+
+unsigned long
+hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
+ unsigned long len, unsigned long pgoff, unsigned long flags)
+{
+ struct hstate *h = hstate_file(file);
+
+ if (len & ~huge_page_mask(h))
+ return -EINVAL;
+ if (len > TASK_SIZE)
+ return -ENOMEM;
+
+ if (flags & MAP_FIXED)
+ if (prepare_hugepage_range(file, addr, len))
+ return -EINVAL;
+
+ if (addr)
+ addr = ALIGN(addr, huge_page_size(h));
+
+ /* we need to make sure the colouring is OK */
+ return arch_get_unmapped_area(file, addr, len, pgoff, flags);
+}
+
+
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+ unsigned long addr, unsigned long sz)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte = NULL;
+
+ /* We must align the address, because our caller will run
+ * set_huge_pte_at() on whatever we return, which writes out
+ * all of the sub-ptes for the hugepage range. So we have
+ * to give it the first such sub-pte.
+ */
+ addr &= HPAGE_MASK;
+
+ pgd = pgd_offset(mm, addr);
+ pud = pud_alloc(mm, pgd, addr);
+ if (pud) {
+ pmd = pmd_alloc(mm, pud, addr);
+ if (pmd)
+ pte = pte_alloc_map(mm, NULL, pmd, addr);
+ }
+ return pte;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
+{
+ pgd_t *pgd;
+ pud_t *pud;
+ pmd_t *pmd;
+ pte_t *pte = NULL;
+
+ addr &= HPAGE_MASK;
+
+ pgd = pgd_offset(mm, addr);
+ if (!pgd_none(*pgd)) {
+ pud = pud_offset(pgd, addr);
+ if (!pud_none(*pud)) {
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_none(*pmd))
+ pte = pte_offset_map(pmd, addr);
+ }
+ }
+ return pte;
+}
+
+/* Purge data and instruction TLB entries. Must be called holding
+ * the pa_tlb_lock. The TLB purge instructions are slow on SMP
+ * machines since the purge must be broadcast to all CPUs.
+ */
+static inline void purge_tlb_entries_huge(struct mm_struct *mm, unsigned long addr)
+{
+ int i;
+
+ /* We may use multiple physical huge pages (e.g. 2x1 MB) to emulate
+ * Linux standard huge pages (e.g. 2 MB) */
+ BUILD_BUG_ON(REAL_HPAGE_SHIFT > HPAGE_SHIFT);
+
+ addr &= HPAGE_MASK;
+ addr |= _HUGE_PAGE_SIZE_ENCODING_DEFAULT;
+
+ for (i = 0; i < (1 << (HPAGE_SHIFT-REAL_HPAGE_SHIFT)); i++) {
+ mtsp(mm->context, 1);
+ pdtlb(addr);
+ if (unlikely(split_tlb))
+ pitlb(addr);
+ addr += (1UL << REAL_HPAGE_SHIFT);
+ }
+}
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep, pte_t entry)
+{
+ unsigned long addr_start;
+ int i;
+
+ addr &= HPAGE_MASK;
+ addr_start = addr;
+
+ for (i = 0; i < (1 << HUGETLB_PAGE_ORDER); i++) {
+ /* Directly write pte entry. We could call set_pte_at(mm, addr, ptep, entry)
+ * instead, but then we get double locking on pa_tlb_lock. */
+ *ptep = entry;
+ ptep++;
+
+ /* Drop the PAGE_SIZE/non-huge tlb entry */
+ purge_tlb_entries(mm, addr);
+
+ addr += PAGE_SIZE;
+ pte_val(entry) += PAGE_SIZE;
+ }
+
+ purge_tlb_entries_huge(mm, addr_start);
+}
+
+
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
+ pte_t *ptep)
+{
+ pte_t entry;
+
+ entry = *ptep;
+ set_huge_pte_at(mm, addr, ptep, __pte(0));
+
+ return entry;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+ return 0;
+}
+
+int pud_huge(pud_t pud)
+{
+ return 0;
+}