1 files changed, 370 insertions, 0 deletions

diff --git a/arch/s390/mm/hugetlbpage.c b/arch/s390/mm/hugetlbpage.c
new file mode 100644
index 000000000..ff8234bca
--- /dev/null
+++ b/arch/s390/mm/hugetlbpage.c
@@ -0,0 +1,370 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  IBM System z Huge TLB Page Support for Kernel.
+ *
+ *    Copyright IBM Corp. 2007,2020
+ *    Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "hugetlb"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/mm.h>
+#include <linux/hugetlb.h>
+#include <linux/mman.h>
+#include <linux/sched/mm.h>
+#include <linux/security.h>
+
+/*
+ * If the bit selected by single-bit bitmask "a" is set within "x", move
+ * it to the position indicated by single-bit bitmask "b".
+ */
+#define move_set_bit(x, a, b)	(((x) & (a)) >> ilog2(a) << ilog2(b))
+
+static inline unsigned long __pte_to_rste(pte_t pte)
+{
+	unsigned long rste;
+
+	/*
+	 * Convert encoding		  pte bits	pmd / pud bits
+	 *				lIR.uswrdy.p	dy..R...I...wr
+	 * empty			010.000000.0 -> 00..0...1...00
+	 * prot-none, clean, old	111.000000.1 -> 00..1...1...00
+	 * prot-none, clean, young	111.000001.1 -> 01..1...1...00
+	 * prot-none, dirty, old	111.000010.1 -> 10..1...1...00
+	 * prot-none, dirty, young	111.000011.1 -> 11..1...1...00
+	 * read-only, clean, old	111.000100.1 -> 00..1...1...01
+	 * read-only, clean, young	101.000101.1 -> 01..1...0...01
+	 * read-only, dirty, old	111.000110.1 -> 10..1...1...01
+	 * read-only, dirty, young	101.000111.1 -> 11..1...0...01
+	 * read-write, clean, old	111.001100.1 -> 00..1...1...11
+	 * read-write, clean, young	101.001101.1 -> 01..1...0...11
+	 * read-write, dirty, old	110.001110.1 -> 10..0...1...11
+	 * read-write, dirty, young	100.001111.1 -> 11..0...0...11
+	 * HW-bits: R read-only, I invalid
+	 * SW-bits: p present, y young, d dirty, r read, w write, s special,
+	 *	    u unused, l large
+	 */
+	if (pte_present(pte)) {
+		rste = pte_val(pte) & PAGE_MASK;
+		rste |= move_set_bit(pte_val(pte), _PAGE_READ,
+				     _SEGMENT_ENTRY_READ);
+		rste |= move_set_bit(pte_val(pte), _PAGE_WRITE,
+				     _SEGMENT_ENTRY_WRITE);
+		rste |= move_set_bit(pte_val(pte), _PAGE_INVALID,
+				     _SEGMENT_ENTRY_INVALID);
+		rste |= move_set_bit(pte_val(pte), _PAGE_PROTECT,
+				     _SEGMENT_ENTRY_PROTECT);
+		rste |= move_set_bit(pte_val(pte), _PAGE_DIRTY,
+				     _SEGMENT_ENTRY_DIRTY);
+		rste |= move_set_bit(pte_val(pte), _PAGE_YOUNG,
+				     _SEGMENT_ENTRY_YOUNG);
+#ifdef CONFIG_MEM_SOFT_DIRTY
+		rste |= move_set_bit(pte_val(pte), _PAGE_SOFT_DIRTY,
+				     _SEGMENT_ENTRY_SOFT_DIRTY);
+#endif
+		rste |= move_set_bit(pte_val(pte), _PAGE_NOEXEC,
+				     _SEGMENT_ENTRY_NOEXEC);
+	} else
+		rste = _SEGMENT_ENTRY_EMPTY;
+	return rste;
+}
+
+static inline pte_t __rste_to_pte(unsigned long rste)
+{
+	int present;
+	pte_t pte;
+
+	if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
+		present = pud_present(__pud(rste));
+	else
+		present = pmd_present(__pmd(rste));
+
+	/*
+	 * Convert encoding		pmd / pud bits	    pte bits
+	 *				dy..R...I...wr	  lIR.uswrdy.p
+	 * empty			00..0...1...00 -> 010.000000.0
+	 * prot-none, clean, old	00..1...1...00 -> 111.000000.1
+	 * prot-none, clean, young	01..1...1...00 -> 111.000001.1
+	 * prot-none, dirty, old	10..1...1...00 -> 111.000010.1
+	 * prot-none, dirty, young	11..1...1...00 -> 111.000011.1
+	 * read-only, clean, old	00..1...1...01 -> 111.000100.1
+	 * read-only, clean, young	01..1...0...01 -> 101.000101.1
+	 * read-only, dirty, old	10..1...1...01 -> 111.000110.1
+	 * read-only, dirty, young	11..1...0...01 -> 101.000111.1
+	 * read-write, clean, old	00..1...1...11 -> 111.001100.1
+	 * read-write, clean, young	01..1...0...11 -> 101.001101.1
+	 * read-write, dirty, old	10..0...1...11 -> 110.001110.1
+	 * read-write, dirty, young	11..0...0...11 -> 100.001111.1
+	 * HW-bits: R read-only, I invalid
+	 * SW-bits: p present, y young, d dirty, r read, w write, s special,
+	 *	    u unused, l large
+	 */
+	if (present) {
+		pte_val(pte) = rste & _SEGMENT_ENTRY_ORIGIN_LARGE;
+		pte_val(pte) |= _PAGE_LARGE | _PAGE_PRESENT;
+		pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_READ,
+					     _PAGE_READ);
+		pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_WRITE,
+					     _PAGE_WRITE);
+		pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_INVALID,
+					     _PAGE_INVALID);
+		pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_PROTECT,
+					     _PAGE_PROTECT);
+		pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_DIRTY,
+					     _PAGE_DIRTY);
+		pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_YOUNG,
+					     _PAGE_YOUNG);
+#ifdef CONFIG_MEM_SOFT_DIRTY
+		pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_SOFT_DIRTY,
+					     _PAGE_SOFT_DIRTY);
+#endif
+		pte_val(pte) |= move_set_bit(rste, _SEGMENT_ENTRY_NOEXEC,
+					     _PAGE_NOEXEC);
+	} else
+		pte_val(pte) = _PAGE_INVALID;
+	return pte;
+}
+
+static void clear_huge_pte_skeys(struct mm_struct *mm, unsigned long rste)
+{
+	struct page *page;
+	unsigned long size, paddr;
+
+	if (!mm_uses_skeys(mm) ||
+	    rste & _SEGMENT_ENTRY_INVALID)
+		return;
+
+	if ((rste & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
+		page = pud_page(__pud(rste));
+		size = PUD_SIZE;
+		paddr = rste & PUD_MASK;
+	} else {
+		page = pmd_page(__pmd(rste));
+		size = PMD_SIZE;
+		paddr = rste & PMD_MASK;
+	}
+
+	if (!test_and_set_bit(PG_arch_1, &page->flags))
+		__storage_key_init_range(paddr, paddr + size - 1);
+}
+
+void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
+		     pte_t *ptep, pte_t pte)
+{
+	unsigned long rste;
+
+	rste = __pte_to_rste(pte);
+	if (!MACHINE_HAS_NX)
+		rste &= ~_SEGMENT_ENTRY_NOEXEC;
+
+	/* Set correct table type for 2G hugepages */
+	if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3) {
+		if (likely(pte_present(pte)))
+			rste |= _REGION3_ENTRY_LARGE;
+		rste |= _REGION_ENTRY_TYPE_R3;
+	} else if (likely(pte_present(pte)))
+		rste |= _SEGMENT_ENTRY_LARGE;
+
+	clear_huge_pte_skeys(mm, rste);
+	pte_val(*ptep) = rste;
+}
+
+pte_t huge_ptep_get(pte_t *ptep)
+{
+	return __rste_to_pte(pte_val(*ptep));
+}
+
+pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
+			      unsigned long addr, pte_t *ptep)
+{
+	pte_t pte = huge_ptep_get(ptep);
+	pmd_t *pmdp = (pmd_t *) ptep;
+	pud_t *pudp = (pud_t *) ptep;
+
+	if ((pte_val(*ptep) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
+		pudp_xchg_direct(mm, addr, pudp, __pud(_REGION3_ENTRY_EMPTY));
+	else
+		pmdp_xchg_direct(mm, addr, pmdp, __pmd(_SEGMENT_ENTRY_EMPTY));
+	return pte;
+}
+
+pte_t *huge_pte_alloc(struct mm_struct *mm,
+			unsigned long addr, unsigned long sz)
+{
+	pgd_t *pgdp;
+	p4d_t *p4dp;
+	pud_t *pudp;
+	pmd_t *pmdp = NULL;
+
+	pgdp = pgd_offset(mm, addr);
+	p4dp = p4d_alloc(mm, pgdp, addr);
+	if (p4dp) {
+		pudp = pud_alloc(mm, p4dp, addr);
+		if (pudp) {
+			if (sz == PUD_SIZE)
+				return (pte_t *) pudp;
+			else if (sz == PMD_SIZE)
+				pmdp = pmd_alloc(mm, pudp, addr);
+		}
+	}
+	return (pte_t *) pmdp;
+}
+
+pte_t *huge_pte_offset(struct mm_struct *mm,
+		       unsigned long addr, unsigned long sz)
+{
+	pgd_t *pgdp;
+	p4d_t *p4dp;
+	pud_t *pudp;
+	pmd_t *pmdp = NULL;
+
+	pgdp = pgd_offset(mm, addr);
+	if (pgd_present(*pgdp)) {
+		p4dp = p4d_offset(pgdp, addr);
+		if (p4d_present(*p4dp)) {
+			pudp = pud_offset(p4dp, addr);
+			if (pud_present(*pudp)) {
+				if (pud_large(*pudp))
+					return (pte_t *) pudp;
+				pmdp = pmd_offset(pudp, addr);
+			}
+		}
+	}
+	return (pte_t *) pmdp;
+}
+
+int pmd_huge(pmd_t pmd)
+{
+	return pmd_large(pmd);
+}
+
+int pud_huge(pud_t pud)
+{
+	return pud_large(pud);
+}
+
+struct page *
+follow_huge_pud(struct mm_struct *mm, unsigned long address,
+		pud_t *pud, int flags)
+{
+	if (flags & FOLL_GET)
+		return NULL;
+
+	return pud_page(*pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT);
+}
+
+static __init int setup_hugepagesz(char *opt)
+{
+	unsigned long size;
+	char *string = opt;
+
+	size = memparse(opt, &opt);
+	if (MACHINE_HAS_EDAT1 && size == PMD_SIZE) {
+		hugetlb_add_hstate(PMD_SHIFT - PAGE_SHIFT);
+	} else if (MACHINE_HAS_EDAT2 && size == PUD_SIZE) {
+		hugetlb_add_hstate(PUD_SHIFT - PAGE_SHIFT);
+	} else {
+		hugetlb_bad_size();
+		pr_err("hugepagesz= specifies an unsupported page size %s\n",
+			string);
+		return 0;
+	}
+	return 1;
+}
+__setup("hugepagesz=", setup_hugepagesz);
+
+static unsigned long hugetlb_get_unmapped_area_bottomup(struct file *file,
+		unsigned long addr, unsigned long len,
+		unsigned long pgoff, unsigned long flags)
+{
+	struct hstate *h = hstate_file(file);
+	struct vm_unmapped_area_info info;
+
+	info.flags = 0;
+	info.length = len;
+	info.low_limit = current->mm->mmap_base;
+	info.high_limit = TASK_SIZE;
+	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+	info.align_offset = 0;
+	return vm_unmapped_area(&info);
+}
+
+static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
+		unsigned long addr0, unsigned long len,
+		unsigned long pgoff, unsigned long flags)
+{
+	struct hstate *h = hstate_file(file);
+	struct vm_unmapped_area_info info;
+	unsigned long addr;
+
+	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+	info.length = len;
+	info.low_limit = max(PAGE_SIZE, mmap_min_addr);
+	info.high_limit = current->mm->mmap_base;
+	info.align_mask = PAGE_MASK & ~huge_page_mask(h);
+	info.align_offset = 0;
+	addr = vm_unmapped_area(&info);
+
+	/*
+	 * A failed mmap() very likely causes application failure,
+	 * so fall back to the bottom-up function here. This scenario
+	 * can happen with large stack limits and large mmap()
+	 * allocations.
+	 */
+	if (addr & ~PAGE_MASK) {
+		VM_BUG_ON(addr != -ENOMEM);
+		info.flags = 0;
+		info.low_limit = TASK_UNMAPPED_BASE;
+		info.high_limit = TASK_SIZE;
+		addr = vm_unmapped_area(&info);
+	}
+
+	return addr;
+}
+
+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);
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma;
+	int rc;
+
+	if (len & ~huge_page_mask(h))
+		return -EINVAL;
+	if (len > TASK_SIZE - mmap_min_addr)
+		return -ENOMEM;
+
+	if (flags & MAP_FIXED) {
+		if (prepare_hugepage_range(file, addr, len))
+			return -EINVAL;
+		goto check_asce_limit;
+	}
+
+	if (addr) {
+		addr = ALIGN(addr, huge_page_size(h));
+		vma = find_vma(mm, addr);
+		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&
+		    (!vma || addr + len <= vm_start_gap(vma)))
+			goto check_asce_limit;
+	}
+
+	if (mm->get_unmapped_area == arch_get_unmapped_area)
+		addr = hugetlb_get_unmapped_area_bottomup(file, addr, len,
+				pgoff, flags);
+	else
+		addr = hugetlb_get_unmapped_area_topdown(file, addr, len,
+				pgoff, flags);
+	if (addr & ~PAGE_MASK)
+		return addr;
+
+check_asce_limit:
+	if (addr + len > current->mm->context.asce_limit &&
+	    addr + len <= TASK_SIZE) {
+		rc = crst_table_upgrade(mm, addr + len);
+		if (rc)
+			return (unsigned long) rc;
+	}
+	return addr;
+}