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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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d28513bc7f
Commit a0668cdc15
cleans up the handling
of kmem_caches for allocating various levels of pagetables.
Unfortunately, it conflicts badly with CONFIG_PPC_SUBPAGE_PROT, due to
the latter's cleverly hidden technique of adding some extra allocation
space to the top level page directory to store the extra information
it needs.
Since that extra allocation really doesn't fit into the cleaned up
page directory allocating scheme, this patch alters
CONFIG_PPC_SUBPAGE_PROT to instead allocate its struct
subpage_prot_table as part of the mm_context_t.
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
221 lines
5.3 KiB
C
221 lines
5.3 KiB
C
/*
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* Copyright 2007-2008 Paul Mackerras, IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/gfp.h>
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#include <linux/slab.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <asm/pgtable.h>
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#include <asm/uaccess.h>
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#include <asm/tlbflush.h>
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/*
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* Free all pages allocated for subpage protection maps and pointers.
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* Also makes sure that the subpage_prot_table structure is
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* reinitialized for the next user.
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*/
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void subpage_prot_free(struct mm_struct *mm)
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{
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struct subpage_prot_table *spt = &mm->context.spt;
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unsigned long i, j, addr;
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u32 **p;
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for (i = 0; i < 4; ++i) {
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if (spt->low_prot[i]) {
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free_page((unsigned long)spt->low_prot[i]);
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spt->low_prot[i] = NULL;
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}
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}
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addr = 0;
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for (i = 0; i < 2; ++i) {
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p = spt->protptrs[i];
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if (!p)
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continue;
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spt->protptrs[i] = NULL;
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for (j = 0; j < SBP_L2_COUNT && addr < spt->maxaddr;
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++j, addr += PAGE_SIZE)
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if (p[j])
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free_page((unsigned long)p[j]);
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free_page((unsigned long)p);
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}
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spt->maxaddr = 0;
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}
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void subpage_prot_init_new_context(struct mm_struct *mm)
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{
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struct subpage_prot_table *spt = &mm->context.spt;
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memset(spt, 0, sizeof(*spt));
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}
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static void hpte_flush_range(struct mm_struct *mm, unsigned long addr,
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int npages)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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spinlock_t *ptl;
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pgd = pgd_offset(mm, addr);
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if (pgd_none(*pgd))
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return;
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pud = pud_offset(pgd, addr);
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if (pud_none(*pud))
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return;
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pmd = pmd_offset(pud, addr);
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if (pmd_none(*pmd))
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return;
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pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
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arch_enter_lazy_mmu_mode();
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for (; npages > 0; --npages) {
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pte_update(mm, addr, pte, 0, 0);
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addr += PAGE_SIZE;
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++pte;
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}
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arch_leave_lazy_mmu_mode();
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pte_unmap_unlock(pte - 1, ptl);
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}
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/*
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* Clear the subpage protection map for an address range, allowing
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* all accesses that are allowed by the pte permissions.
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*/
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static void subpage_prot_clear(unsigned long addr, unsigned long len)
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{
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struct mm_struct *mm = current->mm;
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struct subpage_prot_table *spt = &mm->context.spt;
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u32 **spm, *spp;
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int i, nw;
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unsigned long next, limit;
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down_write(&mm->mmap_sem);
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limit = addr + len;
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if (limit > spt->maxaddr)
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limit = spt->maxaddr;
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for (; addr < limit; addr = next) {
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next = pmd_addr_end(addr, limit);
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if (addr < 0x100000000) {
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spm = spt->low_prot;
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} else {
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spm = spt->protptrs[addr >> SBP_L3_SHIFT];
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if (!spm)
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continue;
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}
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spp = spm[(addr >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1)];
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if (!spp)
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continue;
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spp += (addr >> PAGE_SHIFT) & (SBP_L1_COUNT - 1);
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i = (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
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nw = PTRS_PER_PTE - i;
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if (addr + (nw << PAGE_SHIFT) > next)
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nw = (next - addr) >> PAGE_SHIFT;
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memset(spp, 0, nw * sizeof(u32));
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/* now flush any existing HPTEs for the range */
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hpte_flush_range(mm, addr, nw);
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}
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up_write(&mm->mmap_sem);
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}
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/*
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* Copy in a subpage protection map for an address range.
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* The map has 2 bits per 4k subpage, so 32 bits per 64k page.
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* Each 2-bit field is 0 to allow any access, 1 to prevent writes,
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* 2 or 3 to prevent all accesses.
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* Note that the normal page protections also apply; the subpage
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* protection mechanism is an additional constraint, so putting 0
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* in a 2-bit field won't allow writes to a page that is otherwise
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* write-protected.
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*/
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long sys_subpage_prot(unsigned long addr, unsigned long len, u32 __user *map)
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{
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struct mm_struct *mm = current->mm;
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struct subpage_prot_table *spt = &mm->context.spt;
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u32 **spm, *spp;
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int i, nw;
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unsigned long next, limit;
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int err;
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/* Check parameters */
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if ((addr & ~PAGE_MASK) || (len & ~PAGE_MASK) ||
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addr >= TASK_SIZE || len >= TASK_SIZE || addr + len > TASK_SIZE)
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return -EINVAL;
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if (is_hugepage_only_range(mm, addr, len))
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return -EINVAL;
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if (!map) {
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/* Clear out the protection map for the address range */
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subpage_prot_clear(addr, len);
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return 0;
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}
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if (!access_ok(VERIFY_READ, map, (len >> PAGE_SHIFT) * sizeof(u32)))
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return -EFAULT;
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down_write(&mm->mmap_sem);
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for (limit = addr + len; addr < limit; addr = next) {
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next = pmd_addr_end(addr, limit);
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err = -ENOMEM;
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if (addr < 0x100000000) {
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spm = spt->low_prot;
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} else {
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spm = spt->protptrs[addr >> SBP_L3_SHIFT];
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if (!spm) {
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spm = (u32 **)get_zeroed_page(GFP_KERNEL);
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if (!spm)
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goto out;
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spt->protptrs[addr >> SBP_L3_SHIFT] = spm;
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}
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}
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spm += (addr >> SBP_L2_SHIFT) & (SBP_L2_COUNT - 1);
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spp = *spm;
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if (!spp) {
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spp = (u32 *)get_zeroed_page(GFP_KERNEL);
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if (!spp)
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goto out;
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*spm = spp;
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}
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spp += (addr >> PAGE_SHIFT) & (SBP_L1_COUNT - 1);
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local_irq_disable();
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demote_segment_4k(mm, addr);
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local_irq_enable();
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i = (addr >> PAGE_SHIFT) & (PTRS_PER_PTE - 1);
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nw = PTRS_PER_PTE - i;
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if (addr + (nw << PAGE_SHIFT) > next)
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nw = (next - addr) >> PAGE_SHIFT;
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up_write(&mm->mmap_sem);
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err = -EFAULT;
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if (__copy_from_user(spp, map, nw * sizeof(u32)))
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goto out2;
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map += nw;
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down_write(&mm->mmap_sem);
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/* now flush any existing HPTEs for the range */
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hpte_flush_range(mm, addr, nw);
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}
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if (limit > spt->maxaddr)
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spt->maxaddr = limit;
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err = 0;
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out:
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up_write(&mm->mmap_sem);
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out2:
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return err;
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}
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