diff options
Diffstat (limited to 'arch/s390/mm')
| -rw-r--r-- | arch/s390/mm/Makefile | 2 | ||||
| -rw-r--r-- | arch/s390/mm/dump_pagetables.c | 46 | ||||
| -rw-r--r-- | arch/s390/mm/extmem.c | 18 | ||||
| -rw-r--r-- | arch/s390/mm/fault.c | 1 | ||||
| -rw-r--r-- | arch/s390/mm/gmap.c | 185 | ||||
| -rw-r--r-- | arch/s390/mm/gmap_helpers.c | 221 | ||||
| -rw-r--r-- | arch/s390/mm/init.c | 1 | ||||
| -rw-r--r-- | arch/s390/mm/pgalloc.c | 21 | ||||
| -rw-r--r-- | arch/s390/mm/pgtable.c | 1 |
9 files changed, 297 insertions, 199 deletions
diff --git a/arch/s390/mm/Makefile b/arch/s390/mm/Makefile index 9726b91fe7e4..bd0401cc7ca5 100644 --- a/arch/s390/mm/Makefile +++ b/arch/s390/mm/Makefile @@ -12,3 +12,5 @@ obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o obj-$(CONFIG_PTDUMP) += dump_pagetables.o obj-$(CONFIG_PGSTE) += gmap.o obj-$(CONFIG_PFAULT) += pfault.o + +obj-$(subst m,y,$(CONFIG_KVM)) += gmap_helpers.o diff --git a/arch/s390/mm/dump_pagetables.c b/arch/s390/mm/dump_pagetables.c index d3e943752fa0..ac604b176660 100644 --- a/arch/s390/mm/dump_pagetables.c +++ b/arch/s390/mm/dump_pagetables.c @@ -147,11 +147,48 @@ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, } } +static void note_page_pte(struct ptdump_state *pt_st, unsigned long addr, pte_t pte) +{ + note_page(pt_st, addr, 4, pte_val(pte)); +} + +static void note_page_pmd(struct ptdump_state *pt_st, unsigned long addr, pmd_t pmd) +{ + note_page(pt_st, addr, 3, pmd_val(pmd)); +} + +static void note_page_pud(struct ptdump_state *pt_st, unsigned long addr, pud_t pud) +{ + note_page(pt_st, addr, 2, pud_val(pud)); +} + +static void note_page_p4d(struct ptdump_state *pt_st, unsigned long addr, p4d_t p4d) +{ + note_page(pt_st, addr, 1, p4d_val(p4d)); +} + +static void note_page_pgd(struct ptdump_state *pt_st, unsigned long addr, pgd_t pgd) +{ + note_page(pt_st, addr, 0, pgd_val(pgd)); +} + +static void note_page_flush(struct ptdump_state *pt_st) +{ + pte_t pte_zero = {0}; + + note_page(pt_st, 0, -1, pte_val(pte_zero)); +} + bool ptdump_check_wx(void) { struct pg_state st = { .ptdump = { - .note_page = note_page, + .note_page_pte = note_page_pte, + .note_page_pmd = note_page_pmd, + .note_page_pud = note_page_pud, + .note_page_p4d = note_page_p4d, + .note_page_pgd = note_page_pgd, + .note_page_flush = note_page_flush, .range = (struct ptdump_range[]) { {.start = 0, .end = max_addr}, {.start = 0, .end = 0}, @@ -190,7 +227,12 @@ static int ptdump_show(struct seq_file *m, void *v) { struct pg_state st = { .ptdump = { - .note_page = note_page, + .note_page_pte = note_page_pte, + .note_page_pmd = note_page_pmd, + .note_page_pud = note_page_pud, + .note_page_p4d = note_page_p4d, + .note_page_pgd = note_page_pgd, + .note_page_flush = note_page_flush, .range = (struct ptdump_range[]) { {.start = 0, .end = max_addr}, {.start = 0, .end = 0}, diff --git a/arch/s390/mm/extmem.c b/arch/s390/mm/extmem.c index a6b8b8ea9086..f7da53e212f5 100644 --- a/arch/s390/mm/extmem.c +++ b/arch/s390/mm/extmem.c @@ -530,6 +530,14 @@ segment_modify_shared (char *name, int do_nonshared) return rc; } +static void __dcss_diag_purge_on_cpu_0(void *data) +{ + struct dcss_segment *seg = (struct dcss_segment *)data; + unsigned long dummy; + + dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy); +} + /* * Decrease the use count of a DCSS segment and remove * it from the address space if nobody is using it @@ -538,7 +546,6 @@ segment_modify_shared (char *name, int do_nonshared) void segment_unload(char *name) { - unsigned long dummy; struct dcss_segment *seg; if (!machine_is_vm()) @@ -556,7 +563,14 @@ segment_unload(char *name) kfree(seg->res); vmem_remove_mapping(seg->start_addr, seg->end - seg->start_addr + 1); list_del(&seg->list); - dcss_diag(&purgeseg_scode, seg->dcss_name, &dummy, &dummy); + /* + * Workaround for z/VM issue, where calling the DCSS unload diag on + * a non-IPL CPU would cause bogus sclp maximum memory detection on + * next IPL. + * IPL CPU 0 cannot be set offline, so the dcss_diag() call can + * directly be scheduled to that CPU. + */ + smp_call_function_single(0, __dcss_diag_purge_on_cpu_0, seg, 1); kfree(seg); out_unlock: mutex_unlock(&dcss_lock); diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index da84ff6770de..3829521450dd 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -40,7 +40,6 @@ #include <asm/ptrace.h> #include <asm/fault.h> #include <asm/diag.h> -#include <asm/gmap.h> #include <asm/irq.h> #include <asm/facility.h> #include <asm/uv.h> diff --git a/arch/s390/mm/gmap.c b/arch/s390/mm/gmap.c index a94bd4870c65..012a4366a2ad 100644 --- a/arch/s390/mm/gmap.c +++ b/arch/s390/mm/gmap.c @@ -22,9 +22,9 @@ #include <asm/page-states.h> #include <asm/pgalloc.h> #include <asm/machine.h> +#include <asm/gmap_helpers.h> #include <asm/gmap.h> #include <asm/page.h> -#include <asm/tlb.h> /* * The address is saved in a radix tree directly; NULL would be ambiguous, @@ -620,63 +620,20 @@ EXPORT_SYMBOL(__gmap_link); */ void __gmap_zap(struct gmap *gmap, unsigned long gaddr) { - struct vm_area_struct *vma; unsigned long vmaddr; - spinlock_t *ptl; - pte_t *ptep; + + mmap_assert_locked(gmap->mm); /* Find the vm address for the guest address */ vmaddr = (unsigned long) radix_tree_lookup(&gmap->guest_to_host, gaddr >> PMD_SHIFT); if (vmaddr) { vmaddr |= gaddr & ~PMD_MASK; - - vma = vma_lookup(gmap->mm, vmaddr); - if (!vma || is_vm_hugetlb_page(vma)) - return; - - /* Get pointer to the page table entry */ - ptep = get_locked_pte(gmap->mm, vmaddr, &ptl); - if (likely(ptep)) { - ptep_zap_unused(gmap->mm, vmaddr, ptep, 0); - pte_unmap_unlock(ptep, ptl); - } + gmap_helper_zap_one_page(gmap->mm, vmaddr); } } EXPORT_SYMBOL_GPL(__gmap_zap); -void gmap_discard(struct gmap *gmap, unsigned long from, unsigned long to) -{ - unsigned long gaddr, vmaddr, size; - struct vm_area_struct *vma; - - mmap_read_lock(gmap->mm); - for (gaddr = from; gaddr < to; - gaddr = (gaddr + PMD_SIZE) & PMD_MASK) { - /* Find the vm address for the guest address */ - vmaddr = (unsigned long) - radix_tree_lookup(&gmap->guest_to_host, - gaddr >> PMD_SHIFT); - if (!vmaddr) - continue; - vmaddr |= gaddr & ~PMD_MASK; - /* Find vma in the parent mm */ - vma = find_vma(gmap->mm, vmaddr); - if (!vma) - continue; - /* - * We do not discard pages that are backed by - * hugetlbfs, so we don't have to refault them. - */ - if (is_vm_hugetlb_page(vma)) - continue; - size = min(to - gaddr, PMD_SIZE - (gaddr & ~PMD_MASK)); - zap_page_range_single(vma, vmaddr, size, NULL); - } - mmap_read_unlock(gmap->mm); -} -EXPORT_SYMBOL_GPL(gmap_discard); - static LIST_HEAD(gmap_notifier_list); static DEFINE_SPINLOCK(gmap_notifier_lock); @@ -2269,138 +2226,6 @@ int s390_enable_sie(void) } EXPORT_SYMBOL_GPL(s390_enable_sie); -static int find_zeropage_pte_entry(pte_t *pte, unsigned long addr, - unsigned long end, struct mm_walk *walk) -{ - unsigned long *found_addr = walk->private; - - /* Return 1 of the page is a zeropage. */ - if (is_zero_pfn(pte_pfn(*pte))) { - /* - * Shared zeropage in e.g., a FS DAX mapping? We cannot do the - * right thing and likely don't care: FAULT_FLAG_UNSHARE - * currently only works in COW mappings, which is also where - * mm_forbids_zeropage() is checked. - */ - if (!is_cow_mapping(walk->vma->vm_flags)) - return -EFAULT; - - *found_addr = addr; - return 1; - } - return 0; -} - -static const struct mm_walk_ops find_zeropage_ops = { - .pte_entry = find_zeropage_pte_entry, - .walk_lock = PGWALK_WRLOCK, -}; - -/* - * Unshare all shared zeropages, replacing them by anonymous pages. Note that - * we cannot simply zap all shared zeropages, because this could later - * trigger unexpected userfaultfd missing events. - * - * This must be called after mm->context.allow_cow_sharing was - * set to 0, to avoid future mappings of shared zeropages. - * - * mm contracts with s390, that even if mm were to remove a page table, - * and racing with walk_page_range_vma() calling pte_offset_map_lock() - * would fail, it will never insert a page table containing empty zero - * pages once mm_forbids_zeropage(mm) i.e. - * mm->context.allow_cow_sharing is set to 0. - */ -static int __s390_unshare_zeropages(struct mm_struct *mm) -{ - struct vm_area_struct *vma; - VMA_ITERATOR(vmi, mm, 0); - unsigned long addr; - vm_fault_t fault; - int rc; - - for_each_vma(vmi, vma) { - /* - * We could only look at COW mappings, but it's more future - * proof to catch unexpected zeropages in other mappings and - * fail. - */ - if ((vma->vm_flags & VM_PFNMAP) || is_vm_hugetlb_page(vma)) - continue; - addr = vma->vm_start; - -retry: - rc = walk_page_range_vma(vma, addr, vma->vm_end, - &find_zeropage_ops, &addr); - if (rc < 0) - return rc; - else if (!rc) - continue; - - /* addr was updated by find_zeropage_pte_entry() */ - fault = handle_mm_fault(vma, addr, - FAULT_FLAG_UNSHARE | FAULT_FLAG_REMOTE, - NULL); - if (fault & VM_FAULT_OOM) - return -ENOMEM; - /* - * See break_ksm(): even after handle_mm_fault() returned 0, we - * must start the lookup from the current address, because - * handle_mm_fault() may back out if there's any difficulty. - * - * VM_FAULT_SIGBUS and VM_FAULT_SIGSEGV are unexpected but - * maybe they could trigger in the future on concurrent - * truncation. In that case, the shared zeropage would be gone - * and we can simply retry and make progress. - */ - cond_resched(); - goto retry; - } - - return 0; -} - -static int __s390_disable_cow_sharing(struct mm_struct *mm) -{ - int rc; - - if (!mm->context.allow_cow_sharing) - return 0; - - mm->context.allow_cow_sharing = 0; - - /* Replace all shared zeropages by anonymous pages. */ - rc = __s390_unshare_zeropages(mm); - /* - * Make sure to disable KSM (if enabled for the whole process or - * individual VMAs). Note that nothing currently hinders user space - * from re-enabling it. - */ - if (!rc) - rc = ksm_disable(mm); - if (rc) - mm->context.allow_cow_sharing = 1; - return rc; -} - -/* - * Disable most COW-sharing of memory pages for the whole process: - * (1) Disable KSM and unmerge/unshare any KSM pages. - * (2) Disallow shared zeropages and unshare any zerpages that are mapped. - * - * Not that we currently don't bother with COW-shared pages that are shared - * with parent/child processes due to fork(). - */ -int s390_disable_cow_sharing(void) -{ - int rc; - - mmap_write_lock(current->mm); - rc = __s390_disable_cow_sharing(current->mm); - mmap_write_unlock(current->mm); - return rc; -} -EXPORT_SYMBOL_GPL(s390_disable_cow_sharing); - /* * Enable storage key handling from now on and initialize the storage * keys with the default key. @@ -2468,7 +2293,7 @@ int s390_enable_skey(void) goto out_up; mm->context.uses_skeys = 1; - rc = __s390_disable_cow_sharing(mm); + rc = gmap_helper_disable_cow_sharing(); if (rc) { mm->context.uses_skeys = 0; goto out_up; diff --git a/arch/s390/mm/gmap_helpers.c b/arch/s390/mm/gmap_helpers.c new file mode 100644 index 000000000000..a45d417ad951 --- /dev/null +++ b/arch/s390/mm/gmap_helpers.c @@ -0,0 +1,221 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Helper functions for KVM guest address space mapping code + * + * Copyright IBM Corp. 2007, 2025 + */ +#include <linux/mm_types.h> +#include <linux/mmap_lock.h> +#include <linux/mm.h> +#include <linux/hugetlb.h> +#include <linux/swap.h> +#include <linux/swapops.h> +#include <linux/pagewalk.h> +#include <linux/ksm.h> +#include <asm/gmap_helpers.h> + +/** + * ptep_zap_swap_entry() - discard a swap entry. + * @mm: the mm + * @entry: the swap entry that needs to be zapped + * + * Discards the given swap entry. If the swap entry was an actual swap + * entry (and not a migration entry, for example), the actual swapped + * page is also discarded from swap. + */ +static void ptep_zap_swap_entry(struct mm_struct *mm, swp_entry_t entry) +{ + if (!non_swap_entry(entry)) + dec_mm_counter(mm, MM_SWAPENTS); + else if (is_migration_entry(entry)) + dec_mm_counter(mm, mm_counter(pfn_swap_entry_folio(entry))); + free_swap_and_cache(entry); +} + +/** + * gmap_helper_zap_one_page() - discard a page if it was swapped. + * @mm: the mm + * @vmaddr: the userspace virtual address that needs to be discarded + * + * If the given address maps to a swap entry, discard it. + * + * Context: needs to be called while holding the mmap lock. + */ +void gmap_helper_zap_one_page(struct mm_struct *mm, unsigned long vmaddr) +{ + struct vm_area_struct *vma; + spinlock_t *ptl; + pte_t *ptep; + + mmap_assert_locked(mm); + + /* Find the vm address for the guest address */ + vma = vma_lookup(mm, vmaddr); + if (!vma || is_vm_hugetlb_page(vma)) + return; + + /* Get pointer to the page table entry */ + ptep = get_locked_pte(mm, vmaddr, &ptl); + if (unlikely(!ptep)) + return; + if (pte_swap(*ptep)) + ptep_zap_swap_entry(mm, pte_to_swp_entry(*ptep)); + pte_unmap_unlock(ptep, ptl); +} +EXPORT_SYMBOL_GPL(gmap_helper_zap_one_page); + +/** + * gmap_helper_discard() - discard user pages in the given range + * @mm: the mm + * @vmaddr: starting userspace address + * @end: end address (first address outside the range) + * + * All userpace pages in the range [@vamddr, @end) are discarded and unmapped. + * + * Context: needs to be called while holding the mmap lock. + */ +void gmap_helper_discard(struct mm_struct *mm, unsigned long vmaddr, unsigned long end) +{ + struct vm_area_struct *vma; + + mmap_assert_locked(mm); + + while (vmaddr < end) { + vma = find_vma_intersection(mm, vmaddr, end); + if (!vma) + return; + if (!is_vm_hugetlb_page(vma)) + zap_page_range_single(vma, vmaddr, min(end, vma->vm_end) - vmaddr, NULL); + vmaddr = vma->vm_end; + } +} +EXPORT_SYMBOL_GPL(gmap_helper_discard); + +static int find_zeropage_pte_entry(pte_t *pte, unsigned long addr, + unsigned long end, struct mm_walk *walk) +{ + unsigned long *found_addr = walk->private; + + /* Return 1 of the page is a zeropage. */ + if (is_zero_pfn(pte_pfn(*pte))) { + /* + * Shared zeropage in e.g., a FS DAX mapping? We cannot do the + * right thing and likely don't care: FAULT_FLAG_UNSHARE + * currently only works in COW mappings, which is also where + * mm_forbids_zeropage() is checked. + */ + if (!is_cow_mapping(walk->vma->vm_flags)) + return -EFAULT; + + *found_addr = addr; + return 1; + } + return 0; +} + +static const struct mm_walk_ops find_zeropage_ops = { + .pte_entry = find_zeropage_pte_entry, + .walk_lock = PGWALK_WRLOCK, +}; + +/** __gmap_helper_unshare_zeropages() - unshare all shared zeropages + * @mm: the mm whose zero pages are to be unshared + * + * Unshare all shared zeropages, replacing them by anonymous pages. Note that + * we cannot simply zap all shared zeropages, because this could later + * trigger unexpected userfaultfd missing events. + * + * This must be called after mm->context.allow_cow_sharing was + * set to 0, to avoid future mappings of shared zeropages. + * + * mm contracts with s390, that even if mm were to remove a page table, + * and racing with walk_page_range_vma() calling pte_offset_map_lock() + * would fail, it will never insert a page table containing empty zero + * pages once mm_forbids_zeropage(mm) i.e. + * mm->context.allow_cow_sharing is set to 0. + */ +static int __gmap_helper_unshare_zeropages(struct mm_struct *mm) +{ + struct vm_area_struct *vma; + VMA_ITERATOR(vmi, mm, 0); + unsigned long addr; + vm_fault_t fault; + int rc; + + for_each_vma(vmi, vma) { + /* + * We could only look at COW mappings, but it's more future + * proof to catch unexpected zeropages in other mappings and + * fail. + */ + if ((vma->vm_flags & VM_PFNMAP) || is_vm_hugetlb_page(vma)) + continue; + addr = vma->vm_start; + +retry: + rc = walk_page_range_vma(vma, addr, vma->vm_end, + &find_zeropage_ops, &addr); + if (rc < 0) + return rc; + else if (!rc) + continue; + + /* addr was updated by find_zeropage_pte_entry() */ + fault = handle_mm_fault(vma, addr, + FAULT_FLAG_UNSHARE | FAULT_FLAG_REMOTE, + NULL); + if (fault & VM_FAULT_OOM) + return -ENOMEM; + /* + * See break_ksm(): even after handle_mm_fault() returned 0, we + * must start the lookup from the current address, because + * handle_mm_fault() may back out if there's any difficulty. + * + * VM_FAULT_SIGBUS and VM_FAULT_SIGSEGV are unexpected but + * maybe they could trigger in the future on concurrent + * truncation. In that case, the shared zeropage would be gone + * and we can simply retry and make progress. + */ + cond_resched(); + goto retry; + } + + return 0; +} + +/** + * gmap_helper_disable_cow_sharing() - disable all COW sharing + * + * Disable most COW-sharing of memory pages for the whole process: + * (1) Disable KSM and unmerge/unshare any KSM pages. + * (2) Disallow shared zeropages and unshare any zerpages that are mapped. + * + * Not that we currently don't bother with COW-shared pages that are shared + * with parent/child processes due to fork(). + */ +int gmap_helper_disable_cow_sharing(void) +{ + struct mm_struct *mm = current->mm; + int rc; + + mmap_assert_write_locked(mm); + + if (!mm->context.allow_cow_sharing) + return 0; + + mm->context.allow_cow_sharing = 0; + + /* Replace all shared zeropages by anonymous pages. */ + rc = __gmap_helper_unshare_zeropages(mm); + /* + * Make sure to disable KSM (if enabled for the whole process or + * individual VMAs). Note that nothing currently hinders user space + * from re-enabling it. + */ + if (!rc) + rc = ksm_disable(mm); + if (rc) + mm->context.allow_cow_sharing = 1; + return rc; +} +EXPORT_SYMBOL_GPL(gmap_helper_disable_cow_sharing); diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index afa085e8186c..074bf4fb4ce2 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -40,7 +40,6 @@ #include <asm/kfence.h> #include <asm/dma.h> #include <asm/abs_lowcore.h> -#include <asm/tlb.h> #include <asm/tlbflush.h> #include <asm/sections.h> #include <asm/sclp.h> diff --git a/arch/s390/mm/pgalloc.c b/arch/s390/mm/pgalloc.c index e3a6f8ae156c..b449fd2605b0 100644 --- a/arch/s390/mm/pgalloc.c +++ b/arch/s390/mm/pgalloc.c @@ -12,8 +12,6 @@ #include <asm/mmu_context.h> #include <asm/page-states.h> #include <asm/pgalloc.h> -#include <asm/gmap.h> -#include <asm/tlb.h> #include <asm/tlbflush.h> unsigned long *crst_table_alloc(struct mm_struct *mm) @@ -38,11 +36,15 @@ void crst_table_free(struct mm_struct *mm, unsigned long *table) static void __crst_table_upgrade(void *arg) { struct mm_struct *mm = arg; + struct ctlreg asce; /* change all active ASCEs to avoid the creation of new TLBs */ if (current->active_mm == mm) { - get_lowcore()->user_asce.val = mm->context.asce; - local_ctl_load(7, &get_lowcore()->user_asce); + asce.val = mm->context.asce; + get_lowcore()->user_asce = asce; + local_ctl_load(7, &asce); + if (!test_thread_flag(TIF_ASCE_PRIMARY)) + local_ctl_load(1, &asce); } __tlb_flush_local(); } @@ -52,6 +54,8 @@ int crst_table_upgrade(struct mm_struct *mm, unsigned long end) unsigned long *pgd = NULL, *p4d = NULL, *__pgd; unsigned long asce_limit = mm->context.asce_limit; + mmap_assert_write_locked(mm); + /* upgrade should only happen from 3 to 4, 3 to 5, or 4 to 5 levels */ VM_BUG_ON(asce_limit < _REGION2_SIZE); @@ -75,13 +79,6 @@ int crst_table_upgrade(struct mm_struct *mm, unsigned long end) spin_lock_bh(&mm->page_table_lock); - /* - * This routine gets called with mmap_lock lock held and there is - * no reason to optimize for the case of otherwise. However, if - * that would ever change, the below check will let us know. - */ - VM_BUG_ON(asce_limit != mm->context.asce_limit); - if (p4d) { __pgd = (unsigned long *) mm->pgd; p4d_populate(mm, (p4d_t *) p4d, (pud_t *) __pgd); @@ -145,7 +142,7 @@ unsigned long *page_table_alloc(struct mm_struct *mm) ptdesc = pagetable_alloc(GFP_KERNEL, 0); if (!ptdesc) return NULL; - if (!pagetable_pte_ctor(ptdesc)) { + if (!pagetable_pte_ctor(mm, ptdesc)) { pagetable_free(ptdesc); return NULL; } diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c index 9901934284ec..7df70cd8f739 100644 --- a/arch/s390/mm/pgtable.c +++ b/arch/s390/mm/pgtable.c @@ -20,7 +20,6 @@ #include <linux/ksm.h> #include <linux/mman.h> -#include <asm/tlb.h> #include <asm/tlbflush.h> #include <asm/mmu_context.h> #include <asm/page-states.h> |