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powerpc fixes for 4.1

Browse Source 
- Fix for mm_dec_nr_pmds() from Scott.
 - Fixes for oopses seen with KVM + THP from Aneesh.
 - Build fixes from Aneesh & Shreyas.
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Merge tag 'powerpc-4.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

Pull powerpc fixes from Michael Ellerman:

 - fix for mm_dec_nr_pmds() from Scott.

 - fixes for oopses seen with KVM + THP from Aneesh.

 - build fixes from Aneesh & Shreyas.

* tag 'powerpc-4.1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
  powerpc/mm: Fix build error with CONFIG_PPC_TRANSACTIONAL_MEM disabled
  powerpc/kvm: Fix ppc64_defconfig + PPC_POWERNV=n build error
  powerpc/mm/thp: Return pte address if we find trans_splitting.
  powerpc/mm/thp: Make page table walk safe against thp split/collapse
  KVM: PPC: Remove page table walk helpers
  KVM: PPC: Use READ_ONCE when dereferencing pte_t pointer
  powerpc/hugetlb: Call mm_dec_nr_pmds() in hugetlb_free_pmd_range()
This commit is contained in:
Linus Torvalds 2015-04-26 13:23:15 -07:00
commit 63905bba5b
11 changed files with 137 additions and 117 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
arch/powerpc/include/asm/kvm_book3s_64.h
View File

@ -295,16 +295,17 @@ static inline int hpte_cache_flags_ok(unsigned long ptel, unsigned long io_type)
/*
* If it's present and writable, atomically set dirty and referenced bits and
* return the PTE, otherwise return 0. If we find a transparent hugepage
* and if it is marked splitting we return 0;
* return the PTE, otherwise return 0.
*/
static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing,
unsigned int hugepage)
static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing)
{
pte_t old_pte, new_pte = __pte(0);
while (1) {
old_pte = *ptep;
/*
* Make sure we don't reload from ptep
*/
old_pte = READ_ONCE(*ptep);
/*
* wait until _PAGE_BUSY is clear then set it atomically
*/
@ -312,12 +313,6 @@ static inline pte_t kvmppc_read_update_linux_pte(pte_t *ptep, int writing,
cpu_relax();
continue;
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/* If hugepage and is trans splitting return None */
if (unlikely(hugepage &&
pmd_trans_splitting(pte_pmd(old_pte))))
return __pte(0);
#endif
/* If pte is not present return None */
if (unlikely(!(pte_val(old_pte) & _PAGE_PRESENT)))
return __pte(0);

28
arch/powerpc/include/asm/pgtable.h
View File

@ -247,28 +247,16 @@ extern int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
#define pmd_large(pmd) 0
#define has_transparent_hugepage() 0
#endif
pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
unsigned *shift);
static inline pte_t *lookup_linux_ptep(pgd_t *pgdir, unsigned long hva,
unsigned long *pte_sizep)
static inline pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
unsigned *shift)
{
pte_t *ptep;
unsigned long ps = *pte_sizep;
unsigned int shift;
ptep = find_linux_pte_or_hugepte(pgdir, hva, &shift);
if (!ptep)
return NULL;
if (shift)
*pte_sizep = 1ul << shift;
else
*pte_sizep = PAGE_SIZE;
if (ps > *pte_sizep)
return NULL;
return ptep;
if (!arch_irqs_disabled()) {
pr_info("%s called with irq enabled\n", __func__);
dump_stack();
}
return __find_linux_pte_or_hugepte(pgdir, ea, shift);
}
#endif /* __ASSEMBLY__ */

6
arch/powerpc/kernel/eeh.c
View File

@ -334,9 +334,11 @@ static inline unsigned long eeh_token_to_phys(unsigned long token)
int hugepage_shift;
/*
* We won't find hugepages here, iomem
* We won't find hugepages here(this is iomem). Hence we are not
* worried about _PAGE_SPLITTING/collapse. Also we will not hit
* page table free, because of init_mm.
*/
ptep = find_linux_pte_or_hugepte(init_mm.pgd, token, &hugepage_shift);
ptep = __find_linux_pte_or_hugepte(init_mm.pgd, token, &hugepage_shift);
if (!ptep)
return token;
WARN_ON(hugepage_shift);

10
arch/powerpc/kernel/io-workarounds.c
View File

@ -71,15 +71,15 @@ struct iowa_bus *iowa_mem_find_bus(const PCI_IO_ADDR addr)
vaddr = (unsigned long)PCI_FIX_ADDR(addr);
if (vaddr < PHB_IO_BASE || vaddr >= PHB_IO_END)
return NULL;
ptep = find_linux_pte_or_hugepte(init_mm.pgd, vaddr,
/*
* We won't find huge pages here (iomem). Also can't hit
* a page table free due to init_mm
*/
ptep = __find_linux_pte_or_hugepte(init_mm.pgd, vaddr,
&hugepage_shift);
if (ptep == NULL)
paddr = 0;
else {
/*
* we don't have hugepages backing iomem
*/
WARN_ON(hugepage_shift);
paddr = pte_pfn(*ptep) << PAGE_SHIFT;
}

2
arch/powerpc/kvm/Kconfig
View File

@ -75,7 +75,7 @@ config KVM_BOOK3S_64
config KVM_BOOK3S_64_HV
tristate "KVM support for POWER7 and PPC970 using hypervisor mode in host"
depends on KVM_BOOK3S_64
depends on KVM_BOOK3S_64 && PPC_POWERNV
select KVM_BOOK3S_HV_POSSIBLE
select MMU_NOTIFIER
select CMA

14
arch/powerpc/kvm/book3s_64_mmu_hv.c
View File

@ -535,23 +535,21 @@ int kvmppc_book3s_hv_page_fault(struct kvm_run *run, struct kvm_vcpu *vcpu,
}
/* if the guest wants write access, see if that is OK */
if (!writing && hpte_is_writable(r)) {
unsigned int hugepage_shift;
pte_t *ptep, pte;
unsigned long flags;
/*
* We need to protect against page table destruction
* while looking up and updating the pte.
* hugepage split and collapse.
*/
rcu_read_lock_sched();
local_irq_save(flags);
ptep = find_linux_pte_or_hugepte(current->mm->pgd,
hva, &hugepage_shift);
hva, NULL);
if (ptep) {
pte = kvmppc_read_update_linux_pte(ptep, 1,
hugepage_shift);
pte = kvmppc_read_update_linux_pte(ptep, 1);
if (pte_write(pte))
write_ok = 1;
}
rcu_read_unlock_sched();
local_irq_restore(flags);
}
}

86
arch/powerpc/kvm/book3s_hv_rm_mmu.c
View File

@ -26,11 +26,14 @@ static void *real_vmalloc_addr(void *x)
{
unsigned long addr = (unsigned long) x;
pte_t *p;
p = find_linux_pte_or_hugepte(swapper_pg_dir, addr, NULL);
/*
* assume we don't have huge pages in vmalloc space...
* So don't worry about THP collapse/split. Called
* Only in realmode, hence won't need irq_save/restore.
*/
p = __find_linux_pte_or_hugepte(swapper_pg_dir, addr, NULL);
if (!p || !pte_present(*p))
return NULL;
/* assume we don't have huge pages in vmalloc space... */
addr = (pte_pfn(*p) << PAGE_SHIFT) | (addr & ~PAGE_MASK);
return __va(addr);
}
@ -131,25 +134,6 @@ static void remove_revmap_chain(struct kvm *kvm, long pte_index,
unlock_rmap(rmap);
}
static pte_t lookup_linux_pte_and_update(pgd_t *pgdir, unsigned long hva,
int writing, unsigned long *pte_sizep)
{
pte_t *ptep;
unsigned long ps = *pte_sizep;
unsigned int hugepage_shift;
ptep = find_linux_pte_or_hugepte(pgdir, hva, &hugepage_shift);
if (!ptep)
return __pte(0);
if (hugepage_shift)
*pte_sizep = 1ul << hugepage_shift;
else
*pte_sizep = PAGE_SIZE;
if (ps > *pte_sizep)
return __pte(0);
return kvmppc_read_update_linux_pte(ptep, writing, hugepage_shift);
}
long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
long pte_index, unsigned long pteh, unsigned long ptel,
pgd_t *pgdir, bool realmode, unsigned long *pte_idx_ret)
@ -160,13 +144,13 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
struct revmap_entry *rev;
unsigned long g_ptel;
struct kvm_memory_slot *memslot;
unsigned long pte_size;
unsigned hpage_shift;
unsigned long is_io;
unsigned long *rmap;
pte_t pte;
pte_t *ptep;
unsigned int writing;
unsigned long mmu_seq;
unsigned long rcbits;
unsigned long rcbits, irq_flags = 0;
psize = hpte_page_size(pteh, ptel);
if (!psize)
@ -202,22 +186,46 @@ long kvmppc_do_h_enter(struct kvm *kvm, unsigned long flags,
/* Translate to host virtual address */
hva = __gfn_to_hva_memslot(memslot, gfn);
/* Look up the Linux PTE for the backing page */
pte_size = psize;
pte = lookup_linux_pte_and_update(pgdir, hva, writing, &pte_size);
if (pte_present(pte) && !pte_protnone(pte)) {
if (writing && !pte_write(pte))
/* make the actual HPTE be read-only */
ptel = hpte_make_readonly(ptel);
is_io = hpte_cache_bits(pte_val(pte));
pa = pte_pfn(pte) << PAGE_SHIFT;
pa |= hva & (pte_size - 1);
pa |= gpa & ~PAGE_MASK;
/*
* If we had a page table table change after lookup, we would
* retry via mmu_notifier_retry.
*/
if (realmode)
ptep = __find_linux_pte_or_hugepte(pgdir, hva, &hpage_shift);
else {
local_irq_save(irq_flags);
ptep = find_linux_pte_or_hugepte(pgdir, hva, &hpage_shift);
}
if (ptep) {
pte_t pte;
unsigned int host_pte_size;
if (pte_size < psize)
return H_PARAMETER;
if (hpage_shift)
host_pte_size = 1ul << hpage_shift;
else
host_pte_size = PAGE_SIZE;
/*
* We should always find the guest page size
* to <= host page size, if host is using hugepage
*/
if (host_pte_size < psize) {
if (!realmode)
local_irq_restore(flags);
return H_PARAMETER;
}
pte = kvmppc_read_update_linux_pte(ptep, writing);
if (pte_present(pte) && !pte_protnone(pte)) {
if (writing && !pte_write(pte))
/* make the actual HPTE be read-only */
ptel = hpte_make_readonly(ptel);
is_io = hpte_cache_bits(pte_val(pte));
pa = pte_pfn(pte) << PAGE_SHIFT;
pa |= hva & (host_pte_size - 1);
pa |= gpa & ~PAGE_MASK;
}
}
if (!realmode)
local_irq_restore(irq_flags);
ptel &= ~(HPTE_R_PP0 - psize);
ptel |= pa;

32
arch/powerpc/kvm/e500_mmu_host.c
View File

@ -338,6 +338,7 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
pte_t *ptep;
unsigned int wimg = 0;
pgd_t *pgdir;
unsigned long flags;
/* used to check for invalidations in progress */
mmu_seq = kvm->mmu_notifier_seq;
@ -468,15 +469,28 @@ static inline int kvmppc_e500_shadow_map(struct kvmppc_vcpu_e500 *vcpu_e500,
pgdir = vcpu_e500->vcpu.arch.pgdir;
ptep = lookup_linux_ptep(pgdir, hva, &tsize_pages);
if (pte_present(*ptep))
wimg = (*ptep >> PTE_WIMGE_SHIFT) & MAS2_WIMGE_MASK;
else {
if (printk_ratelimit())
pr_err("%s: pte not present: gfn %lx, pfn %lx\n",
__func__, (long)gfn, pfn);
ret = -EINVAL;
goto out;
/*
* We are just looking at the wimg bits, so we don't
* care much about the trans splitting bit.
* We are holding kvm->mmu_lock so a notifier invalidate
* can't run hence pfn won't change.
*/
local_irq_save(flags);
ptep = find_linux_pte_or_hugepte(pgdir, hva, NULL);
if (ptep) {
pte_t pte = READ_ONCE(*ptep);
if (pte_present(pte)) {
wimg = (pte_val(pte) >> PTE_WIMGE_SHIFT) &
MAS2_WIMGE_MASK;
local_irq_restore(flags);
} else {
local_irq_restore(flags);
pr_err_ratelimited("%s: pte not present: gfn %lx,pfn %lx\n",
__func__, (long)gfn, pfn);
ret = -EINVAL;
goto out;
}
}
kvmppc_e500_ref_setup(ref, gtlbe, pfn, wimg);

3
arch/powerpc/mm/hash_utils_64.c
View File

@ -1066,7 +1066,7 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea,
#endif /* CONFIG_PPC_64K_PAGES */
/* Get PTE and page size from page tables */
ptep = find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
ptep = __find_linux_pte_or_hugepte(pgdir, ea, &hugeshift);
if (ptep == NULL || !pte_present(*ptep)) {
DBG_LOW(" no PTE !\n");
rc = 1;
@ -1394,6 +1394,7 @@ tm_abort:
tm_abort(TM_CAUSE_TLBI);
}
#endif
return;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

32
arch/powerpc/mm/hugetlbpage.c
View File

@ -109,7 +109,7 @@ int pgd_huge(pgd_t pgd)
pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
{
/* Only called for hugetlbfs pages, hence can ignore THP */
return find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL);
}
static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
@ -581,6 +581,7 @@ static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
pmd = pmd_offset(pud, start);
pud_clear(pud);
pmd_free_tlb(tlb, pmd, start);
mm_dec_nr_pmds(tlb->mm);
}
static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
@ -681,28 +682,35 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
} while (addr = next, addr != end);
}
/*
* We are holding mmap_sem, so a parallel huge page collapse cannot run.
* To prevent hugepage split, disable irq.
*/
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
pte_t *ptep;
struct page *page;
unsigned shift;
unsigned long mask;
unsigned long mask, flags;
/*
* Transparent hugepages are handled by generic code. We can skip them
* here.
*/
local_irq_save(flags);
ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
/* Verify it is a huge page else bail. */
if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep))
if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep)) {
local_irq_restore(flags);
return ERR_PTR(-EINVAL);
}
mask = (1UL << shift) - 1;
page = pte_page(*ptep);
if (page)
page += (address & mask) / PAGE_SIZE;
local_irq_restore(flags);
return page;
}
@ -949,9 +957,12 @@ void flush_dcache_icache_hugepage(struct page *page)
*
* So long as we atomically load page table pointers we are safe against teardown,
* we can follow the address down to the the page and take a ref on it.
* This function need to be called with interrupts disabled. We use this variant
* when we have MSR[EE] = 0 but the paca->soft_enabled = 1
*/
pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift)
pte_t *__find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea,
unsigned *shift)
{
pgd_t pgd, *pgdp;
pud_t pud, *pudp;
@ -1003,12 +1014,11 @@ pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift
* A hugepage collapse is captured by pmd_none, because
* it mark the pmd none and do a hpte invalidate.
*
* A hugepage split is captured by pmd_trans_splitting
* because we mark the pmd trans splitting and do a
* hpte invalidate
*
* We don't worry about pmd_trans_splitting here, The
* caller if it needs to handle the splitting case
* should check for that.
*/
if (pmd_none(pmd) || pmd_trans_splitting(pmd))
if (pmd_none(pmd))
return NULL;
if (pmd_huge(pmd) || pmd_large(pmd)) {
@ -1030,7 +1040,7 @@ out:
*shift = pdshift;
return ret_pte;
}
EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte);
EXPORT_SYMBOL_GPL(__find_linux_pte_or_hugepte);
int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)

24
arch/powerpc/perf/callchain.c
View File

@ -111,41 +111,45 @@ perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
* interrupt context, so if the access faults, we read the page tables
* to find which page (if any) is mapped and access it directly.
*/
static int read_user_stack_slow(void __user *ptr, void *ret, int nb)
static int read_user_stack_slow(void __user *ptr, void *buf, int nb)
{
int ret = -EFAULT;
pgd_t *pgdir;
pte_t *ptep, pte;
unsigned shift;
unsigned long addr = (unsigned long) ptr;
unsigned long offset;
unsigned long pfn;
unsigned long pfn, flags;
void *kaddr;
pgdir = current->mm->pgd;
if (!pgdir)
return -EFAULT;
local_irq_save(flags);
ptep = find_linux_pte_or_hugepte(pgdir, addr, &shift);
if (!ptep)
goto err_out;
if (!shift)
shift = PAGE_SHIFT;
/* align address to page boundary */
offset = addr & ((1UL << shift) - 1);
addr -= offset;
if (ptep == NULL)
return -EFAULT;
pte = *ptep;
pte = READ_ONCE(*ptep);
if (!pte_present(pte) || !(pte_val(pte) & _PAGE_USER))
return -EFAULT;
goto err_out;
pfn = pte_pfn(pte);
if (!page_is_ram(pfn))
return -EFAULT;
goto err_out;
/* no highmem to worry about here */
kaddr = pfn_to_kaddr(pfn);
memcpy(ret, kaddr + offset, nb);
return 0;
memcpy(buf, kaddr + offset, nb);
ret = 0;
err_out:
local_irq_restore(flags);
return ret;
}
static int read_user_stack_64(unsigned long __user *ptr, unsigned long *ret)