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authorLinus Torvalds <torvalds@linux-foundation.org>2015-05-19 11:19:49 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-05-19 11:19:49 -0700
commit416716ed390782e373875f39b39ee23c91902688 (patch)
treeaebef7c785d76634dc2b15803f590101ddbf1ceb /arch
parent68465bb08ca68ab00997ff54a3a27dcb8c541357 (diff)
parent5e95235ccd5442d4a4fe11ec4eb99ba1b7959368 (diff)
Merge tag 'powerpc-4.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux
Pull powerpc fixes from Michael Ellerman: - THP/hugetlb fixes from Aneesh. - MCE fix from Daniel. - TOC fix from Anton. * tag 'powerpc-4.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux: powerpc: Align TOC to 256 bytes powerpc/mce: fix off by one errors in mce event handling powerpc/mm: Return NULL for not present hugetlb page powerpc/thp: Serialize pmd clear against a linux page table walk.
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kernel/mce.c4
-rw-r--r--arch/powerpc/kernel/vmlinux.lds.S1
-rw-r--r--arch/powerpc/mm/hugetlbpage.c25
-rw-r--r--arch/powerpc/mm/pgtable_64.c11
4 files changed, 30 insertions, 11 deletions
diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
index 15c99b649b04..b2eb4686bd8f 100644
--- a/arch/powerpc/kernel/mce.c
+++ b/arch/powerpc/kernel/mce.c
@@ -73,7 +73,7 @@ void save_mce_event(struct pt_regs *regs, long handled,
uint64_t nip, uint64_t addr)
{
uint64_t srr1;
- int index = __this_cpu_inc_return(mce_nest_count);
+ int index = __this_cpu_inc_return(mce_nest_count) - 1;
struct machine_check_event *mce = this_cpu_ptr(&mce_event[index]);
/*
@@ -184,7 +184,7 @@ void machine_check_queue_event(void)
if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
return;
- index = __this_cpu_inc_return(mce_queue_count);
+ index = __this_cpu_inc_return(mce_queue_count) - 1;
/* If queue is full, just return for now. */
if (index >= MAX_MC_EVT) {
__this_cpu_dec(mce_queue_count);
diff --git a/arch/powerpc/kernel/vmlinux.lds.S b/arch/powerpc/kernel/vmlinux.lds.S
index f096e72262f4..1db685104ffc 100644
--- a/arch/powerpc/kernel/vmlinux.lds.S
+++ b/arch/powerpc/kernel/vmlinux.lds.S
@@ -213,6 +213,7 @@ SECTIONS
*(.opd)
}
+ . = ALIGN(256);
.got : AT(ADDR(.got) - LOAD_OFFSET) {
__toc_start = .;
#ifndef CONFIG_RELOCATABLE
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index 0ce968b00b7c..3385e3d0506e 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -689,27 +689,34 @@ void hugetlb_free_pgd_range(struct mmu_gather *tlb,
struct page *
follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
{
- pte_t *ptep;
- struct page *page;
+ pte_t *ptep, pte;
unsigned shift;
unsigned long mask, flags;
+ struct page *page = ERR_PTR(-EINVAL);
+
+ local_irq_save(flags);
+ ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift);
+ if (!ptep)
+ goto no_page;
+ pte = READ_ONCE(*ptep);
/*
+ * Verify it is a huge page else bail.
* 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);
+ if (!shift || pmd_trans_huge(__pmd(pte_val(pte))))
+ goto no_page;
- /* Verify it is a huge page else bail. */
- if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep)) {
- local_irq_restore(flags);
- return ERR_PTR(-EINVAL);
+ if (!pte_present(pte)) {
+ page = NULL;
+ goto no_page;
}
mask = (1UL << shift) - 1;
- page = pte_page(*ptep);
+ page = pte_page(pte);
if (page)
page += (address & mask) / PAGE_SIZE;
+no_page:
local_irq_restore(flags);
return page;
}
diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c
index 59daa5eeec25..6bfadf1aa5cb 100644
--- a/arch/powerpc/mm/pgtable_64.c
+++ b/arch/powerpc/mm/pgtable_64.c
@@ -839,6 +839,17 @@ pmd_t pmdp_get_and_clear(struct mm_struct *mm,
* hash fault look at them.
*/
memset(pgtable, 0, PTE_FRAG_SIZE);
+ /*
+ * Serialize against find_linux_pte_or_hugepte which does lock-less
+ * lookup in page tables with local interrupts disabled. For huge pages
+ * it casts pmd_t to pte_t. Since format of pte_t is different from
+ * pmd_t we want to prevent transit from pmd pointing to page table
+ * to pmd pointing to huge page (and back) while interrupts are disabled.
+ * We clear pmd to possibly replace it with page table pointer in
+ * different code paths. So make sure we wait for the parallel
+ * find_linux_pte_or_hugepage to finish.
+ */
+ kick_all_cpus_sync();
return old_pmd;
}

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