linux.git/arch/arm64, branch v3.15

arm64: mm: fix pmd_write CoW brokenness

2014-05-29T10:31:14+00:00

Commit 9c7e535fcc17 ("arm64: mm: Route pmd thp functions through pte
equivalents") changed the pmd manipulator and accessor functions to
convert the target pmd to a pte, process it with the pte functions, then
convert it back. Along the way, we gained support for PTE_WRITE, however
this is completely ignored by set_pmd_at, and so we fail to set the
PMD_SECT_RDONLY for PMDs, resulting in all sorts of lovely failures (like
CoW not working).

Partially reverting the offending commit (by making use of
PMD_SECT_RDONLY explicitly for pmd_{write,wrprotect,mkwrite} functions)
leads to further issues because pmd_write can then return potentially
incorrect values for page table entries marked as RDONLY, leading to
BUG_ON(pmd_write(entry)) tripping under some THP workloads.

This patch fixes the issue by routing set_pmd_at through set_pte_at,
which correctly takes the PTE_WRITE flag into account. Given that
THP mappings are always anonymous, the additional cache-flushing code
in __sync_icache_dcache won't impose any significant overhead as the
flush will be skipped.

Cc: Catalin Marinas 
Acked-by: Steve Capper 
Tested-by: Marc Zyngier 
Signed-off-by: Will Deacon

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2014-05-20T05:33:48+00:00

Pull two arm64 fixes from Catalin Marinas:
 - arm64 migrate_irqs() fix following commit ffde1de64012 (irqchip: Gic:
   Support forced affinity setting)
 - fix arm64 pud_huge() to return 0 when only 2 levels page tables are
   used (__PAGETABLE_PMD_FOLDED defined and pmd_huge already covers
   block entries at the first level), otherwise KVM gets confused

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: fix pud_huge() for 2-level pagetables
  arm64: use cpu_online_mask when using forced irq_set_affinity

arm64: fix pud_huge() for 2-level pagetables

2014-05-16T16:34:40+00:00

The following happens when trying to run a kvm guest on a kernel
configured for 64k pages. This doesn't happen with 4k pages:

  BUG: failure at include/linux/mm.h:297/put_page_testzero()!
  Kernel panic - not syncing: BUG!
  CPU: 2 PID: 4228 Comm: qemu-system-aar Tainted: GF            3.13.0-0.rc7.31.sa2.k32v1.aarch64.debug #1
  Call trace:
  [] dump_backtrace+0x0/0x16c
  [] show_stack+0x14/0x1c
  [] dump_stack+0x84/0xb0
  [] panic+0xf4/0x220
  [] free_reserved_area+0x0/0x110
  [] free_pages+0x50/0x88
  [] kvm_free_stage2_pgd+0x30/0x40
  [] kvm_arch_destroy_vm+0x18/0x44
  [] kvm_put_kvm+0xf0/0x184
  [] kvm_vm_release+0x10/0x1c
  [] __fput+0xb0/0x288
  [] ____fput+0xc/0x14
  [] task_work_run+0xa8/0x11c
  [] do_notify_resume+0x54/0x58

In arch/arm/kvm/mmu.c:unmap_range(), we end up doing an extra put_page()
on the stage2 pgd which leads to the BUG in put_page_testzero(). This
happens because a pud_huge() test in unmap_range() returns true when it
should always be false with 2-level pages tables used by 64k pages.
This patch removes support for huge puds if 2-level pagetables are
being used.

Signed-off-by: Mark Salter 
[catalin.marinas@arm.com: removed #ifndef around PUD_SIZE check]
Signed-off-by: Catalin Marinas 
Cc:  # v3.11+

Merge tag 'stable/for-linus-3.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

2014-05-13T02:21:01+00:00

Pull xen bug fixes from David Vrabel:
 - Fix arm64 crash on boot.
 - Quiet a noisy arm build warning (virt_to_pfn() redefined).

* tag 'stable/for-linus-3.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  arm64: introduce virt_to_pfn
  xen/events/fifo: correctly align bitops
  arm/xen: Remove definiition of virt_to_pfn in asm/xen/page.h

arm64: use cpu_online_mask when using forced irq_set_affinity

2014-05-12T15:25:07+00:00

Commit 01f8fa4f01d8("genirq: Allow forcing cpu affinity of interrupts")
enabled the forced irq_set_affinity which previously refused to route an
interrupt to an offline cpu.

Commit ffde1de64012("irqchip: Gic: Support forced affinity setting")
implements this force logic and disables the cpu online check for GIC
interrupt controller.

When __cpu_disable calls migrate_irqs, it disables the current cpu in
cpu_online_mask and uses forced irq_set_affinity to migrate the IRQs
away from the cpu but passes affinity mask with the cpu being offlined
also included in it.

When calling irq_set_affinity with force == true in a cpu hotplug path,
the caller must ensure that the cpu being offlined is not present in the
affinity mask or it may be selected as the target CPU, leading to the
interrupt not being migrated.

This patch uses cpu_online_mask when using forced irq_set_affinity so
that the IRQs are properly migrated away.

Signed-off-by: Sudeep Holla 
Acked-by: Mark Rutland 
Cc: Will Deacon 
Signed-off-by: Catalin Marinas

arm64: introduce virt_to_pfn

2014-05-12T10:51:28+00:00

virt_to_pfn has been defined in arch/arm/include/asm/memory.h by commit
e26a9e0 "ARM: Better virt_to_page() handling" and Xen has come to rely
on it.  Introduce virt_to_pfn on arm64 too.

Signed-off-by: Stefano Stabellini 
Acked-by: Catalin Marinas

arm64: Mark the Applied Micro X-Gene SATA controller as DMA coherent

2014-05-03T21:20:35+00:00

Since the default DMA ops for arm64 are non-coherent, mark the X-Gene
controller explicitly as dma-coherent to avoid additional cache
maintenance.

Signed-off-by: Catalin Marinas 
Cc: Loc Ho

arm64: Use bus notifiers to set per-device coherent DMA ops

2014-05-03T21:20:34+00:00

Recently, the default DMA ops have been changed to non-coherent for
alignment with 32-bit ARM platforms (and DT files). This patch adds bus
notifiers to be able to set the coherent DMA ops (with no cache
maintenance) for devices explicitly marked as coherent via the
"dma-coherent" DT property.

Signed-off-by: Catalin Marinas

arm64: Make default dma_ops to be noncoherent

2014-05-03T21:20:33+00:00

Currently arm64 dma_ops is by default made coherent which makes it
opposite in default policy from arm.

Make default dma_ops to be noncoherent (same as arm), as currently there
aren't any dma-capable drivers which assumes coherent ops

Signed-off-by: Ritesh Harjani 
Acked-by: Will Deacon 
Signed-off-by: Catalin Marinas

arm64: fixmap: fix missing sub-page offset for earlyprintk

2014-05-03T21:20:31+00:00

Commit d57c33c5daa4 (add generic fixmap.h) added (among other
similar things) set_fixmap_io to deal with early ioremap of devices.

More recently, commit bf4b558eba92 (arm64: add early_ioremap support)
converted the arm64 earlyprintk to use set_fixmap_io. A side effect of
this conversion is that my virtual machines have stopped booting when
I pass "earlyprintk=uart8250-8bit,0x3f8" to the guest kernel.

Turns out that the new earlyprintk code doesn't care at all about
sub-page offsets, and just assumes that the earlyprintk device will
be page-aligned. Obviously, that doesn't play well with the above example.

Further investigation shows that set_fixmap_io uses __set_fixmap instead
of __set_fixmap_offset. A fix is to introduce a set_fixmap_offset_io that
uses the latter, and to remove the superflous call to fix_to_virt
(which only returns the value that set_fixmap_io has already given us).

With this applied, my VMs are back in business. Tested on a Cortex-A57
platform with kvmtool as platform emulation.

Cc: Will Deacon 
Acked-by: Mark Salter 
Acked-by: Arnd Bergmann 
Signed-off-by: Marc Zyngier 
Signed-off-by: Catalin Marinas