* [PATCH 00/34] x86: Memory Protection Keys (v5)
@ 2015-12-04 1:14 Dave Hansen
2015-12-04 1:14 ` Dave Hansen
` (3 more replies)
0 siblings, 4 replies; 11+ messages in thread
From: Dave Hansen @ 2015-12-04 1:14 UTC (permalink / raw)
To: linux-kernel-u79uwXL29TY76Z2rM5mHXA
Cc: linux-mm-Bw31MaZKKs3YtjvyW6yDsg, x86-DgEjT+Ai2ygdnm+yROfE0A,
Dave Hansen, linux-api-u79uwXL29TY76Z2rM5mHXA,
linux-arch-u79uwXL29TY76Z2rM5mHXA,
aarcange-H+wXaHxf7aLQT0dZR+AlfA,
akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b, jack-AlSwsSmVLrQ,
kirill.shutemov-VuQAYsv1563Yd54FQh9/CA,
n-horiguchi-PaJj6Psr51x8UrSeD/g0lQ
Memory Protection Keys for User pages is a CPU feature which will
first appear on Skylake Servers, but will also be supported on
future non-server parts. It provides a mechanism for enforcing
page-based protections, but without requiring modification of the
page tables when an application changes protection domains. See
the Documentation/ patch for more details.
Changes from v4:
* Made "allow setting of XSAVE state" safe if we got preempted
between when we saved our FPU state and when we restore it.
(I would appreciate a look from Ingo on this patch).
* Fixed up a few things from Thomas's latest comments: splt up
siginfo in to x86 and generic, removed extra 'eax' variable
in rdpkru function, reworked vm_flags assignment, reworded
a comment in pte_allows_gup()
* Add missing DISABLED/REQUIRED_MASK14 in cpufeature.h
* Added comment about compile optimization in fault path
* Left get_user_pages_locked() alone. Andrea thinks we need it.
Changes from RFCv3:
* Added 'current' and 'foreign' variants of get_user_pages() to
help indicate whether protection keys should be enforced.
Thanks to Jerome Glisse for pointing out this issue.
* Added "allocation" and set/get system calls so that we can do
management of proection keys in the kernel. This opens the
door to use of specific protection keys for kernel use in the
future, such as for execute-only memory.
* Removed the kselftest code for the moment. It will be
submitted separately.
Thanks Ingo and Thomas for most of these):
Changes from RFCv2 (Thanks Ingo and Thomas for most of these):
* few minor compile warnings
* changed 'nopku' interaction with cpuid bits. Now, we do not
clear the PKU cpuid bit, we just skip enabling it.
* changed __pkru_allows_write() to also check access disable bit
* removed the unused write_pkru()
* made si_pkey a u64 and added some patch description details.
Also made it share space in siginfo with MPX and clarified
comments.
* give some real text for the Processor Trace xsave state
* made vma_pkey() less ugly (and much more optimized actually)
* added SEGV_PKUERR to copy_siginfo_to_user()
* remove page table walk when filling in si_pkey, added some
big fat comments about it being inherently racy.
* added self test code
This code is not runnable to anyone outside of Intel unless they
have some special hardware or a fancy simulator. If you are
interested in running this for real, please get in touch with me.
Hardware is available to a very small but nonzero number of
people.
This set is also available here (with the new syscall):
git://git.kernel.org/pub/scm/linux/kernel/git/daveh/x86-pkeys.git pkeys-v014
=== diffstat ===
Dave Hansen (34):
mm, gup: introduce concept of "foreign" get_user_pages()
x86, fpu: add placeholder for Processor Trace XSAVE state
x86, pkeys: Add Kconfig option
x86, pkeys: cpuid bit definition
x86, pkeys: define new CR4 bit
x86, pkeys: add PKRU xsave fields and data structure(s)
x86, pkeys: PTE bits for storing protection key
x86, pkeys: new page fault error code bit: PF_PK
x86, pkeys: store protection in high VMA flags
x86, pkeys: arch-specific protection bits
x86, pkeys: pass VMA down in to fault signal generation code
signals, pkeys: notify userspace about protection key faults
x86, pkeys: fill in pkey field in siginfo
x86, pkeys: add functions to fetch PKRU
mm: factor out VMA fault permission checking
x86, mm: simplify get_user_pages() PTE bit handling
x86, pkeys: check VMAs and PTEs for protection keys
mm: add gup flag to indicate "foreign" mm access
x86, pkeys: optimize fault handling in access_error()
x86, pkeys: differentiate instruction fetches
x86, pkeys: dump PKRU with other kernel registers
x86, pkeys: dump PTE pkey in /proc/pid/smaps
x86, pkeys: add Kconfig prompt to existing config option
mm, multi-arch: pass a protection key in to calc_vm_flag_bits()
x86, pkeys: add arch_validate_pkey()
mm: implement new mprotect_key() system call
x86, pkeys: make mprotect_key() mask off additional vm_flags
x86: wire up mprotect_key() system call
x86: separate out LDT init from context init
x86, fpu: allow setting of XSAVE state
x86, pkeys: allocation/free syscalls
x86, pkeys: add pkey set/get syscalls
x86, pkeys: actually enable Memory Protection Keys in CPU
x86, pkeys: Documentation
Documentation/kernel-parameters.txt | 3 +
Documentation/x86/protection-keys.txt | 53 +++++
arch/mips/mm/gup.c | 3 +-
arch/powerpc/include/asm/mman.h | 5 +-
arch/powerpc/include/asm/mmu_context.h | 12 +
arch/s390/include/asm/mmu_context.h | 12 +
arch/s390/mm/gup.c | 3 +-
arch/sh/mm/gup.c | 2 +-
arch/sparc/mm/gup.c | 2 +-
arch/unicore32/include/asm/mmu_context.h | 12 +
arch/x86/Kconfig | 16 ++
arch/x86/entry/syscalls/syscall_32.tbl | 5 +
arch/x86/entry/syscalls/syscall_64.tbl | 5 +
arch/x86/include/asm/cpufeature.h | 56 +++--
arch/x86/include/asm/disabled-features.h | 13 ++
arch/x86/include/asm/fpu/internal.h | 2 +
arch/x86/include/asm/fpu/types.h | 12 +
arch/x86/include/asm/fpu/xstate.h | 4 +-
arch/x86/include/asm/mmu.h | 7 +
arch/x86/include/asm/mmu_context.h | 110 ++++++++-
arch/x86/include/asm/pgtable.h | 38 +++
arch/x86/include/asm/pgtable_types.h | 34 ++-
arch/x86/include/asm/pkeys.h | 67 ++++++
arch/x86/include/asm/required-features.h | 5 +
arch/x86/include/asm/special_insns.h | 22 ++
arch/x86/include/uapi/asm/mman.h | 22 ++
arch/x86/include/uapi/asm/processor-flags.h | 2 +
arch/x86/kernel/cpu/common.c | 42 ++++
arch/x86/kernel/fpu/core.c | 63 +++++
arch/x86/kernel/fpu/xstate.c | 241 +++++++++++++++++++-
arch/x86/kernel/ldt.c | 4 +-
arch/x86/kernel/process_64.c | 2 +
arch/x86/kernel/setup.c | 9 +
arch/x86/mm/fault.c | 158 +++++++++++--
arch/x86/mm/gup.c | 51 +++--
arch/x86/mm/mpx.c | 4 +-
drivers/char/agp/frontend.c | 2 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 4 +-
drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
drivers/gpu/drm/radeon/radeon_ttm.c | 4 +-
drivers/gpu/drm/via/via_dmablit.c | 3 +-
drivers/infiniband/core/umem.c | 2 +-
drivers/infiniband/core/umem_odp.c | 8 +-
drivers/infiniband/hw/mthca/mthca_memfree.c | 3 +-
drivers/infiniband/hw/qib/qib_user_pages.c | 3 +-
drivers/infiniband/hw/usnic/usnic_uiom.c | 2 +-
drivers/iommu/amd_iommu_v2.c | 8 +-
drivers/media/pci/ivtv/ivtv-udma.c | 4 +-
drivers/media/pci/ivtv/ivtv-yuv.c | 10 +-
drivers/media/v4l2-core/videobuf-dma-sg.c | 3 +-
drivers/misc/sgi-gru/grufault.c | 3 +-
drivers/scsi/st.c | 2 -
drivers/staging/android/ashmem.c | 4 +-
drivers/video/fbdev/pvr2fb.c | 4 +-
drivers/virt/fsl_hypervisor.c | 5 +-
fs/exec.c | 8 +-
fs/proc/task_mmu.c | 5 +
include/asm-generic/mm_hooks.h | 12 +
include/linux/mm.h | 55 ++++-
include/linux/mman.h | 6 +-
include/linux/pkeys.h | 59 +++++
include/uapi/asm-generic/mman-common.h | 5 +
include/uapi/asm-generic/siginfo.h | 17 +-
kernel/events/uprobes.c | 4 +-
kernel/signal.c | 4 +
mm/Kconfig | 13 ++
mm/frame_vector.c | 2 +-
mm/gup.c | 93 ++++++--
mm/ksm.c | 10 +-
mm/memory.c | 8 +-
mm/mempolicy.c | 6 +-
mm/mmap.c | 2 +-
mm/mprotect.c | 136 ++++++++++-
mm/nommu.c | 35 ++-
mm/process_vm_access.c | 6 +-
mm/util.c | 4 +-
net/ceph/pagevec.c | 2 +-
security/tomoyo/domain.c | 9 +-
virt/kvm/async_pf.c | 2 +-
virt/kvm/kvm_main.c | 13 +-
80 files changed, 1470 insertions(+), 223 deletions(-)
Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: aarcange-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org
Cc: akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org
Cc: jack-AlSwsSmVLrQ@public.gmane.org
Cc: kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org
Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Cc: n-horiguchi-PaJj6Psr51x8UrSeD/g0lQ@public.gmane.org
Cc: x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 00/34] x86: Memory Protection Keys (v5)
2015-12-04 1:14 [PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen
@ 2015-12-04 1:14 ` Dave Hansen
2015-12-04 1:14 ` [PATCH 18/34] mm: add gup flag to indicate "foreign" mm access Dave Hansen
` (2 subsequent siblings)
3 siblings, 0 replies; 11+ messages in thread
From: Dave Hansen @ 2015-12-04 1:14 UTC (permalink / raw)
To: linux-kernel
Cc: linux-mm, x86, Dave Hansen, linux-api, linux-arch, aarcange, akpm,
jack, kirill.shutemov, n-horiguchi
Memory Protection Keys for User pages is a CPU feature which will
first appear on Skylake Servers, but will also be supported on
future non-server parts. It provides a mechanism for enforcing
page-based protections, but without requiring modification of the
page tables when an application changes protection domains. See
the Documentation/ patch for more details.
Changes from v4:
* Made "allow setting of XSAVE state" safe if we got preempted
between when we saved our FPU state and when we restore it.
(I would appreciate a look from Ingo on this patch).
* Fixed up a few things from Thomas's latest comments: splt up
siginfo in to x86 and generic, removed extra 'eax' variable
in rdpkru function, reworked vm_flags assignment, reworded
a comment in pte_allows_gup()
* Add missing DISABLED/REQUIRED_MASK14 in cpufeature.h
* Added comment about compile optimization in fault path
* Left get_user_pages_locked() alone. Andrea thinks we need it.
Changes from RFCv3:
* Added 'current' and 'foreign' variants of get_user_pages() to
help indicate whether protection keys should be enforced.
Thanks to Jerome Glisse for pointing out this issue.
* Added "allocation" and set/get system calls so that we can do
management of proection keys in the kernel. This opens the
door to use of specific protection keys for kernel use in the
future, such as for execute-only memory.
* Removed the kselftest code for the moment. It will be
submitted separately.
Thanks Ingo and Thomas for most of these):
Changes from RFCv2 (Thanks Ingo and Thomas for most of these):
* few minor compile warnings
* changed 'nopku' interaction with cpuid bits. Now, we do not
clear the PKU cpuid bit, we just skip enabling it.
* changed __pkru_allows_write() to also check access disable bit
* removed the unused write_pkru()
* made si_pkey a u64 and added some patch description details.
Also made it share space in siginfo with MPX and clarified
comments.
* give some real text for the Processor Trace xsave state
* made vma_pkey() less ugly (and much more optimized actually)
* added SEGV_PKUERR to copy_siginfo_to_user()
* remove page table walk when filling in si_pkey, added some
big fat comments about it being inherently racy.
* added self test code
This code is not runnable to anyone outside of Intel unless they
have some special hardware or a fancy simulator. If you are
interested in running this for real, please get in touch with me.
Hardware is available to a very small but nonzero number of
people.
This set is also available here (with the new syscall):
git://git.kernel.org/pub/scm/linux/kernel/git/daveh/x86-pkeys.git pkeys-v014
=== diffstat ===
Dave Hansen (34):
mm, gup: introduce concept of "foreign" get_user_pages()
x86, fpu: add placeholder for Processor Trace XSAVE state
x86, pkeys: Add Kconfig option
x86, pkeys: cpuid bit definition
x86, pkeys: define new CR4 bit
x86, pkeys: add PKRU xsave fields and data structure(s)
x86, pkeys: PTE bits for storing protection key
x86, pkeys: new page fault error code bit: PF_PK
x86, pkeys: store protection in high VMA flags
x86, pkeys: arch-specific protection bits
x86, pkeys: pass VMA down in to fault signal generation code
signals, pkeys: notify userspace about protection key faults
x86, pkeys: fill in pkey field in siginfo
x86, pkeys: add functions to fetch PKRU
mm: factor out VMA fault permission checking
x86, mm: simplify get_user_pages() PTE bit handling
x86, pkeys: check VMAs and PTEs for protection keys
mm: add gup flag to indicate "foreign" mm access
x86, pkeys: optimize fault handling in access_error()
x86, pkeys: differentiate instruction fetches
x86, pkeys: dump PKRU with other kernel registers
x86, pkeys: dump PTE pkey in /proc/pid/smaps
x86, pkeys: add Kconfig prompt to existing config option
mm, multi-arch: pass a protection key in to calc_vm_flag_bits()
x86, pkeys: add arch_validate_pkey()
mm: implement new mprotect_key() system call
x86, pkeys: make mprotect_key() mask off additional vm_flags
x86: wire up mprotect_key() system call
x86: separate out LDT init from context init
x86, fpu: allow setting of XSAVE state
x86, pkeys: allocation/free syscalls
x86, pkeys: add pkey set/get syscalls
x86, pkeys: actually enable Memory Protection Keys in CPU
x86, pkeys: Documentation
Documentation/kernel-parameters.txt | 3 +
Documentation/x86/protection-keys.txt | 53 +++++
arch/mips/mm/gup.c | 3 +-
arch/powerpc/include/asm/mman.h | 5 +-
arch/powerpc/include/asm/mmu_context.h | 12 +
arch/s390/include/asm/mmu_context.h | 12 +
arch/s390/mm/gup.c | 3 +-
arch/sh/mm/gup.c | 2 +-
arch/sparc/mm/gup.c | 2 +-
arch/unicore32/include/asm/mmu_context.h | 12 +
arch/x86/Kconfig | 16 ++
arch/x86/entry/syscalls/syscall_32.tbl | 5 +
arch/x86/entry/syscalls/syscall_64.tbl | 5 +
arch/x86/include/asm/cpufeature.h | 56 +++--
arch/x86/include/asm/disabled-features.h | 13 ++
arch/x86/include/asm/fpu/internal.h | 2 +
arch/x86/include/asm/fpu/types.h | 12 +
arch/x86/include/asm/fpu/xstate.h | 4 +-
arch/x86/include/asm/mmu.h | 7 +
arch/x86/include/asm/mmu_context.h | 110 ++++++++-
arch/x86/include/asm/pgtable.h | 38 +++
arch/x86/include/asm/pgtable_types.h | 34 ++-
arch/x86/include/asm/pkeys.h | 67 ++++++
arch/x86/include/asm/required-features.h | 5 +
arch/x86/include/asm/special_insns.h | 22 ++
arch/x86/include/uapi/asm/mman.h | 22 ++
arch/x86/include/uapi/asm/processor-flags.h | 2 +
arch/x86/kernel/cpu/common.c | 42 ++++
arch/x86/kernel/fpu/core.c | 63 +++++
arch/x86/kernel/fpu/xstate.c | 241 +++++++++++++++++++-
arch/x86/kernel/ldt.c | 4 +-
arch/x86/kernel/process_64.c | 2 +
arch/x86/kernel/setup.c | 9 +
arch/x86/mm/fault.c | 158 +++++++++++--
arch/x86/mm/gup.c | 51 +++--
arch/x86/mm/mpx.c | 4 +-
drivers/char/agp/frontend.c | 2 +-
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 4 +-
drivers/gpu/drm/i915/i915_gem_userptr.c | 2 +-
drivers/gpu/drm/radeon/radeon_ttm.c | 4 +-
drivers/gpu/drm/via/via_dmablit.c | 3 +-
drivers/infiniband/core/umem.c | 2 +-
drivers/infiniband/core/umem_odp.c | 8 +-
drivers/infiniband/hw/mthca/mthca_memfree.c | 3 +-
drivers/infiniband/hw/qib/qib_user_pages.c | 3 +-
drivers/infiniband/hw/usnic/usnic_uiom.c | 2 +-
drivers/iommu/amd_iommu_v2.c | 8 +-
drivers/media/pci/ivtv/ivtv-udma.c | 4 +-
drivers/media/pci/ivtv/ivtv-yuv.c | 10 +-
drivers/media/v4l2-core/videobuf-dma-sg.c | 3 +-
drivers/misc/sgi-gru/grufault.c | 3 +-
drivers/scsi/st.c | 2 -
drivers/staging/android/ashmem.c | 4 +-
drivers/video/fbdev/pvr2fb.c | 4 +-
drivers/virt/fsl_hypervisor.c | 5 +-
fs/exec.c | 8 +-
fs/proc/task_mmu.c | 5 +
include/asm-generic/mm_hooks.h | 12 +
include/linux/mm.h | 55 ++++-
include/linux/mman.h | 6 +-
include/linux/pkeys.h | 59 +++++
include/uapi/asm-generic/mman-common.h | 5 +
include/uapi/asm-generic/siginfo.h | 17 +-
kernel/events/uprobes.c | 4 +-
kernel/signal.c | 4 +
mm/Kconfig | 13 ++
mm/frame_vector.c | 2 +-
mm/gup.c | 93 ++++++--
mm/ksm.c | 10 +-
mm/memory.c | 8 +-
mm/mempolicy.c | 6 +-
mm/mmap.c | 2 +-
mm/mprotect.c | 136 ++++++++++-
mm/nommu.c | 35 ++-
mm/process_vm_access.c | 6 +-
mm/util.c | 4 +-
net/ceph/pagevec.c | 2 +-
security/tomoyo/domain.c | 9 +-
virt/kvm/async_pf.c | 2 +-
virt/kvm/kvm_main.c | 13 +-
80 files changed, 1470 insertions(+), 223 deletions(-)
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: aarcange@redhat.com
Cc: akpm@linux-foundation.org
Cc: jack@suse.cz
Cc: kirill.shutemov@linux.intel.com
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: n-horiguchi@ah.jp.nec.com
Cc: x86@kernel.org
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 18/34] mm: add gup flag to indicate "foreign" mm access
2015-12-04 1:14 [PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen
2015-12-04 1:14 ` Dave Hansen
@ 2015-12-04 1:14 ` Dave Hansen
2015-12-04 1:14 ` Dave Hansen
2015-12-04 1:14 ` [PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen
2015-12-04 23:31 ` [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski
3 siblings, 1 reply; 11+ messages in thread
From: Dave Hansen @ 2015-12-04 1:14 UTC (permalink / raw)
To: linux-kernel; +Cc: linux-mm, x86, Dave Hansen, dave.hansen, linux-arch
From: Dave Hansen <dave.hansen@linux.intel.com>
We try to enforce protection keys in software the same way that we
do in hardware. (See long example below).
But, we only want to do this when accessing our *own* process's
memory. If GDB set PKRU[6].AD=1 (disable access to PKEY 6), then
tried to PTRACE_POKE a target process which just happened to have
some mprotect_pkey(pkey=6) memory, we do *not* want to deny the
debugger access to that memory. PKRU is fundamentally a
thread-local structure and we do not want to enforce it on access
to _another_ thread's data.
This gets especially tricky when we have workqueues or other
delayed-work mechanisms that might run in a random process's context.
We can check that we only enforce pkeys when operating on our *own* mm,
but delayed work gets performed when a random user context is active.
We might end up with a situation where a delayed-work gup fails when
running randomly under its "own" task but succeeds when running under
another process. We want to avoid that.
To avoid that, we add a GUP flag: FOLL_FOREIGN and a fault flag:
FAULT_FLAG_FOREIGN. They indicate that we are walking an mm
which is not guranteed to be the same as current->mm and should
not be subject to protection key enforcement.
Thanks to Jerome Glisse for pointing out this scenario.
*** Why do we enforce protection keys in software?? ***
Imagine that we disabled access to the memory pointer to by 'buf'.
The, we implemented sys_write() like this:
sys_read(fd, buf, len...)
{
struct page *page = follow_page(buf);
void *buf_mapped = kmap(page);
memcpy(buf_mapped, fd_data, len);
...
}
This writes to 'buf' via a *kernel* mapping, without a protection
key. While this implementation does the same thing:
sys_read(fd, buf, len...)
{
copy_to_user(buf, fd_data, len);
...
}
but would hit a protection key fault because the userspace 'buf'
mapping has a protection key set.
To provide consistency, and to make key-protected memory work
as much like mprotect()ed memory as possible, we try to enforce
the same protections as the hardware would when the *kernel* walks
the page tables (and other mm structures).
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-arch@vger.kernel.org
---
b/arch/powerpc/include/asm/mmu_context.h | 3 ++-
b/arch/s390/include/asm/mmu_context.h | 3 ++-
b/arch/unicore32/include/asm/mmu_context.h | 3 ++-
b/arch/x86/include/asm/mmu_context.h | 5 +++--
b/drivers/iommu/amd_iommu_v2.c | 8 +++++---
b/include/asm-generic/mm_hooks.h | 3 ++-
b/include/linux/mm.h | 2 ++
b/mm/gup.c | 15 ++++++++++-----
b/mm/ksm.c | 10 ++++++++--
b/mm/memory.c | 3 ++-
10 files changed, 38 insertions(+), 17 deletions(-)
diff -puN arch/powerpc/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag arch/powerpc/include/asm/mmu_context.h
--- a/arch/powerpc/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.223698386 -0800
+++ b/arch/powerpc/include/asm/mmu_context.h 2015-12-03 16:21:26.241699202 -0800
@@ -148,7 +148,8 @@ static inline void arch_bprm_mm_init(str
{
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* by default, allow everything */
return true;
diff -puN arch/s390/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag arch/s390/include/asm/mmu_context.h
--- a/arch/s390/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.224698431 -0800
+++ b/arch/s390/include/asm/mmu_context.h 2015-12-03 16:21:26.242699248 -0800
@@ -130,7 +130,8 @@ static inline void arch_bprm_mm_init(str
{
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* by default, allow everything */
return true;
diff -puN arch/unicore32/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag arch/unicore32/include/asm/mmu_context.h
--- a/arch/unicore32/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.226698522 -0800
+++ b/arch/unicore32/include/asm/mmu_context.h 2015-12-03 16:21:26.242699248 -0800
@@ -97,7 +97,8 @@ static inline void arch_bprm_mm_init(str
{
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* by default, allow everything */
return true;
diff -puN arch/x86/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag arch/x86/include/asm/mmu_context.h
--- a/arch/x86/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.228698613 -0800
+++ b/arch/x86/include/asm/mmu_context.h 2015-12-03 16:21:26.242699248 -0800
@@ -299,10 +299,11 @@ static inline bool vma_is_foreign(struct
return false;
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* allow access if the VMA is not one from this process */
- if (vma_is_foreign(vma))
+ if (foreign || vma_is_foreign(vma))
return true;
return __pkru_allows_pkey(vma_pkey(vma), write);
}
diff -puN drivers/iommu/amd_iommu_v2.c~pkeys-12-gup-fault-foreign-flag drivers/iommu/amd_iommu_v2.c
--- a/drivers/iommu/amd_iommu_v2.c~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.229698658 -0800
+++ b/drivers/iommu/amd_iommu_v2.c 2015-12-03 16:21:26.243699293 -0800
@@ -500,9 +500,11 @@ static void do_fault(struct work_struct
struct mm_struct *mm;
struct vm_area_struct *vma;
u64 address;
- int ret, write;
+ int ret, flags;
- write = !!(fault->flags & PPR_FAULT_WRITE);
+ if (fault->flags & PPR_FAULT_WRITE)
+ flags = FAULT_FLAG_WRITE;
+ flags |= FAULT_FLAG_FOREIGN;
mm = fault->state->mm;
address = fault->address;
@@ -523,7 +525,7 @@ static void do_fault(struct work_struct
goto out;
}
- ret = handle_mm_fault(mm, vma, address, write);
+ ret = handle_mm_fault(mm, vma, address, flags);
if (ret & VM_FAULT_ERROR) {
/* failed to service fault */
up_read(&mm->mmap_sem);
diff -puN include/asm-generic/mm_hooks.h~pkeys-12-gup-fault-foreign-flag include/asm-generic/mm_hooks.h
--- a/include/asm-generic/mm_hooks.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.231698749 -0800
+++ b/include/asm-generic/mm_hooks.h 2015-12-03 16:21:26.243699293 -0800
@@ -26,7 +26,8 @@ static inline void arch_bprm_mm_init(str
{
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* by default, allow everything */
return true;
diff -puN include/linux/mm.h~pkeys-12-gup-fault-foreign-flag include/linux/mm.h
--- a/include/linux/mm.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.233698839 -0800
+++ b/include/linux/mm.h 2015-12-03 16:21:26.244699338 -0800
@@ -232,6 +232,7 @@ extern pgprot_t protection_map[16];
#define FAULT_FLAG_KILLABLE 0x10 /* The fault task is in SIGKILL killable region */
#define FAULT_FLAG_TRIED 0x20 /* Second try */
#define FAULT_FLAG_USER 0x40 /* The fault originated in userspace */
+#define FAULT_FLAG_FOREIGN 0x80 /* faulting for non current tsk/mm */
/*
* vm_fault is filled by the the pagefault handler and passed to the vma's
@@ -2138,6 +2139,7 @@ static inline struct page *follow_page(s
#define FOLL_MIGRATION 0x400 /* wait for page to replace migration entry */
#define FOLL_TRIED 0x800 /* a retry, previous pass started an IO */
#define FOLL_MLOCK 0x1000 /* lock present pages */
+#define FOLL_FOREIGN 0x2000 /* we are working on non-current tsk/mm */
typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
void *data);
diff -puN mm/gup.c~pkeys-12-gup-fault-foreign-flag mm/gup.c
--- a/mm/gup.c~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.234698885 -0800
+++ b/mm/gup.c 2015-12-03 16:21:26.245699384 -0800
@@ -310,6 +310,8 @@ static int faultin_page(struct task_stru
return -ENOENT;
if (*flags & FOLL_WRITE)
fault_flags |= FAULT_FLAG_WRITE;
+ if (*flags & FOLL_FOREIGN)
+ fault_flags |= FAULT_FLAG_FOREIGN;
if (nonblocking)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
if (*flags & FOLL_NOWAIT)
@@ -360,11 +362,13 @@ static int faultin_page(struct task_stru
static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
{
vm_flags_t vm_flags = vma->vm_flags;
+ int write = (gup_flags & FOLL_WRITE);
+ int foreign = (gup_flags & FOLL_FOREIGN);
if (vm_flags & (VM_IO | VM_PFNMAP))
return -EFAULT;
- if (gup_flags & FOLL_WRITE) {
+ if (write) {
if (!(vm_flags & VM_WRITE)) {
if (!(gup_flags & FOLL_FORCE))
return -EFAULT;
@@ -392,7 +396,7 @@ static int check_vma_flags(struct vm_are
if (!(vm_flags & VM_MAYREAD))
return -EFAULT;
}
- if (!arch_vma_access_permitted(vma, (gup_flags & FOLL_WRITE)))
+ if (!arch_vma_access_permitted(vma, write, foreign))
return -EFAULT;
return 0;
}
@@ -562,7 +566,8 @@ EXPORT_SYMBOL(__get_user_pages);
bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags)
{
- bool write = !!(fault_flags & FAULT_FLAG_WRITE);
+ bool write = !!(fault_flags & FAULT_FLAG_WRITE);
+ bool foreign = !!(fault_flags & FAULT_FLAG_FOREIGN);
vm_flags_t vm_flags = write ? VM_WRITE : VM_READ;
if (!(vm_flags & vma->vm_flags))
@@ -570,9 +575,9 @@ bool vma_permits_fault(struct vm_area_st
/*
* The architecture might have a hardware protection
- * mechanism other than read/write that can deny access
+ * mechanism other than read/write that can deny access.
*/
- if (!arch_vma_access_permitted(vma, write))
+ if (!arch_vma_access_permitted(vma, write, foreign))
return false;
return true;
diff -puN mm/ksm.c~pkeys-12-gup-fault-foreign-flag mm/ksm.c
--- a/mm/ksm.c~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.236698975 -0800
+++ b/mm/ksm.c 2015-12-03 16:21:26.246699429 -0800
@@ -359,6 +359,10 @@ static inline bool ksm_test_exit(struct
* in case the application has unmapped and remapped mm,addr meanwhile.
* Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP
* mmap of /dev/mem or /dev/kmem, where we would not want to touch it.
+ *
+ * FAULT_FLAG/FOLL_FOREIGN are because we do this outside the context
+ * of the process that owns 'vma'. We also do not want to enforce
+ * protection keys here anyway.
*/
static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
{
@@ -367,12 +371,14 @@ static int break_ksm(struct vm_area_stru
do {
cond_resched();
- page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION);
+ page = follow_page(vma, addr,
+ FOLL_GET | FOLL_MIGRATION | FOLL_FOREIGN);
if (IS_ERR_OR_NULL(page))
break;
if (PageKsm(page))
ret = handle_mm_fault(vma->vm_mm, vma, addr,
- FAULT_FLAG_WRITE);
+ FAULT_FLAG_WRITE |
+ FAULT_FLAG_FOREIGN);
else
ret = VM_FAULT_WRITE;
put_page(page);
diff -puN mm/memory.c~pkeys-12-gup-fault-foreign-flag mm/memory.c
--- a/mm/memory.c~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.238699066 -0800
+++ b/mm/memory.c 2015-12-03 16:21:26.247699474 -0800
@@ -3345,7 +3345,8 @@ static int __handle_mm_fault(struct mm_s
pmd_t *pmd;
pte_t *pte;
- if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE))
+ if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
+ flags & FAULT_FLAG_FOREIGN))
return VM_FAULT_SIGSEGV;
if (unlikely(is_vm_hugetlb_page(vma)))
_
--
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the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
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^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 18/34] mm: add gup flag to indicate "foreign" mm access
2015-12-04 1:14 ` [PATCH 18/34] mm: add gup flag to indicate "foreign" mm access Dave Hansen
@ 2015-12-04 1:14 ` Dave Hansen
0 siblings, 0 replies; 11+ messages in thread
From: Dave Hansen @ 2015-12-04 1:14 UTC (permalink / raw)
To: linux-kernel; +Cc: linux-mm, x86, Dave Hansen, dave.hansen, linux-arch
From: Dave Hansen <dave.hansen@linux.intel.com>
We try to enforce protection keys in software the same way that we
do in hardware. (See long example below).
But, we only want to do this when accessing our *own* process's
memory. If GDB set PKRU[6].AD=1 (disable access to PKEY 6), then
tried to PTRACE_POKE a target process which just happened to have
some mprotect_pkey(pkey=6) memory, we do *not* want to deny the
debugger access to that memory. PKRU is fundamentally a
thread-local structure and we do not want to enforce it on access
to _another_ thread's data.
This gets especially tricky when we have workqueues or other
delayed-work mechanisms that might run in a random process's context.
We can check that we only enforce pkeys when operating on our *own* mm,
but delayed work gets performed when a random user context is active.
We might end up with a situation where a delayed-work gup fails when
running randomly under its "own" task but succeeds when running under
another process. We want to avoid that.
To avoid that, we add a GUP flag: FOLL_FOREIGN and a fault flag:
FAULT_FLAG_FOREIGN. They indicate that we are walking an mm
which is not guranteed to be the same as current->mm and should
not be subject to protection key enforcement.
Thanks to Jerome Glisse for pointing out this scenario.
*** Why do we enforce protection keys in software?? ***
Imagine that we disabled access to the memory pointer to by 'buf'.
The, we implemented sys_write() like this:
sys_read(fd, buf, len...)
{
struct page *page = follow_page(buf);
void *buf_mapped = kmap(page);
memcpy(buf_mapped, fd_data, len);
...
}
This writes to 'buf' via a *kernel* mapping, without a protection
key. While this implementation does the same thing:
sys_read(fd, buf, len...)
{
copy_to_user(buf, fd_data, len);
...
}
but would hit a protection key fault because the userspace 'buf'
mapping has a protection key set.
To provide consistency, and to make key-protected memory work
as much like mprotect()ed memory as possible, we try to enforce
the same protections as the hardware would when the *kernel* walks
the page tables (and other mm structures).
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-arch@vger.kernel.org
---
b/arch/powerpc/include/asm/mmu_context.h | 3 ++-
b/arch/s390/include/asm/mmu_context.h | 3 ++-
b/arch/unicore32/include/asm/mmu_context.h | 3 ++-
b/arch/x86/include/asm/mmu_context.h | 5 +++--
b/drivers/iommu/amd_iommu_v2.c | 8 +++++---
b/include/asm-generic/mm_hooks.h | 3 ++-
b/include/linux/mm.h | 2 ++
b/mm/gup.c | 15 ++++++++++-----
b/mm/ksm.c | 10 ++++++++--
b/mm/memory.c | 3 ++-
10 files changed, 38 insertions(+), 17 deletions(-)
diff -puN arch/powerpc/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag arch/powerpc/include/asm/mmu_context.h
--- a/arch/powerpc/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.223698386 -0800
+++ b/arch/powerpc/include/asm/mmu_context.h 2015-12-03 16:21:26.241699202 -0800
@@ -148,7 +148,8 @@ static inline void arch_bprm_mm_init(str
{
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* by default, allow everything */
return true;
diff -puN arch/s390/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag arch/s390/include/asm/mmu_context.h
--- a/arch/s390/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.224698431 -0800
+++ b/arch/s390/include/asm/mmu_context.h 2015-12-03 16:21:26.242699248 -0800
@@ -130,7 +130,8 @@ static inline void arch_bprm_mm_init(str
{
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* by default, allow everything */
return true;
diff -puN arch/unicore32/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag arch/unicore32/include/asm/mmu_context.h
--- a/arch/unicore32/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.226698522 -0800
+++ b/arch/unicore32/include/asm/mmu_context.h 2015-12-03 16:21:26.242699248 -0800
@@ -97,7 +97,8 @@ static inline void arch_bprm_mm_init(str
{
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* by default, allow everything */
return true;
diff -puN arch/x86/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag arch/x86/include/asm/mmu_context.h
--- a/arch/x86/include/asm/mmu_context.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.228698613 -0800
+++ b/arch/x86/include/asm/mmu_context.h 2015-12-03 16:21:26.242699248 -0800
@@ -299,10 +299,11 @@ static inline bool vma_is_foreign(struct
return false;
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* allow access if the VMA is not one from this process */
- if (vma_is_foreign(vma))
+ if (foreign || vma_is_foreign(vma))
return true;
return __pkru_allows_pkey(vma_pkey(vma), write);
}
diff -puN drivers/iommu/amd_iommu_v2.c~pkeys-12-gup-fault-foreign-flag drivers/iommu/amd_iommu_v2.c
--- a/drivers/iommu/amd_iommu_v2.c~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.229698658 -0800
+++ b/drivers/iommu/amd_iommu_v2.c 2015-12-03 16:21:26.243699293 -0800
@@ -500,9 +500,11 @@ static void do_fault(struct work_struct
struct mm_struct *mm;
struct vm_area_struct *vma;
u64 address;
- int ret, write;
+ int ret, flags;
- write = !!(fault->flags & PPR_FAULT_WRITE);
+ if (fault->flags & PPR_FAULT_WRITE)
+ flags = FAULT_FLAG_WRITE;
+ flags |= FAULT_FLAG_FOREIGN;
mm = fault->state->mm;
address = fault->address;
@@ -523,7 +525,7 @@ static void do_fault(struct work_struct
goto out;
}
- ret = handle_mm_fault(mm, vma, address, write);
+ ret = handle_mm_fault(mm, vma, address, flags);
if (ret & VM_FAULT_ERROR) {
/* failed to service fault */
up_read(&mm->mmap_sem);
diff -puN include/asm-generic/mm_hooks.h~pkeys-12-gup-fault-foreign-flag include/asm-generic/mm_hooks.h
--- a/include/asm-generic/mm_hooks.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.231698749 -0800
+++ b/include/asm-generic/mm_hooks.h 2015-12-03 16:21:26.243699293 -0800
@@ -26,7 +26,8 @@ static inline void arch_bprm_mm_init(str
{
}
-static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, bool write)
+static inline bool arch_vma_access_permitted(struct vm_area_struct *vma,
+ bool write, bool foreign)
{
/* by default, allow everything */
return true;
diff -puN include/linux/mm.h~pkeys-12-gup-fault-foreign-flag include/linux/mm.h
--- a/include/linux/mm.h~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.233698839 -0800
+++ b/include/linux/mm.h 2015-12-03 16:21:26.244699338 -0800
@@ -232,6 +232,7 @@ extern pgprot_t protection_map[16];
#define FAULT_FLAG_KILLABLE 0x10 /* The fault task is in SIGKILL killable region */
#define FAULT_FLAG_TRIED 0x20 /* Second try */
#define FAULT_FLAG_USER 0x40 /* The fault originated in userspace */
+#define FAULT_FLAG_FOREIGN 0x80 /* faulting for non current tsk/mm */
/*
* vm_fault is filled by the the pagefault handler and passed to the vma's
@@ -2138,6 +2139,7 @@ static inline struct page *follow_page(s
#define FOLL_MIGRATION 0x400 /* wait for page to replace migration entry */
#define FOLL_TRIED 0x800 /* a retry, previous pass started an IO */
#define FOLL_MLOCK 0x1000 /* lock present pages */
+#define FOLL_FOREIGN 0x2000 /* we are working on non-current tsk/mm */
typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
void *data);
diff -puN mm/gup.c~pkeys-12-gup-fault-foreign-flag mm/gup.c
--- a/mm/gup.c~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.234698885 -0800
+++ b/mm/gup.c 2015-12-03 16:21:26.245699384 -0800
@@ -310,6 +310,8 @@ static int faultin_page(struct task_stru
return -ENOENT;
if (*flags & FOLL_WRITE)
fault_flags |= FAULT_FLAG_WRITE;
+ if (*flags & FOLL_FOREIGN)
+ fault_flags |= FAULT_FLAG_FOREIGN;
if (nonblocking)
fault_flags |= FAULT_FLAG_ALLOW_RETRY;
if (*flags & FOLL_NOWAIT)
@@ -360,11 +362,13 @@ static int faultin_page(struct task_stru
static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags)
{
vm_flags_t vm_flags = vma->vm_flags;
+ int write = (gup_flags & FOLL_WRITE);
+ int foreign = (gup_flags & FOLL_FOREIGN);
if (vm_flags & (VM_IO | VM_PFNMAP))
return -EFAULT;
- if (gup_flags & FOLL_WRITE) {
+ if (write) {
if (!(vm_flags & VM_WRITE)) {
if (!(gup_flags & FOLL_FORCE))
return -EFAULT;
@@ -392,7 +396,7 @@ static int check_vma_flags(struct vm_are
if (!(vm_flags & VM_MAYREAD))
return -EFAULT;
}
- if (!arch_vma_access_permitted(vma, (gup_flags & FOLL_WRITE)))
+ if (!arch_vma_access_permitted(vma, write, foreign))
return -EFAULT;
return 0;
}
@@ -562,7 +566,8 @@ EXPORT_SYMBOL(__get_user_pages);
bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags)
{
- bool write = !!(fault_flags & FAULT_FLAG_WRITE);
+ bool write = !!(fault_flags & FAULT_FLAG_WRITE);
+ bool foreign = !!(fault_flags & FAULT_FLAG_FOREIGN);
vm_flags_t vm_flags = write ? VM_WRITE : VM_READ;
if (!(vm_flags & vma->vm_flags))
@@ -570,9 +575,9 @@ bool vma_permits_fault(struct vm_area_st
/*
* The architecture might have a hardware protection
- * mechanism other than read/write that can deny access
+ * mechanism other than read/write that can deny access.
*/
- if (!arch_vma_access_permitted(vma, write))
+ if (!arch_vma_access_permitted(vma, write, foreign))
return false;
return true;
diff -puN mm/ksm.c~pkeys-12-gup-fault-foreign-flag mm/ksm.c
--- a/mm/ksm.c~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.236698975 -0800
+++ b/mm/ksm.c 2015-12-03 16:21:26.246699429 -0800
@@ -359,6 +359,10 @@ static inline bool ksm_test_exit(struct
* in case the application has unmapped and remapped mm,addr meanwhile.
* Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP
* mmap of /dev/mem or /dev/kmem, where we would not want to touch it.
+ *
+ * FAULT_FLAG/FOLL_FOREIGN are because we do this outside the context
+ * of the process that owns 'vma'. We also do not want to enforce
+ * protection keys here anyway.
*/
static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
{
@@ -367,12 +371,14 @@ static int break_ksm(struct vm_area_stru
do {
cond_resched();
- page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION);
+ page = follow_page(vma, addr,
+ FOLL_GET | FOLL_MIGRATION | FOLL_FOREIGN);
if (IS_ERR_OR_NULL(page))
break;
if (PageKsm(page))
ret = handle_mm_fault(vma->vm_mm, vma, addr,
- FAULT_FLAG_WRITE);
+ FAULT_FLAG_WRITE |
+ FAULT_FLAG_FOREIGN);
else
ret = VM_FAULT_WRITE;
put_page(page);
diff -puN mm/memory.c~pkeys-12-gup-fault-foreign-flag mm/memory.c
--- a/mm/memory.c~pkeys-12-gup-fault-foreign-flag 2015-12-03 16:21:26.238699066 -0800
+++ b/mm/memory.c 2015-12-03 16:21:26.247699474 -0800
@@ -3345,7 +3345,8 @@ static int __handle_mm_fault(struct mm_s
pmd_t *pmd;
pte_t *pte;
- if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE))
+ if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE,
+ flags & FAULT_FLAG_FOREIGN))
return VM_FAULT_SIGSEGV;
if (unlikely(is_vm_hugetlb_page(vma)))
_
^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits()
2015-12-04 1:14 [PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen
2015-12-04 1:14 ` Dave Hansen
2015-12-04 1:14 ` [PATCH 18/34] mm: add gup flag to indicate "foreign" mm access Dave Hansen
@ 2015-12-04 1:14 ` Dave Hansen
2015-12-04 1:14 ` Dave Hansen
2015-12-04 23:31 ` [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski
3 siblings, 1 reply; 11+ messages in thread
From: Dave Hansen @ 2015-12-04 1:14 UTC (permalink / raw)
To: linux-kernel
Cc: linux-mm, x86, Dave Hansen, dave.hansen, linux-api, linux-arch
From: Dave Hansen <dave.hansen@linux.intel.com>
This plumbs a protection key through calc_vm_flag_bits(). We
could have done this in calc_vm_prot_bits(), but I did not feel
super strongly which way to go. It was pretty arbitrary which
one to use.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
---
b/arch/powerpc/include/asm/mman.h | 5 +++--
b/drivers/char/agp/frontend.c | 2 +-
b/drivers/staging/android/ashmem.c | 4 ++--
b/include/linux/mman.h | 6 +++---
b/mm/mmap.c | 2 +-
b/mm/mprotect.c | 2 +-
b/mm/nommu.c | 2 +-
7 files changed, 12 insertions(+), 11 deletions(-)
diff -puN arch/powerpc/include/asm/mman.h~pkeys-84-calc_vm_prot_bits arch/powerpc/include/asm/mman.h
--- a/arch/powerpc/include/asm/mman.h~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.142830772 -0800
+++ b/arch/powerpc/include/asm/mman.h 2015-12-03 16:21:29.155831361 -0800
@@ -18,11 +18,12 @@
* This file is included by linux/mman.h, so we can't use cacl_vm_prot_bits()
* here. How important is the optimization?
*/
-static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot)
+static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
+ unsigned long pkey)
{
return (prot & PROT_SAO) ? VM_SAO : 0;
}
-#define arch_calc_vm_prot_bits(prot) arch_calc_vm_prot_bits(prot)
+#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
{
diff -puN drivers/char/agp/frontend.c~pkeys-84-calc_vm_prot_bits drivers/char/agp/frontend.c
--- a/drivers/char/agp/frontend.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.143830817 -0800
+++ b/drivers/char/agp/frontend.c 2015-12-03 16:21:29.155831361 -0800
@@ -156,7 +156,7 @@ static pgprot_t agp_convert_mmap_flags(i
{
unsigned long prot_bits;
- prot_bits = calc_vm_prot_bits(prot) | VM_SHARED;
+ prot_bits = calc_vm_prot_bits(prot, 0) | VM_SHARED;
return vm_get_page_prot(prot_bits);
}
diff -puN drivers/staging/android/ashmem.c~pkeys-84-calc_vm_prot_bits drivers/staging/android/ashmem.c
--- a/drivers/staging/android/ashmem.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.145830908 -0800
+++ b/drivers/staging/android/ashmem.c 2015-12-03 16:21:29.156831407 -0800
@@ -372,8 +372,8 @@ static int ashmem_mmap(struct file *file
}
/* requested protection bits must match our allowed protection mask */
- if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask)) &
- calc_vm_prot_bits(PROT_MASK))) {
+ if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask, 0)) &
+ calc_vm_prot_bits(PROT_MASK, 0))) {
ret = -EPERM;
goto out;
}
diff -puN include/linux/mman.h~pkeys-84-calc_vm_prot_bits include/linux/mman.h
--- a/include/linux/mman.h~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.147830999 -0800
+++ b/include/linux/mman.h 2015-12-03 16:21:29.156831407 -0800
@@ -35,7 +35,7 @@ static inline void vm_unacct_memory(long
*/
#ifndef arch_calc_vm_prot_bits
-#define arch_calc_vm_prot_bits(prot) 0
+#define arch_calc_vm_prot_bits(prot, pkey) 0
#endif
#ifndef arch_vm_get_page_prot
@@ -70,12 +70,12 @@ static inline int arch_validate_prot(uns
* Combine the mmap "prot" argument into "vm_flags" used internally.
*/
static inline unsigned long
-calc_vm_prot_bits(unsigned long prot)
+calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
{
return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
_calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
_calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
- arch_calc_vm_prot_bits(prot);
+ arch_calc_vm_prot_bits(prot, pkey);
}
/*
diff -puN mm/mmap.c~pkeys-84-calc_vm_prot_bits mm/mmap.c
--- a/mm/mmap.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.148831044 -0800
+++ b/mm/mmap.c 2015-12-03 16:21:29.157831452 -0800
@@ -1309,7 +1309,7 @@ unsigned long do_mmap(struct file *file,
* to. we assume access permissions have been handled by the open
* of the memory object, so we don't do any here.
*/
- vm_flags |= calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
+ vm_flags |= calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags) |
mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
if (flags & MAP_LOCKED)
diff -puN mm/mprotect.c~pkeys-84-calc_vm_prot_bits mm/mprotect.c
--- a/mm/mprotect.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.150831135 -0800
+++ b/mm/mprotect.c 2015-12-03 16:21:29.158831497 -0800
@@ -373,7 +373,7 @@ SYSCALL_DEFINE3(mprotect, unsigned long,
if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
prot |= PROT_EXEC;
- vm_flags = calc_vm_prot_bits(prot);
+ vm_flags = calc_vm_prot_bits(prot, 0);
down_write(¤t->mm->mmap_sem);
diff -puN mm/nommu.c~pkeys-84-calc_vm_prot_bits mm/nommu.c
--- a/mm/nommu.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.152831225 -0800
+++ b/mm/nommu.c 2015-12-03 16:21:29.158831497 -0800
@@ -1090,7 +1090,7 @@ static unsigned long determine_vm_flags(
{
unsigned long vm_flags;
- vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
+ vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags);
/* vm_flags |= mm->def_flags; */
if (!(capabilities & NOMMU_MAP_DIRECT)) {
_
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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see: http://www.linux-mm.org/ .
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^ permalink raw reply [flat|nested] 11+ messages in thread
* [PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits()
2015-12-04 1:14 ` [PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen
@ 2015-12-04 1:14 ` Dave Hansen
0 siblings, 0 replies; 11+ messages in thread
From: Dave Hansen @ 2015-12-04 1:14 UTC (permalink / raw)
To: linux-kernel
Cc: linux-mm, x86, Dave Hansen, dave.hansen, linux-api, linux-arch
From: Dave Hansen <dave.hansen@linux.intel.com>
This plumbs a protection key through calc_vm_flag_bits(). We
could have done this in calc_vm_prot_bits(), but I did not feel
super strongly which way to go. It was pretty arbitrary which
one to use.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
---
b/arch/powerpc/include/asm/mman.h | 5 +++--
b/drivers/char/agp/frontend.c | 2 +-
b/drivers/staging/android/ashmem.c | 4 ++--
b/include/linux/mman.h | 6 +++---
b/mm/mmap.c | 2 +-
b/mm/mprotect.c | 2 +-
b/mm/nommu.c | 2 +-
7 files changed, 12 insertions(+), 11 deletions(-)
diff -puN arch/powerpc/include/asm/mman.h~pkeys-84-calc_vm_prot_bits arch/powerpc/include/asm/mman.h
--- a/arch/powerpc/include/asm/mman.h~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.142830772 -0800
+++ b/arch/powerpc/include/asm/mman.h 2015-12-03 16:21:29.155831361 -0800
@@ -18,11 +18,12 @@
* This file is included by linux/mman.h, so we can't use cacl_vm_prot_bits()
* here. How important is the optimization?
*/
-static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot)
+static inline unsigned long arch_calc_vm_prot_bits(unsigned long prot,
+ unsigned long pkey)
{
return (prot & PROT_SAO) ? VM_SAO : 0;
}
-#define arch_calc_vm_prot_bits(prot) arch_calc_vm_prot_bits(prot)
+#define arch_calc_vm_prot_bits(prot, pkey) arch_calc_vm_prot_bits(prot, pkey)
static inline pgprot_t arch_vm_get_page_prot(unsigned long vm_flags)
{
diff -puN drivers/char/agp/frontend.c~pkeys-84-calc_vm_prot_bits drivers/char/agp/frontend.c
--- a/drivers/char/agp/frontend.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.143830817 -0800
+++ b/drivers/char/agp/frontend.c 2015-12-03 16:21:29.155831361 -0800
@@ -156,7 +156,7 @@ static pgprot_t agp_convert_mmap_flags(i
{
unsigned long prot_bits;
- prot_bits = calc_vm_prot_bits(prot) | VM_SHARED;
+ prot_bits = calc_vm_prot_bits(prot, 0) | VM_SHARED;
return vm_get_page_prot(prot_bits);
}
diff -puN drivers/staging/android/ashmem.c~pkeys-84-calc_vm_prot_bits drivers/staging/android/ashmem.c
--- a/drivers/staging/android/ashmem.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.145830908 -0800
+++ b/drivers/staging/android/ashmem.c 2015-12-03 16:21:29.156831407 -0800
@@ -372,8 +372,8 @@ static int ashmem_mmap(struct file *file
}
/* requested protection bits must match our allowed protection mask */
- if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask)) &
- calc_vm_prot_bits(PROT_MASK))) {
+ if (unlikely((vma->vm_flags & ~calc_vm_prot_bits(asma->prot_mask, 0)) &
+ calc_vm_prot_bits(PROT_MASK, 0))) {
ret = -EPERM;
goto out;
}
diff -puN include/linux/mman.h~pkeys-84-calc_vm_prot_bits include/linux/mman.h
--- a/include/linux/mman.h~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.147830999 -0800
+++ b/include/linux/mman.h 2015-12-03 16:21:29.156831407 -0800
@@ -35,7 +35,7 @@ static inline void vm_unacct_memory(long
*/
#ifndef arch_calc_vm_prot_bits
-#define arch_calc_vm_prot_bits(prot) 0
+#define arch_calc_vm_prot_bits(prot, pkey) 0
#endif
#ifndef arch_vm_get_page_prot
@@ -70,12 +70,12 @@ static inline int arch_validate_prot(uns
* Combine the mmap "prot" argument into "vm_flags" used internally.
*/
static inline unsigned long
-calc_vm_prot_bits(unsigned long prot)
+calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
{
return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
_calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
_calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
- arch_calc_vm_prot_bits(prot);
+ arch_calc_vm_prot_bits(prot, pkey);
}
/*
diff -puN mm/mmap.c~pkeys-84-calc_vm_prot_bits mm/mmap.c
--- a/mm/mmap.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.148831044 -0800
+++ b/mm/mmap.c 2015-12-03 16:21:29.157831452 -0800
@@ -1309,7 +1309,7 @@ unsigned long do_mmap(struct file *file,
* to. we assume access permissions have been handled by the open
* of the memory object, so we don't do any here.
*/
- vm_flags |= calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
+ vm_flags |= calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags) |
mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
if (flags & MAP_LOCKED)
diff -puN mm/mprotect.c~pkeys-84-calc_vm_prot_bits mm/mprotect.c
--- a/mm/mprotect.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.150831135 -0800
+++ b/mm/mprotect.c 2015-12-03 16:21:29.158831497 -0800
@@ -373,7 +373,7 @@ SYSCALL_DEFINE3(mprotect, unsigned long,
if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC))
prot |= PROT_EXEC;
- vm_flags = calc_vm_prot_bits(prot);
+ vm_flags = calc_vm_prot_bits(prot, 0);
down_write(¤t->mm->mmap_sem);
diff -puN mm/nommu.c~pkeys-84-calc_vm_prot_bits mm/nommu.c
--- a/mm/nommu.c~pkeys-84-calc_vm_prot_bits 2015-12-03 16:21:29.152831225 -0800
+++ b/mm/nommu.c 2015-12-03 16:21:29.158831497 -0800
@@ -1090,7 +1090,7 @@ static unsigned long determine_vm_flags(
{
unsigned long vm_flags;
- vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags);
+ vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(flags);
/* vm_flags |= mm->def_flags; */
if (!(capabilities & NOMMU_MAP_DIRECT)) {
_
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 00/34] x86: Memory Protection Keys (v5)
2015-12-04 1:14 [PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen
` (2 preceding siblings ...)
2015-12-04 1:14 ` [PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen
@ 2015-12-04 23:31 ` Andy Lutomirski
[not found] ` <CALCETrXwVb99hAvqR2o54aPwtpr8oubROtiRt45SiYRfUTAxCw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
3 siblings, 1 reply; 11+ messages in thread
From: Andy Lutomirski @ 2015-12-04 23:31 UTC (permalink / raw)
To: Dave Hansen
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, X86 ML,
Linux API, linux-arch, Andrea Arcangeli, Andrew Morton, Jan Kara,
Kirill A. Shutemov, Naoya Horiguchi
On Thu, Dec 3, 2015 at 5:14 PM, Dave Hansen <dave@sr71.net> wrote:
> Memory Protection Keys for User pages is a CPU feature which will
> first appear on Skylake Servers, but will also be supported on
> future non-server parts. It provides a mechanism for enforcing
> page-based protections, but without requiring modification of the
> page tables when an application changes protection domains. See
> the Documentation/ patch for more details.
What, if anything, happened to the signal handling parts?
Also, do you have a git tree for this somewhere? I can't actually
enable it (my laptop, while very shiny, is not a Skylake server), but
I can poke around a bit.
--Andy
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 00/34] x86: Memory Protection Keys (v5)
[not found] ` <CALCETrXwVb99hAvqR2o54aPwtpr8oubROtiRt45SiYRfUTAxCw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
@ 2015-12-04 23:38 ` Dave Hansen
2015-12-04 23:38 ` Dave Hansen
[not found] ` <56622401.20001-gkUM19QKKo4@public.gmane.org>
0 siblings, 2 replies; 11+ messages in thread
From: Dave Hansen @ 2015-12-04 23:38 UTC (permalink / raw)
To: Andy Lutomirski
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, X86 ML,
Linux API, linux-arch, Andrea Arcangeli, Andrew Morton, Jan Kara,
Kirill A. Shutemov, Naoya Horiguchi
On 12/04/2015 03:31 PM, Andy Lutomirski wrote:
> On Thu, Dec 3, 2015 at 5:14 PM, Dave Hansen <dave-gkUM19QKKo4@public.gmane.org> wrote:
>> Memory Protection Keys for User pages is a CPU feature which will
>> first appear on Skylake Servers, but will also be supported on
>> future non-server parts. It provides a mechanism for enforcing
>> page-based protections, but without requiring modification of the
>> page tables when an application changes protection domains. See
>> the Documentation/ patch for more details.
>
> What, if anything, happened to the signal handling parts?
Patches 12 and 13 contain most of it:
x86, pkeys: fill in pkey field in siginfo
signals, pkeys: notify userspace about protection key faults
I decided to just not try to preserve the pkey_get/set() semantics
across entering and returning from signals, fwiw.
> Also, do you have a git tree for this somewhere? I can't actually
> enable it (my laptop, while very shiny, is not a Skylake server), but
> I can poke around a bit.
http://git.kernel.org/cgit/linux/kernel/git/daveh/x86-pkeys.git/
Thanks for taking a look!
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 00/34] x86: Memory Protection Keys (v5)
2015-12-04 23:38 ` Dave Hansen
@ 2015-12-04 23:38 ` Dave Hansen
[not found] ` <56622401.20001-gkUM19QKKo4@public.gmane.org>
1 sibling, 0 replies; 11+ messages in thread
From: Dave Hansen @ 2015-12-04 23:38 UTC (permalink / raw)
To: Andy Lutomirski
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, X86 ML,
Linux API, linux-arch, Andrea Arcangeli, Andrew Morton, Jan Kara,
Kirill A. Shutemov, Naoya Horiguchi
On 12/04/2015 03:31 PM, Andy Lutomirski wrote:
> On Thu, Dec 3, 2015 at 5:14 PM, Dave Hansen <dave@sr71.net> wrote:
>> Memory Protection Keys for User pages is a CPU feature which will
>> first appear on Skylake Servers, but will also be supported on
>> future non-server parts. It provides a mechanism for enforcing
>> page-based protections, but without requiring modification of the
>> page tables when an application changes protection domains. See
>> the Documentation/ patch for more details.
>
> What, if anything, happened to the signal handling parts?
Patches 12 and 13 contain most of it:
x86, pkeys: fill in pkey field in siginfo
signals, pkeys: notify userspace about protection key faults
I decided to just not try to preserve the pkey_get/set() semantics
across entering and returning from signals, fwiw.
> Also, do you have a git tree for this somewhere? I can't actually
> enable it (my laptop, while very shiny, is not a Skylake server), but
> I can poke around a bit.
http://git.kernel.org/cgit/linux/kernel/git/daveh/x86-pkeys.git/
Thanks for taking a look!
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 00/34] x86: Memory Protection Keys (v5)
[not found] ` <56622401.20001-gkUM19QKKo4@public.gmane.org>
@ 2015-12-11 20:16 ` Andy Lutomirski
2015-12-11 20:16 ` Andy Lutomirski
0 siblings, 1 reply; 11+ messages in thread
From: Andy Lutomirski @ 2015-12-11 20:16 UTC (permalink / raw)
To: Dave Hansen
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, X86 ML,
Linux API, linux-arch, Andrea Arcangeli, Andrew Morton, Jan Kara,
Kirill A. Shutemov, Naoya Horiguchi
On Fri, Dec 4, 2015 at 3:38 PM, Dave Hansen <dave-gkUM19QKKo4@public.gmane.org> wrote:
> On 12/04/2015 03:31 PM, Andy Lutomirski wrote:
>> On Thu, Dec 3, 2015 at 5:14 PM, Dave Hansen <dave-gkUM19QKKo4@public.gmane.org> wrote:
>>> Memory Protection Keys for User pages is a CPU feature which will
>>> first appear on Skylake Servers, but will also be supported on
>>> future non-server parts. It provides a mechanism for enforcing
>>> page-based protections, but without requiring modification of the
>>> page tables when an application changes protection domains. See
>>> the Documentation/ patch for more details.
>>
>> What, if anything, happened to the signal handling parts?
>
> Patches 12 and 13 contain most of it:
>
> x86, pkeys: fill in pkey field in siginfo
> signals, pkeys: notify userspace about protection key faults
>
> I decided to just not try to preserve the pkey_get/set() semantics
> across entering and returning from signals, fwiw.
Hmm. I'll see if I can find some time this weekend to play with that
bit. Maybe I can test by faking it and tweaking MPX instead of PKRU.
--Andy
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH 00/34] x86: Memory Protection Keys (v5)
2015-12-11 20:16 ` Andy Lutomirski
@ 2015-12-11 20:16 ` Andy Lutomirski
0 siblings, 0 replies; 11+ messages in thread
From: Andy Lutomirski @ 2015-12-11 20:16 UTC (permalink / raw)
To: Dave Hansen
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, X86 ML,
Linux API, linux-arch, Andrea Arcangeli, Andrew Morton, Jan Kara,
Kirill A. Shutemov, Naoya Horiguchi
On Fri, Dec 4, 2015 at 3:38 PM, Dave Hansen <dave@sr71.net> wrote:
> On 12/04/2015 03:31 PM, Andy Lutomirski wrote:
>> On Thu, Dec 3, 2015 at 5:14 PM, Dave Hansen <dave@sr71.net> wrote:
>>> Memory Protection Keys for User pages is a CPU feature which will
>>> first appear on Skylake Servers, but will also be supported on
>>> future non-server parts. It provides a mechanism for enforcing
>>> page-based protections, but without requiring modification of the
>>> page tables when an application changes protection domains. See
>>> the Documentation/ patch for more details.
>>
>> What, if anything, happened to the signal handling parts?
>
> Patches 12 and 13 contain most of it:
>
> x86, pkeys: fill in pkey field in siginfo
> signals, pkeys: notify userspace about protection key faults
>
> I decided to just not try to preserve the pkey_get/set() semantics
> across entering and returning from signals, fwiw.
Hmm. I'll see if I can find some time this weekend to play with that
bit. Maybe I can test by faking it and tweaking MPX instead of PKRU.
--Andy
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2015-12-11 20:16 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2015-12-04 1:14 [PATCH 00/34] x86: Memory Protection Keys (v5) Dave Hansen
2015-12-04 1:14 ` Dave Hansen
2015-12-04 1:14 ` [PATCH 18/34] mm: add gup flag to indicate "foreign" mm access Dave Hansen
2015-12-04 1:14 ` Dave Hansen
2015-12-04 1:14 ` [PATCH 24/34] mm, multi-arch: pass a protection key in to calc_vm_flag_bits() Dave Hansen
2015-12-04 1:14 ` Dave Hansen
2015-12-04 23:31 ` [PATCH 00/34] x86: Memory Protection Keys (v5) Andy Lutomirski
[not found] ` <CALCETrXwVb99hAvqR2o54aPwtpr8oubROtiRt45SiYRfUTAxCw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-12-04 23:38 ` Dave Hansen
2015-12-04 23:38 ` Dave Hansen
[not found] ` <56622401.20001-gkUM19QKKo4@public.gmane.org>
2015-12-11 20:16 ` Andy Lutomirski
2015-12-11 20:16 ` Andy Lutomirski
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