linux/include/asm-generic
Peter Xu f1eb1bacfb mm/uffd: always wr-protect pte in pte|pmd_mkuffd_wp()
This patch is a cleanup to always wr-protect pte/pmd in mkuffd_wp paths.

The reasons I still think this patch is worthwhile, are:

  (1) It is a cleanup already; diffstat tells.

  (2) It just feels natural after I thought about this, if the pte is uffd
      protected, let's remove the write bit no matter what it was.

  (2) Since x86 is the only arch that supports uffd-wp, it also redefines
      pte|pmd_mkuffd_wp() in that it should always contain removals of
      write bits.  It means any future arch that want to implement uffd-wp
      should naturally follow this rule too.  It's good to make it a
      default, even if with vm_page_prot changes on VM_UFFD_WP.

  (3) It covers more than vm_page_prot.  So no chance of any potential
      future "accident" (like pte_mkdirty() sparc64 or loongarch, even
      though it just got its pte_mkdirty fixed <1 month ago).  It'll be
      fairly clear when reading the code too that we don't worry anything
      before a pte_mkuffd_wp() on uncertainty of the write bit.

We may call pte_wrprotect() one more time in some paths (e.g.  thp split),
but that should be fully local bitop instruction so the overhead should be
negligible.

Although this patch should logically also fix all the known issues on
uffd-wp too recently on page migration (not for numa hint recovery - that
may need another explcit pte_wrprotect), but this is not the plan for that
fix.  So no fixes, and stable doesn't need this.

Link: https://lkml.kernel.org/r/20221214201533.1774616-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ives van Hoorne <ives@codesandbox.io>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-01-18 17:12:37 -08:00
..
bitops wait_on_bit: add an acquire memory barrier 2022-08-26 09:30:25 -07:00
vdso lib/vdso: Avoid highres update if clocksource is not VDSO capable 2020-02-17 20:12:17 +01:00
access_ok.h uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
archrandom.h random: handle archrandom with multiple longs 2022-07-25 13:26:14 +02:00
asm-offsets.h
asm-prototypes.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
atomic64.h locking/atomic: delete !ARCH_ATOMIC remnants 2021-05-26 13:20:52 +02:00
atomic.h locking/atomic: delete !ARCH_ATOMIC remnants 2021-05-26 13:20:52 +02:00
audit_change_attr.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit_dir_write.h audit: Avoid build failures on systems without renameat 2018-01-30 19:07:54 -08:00
audit_read.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
audit_signal.h
audit_write.h audit/stable-4.15 PR 20171113 2017-11-15 13:28:48 -08:00
barrier.h asm-generic: Add memory barrier dma_mb() 2022-06-23 18:34:58 +01:00
bitops.h include: move find.h from asm_generic to linux 2022-01-15 08:47:31 -08:00
bitsperlong.h lib: extend the scope of small_const_nbits() macro 2021-05-06 19:24:11 -07:00
bug.h treewide: Drop WARN_ON_FUNCTION_MISMATCH 2022-09-26 10:13:14 -07:00
bugs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cache.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
cacheflush.h asm-generic: instrument usercopy in cacheflush.h 2022-10-03 14:03:18 -07:00
checksum.h unify generic instances of csum_partial_copy_nocheck() 2020-08-20 15:45:14 -04:00
cmpxchg-local.h locking/atomic: cmpxchg: make generic a prefix 2021-05-26 13:20:50 +02:00
cmpxchg.h locking/atomic: delete !ARCH_ATOMIC remnants 2021-05-26 13:20:52 +02:00
compat.h asm-generic: compat: fix compat_arg_u64() and compat_arg_u64_dual() 2022-11-01 10:20:11 +11:00
current.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
delay.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
device.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 428 2019-06-05 17:37:16 +02:00
div64.h ARM: 9117/1: asm-generic: div64: Remove always-true __div64_const32_is_OK() 2021-08-20 11:39:28 +01:00
dma-mapping.h dma-mapping: bypass indirect calls for dma-direct 2018-12-13 21:06:18 +01:00
dma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
early_ioremap.h mm/early_ioremap.c: remove redundant early_ioremap_shutdown() 2021-09-08 11:50:24 -07:00
emergency-restart.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
error-injection.h asm-generic/error-injection.h: fix a spelling mistake, and a coding style issue 2021-12-17 14:12:14 +01:00
exec.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
export.h kbuild: link symbol CRCs at final link, removing CONFIG_MODULE_REL_CRCS 2022-05-24 16:33:20 +09:00
extable.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fb.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fixmap.h mm: introduce common STRUCT_PAGE_MAX_SHIFT define 2018-12-14 15:05:45 -08:00
flat.h binfmt_flat: remove the persistent argument from flat_get_addr_from_rp 2019-06-24 09:16:47 +10:00
ftrace.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
futex.h futex: Fix additional regressions 2021-12-11 23:31:51 +01:00
getorder.h asm-generic: force inlining of get_order() to work around gcc10 poor decision 2020-12-15 22:46:15 -08:00
gpio.h gpiolib: Get rid of ARCH_NR_GPIOS 2022-10-17 11:03:09 +02:00
hardirq.h irqstat: Move declaration into asm-generic/hardirq.h 2020-11-23 10:31:06 +01:00
hugetlb.h mm/uffd: always wr-protect pte in pte|pmd_mkuffd_wp() 2023-01-18 17:12:37 -08:00
hw_irq.h
hyperv-tlfs.h ARM64: 2022-12-15 11:12:21 -08:00
ide_iops.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
int-ll64.h int-ll64.h: define u{8,16,32,64} and s{8,16,32,64} based on uapi header 2018-06-07 17:34:38 -07:00
io.h asm-generic/io: Add _RET_IP_ to MMIO trace for more accurate debug info 2022-11-21 22:02:10 +01:00
ioctl.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
iomap.h parisc: Declare pci_iounmap() parisc version only when CONFIG_PCI enabled 2021-09-19 10:36:09 -07:00
irq_regs.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
irq_work.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irq.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
irqflags.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kbuild xen: branch for v6.0-rc1 2022-08-04 15:10:55 -07:00
kdebug.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
kmap_size.h mm/highmem: Provide and use CONFIG_DEBUG_KMAP_LOCAL 2020-11-24 14:42:08 +01:00
kprobes.h treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
kvm_para.h KVM: Introduce paravirtualization hints and KVM_HINTS_DEDICATED 2018-03-06 18:40:44 +01:00
kvm_types.h KVM: Move x86's version of struct kvm_mmu_memory_cache to common code 2020-07-09 13:29:42 -04:00
linkage.h
local64.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
local.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
logic_io.h logic_io instance of iounmap() needs volatile on argument 2021-12-21 21:31:08 +01:00
mcs_spinlock.h
memory_model.h mm: remove CONFIG_DISCONTIGMEM 2021-06-29 10:53:55 -07:00
mm_hooks.h mm: remove arch_bprm_mm_init() hook 2020-01-23 10:41:16 -08:00
mmiowb_types.h asm-generic/mmiowb: Add generic implementation of mmiowb() tracking 2019-04-08 11:59:39 +01:00
mmiowb.h asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible() 2020-07-17 10:02:03 +01:00
mmu_context.h asm-generic: add generic MMU versions of mmu context functions 2020-10-26 16:45:03 +01:00
mmu.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
module.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
module.lds.h kbuild: preprocess module linker script 2020-09-25 00:36:41 +09:00
mshyperv.h x86/hyperv: Introduce HV_MAX_SPARSE_VCPU_BANKS/HV_VCPUS_PER_SPARSE_BANK constants 2022-11-18 12:59:07 -05:00
msi.h genirq: Get rid of GENERIC_MSI_IRQ_DOMAIN 2022-11-17 15:15:20 +01:00
nommu_context.h asm-generic: add generic MMU versions of mmu context functions 2020-10-26 16:45:03 +01:00
numa.h numa: Move numa implementation to common code 2021-01-14 15:08:55 -08:00
page.h c6x: remove architecture 2021-01-20 09:30:45 +01:00
param.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
parport.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pci_iomap.h PCI: Stub __pci_ioport_map() for arches that don't support it at all 2022-07-29 12:01:00 -05:00
pci.h asm-generic: Add new pci.h and use it 2022-07-22 17:34:57 -05:00
percpu.h asm-generic: percpu: avoid Wshadow warning 2020-10-26 23:54:48 +00:00
pgalloc.h asm-generic: Prepare for riscv use of pud_alloc_one and pud_free 2022-01-19 17:54:08 -08:00
pgtable_uffd.h userfaultfd: wp: add pmd_swp_*uffd_wp() helpers 2020-04-07 10:43:39 -07:00
pgtable-nop4d.h mm: rename p4d_page_vaddr to p4d_pgtable and make it return pud_t * 2021-07-08 11:48:22 -07:00
pgtable-nopmd.h riscv/mm: fix two page table check related issues 2022-05-19 14:08:48 -07:00
pgtable-nopud.h mm: rename p4d_page_vaddr to p4d_pgtable and make it return pud_t * 2021-07-08 11:48:22 -07:00
preempt.h sched/core: Initialize the idle task with preemption disabled 2021-05-12 13:01:45 +02:00
qrwlock_types.h locking/qrwlock: Change "queue rwlock" to "queued rwlock" 2022-05-11 16:27:04 +02:00
qrwlock.h asm-generic changes for 5.19 2022-05-26 10:50:30 -07:00
qspinlock_types.h locking/qspinlock: Do not include atomic.h from qspinlock_types.h 2020-07-29 16:14:19 +02:00
qspinlock.h asm-generic: qspinlock: Indicate the use of mixed-size atomics 2022-05-11 11:49:47 -07:00
resource.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rwonce.h asm/rwonce: Don't pull <asm/barrier.h> into 'asm-generic/rwonce.h' 2020-07-21 10:50:36 +01:00
seccomp.h seccomp: Use -1 marker for end of mode 1 syscall list 2020-07-10 16:01:52 -07:00
sections.h asm-generic: sections: refactor memory_intersects 2022-08-28 14:02:45 -07:00
serial.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
set_memory.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
shmparam.h treewide: remove SPDX "WITH Linux-syscall-note" from kernel-space headers 2019-05-14 19:52:48 -07:00
signal.h asm-generic: Remove empty #ifdef SA_RESTORER 2022-09-10 09:56:53 +02:00
simd.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
softirq_stack.h asm-generic: Conditionally enable do_softirq_own_stack() via Kconfig. 2022-09-05 17:20:55 +02:00
spinlock_types.h asm-generic: ticket-lock: New generic ticket-based spinlock 2022-05-11 11:49:38 -07:00
spinlock.h asm-generic: ticket-lock: New generic ticket-based spinlock 2022-05-11 11:49:38 -07:00
statfs.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
string.h
switch_to.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36 2019-05-24 17:27:11 +02:00
syscall.h ptrace: Create ptrace_report_syscall_{entry,exit} in ptrace.h 2022-03-10 13:35:08 -06:00
syscalls.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
timex.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tlb.h mm: delay page_remove_rmap() until after the TLB has been flushed 2022-11-30 15:58:50 -08:00
tlbflush.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
topology.h mm: replace CONFIG_NEED_MULTIPLE_NODES with CONFIG_NUMA 2021-06-29 10:53:55 -07:00
trace_clock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
uaccess.h uaccess: remove CONFIG_SET_FS 2022-02-25 09:36:06 +01:00
unaligned.h asm-generic: make parameter types consistent in _unaligned_be48() 2022-09-11 21:55:12 -07:00
user.h
vermagic.h arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> 2020-04-23 10:50:26 +09:00
vga.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vmlinux.lds.h arch: fix broken BuildID for arm64 and riscv 2022-12-30 17:21:51 +09:00
vtime.h
word-at-a-time.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
xor.h lib/xor: make xor prototypes more friendly to compiler vectorization 2022-02-11 20:39:39 +11:00