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Subject[PATCH 00/39 v8] PTI support for x86-32
Date
Hi,

here is version 8 of my patches to enable PTI on x86-32. The
last version got some good review which I mostly worked into
this version.

I didn't rebase it to v4.18-rc5, as that base didn't boot on
x86-32 because of a regression introduced by

e181ae0c5db9 ('mm: zero unavailable pages before memmap init')

But that is already being worked on. The rebase I tried
showed no conflicts, so these patches should apply cleanly
there as well.

The changes to v7 are:

* Fixed kbuild error (one patch failed to build)

* Removed segment loading changes from SAVE_ALL

* More restrictive entry-stack check in
SWITCH_TO_KERNEL_STACK

* Renamed TSS_entry_stack to TSS_entry2task_stack

* Documented properly what will go into TSS.sp1

* Fixed comment for clearing high-bits of the dword
containing CS-slot in pt_regs

* Fixed X86_FEATURE_PCID check for x86-32 in pti_init()

* Made entry-debugging depend on CONFIG_DEBUG_ENTRY
instead of a new config option

* Dropped cpu_current_top_of_stack->tss.sp1 patch.
It was actually subtly broken on x86-32 because
there is a difference between the task-stack
pointer and cpu_current_top_of_stack. The formula
is:

task_stack = cpu_current_top_of_stack - padding

On x86-64 the padding is zero, so there is no
difference, but on x86-32 it is 8 or 16 bytes so
that cpu_current_top_of_stack can't point to
tss.sp1 without breaking current_pt_regs().

* Renamed update_sp0 to update_task_stack() and made
that function update TSS.sp1 on x86-32. This is
also needed for VM86 mode. I think it can also be
implemented this way on x86-64, but that will be a
separate patch outside of this patch-set.

The patches still need fixes already in tip-tree to work
correctly. I merged these fixes into the branch I pushed to

git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git pti-x32-v8

for easier testing. The code survived >12h overnight testing
with my usual

* 'perf top' for NMI load

* x86-selftests in a loop (except mpx and pkeys
which are not supported on the machine)

* kernel-compile in a loop

all in parallel. I also boot-tested x86-64 and !PAE config
again and ran my GLB-test to make sure that the global
mappings between user and kernel page-table are identical.
All that succeeded and showed no regressions.

Previous versions of this patch-set are:

* For v7:
Post : https://lore.kernel.org/lkml/1531308586-29340-1-git-send-email-joro@8bytes.org/
Git : git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git pti-x32-v7

* For v6:
Post : https://lore.kernel.org/lkml/1524498460-25530-1-git-send-email-joro@8bytes.org/
Git : git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git pti-x32-v6

* For v5:
Post : https://marc.info/?l=linux-kernel&m=152389297705480&w=2
Git : git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git pti-x32-v5

* For v4:
Post : https://marc.info/?l=linux-kernel&m=152122860630236&w=2
Git : git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git pti-x32-v4

* For v3:
Post : https://marc.info/?l=linux-kernel&m=152024559419876&w=2
Git : git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git pti-x32-v3

* For v2:
Post : https://marc.info/?l=linux-kernel&m=151816914932088&w=2
Git : git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git pti-x32-v2

Please review.

Thanks,

Joerg


Joerg Roedel (39):
x86/asm-offsets: Move TSS_sp0 and TSS_sp1 to asm-offsets.c
x86/entry/32: Rename TSS_sysenter_sp0 to TSS_entry2task_stack
x86/entry/32: Load task stack from x86_tss.sp1 in SYSENTER handler
x86/entry/32: Put ESPFIX code into a macro
x86/entry/32: Unshare NMI return path
x86/entry/32: Split off return-to-kernel path
x86/entry/32: Enter the kernel via trampoline stack
x86/entry/32: Leave the kernel via trampoline stack
x86/entry/32: Introduce SAVE_ALL_NMI and RESTORE_ALL_NMI
x86/entry/32: Handle Entry from Kernel-Mode on Entry-Stack
x86/entry/32: Simplify debug entry point
x86/entry/32: Add PTI cr3 switch to non-NMI entry/exit points
x86/entry/32: Add PTI cr3 switches to NMI handler code
x86/entry: Rename update_sp0 to update_task_stack
x86/pgtable: Rename pti_set_user_pgd to pti_set_user_pgtbl
x86/pgtable/pae: Unshare kernel PMDs when PTI is enabled
x86/pgtable/32: Allocate 8k page-tables when PTI is enabled
x86/pgtable: Move pgdp kernel/user conversion functions to pgtable.h
x86/pgtable: Move pti_set_user_pgtbl() to pgtable.h
x86/pgtable: Move two more functions from pgtable_64.h to pgtable.h
x86/mm/pae: Populate valid user PGD entries
x86/mm/pae: Populate the user page-table with user pgd's
x86/mm/legacy: Populate the user page-table with user pgd's
x86/mm/pti: Add an overflow check to pti_clone_pmds()
x86/mm/pti: Define X86_CR3_PTI_PCID_USER_BIT on x86_32
x86/mm/pti: Clone CPU_ENTRY_AREA on PMD level on x86_32
x86/mm/pti: Make pti_clone_kernel_text() compile on 32 bit
x86/mm/pti: Keep permissions when cloning kernel text in
pti_clone_kernel_text()
x86/mm/pti: Introduce pti_finalize()
x86/mm/pti: Clone entry-text again in pti_finalize()
x86/mm/dump_pagetables: Define INIT_PGD
x86/pgtable/pae: Use separate kernel PMDs for user page-table
x86/ldt: Reserve address-space range on 32 bit for the LDT
x86/ldt: Define LDT_END_ADDR
x86/ldt: Split out sanity check in map_ldt_struct()
x86/ldt: Enable LDT user-mapping for PAE
x86/pti: Allow CONFIG_PAGE_TABLE_ISOLATION for x86_32
x86/mm/pti: Add Warning when booting on a PCID capable CPU
x86/entry/32: Add debug code to check entry/exit cr3

arch/x86/entry/entry_32.S | 624 +++++++++++++++++++++++-----
arch/x86/include/asm/mmu_context.h | 5 -
arch/x86/include/asm/pgtable-2level.h | 9 +
arch/x86/include/asm/pgtable-2level_types.h | 3 +
arch/x86/include/asm/pgtable-3level.h | 7 +
arch/x86/include/asm/pgtable-3level_types.h | 6 +-
arch/x86/include/asm/pgtable.h | 87 ++++
arch/x86/include/asm/pgtable_32.h | 2 -
arch/x86/include/asm/pgtable_32_types.h | 9 +-
arch/x86/include/asm/pgtable_64.h | 89 +---
arch/x86/include/asm/pgtable_64_types.h | 3 +
arch/x86/include/asm/pgtable_types.h | 28 +-
arch/x86/include/asm/processor-flags.h | 8 +-
arch/x86/include/asm/pti.h | 3 +-
arch/x86/include/asm/sections.h | 1 +
arch/x86/include/asm/switch_to.h | 16 +-
arch/x86/kernel/asm-offsets.c | 5 +
arch/x86/kernel/asm-offsets_32.c | 10 +-
arch/x86/kernel/asm-offsets_64.c | 2 -
arch/x86/kernel/cpu/common.c | 5 +-
arch/x86/kernel/head_32.S | 20 +-
arch/x86/kernel/ldt.c | 137 ++++--
arch/x86/kernel/process.c | 2 -
arch/x86/kernel/process_32.c | 2 +-
arch/x86/kernel/process_64.c | 2 +-
arch/x86/kernel/vm86_32.c | 4 +-
arch/x86/kernel/vmlinux.lds.S | 17 +-
arch/x86/mm/dump_pagetables.c | 21 +-
arch/x86/mm/init_64.c | 6 -
arch/x86/mm/pgtable.c | 105 ++++-
arch/x86/mm/pti.c | 73 +++-
include/linux/pti.h | 1 +
init/main.c | 7 +
security/Kconfig | 2 +-
34 files changed, 1014 insertions(+), 307 deletions(-)

--
2.7.4

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