Pull PCI fixes from Bjorn Helgaas:
- Revert emulation of Marvell Armada A3720 expansion ROM because it
doesn't work as expected (Marek Behún)
- Assert PERST# in Apple M1 driver to fix initialization when booting
from bootloaders using PCIe, such as U-Boot (Marc Zyngier)
- Describe PERST# as active low in Apple T8103 DT and update driver to
match (Marc Zyngier)
* tag 'pci-v5.16-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
PCI: apple: Fix PERST# polarity
arm64: dts: apple: t8103: Mark PCIe PERST# polarity active low in DT
PCI: apple: Follow the PCIe specifications when resetting the port
Revert "PCI: aardvark: Fix support for PCI_ROM_ADDRESS1 on emulated bridge"
Pull arm64 fixes from Will Deacon:
"Three arm64 fixes for -rc4.
One of them is just a trivial documentation fix, whereas the other two
address a warning in the kexec code and a crash in ftrace on systems
implementing BTI.
The latter patch has a couple of ugly ifdefs which Mark plans to clean
up separately, but as-is the patch is straightforward for backporting
to stable kernels.
Summary:
- Add missing BTI landing instructions to the ftrace*_caller
trampolines
- Fix kexec() WARN when DEBUG_VIRTUAL is enabled
- Fix PAC documentation by removing stale references to compiler
flags"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: ftrace: add missing BTIs
arm64: kexec: use __pa_symbol(empty_zero_page)
arm64: update PAC description for kernel
When branch target identifiers are in use, code reachable via an
indirect branch requires a BTI landing pad at the branch target site.
When building FTRACE_WITH_REGS atop patchable-function-entry, we miss
BTIs at the start start of the `ftrace_caller` and `ftrace_regs_caller`
trampolines, and when these are called from a module via a PLT (which
will use a `BR X16`), we will encounter a BTI failure, e.g.
| # insmod lkdtm.ko
| lkdtm: No crash points registered, enable through debugfs
| # echo function_graph > /sys/kernel/debug/tracing/current_tracer
| # cat /sys/kernel/debug/provoke-crash/DIRECT
| Unhandled 64-bit el1h sync exception on CPU0, ESR 0x34000001 -- BTI
| CPU: 0 PID: 174 Comm: cat Not tainted 5.16.0-rc2-dirty #3
| Hardware name: linux,dummy-virt (DT)
| pstate: 60400405 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=jc)
| pc : ftrace_caller+0x0/0x3c
| lr : lkdtm_debugfs_open+0xc/0x20 [lkdtm]
| sp : ffff800012e43b00
| x29: ffff800012e43b00 x28: 0000000000000000 x27: ffff800012e43c88
| x26: 0000000000000000 x25: 0000000000000000 x24: ffff0000c171f200
| x23: ffff0000c27b1e00 x22: ffff0000c2265240 x21: ffff0000c23c8c30
| x20: ffff8000090ba380 x19: 0000000000000000 x18: 0000000000000000
| x17: 0000000000000000 x16: ffff80001002bb4c x15: 0000000000000000
| x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000900ff0
| x11: ffff0000c4166310 x10: ffff800012e43b00 x9 : ffff8000104f2384
| x8 : 0000000000000001 x7 : 0000000000000000 x6 : 000000000000003f
| x5 : 0000000000000040 x4 : ffff800012e43af0 x3 : 0000000000000001
| x2 : ffff8000090b0000 x1 : ffff0000c171f200 x0 : ffff0000c23c8c30
| Kernel panic - not syncing: Unhandled exception
| CPU: 0 PID: 174 Comm: cat Not tainted 5.16.0-rc2-dirty #3
| Hardware name: linux,dummy-virt (DT)
| Call trace:
| dump_backtrace+0x0/0x1a4
| show_stack+0x24/0x30
| dump_stack_lvl+0x68/0x84
| dump_stack+0x1c/0x38
| panic+0x168/0x360
| arm64_exit_nmi.isra.0+0x0/0x80
| el1h_64_sync_handler+0x68/0xd4
| el1h_64_sync+0x78/0x7c
| ftrace_caller+0x0/0x3c
| do_dentry_open+0x134/0x3b0
| vfs_open+0x38/0x44
| path_openat+0x89c/0xe40
| do_filp_open+0x8c/0x13c
| do_sys_openat2+0xbc/0x174
| __arm64_sys_openat+0x6c/0xbc
| invoke_syscall+0x50/0x120
| el0_svc_common.constprop.0+0xdc/0x100
| do_el0_svc+0x84/0xa0
| el0_svc+0x28/0x80
| el0t_64_sync_handler+0xa8/0x130
| el0t_64_sync+0x1a0/0x1a4
| SMP: stopping secondary CPUs
| Kernel Offset: disabled
| CPU features: 0x0,00000f42,da660c5f
| Memory Limit: none
| ---[ end Kernel panic - not syncing: Unhandled exception ]---
Fix this by adding the required `BTI C`, as we only require these to be
reachable via BL for direct calls or BR X16/X17 for PLTs. For now, these
are open-coded in the function prologue, matching the style of the
`__hwasan_tag_mismatch` trampoline.
In future we may wish to consider adding a new SYM_CODE_START_*()
variant which has an implicit BTI.
When ftrace is built atop mcount, the trampolines are marked with
SYM_FUNC_START(), and so get an implicit BTI. We may need to change
these over to SYM_CODE_START() in future for RELIABLE_STACKTRACE, in
case we need to apply special care aroud the return address being
rewritten.
Fixes: 97fed779f2 ("arm64: bti: Provide Kconfig for kernel mode BTI")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211129135709.2274019-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
In machine_kexec_post_load() we use __pa() on `empty_zero_page`, so that
we can use the physical address during arm64_relocate_new_kernel() to
switch TTBR1 to a new set of tables. While `empty_zero_page` is part of
the old kernel, we won't clobber it until after this switch, so using it
is benign.
However, `empty_zero_page` is part of the kernel image rather than a
linear map address, so it is not correct to use __pa(x), and we should
instead use __pa_symbol(x) or __pa(lm_alias(x)). Otherwise, when the
kernel is built with DEBUG_VIRTUAL, we'll encounter splats as below, as
I've seen when fuzzing v5.16-rc3 with Syzkaller:
| ------------[ cut here ]------------
| virt_to_phys used for non-linear address: 000000008492561a (empty_zero_page+0x0/0x1000)
| WARNING: CPU: 3 PID: 11492 at arch/arm64/mm/physaddr.c:15 __virt_to_phys+0x120/0x1c0 arch/arm64/mm/physaddr.c:12
| CPU: 3 PID: 11492 Comm: syz-executor.0 Not tainted 5.16.0-rc3-00001-g48bd452a045c #1
| Hardware name: linux,dummy-virt (DT)
| pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : __virt_to_phys+0x120/0x1c0 arch/arm64/mm/physaddr.c:12
| lr : __virt_to_phys+0x120/0x1c0 arch/arm64/mm/physaddr.c:12
| sp : ffff80001af17bb0
| x29: ffff80001af17bb0 x28: ffff1cc65207b400 x27: ffffb7828730b120
| x26: 0000000000000e11 x25: 0000000000000000 x24: 0000000000000001
| x23: ffffb7828963e000 x22: ffffb78289644000 x21: 0000600000000000
| x20: 000000000000002d x19: 0000b78289644000 x18: 0000000000000000
| x17: 74706d6528206131 x16: 3635323934383030 x15: 303030303030203a
| x14: 1ffff000035e2eb8 x13: ffff6398d53f4f0f x12: 1fffe398d53f4f0e
| x11: 1fffe398d53f4f0e x10: ffff6398d53f4f0e x9 : ffffb7827c6f76dc
| x8 : ffff1cc6a9fa7877 x7 : 0000000000000001 x6 : ffff6398d53f4f0f
| x5 : 0000000000000000 x4 : 0000000000000000 x3 : ffff1cc66f2a99c0
| x2 : 0000000000040000 x1 : d7ce7775b09b5d00 x0 : 0000000000000000
| Call trace:
| __virt_to_phys+0x120/0x1c0 arch/arm64/mm/physaddr.c:12
| machine_kexec_post_load+0x284/0x670 arch/arm64/kernel/machine_kexec.c:150
| do_kexec_load+0x570/0x670 kernel/kexec.c:155
| __do_sys_kexec_load kernel/kexec.c:250 [inline]
| __se_sys_kexec_load kernel/kexec.c:231 [inline]
| __arm64_sys_kexec_load+0x1d8/0x268 kernel/kexec.c:231
| __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
| invoke_syscall+0x90/0x2e0 arch/arm64/kernel/syscall.c:52
| el0_svc_common.constprop.2+0x1e4/0x2f8 arch/arm64/kernel/syscall.c:142
| do_el0_svc+0xf8/0x150 arch/arm64/kernel/syscall.c:181
| el0_svc+0x60/0x248 arch/arm64/kernel/entry-common.c:603
| el0t_64_sync_handler+0x90/0xb8 arch/arm64/kernel/entry-common.c:621
| el0t_64_sync+0x180/0x184 arch/arm64/kernel/entry.S:572
| irq event stamp: 2428
| hardirqs last enabled at (2427): [<ffffb7827c6f2308>] __up_console_sem+0xf0/0x118 kernel/printk/printk.c:255
| hardirqs last disabled at (2428): [<ffffb7828223df98>] el1_dbg+0x28/0x80 arch/arm64/kernel/entry-common.c:375
| softirqs last enabled at (2424): [<ffffb7827c411c00>] softirq_handle_end kernel/softirq.c:401 [inline]
| softirqs last enabled at (2424): [<ffffb7827c411c00>] __do_softirq+0xa28/0x11e4 kernel/softirq.c:587
| softirqs last disabled at (2417): [<ffffb7827c59015c>] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline]
| softirqs last disabled at (2417): [<ffffb7827c59015c>] invoke_softirq kernel/softirq.c:439 [inline]
| softirqs last disabled at (2417): [<ffffb7827c59015c>] __irq_exit_rcu kernel/softirq.c:636 [inline]
| softirqs last disabled at (2417): [<ffffb7827c59015c>] irq_exit_rcu+0x53c/0x688 kernel/softirq.c:648
| ---[ end trace 0ca578534e7ca938 ]---
With or without DEBUG_VIRTUAL __pa() will fall back to __kimg_to_phys()
for non-linear addresses, and will happen to do the right thing in this
case, even with the warning. But we should not depend upon this, and to
keep the warning useful we should fix this case.
Fix this issue by using __pa_symbol(), which handles kernel image
addresses (and checks its input is a kernel image address). This matches
what we do elsewhere, e.g. in arch/arm64/include/asm/pgtable.h:
| #define ZERO_PAGE(vaddr) phys_to_page(__pa_symbol(empty_zero_page))
Fixes: 3744b5280e ("arm64: kexec: install a copy of the linear-map")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/r/20211130121849.3319010-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Pull kvm fixes from Paolo Bonzini:
"ARM64:
- Fix constant sign extension affecting TCR_EL2 and preventing
running on ARMv8.7 models due to spurious bits being set
- Fix use of helpers using PSTATE early on exit by always sampling it
as soon as the exit takes place
- Move pkvm's 32bit handling into a common helper
RISC-V:
- Fix incorrect KVM_MAX_VCPUS value
- Unmap stage2 mapping when deleting/moving a memslot
x86:
- Fix and downgrade BUG_ON due to uninitialized cache
- Many APICv and MOVE_ENC_CONTEXT_FROM fixes
- Correctly emulate TLB flushes around nested vmentry/vmexit and when
the nested hypervisor uses VPID
- Prevent modifications to CPUID after the VM has run
- Other smaller bugfixes
Generic:
- Memslot handling bugfixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (44 commits)
KVM: fix avic_set_running for preemptable kernels
KVM: VMX: clear vmx_x86_ops.sync_pir_to_irr if APICv is disabled
KVM: SEV: accept signals in sev_lock_two_vms
KVM: SEV: do not take kvm->lock when destroying
KVM: SEV: Prohibit migration of a VM that has mirrors
KVM: SEV: Do COPY_ENC_CONTEXT_FROM with both VMs locked
selftests: sev_migrate_tests: add tests for KVM_CAP_VM_COPY_ENC_CONTEXT_FROM
KVM: SEV: move mirror status to destination of KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM
KVM: SEV: initialize regions_list of a mirror VM
KVM: SEV: cleanup locking for KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM
KVM: SEV: do not use list_replace_init on an empty list
KVM: x86: Use a stable condition around all VT-d PI paths
KVM: x86: check PIR even for vCPUs with disabled APICv
KVM: VMX: prepare sync_pir_to_irr for running with APICv disabled
KVM: selftests: page_table_test: fix calculation of guest_test_phys_mem
KVM: x86/mmu: Handle "default" period when selectively waking kthread
KVM: MMU: shadow nested paging does not have PKU
KVM: x86/mmu: Remove spurious TLB flushes in TDP MMU zap collapsible path
KVM: x86/mmu: Use yield-safe TDP MMU root iter in MMU notifier unmapping
KVM: X86: Use vcpu->arch.walk_mmu for kvm_mmu_invlpg()
...
Pull arm64 fixes from Will Deacon:
"Three arm64 fixes.
The main one is a fix to the way in which we evaluate the macro
arguments to our uaccess routines, which we _think_ might be the root
cause behind some unkillable tasks we've seen in the Android arm64 CI
farm (testing is ongoing). In any case, it's worth fixing.
Other than that, we've toned down an over-zealous VM_BUG_ON() and
fixed ftrace stack unwinding in a bunch of cases.
Summary:
- Evaluate uaccess macro arguments outside of the critical section
- Tighten up VM_BUG_ON() in pmd_populate_kernel() to avoid false positive
- Fix ftrace stack unwinding using HAVE_FUNCTION_GRAPH_RET_ADDR_PTR"
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: uaccess: avoid blocking within critical sections
arm64: mm: Fix VM_BUG_ON(mm != &init_mm) for trans_pgd
arm64: ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR
KVM/arm64 fixes for 5.16, take #2
- Fix constant sign extension affecting TCR_EL2 and preventing
running on ARMv8.7 models due to spurious bits being set
- Fix use of helpers using PSTATE early on exit by always sampling
it as soon as the exit takes place
- Move pkvm's 32bit handling into a common helper
Having a signed (1 << 31) constant for TCR_EL2_RES1 and CPTR_EL2_TCPAC
causes the upper 32-bit to be set to 1 when assigning them to a 64-bit
variable. Bit 32 in TCR_EL2 is no longer RES0 in ARMv8.7: with FEAT_LPA2
it changes the meaning of bits 49:48 and 9:8 in the stage 1 EL2 page
table entries. As a result of the sign-extension, a non-VHE kernel can
no longer boot on a model with ARMv8.7 enabled.
CPTR_EL2 still has the top 32 bits RES0 but we should preempt any future
problems
Make these top bit constants unsigned as per commit df655b75c4
("arm64: KVM: Avoid setting the upper 32 bits of VTCR_EL2 to 1").
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Chris January <Chris.January@arm.com>
Cc: <stable@vger.kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211125152014.2806582-1-catalin.marinas@arm.com
Protected KVM is trying to turn AArch32 exceptions into an illegal
exception entry. Unfortunately, it does that in a way that is a bit
abrupt, and too early for PSTATE to be available.
Instead, move it to the fixup code, which is a more reasonable place
for it. This will also be useful for the NV code.
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
In order to be able to use primitives such as vcpu_mode_is_32bit(),
we need to synchronize the guest PSTATE. However, this is currently
done deep into the bowels of the world-switch code, and we do have
helpers evaluating this much earlier (__vgic_v3_perform_cpuif_access
and handle_aarch32_guest, for example).
Move the saving of the guest pstate into the early fixups, which
cures the first issue. The second one will be addressed separately.
Tested-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
As Vincent reports in:
https://lore.kernel.org/r/20211118163417.21617-1-vincent.whitchurch@axis.com
The put_user() in schedule_tail() can get stuck in a livelock, similar
to a problem recently fixed on riscv in commit:
285a76bb2c ("riscv: evaluate put_user() arg before enabling user access")
In __raw_put_user() we have a critical section between
uaccess_ttbr0_enable() and uaccess_ttbr0_disable() where we cannot
safely call into the scheduler without having taken an exception, as
schedule() and other scheduling functions will not save/restore the
TTBR0 state. If either of the `x` or `ptr` arguments to __raw_put_user()
contain a blocking call, we may call into the scheduler within the
critical section. This can result in two problems:
1) The access within the critical section will occur without the
required TTBR0 tables installed. This will fault, and where the
required tables permit access, the access will be retried without the
required tables, resulting in a livelock.
2) When TTBR0 SW PAN is in use, check_and_switch_context() does not
modify TTBR0, leaving a stale value installed. The mappings of the
blocked task will erroneously be accessible to regular accesses in
the context of the new task. Additionally, if the tables are
subsequently freed, local TLB maintenance required to reuse the ASID
may be lost, potentially resulting in TLB corruption (e.g. in the
presence of CnP).
The same issue exists for __raw_get_user() in the critical section
between uaccess_ttbr0_enable() and uaccess_ttbr0_disable().
A similar issue exists for __get_kernel_nofault() and
__put_kernel_nofault() for the critical section between
__uaccess_enable_tco_async() and __uaccess_disable_tco_async(), as the
TCO state is not context-switched by direct calls into the scheduler.
Here the TCO state may be lost from the context of the current task,
resulting in unexpected asynchronous tag check faults. It may also be
leaked to another task, suppressing expected tag check faults.
To fix all of these cases, we must ensure that we do not directly call
into the scheduler in their respective critical sections. This patch
reworks __raw_put_user(), __raw_get_user(), __get_kernel_nofault(), and
__put_kernel_nofault(), ensuring that parameters are evaluated outside
of the critical sections. To make this requirement clear, comments are
added describing the problem, and line spaces added to separate the
critical sections from other portions of the macros.
For __raw_get_user() and __raw_put_user() the `err` parameter is
conditionally assigned to, and we must currently evaluate this in the
critical section. This behaviour is relied upon by the signal code,
which uses chains of put_user_error() and get_user_error(), checking the
return value at the end. In all cases, the `err` parameter is a plain
int rather than a more complex expression with a blocking call, so this
is safe.
In future we should try to clean up the `err` usage to remove the
potential for this to be a problem.
Aside from the changes to time of evaluation, there should be no
functional change as a result of this patch.
Reported-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20211118163417.21617-1-vincent.whitchurch@axis.com
Fixes: f253d827f3 ("arm64: uaccess: refactor __{get,put}_user")
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20211122125820.55286-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Pull KVM fixes from Paolo Bonzini:
"Selftest changes:
- Cleanups for the perf test infrastructure and mapping hugepages
- Avoid contention on mmap_sem when the guests start to run
- Add event channel upcall support to xen_shinfo_test
x86 changes:
- Fixes for Xen emulation
- Kill kvm_map_gfn() / kvm_unmap_gfn() and broken gfn_to_pfn_cache
- Fixes for migration of 32-bit nested guests on 64-bit hypervisor
- Compilation fixes
- More SEV cleanups
Generic:
- Cap the return value of KVM_CAP_NR_VCPUS to both KVM_CAP_MAX_VCPUS
and num_online_cpus(). Most architectures were only using one of
the two"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (42 commits)
KVM: x86: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
KVM: s390: Cap KVM_CAP_NR_VCPUS by num_online_cpus()
KVM: RISC-V: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
KVM: PPC: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
KVM: MIPS: Cap KVM_CAP_NR_VCPUS by KVM_CAP_MAX_VCPUS
KVM: arm64: Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus()
KVM: x86: Assume a 64-bit hypercall for guests with protected state
selftests: KVM: Add /x86_64/sev_migrate_tests to .gitignore
riscv: kvm: fix non-kernel-doc comment block
KVM: SEV: Fix typo in and tweak name of cmd_allowed_from_miror()
KVM: SEV: Drop a redundant setting of sev->asid during initialization
KVM: SEV: WARN if SEV-ES is marked active but SEV is not
KVM: SEV: Set sev_info.active after initial checks in sev_guest_init()
KVM: SEV: Disallow COPY_ENC_CONTEXT_FROM if target has created vCPUs
KVM: Kill kvm_map_gfn() / kvm_unmap_gfn() and gfn_to_pfn_cache
KVM: nVMX: Use a gfn_to_hva_cache for vmptrld
KVM: nVMX: Use kvm_read_guest_offset_cached() for nested VMCS check
KVM: x86/xen: Use sizeof_field() instead of open-coding it
KVM: nVMX: Use kvm_{read,write}_guest_cached() for shadow_vmcs12
KVM: x86/xen: Fix get_attr of KVM_XEN_ATTR_TYPE_SHARED_INFO
...
Generally, it doesn't make sense to return the recommended maximum number
of vCPUs which exceeds the maximum possible number of vCPUs.
Note: ARM64 is special as the value returned by KVM_CAP_MAX_VCPUS differs
depending on whether it is a system-wide ioctl or a per-VM one. Previously,
KVM_CAP_NR_VCPUS didn't have this difference and it seems preferable to
keep the status quo. Cap KVM_CAP_NR_VCPUS by kvm_arm_default_max_vcpus()
which is what gets returned by system-wide KVM_CAP_MAX_VCPUS.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211116163443.88707-2-vkuznets@redhat.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
trans_pgd_create_copy() can hit "VM_BUG_ON(mm != &init_mm)" in the
function pmd_populate_kernel().
This is the combined consequence of commit 5de59884ac ("arm64:
trans_pgd: pass NULL instead of init_mm to *_populate functions"), which
replaced &init_mm with NULL and commit 59511cfd08 ("arm64: mm: use XN
table mapping attributes for user/kernel mappings"), which introduced
the VM_BUG_ON.
Since the former sounds reasonable, it is better to work on the later.
From the perspective of trans_pgd, two groups of functions are
considered in the later one:
pmd_populate_kernel()
mm == NULL should be fixed, else it hits VM_BUG_ON()
p?d_populate()
mm == NULL means PXN, that is OK, since trans_pgd only copies a
linear map, no execution will happen on the map.
So it is good enough to just relax VM_BUG_ON() to disregard mm == NULL
Fixes: 59511cfd08 ("arm64: mm: use XN table mapping attributes for user/kernel mappings")
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: <stable@vger.kernel.org> # 5.13.x
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: James Morse <james.morse@arm.com>
Cc: Matthias Brugger <mbrugger@suse.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/r/20211112052214.9086-1-kernelfans@gmail.com
Signed-off-by: Will Deacon <will@kernel.org>
When CONFIG_FUNCTION_GRAPH_TRACER is selected and the function graph
tracer is in use, unwind_frame() may erroneously associate a traced
function with an incorrect return address. This can happen when starting
an unwind from a pt_regs, or when unwinding across an exception
boundary.
This can be seen when recording with perf while the function graph
tracer is in use. For example:
| # echo function_graph > /sys/kernel/debug/tracing/current_tracer
| # perf record -g -e raw_syscalls:sys_enter:k /bin/true
| # perf report
... reports the callchain erroneously as:
| el0t_64_sync
| el0t_64_sync_handler
| el0_svc_common.constprop.0
| perf_callchain
| get_perf_callchain
| syscall_trace_enter
| syscall_trace_enter
... whereas when the function graph tracer is not in use, it reports:
| el0t_64_sync
| el0t_64_sync_handler
| el0_svc
| do_el0_svc
| el0_svc_common.constprop.0
| syscall_trace_enter
| syscall_trace_enter
The underlying problem is that ftrace_graph_get_ret_stack() takes an
index offset from the most recent entry added to the fgraph return
stack. We start an unwind at offset 0, and increment the offset each
time we encounter a rewritten return address (i.e. when we see
`return_to_handler`). This is broken in two cases:
1) Between creating a pt_regs and starting the unwind, function calls
may place entries on the stack, leaving an arbitrary offset which we
can only determine by performing a full unwind from the caller of the
unwind code (and relying on none of the unwind code being
instrumented).
This can result in erroneous entries being reported in a backtrace
recorded by perf or kfence when the function graph tracer is in use.
Currently show_regs() is unaffected as dump_backtrace() performs an
initial unwind.
2) When unwinding across an exception boundary (whether continuing an
unwind or starting a new unwind from regs), we currently always skip
the LR of the interrupted context. Where this was live and contained
a rewritten address, we won't consume the corresponding fgraph ret
stack entry, leaving subsequent entries off-by-one.
This can result in erroneous entries being reported in a backtrace
performed by any in-kernel unwinder when that backtrace crosses an
exception boundary, with entries after the boundary being reported
incorrectly. This includes perf, kfence, show_regs(), panic(), etc.
To fix this, we need to be able to uniquely identify each rewritten
return address such that we can map this back to the original return
address. We can use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR to associate
each rewritten return address with a unique location on the stack. As
the return address is passed in the LR (and so is not guaranteed a
unique location in memory), we use the FP upon entry to the function
(i.e. the address of the caller's frame record) as the return address
pointer. Any nested call will have a different FP value as the caller
must create its own frame record and update FP to point to this.
Since ftrace_graph_ret_addr() requires the return address with the PAC
stripped, the stripping of the PAC is moved before the fixup of the
rewritten address. As we would unconditionally strip the PAC, moving
this earlier is not harmful, and we can avoid a redundant strip in the
return address fixup code.
I've tested this with the perf case above, the ftrace selftests, and
a number of ad-hoc unwinder tests. The tests all pass, and I have seen
no unexpected behaviour as a result of this change. I've tested with
pointer authentication under QEMU TCG where magic-sysrq+l correctly
recovers the original return addresses.
Note that this doesn't fix the issue of skipping a live LR at an
exception boundary, which is a more general problem and requires more
substantial rework. Were we to consume the LR in all cases this would
result in warnings where the interrupted context's LR contains
`return_to_handler`, but the FP has been altered, e.g.
| func:
| <--- ftrace entry ---> // logs FP & LR, rewrites LR
| STP FP, LR, [SP, #-16]!
| MOV FP, SP
| <--- INTERRUPT --->
... as ftrace_graph_get_ret_stack() fill not find a matching entry,
triggering the WARN_ON_ONCE() in unwind_frame().
Link: https://lore.kernel.org/r/20211025164925.GB2001@C02TD0UTHF1T.local
Link: https://lore.kernel.org/r/20211027132529.30027-1-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20211029162245.39761-1-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
Pull more kvm updates from Paolo Bonzini:
"New x86 features:
- Guest API and guest kernel support for SEV live migration
- SEV and SEV-ES intra-host migration
Bugfixes and cleanups for x86:
- Fix misuse of gfn-to-pfn cache when recording guest steal time /
preempted status
- Fix selftests on APICv machines
- Fix sparse warnings
- Fix detection of KVM features in CPUID
- Cleanups for bogus writes to MSR_KVM_PV_EOI_EN
- Fixes and cleanups for MSR bitmap handling
- Cleanups for INVPCID
- Make x86 KVM_SOFT_MAX_VCPUS consistent with other architectures
Bugfixes for ARM:
- Fix finalization of host stage2 mappings
- Tighten the return value of kvm_vcpu_preferred_target()
- Make sure the extraction of ESR_ELx.EC is limited to architected
bits"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (34 commits)
KVM: SEV: unify cgroup cleanup code for svm_vm_migrate_from
KVM: x86: move guest_pv_has out of user_access section
KVM: x86: Drop arbitrary KVM_SOFT_MAX_VCPUS
KVM: Move INVPCID type check from vmx and svm to the common kvm_handle_invpcid()
KVM: VMX: Add a helper function to retrieve the GPR index for INVPCID, INVVPID, and INVEPT
KVM: nVMX: Clean up x2APIC MSR handling for L2
KVM: VMX: Macrofy the MSR bitmap getters and setters
KVM: nVMX: Handle dynamic MSR intercept toggling
KVM: nVMX: Query current VMCS when determining if MSR bitmaps are in use
KVM: x86: Don't update vcpu->arch.pv_eoi.msr_val when a bogus value was written to MSR_KVM_PV_EOI_EN
KVM: x86: Rename kvm_lapic_enable_pv_eoi()
KVM: x86: Make sure KVM_CPUID_FEATURES really are KVM_CPUID_FEATURES
KVM: x86: Add helper to consolidate core logic of SET_CPUID{2} flows
kvm: mmu: Use fast PF path for access tracking of huge pages when possible
KVM: x86/mmu: Properly dereference rcu-protected TDP MMU sptep iterator
KVM: x86: inhibit APICv when KVM_GUESTDBG_BLOCKIRQ active
kvm: x86: Convert return type of *is_valid_rdpmc_ecx() to bool
KVM: x86: Fix recording of guest steal time / preempted status
selftest: KVM: Add intra host migration tests
selftest: KVM: Add open sev dev helper
...
KVM/arm64 fixes for 5.16, take #1
- Fix the host S2 finalization by solely iterating over the memblocks
instead of the whole IPA space
- Tighten the return value of kvm_vcpu_preferred_target() now that
32bit support is long gone
- Make sure the extraction of ESR_ELx.EC is limited to the architected
bits
- Comment fixups
Merge more updates from Andrew Morton:
"The post-linux-next material.
7 patches.
Subsystems affected by this patch series (all mm): debug,
slab-generic, migration, memcg, and kasan"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
kasan: add kasan mode messages when kasan init
mm: unexport {,un}lock_page_memcg
mm: unexport folio_memcg_{,un}lock
mm/migrate.c: remove MIGRATE_PFN_LOCKED
mm: migrate: simplify the file-backed pages validation when migrating its mapping
mm: allow only SLUB on PREEMPT_RT
mm/page_owner.c: modify the type of argument "order" in some functions
Pull char/misc fix from Greg KH:
"Here is a single fix for 5.16-rc1 to resolve a build problem that came
in through the coresight tree (and as such came in through the
char/misc tree merge in the 5.16-rc1 merge window).
It resolves a build problem with 'allmodconfig' on arm64 and is acked
by the proper subsystem maintainers. It has been in linux-next all
week with no reported problems"
* tag 'char-misc-5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
arm64: cpufeature: Export this_cpu_has_cap helper
Pull arm64 fixes from Will Deacon:
- Fix double-evaluation of 'pte' macro argument when using 52-bit PAs
- Fix signedness of some MTE prctl PR_* constants
- Fix kmemleak memory usage by skipping early pgtable allocations
- Fix printing of CPU feature register strings
- Remove redundant -nostdlib linker flag for vDSO binaries
* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
arm64: pgtable: make __pte_to_phys/__phys_to_pte_val inline functions
arm64: Track no early_pgtable_alloc() for kmemleak
arm64: mte: change PR_MTE_TCF_NONE back into an unsigned long
arm64: vdso: remove -nostdlib compiler flag
arm64: arm64_ftr_reg->name may not be a human-readable string
Pull asm-generic cleanup from Arnd Bergmann:
"This is a single cleanup from Peter Collingbourne, removing some dead
code"
* tag 'asm-generic-5.16' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
arch: remove unused function syscall_set_arguments()
Pull xen updates from Juergen Gross:
- a series to speed up the boot of Xen PV guests
- some cleanups in Xen related code
- replacement of license texts with the appropriate SPDX headers and
fixing of wrong SPDX headers in Xen header files
- a small series making paravirtualized interrupt masking much simpler
and at the same time removing complaints of objtool
- a fix for Xen ballooning hogging workqueues for too long
- enablement of the Xen pciback driver for Arm
- some further small fixes/enhancements
* tag 'for-linus-5.16b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (22 commits)
xen/balloon: fix unused-variable warning
xen/balloon: rename alloc/free_xenballooned_pages
xen/balloon: add late_initcall_sync() for initial ballooning done
x86/xen: remove 32-bit awareness from startup_xen
xen: remove highmem remnants
xen: allow pv-only hypercalls only with CONFIG_XEN_PV
x86/xen: remove 32-bit pv leftovers
xen-pciback: allow compiling on other archs than x86
x86/xen: switch initial pvops IRQ functions to dummy ones
x86/xen: remove xen_have_vcpu_info_placement flag
x86/pvh: add prototype for xen_pvh_init()
xen: Fix implicit type conversion
xen: fix wrong SPDX headers of Xen related headers
xen/pvcalls-back: Remove redundant 'flush_workqueue()' calls
x86/xen: Remove redundant irq_enter/exit() invocations
xen-pciback: Fix return in pm_ctrl_init()
xen/x86: restrict PV Dom0 identity mapping
xen/x86: there's no highmem anymore in PV mode
xen/x86: adjust handling of the L3 user vsyscall special page table
xen/x86: adjust xen_set_fixmap()
...
