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2376e75cc7
linux/arch/arm64/include/asm
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Mark Rutland 2376e75cc7 arm64: sdei: explicitly simulate PAN/UAO entry 
In preparation for removing addr_limit and set_fs() we must decouple the
SDEI PAN/UAO manipulation from the uaccess code, and explicitly
reinitialize these as required.

SDEI enters the kernel with a non-architectural exception, and prior to
the most recent revision of the specification (ARM DEN 0054B), PSTATE
bits (e.g. PAN, UAO) are not manipulated in the same way as for
architectural exceptions. Notably, older versions of the spec can be
read ambiguously as to whether PSTATE bits are inherited unchanged from
the interrupted context or whether they are generated from scratch, with
TF-A doing the latter.

We have three cases to consider:

1) The existing TF-A implementation of SDEI will clear PAN and clear UAO
   (along with other bits in PSTATE) when delivering an SDEI exception.

2) In theory, implementations of SDEI prior to revision B could inherit
   PAN and UAO (along with other bits in PSTATE) unchanged from the
   interrupted context. However, in practice such implementations do not
   exist.

3) Going forward, new implementations of SDEI must clear UAO, and
   depending on SCTLR_ELx.SPAN must either inherit or set PAN.

As we can ignore (2) we can assume that upon SDEI entry, UAO is always
clear, though PAN may be clear, inherited, or set per SCTLR_ELx.SPAN.
Therefore, we must explicitly initialize PAN, but do not need to do
anything for UAO.

Considering what we need to do:

* When set_fs() is removed, force_uaccess_begin() will have no HW
  side-effects. As this only clears UAO, which we can assume has already
  been cleared upon entry, this is not a problem. We do not need to add
  code to manipulate UAO explicitly.

* PAN may be cleared upon entry (in case 1 above), so where a kernel is
  built to use PAN and this is supported by all CPUs, the kernel must
  set PAN upon entry to ensure expected behaviour.

* PAN may be inherited from the interrupted context (in case 3 above),
  and so where a kernel is not built to use PAN or where PAN support is
  not uniform across CPUs, the kernel must clear PAN to ensure expected
  behaviour.

This patch reworks the SDEI code accordingly, explicitly setting PAN to
the expected state in all cases. To cater for the cases where the kernel
does not use PAN or this is not uniformly supported by hardware we add a
new cpu_has_pan() helper which can be used regardless of whether the
kernel is built to use PAN.

The existing system_uses_ttbr0_pan() is redefined in terms of
system_uses_hw_pan() both for clarity and as a minor optimization when
HW PAN is not selected.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: James Morse <james.morse@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20201202131558.39270-3-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2020-12-02 19:48:57 +00:00
..
vdso vdso/treewide: Add vdso_data pointer argument to __arch_get_hw_counter() 2020-08-06 10:57:30 +02:00
xen xen/arm: do not setup the runstate info page if kpti is enabled 2020-10-04 18:41:33 -05:00
acenv.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
acpi.h arm64/acpi: disallow AML memory opregions to access kernel memory 2020-07-14 18:02:03 +01:00
alternative-macros.h arm64: alternatives: Split up alternative.h 2020-11-09 21:49:34 +00:00
alternative.h arm64: alternatives: Split up alternative.h 2020-11-09 21:49:34 +00:00
arch_gicv3.h irqchip/gic-v3: Support pseudo-NMIs when SCR_EL3.FIQ == 0 2020-09-13 17:52:04 +01:00
arch_timer.h arm64: arch_timer: Allow an workaround descriptor to disable compat vdso 2020-07-08 21:57:51 +01:00
archrandom.h arm64: random: Remove no longer needed prototypes 2020-10-07 14:17:20 +01:00
arm_dsu_pmu.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
arm-cci.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
asm_pointer_auth.h arm64: simplify ptrauth initialization 2020-04-28 11:23:21 +01:00
asm-bug.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
asm-offsets.h
asm-prototypes.h
asm-uaccess.h arm64: alternatives: Split up alternative.h 2020-11-09 21:49:34 +00:00
assembler.h kvm: arm64: Remove hyp_adr/ldr_this_cpu 2020-09-30 08:37:07 +01:00
atomic_ll_sc.h arm64: Move the LSE gas support detection to Kconfig 2020-01-15 12:50:48 +00:00
atomic_lse.h arm64: lse: fix LSE atomics with LLVM's integrated assembler 2020-01-16 17:25:10 +00:00
atomic.h locking/atomic: Move ATOMIC_INIT into linux/types.h 2020-07-29 16:14:18 +02:00
barrier.h iommu/arm-smmu-v3: Ensure queue is read after updating prod pointer 2020-09-28 22:57:43 +01:00
bitops.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
bitrev.h
boot.h arm64: get rid of TEXT_OFFSET 2020-09-07 15:00:52 +01:00
brk-imm.h arm64: kprobes: Use BRK instead of single-step when executing instructions out-of-line 2020-11-03 14:03:38 +00:00
bug.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
cache.h arm64: avoid -Woverride-init warning 2020-10-28 13:38:36 +00:00
cacheflush.h arm64: use asm-generic/cacheflush.h 2020-06-08 11:05:57 -07:00
checksum.h arm64: csum: Fix handling of bad packets 2020-07-30 17:01:38 +01:00
clocksource.h arm64: Introduce asm/vdso/clocksource.h 2020-03-21 15:23:55 +01:00
cmpxchg.h arm64: fix unreachable code issue with cmpxchg 2019-09-17 12:11:50 +01:00
compat.h compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h> 2020-09-17 13:00:46 -04:00
compiler.h arm64: use a common .arch preamble for inline assembly 2020-08-28 11:15:15 +01:00
cpu_ops.h arm64: fix some spelling mistakes in the comments by codespell 2020-09-07 14:18:50 +01:00
cpu.h Revert "arm64: initialize per-cpu offsets earlier" 2020-10-09 11:24:17 +01:00
cpucaps.h arm64: cpufeatures: Add capability for LDAPR instruction 2020-11-09 21:49:34 +00:00
cpufeature.h arm64: sdei: explicitly simulate PAN/UAO entry 2020-12-02 19:48:57 +00:00
cpuidle.h
cputype.h arm64: Add part number for Arm Cortex-A77 2020-10-29 12:56:01 +00:00
current.h
daifflags.h arm64: acpi: fix DAIF manipulation with pNMI 2020-01-22 14:41:22 +00:00
dcc.h
debug-monitors.h arm64: kprobes: Use BRK instead of single-step when executing instructions out-of-line 2020-11-03 14:03:38 +00:00
device.h arm64: Remove dev->archdata.iommu pointer 2020-06-30 11:59:49 +02:00
dmi.h
efi.h efi/libstub: arm32: Base FDT and initrd placement on image address 2020-09-16 18:53:42 +03:00
elf.h Split the old READ_IMPLIES_EXEC workaround from executable PT_GNU_STACK 2020-06-05 13:45:21 -07:00
esr.h arm64: ptrauth: Introduce Armv8.3 pointer authentication enhancements 2020-09-14 12:07:02 +01:00
exception.h arm64: ptrauth: Introduce Armv8.3 pointer authentication enhancements 2020-09-14 12:07:02 +01:00
exec.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
extable.h arm64: Improve diagnostics when trapping BRK with FAULT_BRK_IMM 2020-09-18 16:35:54 +01:00
fb.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
fixmap.h arm64/fixmap: make notes of fixed_addresses more precisely 2020-08-08 19:25:04 +01:00
fpsimd.h arm64/sve: Implement a helper to load SVE registers from FPSIMD state 2020-09-21 18:06:33 +01:00
fpsimdmacros.h arm64/sve: Implement a helper to flush SVE registers 2020-09-21 18:06:33 +01:00
ftrace.h arm64: implement ftrace with regs 2019-11-06 14:17:35 +00:00
futex.h futex: arch_futex_atomic_op_inuser() calling conventions change 2020-03-27 23:58:51 -04:00
hardirq.h arm64: Remove custom IRQ stat accounting 2020-09-17 16:37:28 +01:00
hugetlb.h arm64/hugetlb: Reserve CMA areas for gigantic pages on 16K and 64K configs 2020-07-15 13:38:03 +01:00
hw_breakpoint.h arm64: remove pointless __KERNEL__ guards 2019-08-05 11:06:33 +01:00
hwcap.h Merge branch 'for-next/mte' into for-next/core 2020-10-02 12:16:11 +01:00
hyp_image.h kvm: arm64: Move nVHE hyp namespace macros to hyp_image.h 2020-09-30 08:33:52 +01:00
hypervisor.h
image.h
insn.h arm64: alternatives: Split up alternative.h 2020-11-09 21:49:34 +00:00
io.h iommu/arm-smmu-v3: Ensure queue is read after updating prod pointer 2020-09-28 22:57:43 +01:00
irq_work.h arm64: Kill __smp_cross_call and co 2020-09-17 16:37:28 +01:00
irq.h
irqflags.h arm64: Implement arch_irqs_disabled() 2020-08-26 12:41:55 +02:00
jump_label.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
kasan.h arm64: mm: Introduce vabits_actual 2019-08-09 11:17:21 +01:00
Kbuild KVM: arm64: Use common KVM implementation of MMU memory caches 2020-07-09 13:29:43 -04:00
kernel-pgtable.h arm64: get rid of TEXT_OFFSET 2020-09-07 15:00:52 +01:00
kexec.h Revert "arm64: kexec: make dtb_mem always enabled" 2020-01-10 16:00:50 +00:00
kgdb.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
kprobes.h arm64: kprobes: Use BRK instead of single-step when executing instructions out-of-line 2020-11-03 14:03:38 +00:00
kvm_arm.h Merge branch 'for-next/mte' into for-next/core 2020-10-02 12:16:11 +01:00
kvm_asm.h Merge branch 'kvm-arm64/hyp-pcpu' into kvmarm-master/next 2020-09-30 14:05:35 +01:00
kvm_coproc.h KVM/arm64 updates for Linux 5.9: 2020-08-09 12:58:23 -04:00
kvm_emulate.h KVM/arm64 updates for Linux 5.10 2020-10-20 08:14:25 -04:00
kvm_host.h KVM: arm64: Fix AArch32 handling of DBGD{CCINT,SCRext} and DBGVCR 2020-10-29 19:49:03 +00:00
kvm_hyp.h KVM: arm64: nVHE: Handle hyp panics 2020-09-15 18:39:03 +01:00
kvm_mmu.h Merge branch 'kvm-arm64/hyp-pcpu' into kvmarm-master/next 2020-09-30 14:05:35 +01:00
kvm_pgtable.h KVM: arm64: Add support for relaxing stage-2 perms in generic page-table code 2020-09-11 15:51:15 +01:00
kvm_ptrauth.h KVM: arm64: Update context references from host to hyp 2020-09-15 18:39:02 +01:00
kvm_ras.h
kvm_types.h KVM: arm64: Use common KVM implementation of MMU memory caches 2020-07-09 13:29:43 -04:00
linkage.h arm64: Don't insert a BTI instruction at inner labels 2020-06-24 14:24:29 +01:00
lse.h arm64: lse: Fix LSE atomics with LLVM 2020-02-18 18:10:49 +00:00
memory.h arm64: mm: use single quantity to represent the PA to VA translation 2020-10-15 11:14:57 +01:00
mman.h arm64: mte: Validate the PROT_MTE request via arch_validate_flags() 2020-09-04 12:46:07 +01:00
mmu_context.h arm64: mm: Pin down ASIDs for sharing mm with devices 2020-09-28 22:15:38 +01:00
mmu.h Merge branch 'for-next/ghostbusters' into for-next/core 2020-10-02 12:15:24 +01:00
mmzone.h
module.h arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> 2020-04-23 10:50:26 +09:00
module.lds.h kbuild: preprocess module linker script 2020-09-25 00:36:41 +09:00
mte.h arm64: mte: Enable swap of tagged pages 2020-09-04 12:46:07 +01:00
neon-intrinsics.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
neon.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
numa.h arm64/mm: return cpu_all_mask when node is NUMA_NO_NODE 2020-09-21 22:05:01 +01:00
page-def.h arm64/mm: Unify CONT_PTE_SHIFT 2020-09-11 16:33:43 +01:00
page.h arm64: mte: Add PROT_MTE support to mmap() and mprotect() 2020-09-04 12:46:07 +01:00
paravirt.h arm64: Retrieve stolen time as paravirtualized guest 2019-10-21 19:20:31 +01:00
pci.h arm64: Enable PCI write-combine resources under sysfs 2020-09-18 14:05:13 +01:00
percpu.h kvm: arm64: Remove __hyp_this_cpu_read 2020-09-30 08:33:52 +01:00
perf_event.h arm64: perf: Add support caps under sysfs 2020-09-28 14:53:45 +01:00
pgalloc.h asm-generic: pgalloc: provide generic pgd_free() 2020-08-07 11:33:26 -07:00
pgtable-hwdef.h ARM: 2020-10-23 11:17:56 -07:00
pgtable-prot.h ARM: 2020-10-23 11:17:56 -07:00
pgtable-types.h arm64: add support for folded p4d page tables 2020-06-04 19:06:21 -07:00
pgtable.h arm64: mm: use single quantity to represent the PA to VA translation 2020-10-15 11:14:57 +01:00
pointer_auth.h arm64: sync kernel APIAKey when installing 2020-04-21 15:52:56 +01:00
preempt.h sched/rt, arm64: Use CONFIG_PREEMPTION 2019-12-08 14:37:32 +01:00
probes.h
proc-fns.h arm64: mm: convert cpu_do_switch_mm() to C 2020-02-27 14:30:50 +00:00
processor.h Merge branch 'for-next/mte' into for-next/core 2020-10-02 12:16:11 +01:00
ptdump.h arm64: mm: convert mm/dump.c to use walk_page_range() 2020-02-04 03:05:25 +00:00
ptrace.h arm64: head.S: always initialize PSTATE 2020-12-02 19:44:03 +00:00
pvclock-abi.h KVM: arm64: Implement PV_TIME_FEATURES call 2019-10-21 19:20:27 +01:00
rwonce.h arm64: lto: Strengthen READ_ONCE() to acquire when CONFIG_LTO=y 2020-11-09 21:49:34 +00:00
scs.h scs: Move scs_overflow_check() out of architecture code 2020-05-18 17:47:40 +01:00
sdei.h
seccomp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
sections.h arm64: Remove __exception_text_start and __exception_text_end from asm/section.h 2020-01-08 17:30:19 +00:00
shmparam.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
signal32.h arm64: remove pointless __KERNEL__ guards 2019-08-05 11:06:33 +01:00
simd.h arm64: fpsimd: Make sure SVE setup is complete before SIMD is used 2020-01-14 17:11:21 +00:00
smp_plat.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
smp.h arm64: Remove custom IRQ stat accounting 2020-09-17 16:37:28 +01:00
sparsemem.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
spectre.h arm64: Rewrite Spectre-v4 mitigation code 2020-09-29 16:08:16 +01:00
spinlock_types.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
spinlock.h arm64/spinlock: fix a -Wunused-function warning 2020-02-10 11:29:24 +00:00
stack_pointer.h
stackprotector.h arm64: initialize ptrauth keys for kernel booting task 2020-03-18 09:50:20 +00:00
stacktrace.h arm64: stacktrace: Make stack walk callback consistent with generic code 2020-09-18 14:24:16 +01:00
stage2_pgtable.h KVM: arm64: Remove unused page-table code 2020-09-11 15:51:15 +01:00
stat.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
string.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
suspend.h arm64: Preserve register x18 when CPU is suspended 2020-05-15 16:35:50 +01:00
sync_bitops.h
syscall_wrapper.h arm64: simplify syscall wrapper ifdeffery 2019-10-14 10:55:00 +01:00
syscall.h arm64: compat: Ensure upper 32 bits of x0 are zero on syscall return 2020-07-16 11:41:31 +01:00
sysreg.h arm64: head.S: cleanup SCTLR_ELx initialization 2020-12-02 19:44:03 +00:00
system_misc.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
thread_info.h arm64: mte: Handle synchronous and asynchronous tag check faults 2020-09-04 12:46:06 +01:00
timex.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
tlb.h arm64: tlb: Set the TTL field in flush_tlb_range 2020-07-07 11:23:47 +01:00
tlbflush.h arm64: use a common .arch preamble for inline assembly 2020-08-28 11:15:15 +01:00
topology.h cpufreq,arm,arm64: restructure definitions of arch_set_freq_scale() 2020-10-08 17:17:27 +02:00
traps.h arm64: traps: Allow force_signal_inject to pass esr error code 2020-09-14 12:07:02 +01:00
uaccess.h uaccess: remove segment_eq 2020-08-12 10:57:58 -07:00
unistd32.h mm/madvise: introduce process_madvise() syscall: an external memory hinting API 2020-10-18 09:27:10 -07:00
unistd.h mm/madvise: introduce process_madvise() syscall: an external memory hinting API 2020-10-18 09:27:10 -07:00
uprobes.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
vdso.h arm64/vdso: Add time namespace page 2020-07-24 13:15:20 +01:00
vermagic.h arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> 2020-04-23 10:50:26 +09:00
virt.h arm64: cpufeature: upgrade hyp caps to final 2020-10-30 08:53:10 +00:00
vmalloc.h mm/vmalloc: Add empty <asm/vmalloc.h> headers and use them from <linux/vmalloc.h> 2019-12-10 10:12:55 +01:00
vmap_stack.h mm: reorder includes after introduction of linux/pgtable.h 2020-06-09 09:39:13 -07:00
word-at-a-time.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
xor.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00