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Mark Brown 2813926261 arm64/sve: Lower the maximum allocation for the SVE ptrace regset 
Doug Anderson observed that ChromeOS crashes are being reported which
include failing allocations of order 7 during core dumps due to ptrace
allocating storage for regsets:

  chrome: page allocation failure: order:7,
          mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO),
          nodemask=(null),cpuset=urgent,mems_allowed=0
   ...
  regset_get_alloc+0x1c/0x28
  elf_core_dump+0x3d8/0xd8c
  do_coredump+0xeb8/0x1378

with further investigation showing that this is:

   [   66.957385] DOUG: Allocating 279584 bytes

which is the maximum size of the SVE regset. As Doug observes it is not
entirely surprising that such a large allocation of contiguous memory might
fail on a long running system.

The SVE regset is currently sized to hold SVE registers with a VQ of
SVE_VQ_MAX which is 512, substantially more than the architectural maximum
of 16 which we might see even in a system emulating the limits of the
architecture. Since we don't expose the size we tell the regset core
externally let's define ARCH_SVE_VQ_MAX with the actual architectural
maximum and use that for the regset, we'll still overallocate most of the
time but much less so which will be helpful even if the core is fixed to
not require contiguous allocations.

Specify ARCH_SVE_VQ_MAX in terms of the maximum value that can be written
into ZCR_ELx.LEN (where this is set in the hardware). For consistency
update the maximum SME vector length to be specified in the same style
while we are at it.

We could also teach the ptrace core about runtime discoverable regset sizes
but that would be a more invasive change and this is being observed in
practical systems.

Reported-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Tested-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20240213-arm64-sve-ptrace-regset-size-v2-1-c7600ca74b9b@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
History 2024-02-15 11:48:00 +00:00
..
pi arm64: kernel: Disable latent_entropy GCC plugin in early C runtime 2023-12-12 11:06:27 +00:00
probes arm64: kprobes: Drop ID map text from kprobes blacklist 2023-02-07 18:25:10 +00:00
vdso kbuild: unify vdso_install rules 2023-10-28 21:09:02 +09:00
vdso32 arm64: vdso32: Remove unused vdso32-offsets.h 2024-01-30 11:59:17 +00:00
.gitignore .gitignore: add SPDX License Identifier 2020-03-25 11:50:48 +01:00
acpi.c arm64: acpi: Fix possible memory leak of ffh_ctxt 2023-02-24 14:21:49 +00:00
acpi_numa.c arm64: numa: Don't check node against MAX_NUMNODES 2022-07-19 19:10:28 +01:00
acpi_parking_protocol.c arm64: smp: Remove dedicated wakeup IPI 2023-09-25 17:15:28 +01:00
alternative.c Merge branches 'for-next/kpti', 'for-next/missing-proto-warn', 'for-next/iss2-decode', 'for-next/kselftest', 'for-next/misc', 'for-next/feat_mops', 'for-next/module-alloc', 'for-next/sysreg', 'for-next/cpucap', 'for-next/acpi', 'for-next/kdump', 'for-next/acpi-doc', 'for-next/doc' and 'for-next/tpidr2-fix', remote-tracking branch 'arm64/for-next/perf' into for-next/core 2023-06-23 18:32:20 +01:00
armv8_deprecated.c arm: Remove now superfluous sentinel elem from ctl_table arrays 2023-10-10 15:22:02 -07:00
asm-offsets.c arm64: fpsimd: Bring cond_yield asm macro in line with new rules 2024-01-12 12:48:27 +00:00
cacheinfo.c cacheinfo: Add arm64 early level initializer implementation 2023-04-13 09:32:33 +01:00
compat_alignment.c arm64: compat: Work around uninitialized variable warning 2023-04-05 17:51:47 +01:00
cpu-reset.S arm64: kernel: remove SHF_WRITE|SHF_EXECINSTR from .idmap.text 2023-05-02 12:42:22 +01:00
cpu_errata.c arm64: Subscribe Microsoft Azure Cobalt 100 to ARM Neoverse N2 errata 2024-02-15 11:47:22 +00:00
cpu_ops.c arm64: Introduce get_cpu_ops() helper function 2020-03-24 17:24:19 +00:00
cpufeature.c Generic: 2024-01-17 13:03:37 -08:00
cpuidle.c arm64: Explicitly include correct DT includes 2023-07-31 14:45:38 +01:00
cpuinfo.c arm64: Kill detection of VPIPT i-cache policy 2023-12-05 11:38:03 +00:00
crash_core.c arm64: move PAC masks to <asm/pointer_auth.h> 2023-04-13 12:27:11 +01:00
crash_dump.c vmcore: convert copy_oldmem_page() to take an iov_iter 2022-04-29 14:37:59 -07:00
debug-monitors.c arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-step 2023-04-14 13:39:47 +01:00
efi-header.S arm64: efi: Enable BTI codegen and add PE/COFF annotation 2023-04-20 15:43:45 +02:00
efi-rt-wrapper.S arm64: efi: Avoid workqueue to check whether EFI runtime is live 2023-01-16 15:27:31 +01:00
efi.c TTY/Serial changes for 6.7-rc1 2023-11-03 15:44:25 -10:00
elfcore.c arm64: mte: Avoid the racy walk of the vma list during core dump 2023-01-05 15:12:12 +00:00
entry-common.c arm64: syscall: unmask DAIF earlier for SVCs 2023-08-11 12:23:48 +01:00
entry-fpsimd.S arm64/sme: Implement context switching for ZT0 2023-01-20 12:23:06 +00:00
entry-ftrace.S arm64: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL 2023-06-20 18:38:37 -04:00
entry.S arm64: entry: simplify kernel_exit logic 2024-01-18 11:00:09 +00:00
fpsimd.c arm64/signal: Don't assume that TIF_SVE means we saved SVE state 2024-02-09 16:34:23 +00:00
ftrace.c arm64: module: mandate MODULE_PLTS 2023-06-06 17:39:05 +01:00
head.S arm64: mm: get rid of kimage_vaddr global variable 2023-12-12 11:06:28 +00:00
hibernate-asm.S arm64: kexec: install a copy of the linear-map 2021-10-01 13:31:00 +01:00
hibernate.c arm64: hibernate: remove WARN_ON in save_processor_state 2023-06-21 13:33:49 +01:00
hw_breakpoint.c hw_breakpoint: fix single-stepping when using bpf_overflow_handler 2023-08-18 17:04:09 +01:00
hyp-stub.S ARM64: 2023-07-03 15:32:22 -07:00
idle.c arm64: idle: Tag the arm64 idle functions as __cpuidle 2023-09-25 17:15:28 +01:00
idreg-override.c arm64/kernel: Move 'nokaslr' parsing out of early idreg code 2023-12-12 11:13:53 +00:00
image-vars.h efi: move screen_info into efi init code 2023-10-17 16:33:39 +02:00
image.h arm64: get rid of TEXT_OFFSET 2020-09-07 15:00:52 +01:00
io.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
irq.c arm64: irq: set the correct node for shadow call stack 2023-12-13 12:09:00 +00:00
jump_label.c jump_label: make initial NOP patching the special case 2022-06-24 09:48:55 +02:00
kaslr.c arm64/kernel: Move 'nokaslr' parsing out of early idreg code 2023-12-12 11:13:53 +00:00
kexec_image.c kexec_file, arm64: print out debugging message if required 2023-12-20 15:02:57 -08:00
kgdb.c arm64: kgdb: Set PSTATE.SS to 1 to re-enable single-step 2023-04-14 13:39:47 +01:00
kuser32.S arm64: Update Documentation/arm references 2023-06-12 06:33:48 -06:00
machine_kexec.c kexec_file, arm64: print out debugging message if required 2023-12-20 15:02:57 -08:00
machine_kexec_file.c kexec_file, arm64: print out debugging message if required 2023-12-20 15:02:57 -08:00
Makefile arm64: scs: Disable LTO for SCS patching code 2024-01-30 11:52:46 +00:00
module-plts.c Merge branch 'for-next/cpus_have_const_cap' into for-next/core 2023-10-26 17:10:18 +01:00
module.c arm64: module: rework module VA range selection 2023-06-06 17:39:06 +01:00
mte.c Many singleton patches against the MM code. The patch series which are 2023-11-02 19:38:47 -10:00
paravirt.c arm64: paravirt: remove conduit check in has_pv_steal_clock 2022-11-09 18:11:56 +00:00
patch-scs.c arm64: Apply dynamic shadow call stack patching in two passes 2023-01-26 17:54:15 +00:00
patching.c arm64: patching: Add aarch64_insn_write_literal_u64() 2023-01-24 11:49:43 +00:00
pci.c arm64: Explicitly include correct DT includes 2023-07-31 14:45:38 +01:00
perf_callchain.c arm64: use XPACLRI to strip PAC 2023-04-13 12:27:11 +01:00
perf_regs.c perf: arm64: Add SVE vector granule register to user regs 2022-09-22 15:06:02 +01:00
pointer_auth.c arm64: move preemption disablement to prctl handlers 2021-07-28 18:33:49 +01:00
process.c sysctl-6.7-rc1 2023-11-01 20:51:41 -10:00
proton-pack.c arm64: Avoid cpus_have_const_cap() for ARM64_UNMAP_KERNEL_AT_EL0 2023-10-16 14:17:06 +01:00
psci.c treewide: Drop function_nocfi 2022-09-26 10:13:14 -07:00
ptrace.c arm64/sve: Lower the maximum allocation for the SVE ptrace regset 2024-02-15 11:48:00 +00:00
reloc_test_core.c ARM64: reloc_test: add __init/__exit annotations to module init/exit funcs 2022-09-29 18:04:25 +01:00
reloc_test_syms.S arm64: kernel: Convert to modern annotations for assembly functions 2020-05-04 12:46:03 +01:00
relocate_kernel.S arm64: kexec: load from kimage prior to clobbering 2022-05-17 14:25:35 +01:00
return_address.c arm64: Make return_address() use arch_stack_walk() 2021-12-10 14:06:04 +00:00
sdei.c arm64: sdei: abort running SDEI handlers during crash 2023-08-04 17:35:33 +01:00
setup.c arm64: convert to arch_cpu_is_hotpluggable() 2023-12-06 12:41:49 +09:00
signal.c arm64/signal: Don't assume that TIF_SVE means we saved SVE state 2024-02-09 16:34:23 +00:00
signal32.c x86/shstk: Add user control-protection fault handler 2023-08-02 15:01:50 -07:00
sigreturn32.S arm64: compat: Move sigreturn32.S to .rodata section 2022-07-01 12:05:45 +01:00
sleep.S arm64: kernel: remove SHF_WRITE|SHF_EXECINSTR from .idmap.text 2023-05-02 12:42:22 +01:00
smccc-call.S arm64: smccc: Save lr before calling __arm_smccc_sve_check() 2021-07-21 11:23:25 +01:00
smp.c arm64: Align boot cpucap handling with system cpucap handling 2023-12-13 16:02:01 +00:00
smp_spin_table.c treewide: Drop function_nocfi 2022-09-26 10:13:14 -07:00
stacktrace.c arm64: stacktrace: factor out kunwind_stack_walk() 2023-12-11 11:42:55 +00:00
suspend.c arm64: Avoid cpus_have_const_cap() for ARM64_HAS_DIT 2023-10-16 14:17:04 +01:00
sys.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 234 2019-06-19 17:09:07 +02:00
sys32.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 452 2019-06-19 17:09:08 +02:00
sys_compat.c arm64: Avoid cpus_have_const_cap() for ARM64_WORKAROUND_1542419 2023-10-16 14:17:06 +01:00
syscall.c arm64: syscall: unmask DAIF earlier for SVCs 2023-08-11 12:23:48 +01:00
time.c arm64: Make profile_pc() use arch_stack_walk() 2021-12-10 14:06:04 +00:00
topology.c arm64/amu: Use capacity_ref_freq() to set AMU ratio 2023-12-23 15:52:36 +01:00
trace-events-emulation.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
traps.c ARM: 2023-11-02 15:45:15 -10:00
vdso-wrap.S arm64: do not descend to vdso directories twice 2021-01-20 12:18:46 +00:00
vdso.c arm64: Avoid cpus_have_const_cap() for ARM64_HAS_BTI 2023-10-16 14:17:04 +01:00
vdso32-wrap.S arm64: do not descend to vdso directories twice 2021-01-20 12:18:46 +00:00
vmlinux.lds.S arm64: lds: move .got section out of .text 2023-05-02 13:12:45 +01:00
watchdog_hld.c arm64: enable perf events based hard lockup detector 2023-06-09 17:44:22 -07:00