[PATCH v2 00/21] arm64: Move overflow sp into SP_EL1 and kernel sp into SP_EL0

From: Will Deacon

Date: Fri Sep 18 2026 - 12:29:08 EST


Hi folks,

This is version two of the kernel stack juggling patches I previously
posted here:

https://lore.kernel.org/r/20260907164247.17223-1-will@xxxxxxxxxx

Changes since v1 include:
* Fixed suspend/resume paths to handle the stack pointers properly
* Fixed restoration of ptrauth keys on resume
* Added tags

Cheers,

Will

Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Ada Couprie Diaz <ada.coupriediaz@xxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Vladimir Murzin <vladimir.murzin@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mostafa Saleh <smostafa@xxxxxxxxxx>
Cc: Lorenzo Stoakes <ljs@xxxxxxxxxx>
Cc: Oliver Upton <oupton@xxxxxxxxxx>
Cc: Linus Walleij <linusw@xxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>

--->8

Mostafa Saleh (1):
KVM: arm64: Protect TPIDRRO_EL0 across guest entry/exit

Will Deacon (20):
arm64: entry: Defer setting of TPIDRRO_EL0 until exit to userspace
arm64: entry: Only check for stack overflow on exceptions from EL1
arm64: stackprotector: Temporarily disable per-task stackprotector
arm64: bpf: Add support for generating reads of TPIDRRO_EL0
arm64: Store 'current' in TPIDRRO_EL0 instead of SP_EL0
selftests/bpf: arm64: Use TPIDRRO_EL0 instead of SP_EL0 for 'current'
scripts/gdb: arm64: Use TPIDRRO_EL0 instead of SP_EL0 for 'current'
arm64: stackprotector: Re-enable per-task stackprotector
arm64: percpu: Specialise set_my_cpu_offset() for the primary CPU
arm64: percpu: Annotate __kern_my_cpu_offset() as '__always_inline'
KVM: arm64: Preserve handler/thread bit of EL1 mode in
__finalise_el2()
arm64: sdei: Guard most of asm/sdei.h with CONFIG_ARM_SDE_INTERFACE
arm64: sdei: Support SDEI events from kernel handler and thread modes
arm64: entry: Point SP_EL0 at the overflow stack
arm64: entry: Implement EL1t exception handlers for overflow stack
arm64: entry: Use SPSel to switch to overflow stack
arm64: entry: Split up kernel_ventry macro into separate helper macros
arm64: entry: The great stack switcheroo
arm64: tracing: Advertise a mode of EL1t in synthetic kernel regs
arm64: Rename 'overflow_stack' and OVERFLOW_STACK_SIZE

arch/arm64/Kconfig | 2 +-
arch/arm64/Makefile | 2 +-
arch/arm64/include/asm/assembler.h | 2 +-
arch/arm64/include/asm/current.h | 6 +-
arch/arm64/include/asm/ftrace.h | 4 +-
arch/arm64/include/asm/insn.h | 1 +
arch/arm64/include/asm/kvm_asm.h | 26 +++++
arch/arm64/include/asm/memory.h | 10 +-
arch/arm64/include/asm/percpu.h | 10 +-
arch/arm64/include/asm/perf_event.h | 2 +-
arch/arm64/include/asm/sdei.h | 2 +
arch/arm64/include/asm/stacktrace.h | 9 +-
arch/arm64/include/asm/stacktrace/nvhe.h | 3 +-
arch/arm64/include/uapi/asm/ptrace.h | 1 +
arch/arm64/kernel/asm-offsets.c | 2 +
arch/arm64/kernel/entry-common.c | 51 +++++++--
arch/arm64/kernel/entry.S | 108 +++++++++---------
arch/arm64/kernel/head.S | 8 +-
arch/arm64/kernel/hyp-stub.S | 7 +-
arch/arm64/kernel/process.c | 21 +---
arch/arm64/kernel/sdei.c | 6 +-
arch/arm64/kernel/sleep.S | 3 +-
arch/arm64/kernel/smp.c | 19 ++-
arch/arm64/kernel/stacktrace.c | 2 +-
arch/arm64/kernel/sys_compat.c | 7 --
arch/arm64/kernel/traps.c | 14 +--
arch/arm64/kvm/hyp/entry.S | 15 ++-
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 2 -
arch/arm64/kvm/hyp/nvhe/host.S | 2 +-
arch/arm64/kvm/hyp/nvhe/stacktrace.c | 4 +-
arch/arm64/kvm/stacktrace.c | 4 +-
arch/arm64/mm/proc.S | 16 ++-
arch/arm64/net/bpf_jit.h | 2 +
arch/arm64/net/bpf_jit_comp.c | 4 +-
scripts/gdb/linux/cpus.py | 2 +-
.../selftests/bpf/progs/verifier_jit_inline.c | 2 +-
36 files changed, 230 insertions(+), 151 deletions(-)

--
2.55.0.1082.g2b9226bbc0-goog