From: Muhammad Usama Anjum <usama.anjum@arm.com>
To: Will Deacon <will@kernel.org>, Linus Walleij <linusw@kernel.org>
Cc: usama.anjum@arm.com, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Ard Biesheuvel <ardb@kernel.org>,
Ada Couprie Diaz <ada.coupriediaz@arm.com>,
David Hildenbrand <david@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Vladimir Murzin <vladimir.murzin@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Mostafa Saleh <smostafa@google.com>,
Lorenzo Stoakes <ljs@kernel.org>,
Oliver Upton <oupton@kernel.org>, Marc Zyngier <maz@kernel.org>
Subject: Re: [PATCH v2 00/21] arm64: Move overflow sp into SP_EL1 and kernel sp into SP_EL0
Date: Thu, 1 Oct 2026 10:00:37 +0100 [thread overview]
Message-ID: <15549877-85ad-49ad-b2f2-843dd506ba0a@arm.com> (raw)
In-Reply-To: <ar4KD6FTZzw2Wq6w@willie-the-truck>
On 01/10/2026 8:21 am, Will Deacon wrote:
> On Wed, Sep 30, 2026 at 11:42:51PM +0200, Linus Walleij wrote:
>> On Fri, Sep 18, 2026 at 6:14 PM Will Deacon <will@kernel.org> wrote:
>>
>>> This is version two of the kernel stack juggling patches I previously
>>> posted here:
>>>
>>> https://lore.kernel.org/r/20260907164247.17223-1-will@kernel.org
>>>
>>> Changes since v1 include:
>>> * Fixed suspend/resume paths to handle the stack pointers properly
>>> * Fixed restoration of ptrauth keys on resume
>>> * Added tags
>>
>> Overall I like what I see, but can we split it in two... like first the patches
>> up to fixing the overflow handling using SP_EL0 and finalize that?
>
> Yes, that makes sense (and thanks for going through it). The whole thing
> is bisectable, so lemme go through the feedback I've got so far and send
> out a prefix that we could consider merging as preparatory work.
I'll trigger run on this prefix.
>
>> Hopefully Usama can test just that part and see if it has a lesser
>> performance impact as well.
>
> I'd like to see those numbers at various points during the series, tbh,
> so we can rule out any stack-protector changes etc.
Sure, I can trigger runs on different points if you can mention which would be
more valuable.
--
Thanks,
Usama
next prev parent reply other threads:[~2026-10-01 9:01 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-18 16:13 Will Deacon
2026-09-18 16:13 ` [PATCH v2 01/21] arm64: entry: Defer setting of TPIDRRO_EL0 until exit to userspace Will Deacon
2026-09-30 20:47 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 02/21] arm64: entry: Only check for stack overflow on exceptions from EL1 Will Deacon
2026-09-30 20:50 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 03/21] arm64: stackprotector: Temporarily disable per-task stackprotector Will Deacon
2026-09-30 21:01 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 04/21] arm64: bpf: Add support for generating reads of TPIDRRO_EL0 Will Deacon
2026-09-30 20:53 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 05/21] KVM: arm64: Protect TPIDRRO_EL0 across guest entry/exit Will Deacon
2026-09-30 20:55 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 06/21] arm64: Store 'current' in TPIDRRO_EL0 instead of SP_EL0 Will Deacon
2026-09-30 20:58 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 07/21] selftests/bpf: arm64: Use TPIDRRO_EL0 instead of SP_EL0 for 'current' Will Deacon
2026-09-30 20:58 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 08/21] scripts/gdb: " Will Deacon
2026-09-30 20:59 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 09/21] arm64: stackprotector: Re-enable per-task stackprotector Will Deacon
2026-09-30 21:00 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 10/21] arm64: percpu: Specialise set_my_cpu_offset() for the primary CPU Will Deacon
2026-09-30 21:02 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 11/21] arm64: percpu: Annotate __kern_my_cpu_offset() as '__always_inline' Will Deacon
2026-09-30 21:05 ` Linus Walleij
2026-09-30 21:05 ` Linus Walleij
2026-09-18 16:13 ` [PATCH v2 12/21] KVM: arm64: Preserve handler/thread bit of EL1 mode in __finalise_el2() Will Deacon
2026-09-18 16:13 ` [PATCH v2 13/21] arm64: sdei: Guard most of asm/sdei.h with CONFIG_ARM_SDE_INTERFACE Will Deacon
2026-09-18 16:13 ` [PATCH v2 14/21] arm64: sdei: Support SDEI events from kernel handler and thread modes Will Deacon
2026-09-18 16:13 ` [PATCH v2 15/21] arm64: entry: Point SP_EL0 at the overflow stack Will Deacon
2026-09-21 15:56 ` Catalin Marinas
2026-09-18 16:14 ` [PATCH v2 16/21] arm64: entry: Implement EL1t exception handlers for " Will Deacon
2026-09-30 21:17 ` Linus Walleij
2026-09-18 16:14 ` [PATCH v2 17/21] arm64: entry: Use SPSel to switch to " Will Deacon
2026-09-30 21:22 ` Linus Walleij
2026-09-18 16:14 ` [PATCH v2 18/21] arm64: entry: Split up kernel_ventry macro into separate helper macros Will Deacon
2026-09-30 21:26 ` Linus Walleij
2026-09-18 16:14 ` [PATCH v2 19/21] arm64: entry: The great stack switcheroo Will Deacon
2026-09-19 11:41 ` Bradley Morgan
2026-09-22 13:51 ` Catalin Marinas
2026-09-30 21:36 ` Linus Walleij
2026-10-01 7:27 ` Will Deacon
2026-10-01 8:38 ` Linus Walleij
2026-10-01 11:32 ` Will Deacon
2026-10-01 11:35 ` Linus Walleij
2026-09-18 16:14 ` [PATCH v2 20/21] arm64: tracing: Advertise a mode of EL1t in synthetic kernel regs Will Deacon
2026-09-22 14:00 ` Catalin Marinas
2026-09-18 16:14 ` [PATCH v2 21/21] arm64: Rename 'overflow_stack' and OVERFLOW_STACK_SIZE Will Deacon
2026-09-22 14:01 ` Catalin Marinas
2026-09-24 12:30 ` [PATCH v2 00/21] arm64: Move overflow sp into SP_EL1 and kernel sp into SP_EL0 Usama Anjum
2026-09-30 21:42 ` Linus Walleij
2026-10-01 7:21 ` Will Deacon
2026-10-01 9:00 ` Muhammad Usama Anjum [this message]
2026-10-01 21:19 ` Linus Walleij
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