| From: |
| Mark Rutland <mark.rutland-AT-arm.com> |
| To: |
| linux-arm-kernel-AT-lists.infradead.org |
| Subject: |
| [RFC PATCH 0/8] arm64: move thread_info off of the task stack |
| Date: |
| Thu, 15 Sep 2016 14:49:01 +0100 |
| Message-ID: |
| <1473947349-14521-1-git-send-email-mark.rutland@arm.com> |
| Cc: |
| akpm-AT-linux-foundation.org, ard.biesheuvel-AT-linaro.org, catalin.marinas-AT-arm.com, james.morse-AT-arm.com, keescook-AT-chromium.org, linux-kernel-AT-vger.kernel.org, lorenzo.pieralisi-AT-arm.com, luto-AT-kernel.org, mark.rutland-AT-arm.com, suzuki.poulose-AT-arm.com, takahiro.akashi-AT-linaro.org, will.deacon-AT-arm.com, kernel-hardening-AT-lists.openwall.com |
Building atop of Andy's work on x86 and generic code, these patches move
arm64's thread_info off of the stack and into task_struct. This protects
thread_info from corruption in the face of stack overflow, and serves as
a step towards fully robust stack overflow handling will be addressed by
subsequent patches.
In contrast to x86, we can't place some critical data such as
preempt_count in percpu variables, and we must store these in some
per-task location. This, compounded with the way headers are organised
conspires to require us to still define our own thread_info. I
understand that the longer term plan is to kill off thread_info
entirely, hence I'm sending this as an RFC so we can figure out if/how
we can achieve that.
These patches are based on Andy's x86/vmap_stack branch [1,2], and I've
pushed a copy to me arm64/ti-stack-split branch [3,4]. The result of
these patches boots happily on platforms within reach of my desk, but
has not seen much stressing so far.
Thanks,
Mark.
[1] git://git.kernel.org/pub/scm/linux/kernel/git/luto/linux.git x86/vmap_stack
[2] https://git.kernel.org/cgit/linux/kernel/git/luto/linux.g...
[3] git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git arm64/ti-stack-split
[4] https://git.kernel.org/cgit/linux/kernel/git/mark/linux.g...
Mark Rutland (8):
thread_info: include <current.h> for THREAD_INFO_IN_TASK
thread_info: allow custom in-task thread_info
arm64: thread_info remove stale items
arm64: asm-offsets: remove unused definitions
arm64: assembler: introduce ldr_this_cpu
arm64: traps: use task_struct instead of thread_info
arm64: move sp_el0 and tpidr_el1 into cpu_suspend_ctx
arm64: split thread_info from task stack
arch/arm64/Kconfig | 2 ++
arch/arm64/include/asm/Kbuild | 1 -
arch/arm64/include/asm/assembler.h | 19 +++++++++++++++----
arch/arm64/include/asm/current.h | 22 ++++++++++++++++++++++
arch/arm64/include/asm/smp.h | 1 +
arch/arm64/include/asm/suspend.h | 2 +-
arch/arm64/include/asm/thread_info.h | 21 ---------------------
arch/arm64/kernel/asm-offsets.c | 3 +--
arch/arm64/kernel/entry.S | 6 +++---
arch/arm64/kernel/head.S | 11 +++++------
arch/arm64/kernel/process.c | 31 ++++++++++++++++++++++++++-----
arch/arm64/kernel/sleep.S | 3 ---
arch/arm64/kernel/smp.c | 2 ++
arch/arm64/kernel/stacktrace.c | 5 +++++
arch/arm64/kernel/suspend.c | 6 ------
arch/arm64/kernel/traps.c | 12 ++++++------
arch/arm64/mm/proc.S | 6 ++++++
include/linux/thread_info.h | 4 +++-
init/Kconfig | 3 +++
19 files changed, 101 insertions(+), 59 deletions(-)
create mode 100644 arch/arm64/include/asm/current.h
--
1.9.1
