Commit 8abf7148 authored Jan 24, 2014 by Lorenzo Pieralisi Committed by Ian Maund Apr 17, 2014

arm64: kernel: fix per-cpu offset restore on resume



The introduction of percpu offset optimisation through tpidr_el1 in:

Commit id :7158627686f02319c50c8d9d78f75d4c8
"arm64: percpu: implement optimised pcpu access using tpidr_el1"

requires cpu_{suspend/resume} to restore the tpidr_el1 register upon resume
so that percpu variables can be addressed correctly when a CPU comes out
of reset from warm-boot.

This patch fixes cpu_{suspend}/{resume} tpidr_el1 restoration on resume, by
calling the set_my_cpu_offset C API, as it is done on primary and secondary
CPUs on cold boot, so that, even if the register used to store the percpu
offset is changed, the save and restore of general purpose registers does not
have to be updated.

Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Git-commit: fb4a96029c8a091c4365f57307e098543b48a222
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Ian Maund <imaund@codeaurora.org>

parent 902b9a88

arch/arm64/kernel/suspend.c

+8 −0

Original line number	Diff line number	Diff line
		#include <linux/percpu.h>
		#include <linux/slab.h>
		#include <asm/cacheflush.h>
		#include <asm/cpu_ops.h>
		@@ -89,6 +90,13 @@ int cpu_suspend(unsigned long arg)
		if (ret == 0) {
		cpu_switch_mm(mm->pgd, mm);
		flush_tlb_all();

		/*
		* Restore per-cpu offset before any kernel
		* subsystem relying on it has a chance to run.
		*/
		set_my_cpu_offset(per_cpu_offset(cpu));

		/*
		* Restore HW breakpoint registers to sane values
		* before debug exceptions are possibly reenabled