Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit d8cd9de3 authored by Mark Rutland's avatar Mark Rutland Committed by Zubin Mithra
Browse files

UPSTREAM: arm64: smp: prepare for smp_processor_id() rework 



Subsequent patches will make smp_processor_id() use a percpu variable.
This will make smp_processor_id() dependent on the percpu offset, and
thus we cannot use smp_processor_id() to figure out what to initialise
the offset to.

Prepare for this by initialising the percpu offset based on
current::cpu, which will work regardless of how smp_processor_id() is
implemented. Also, make this relationship obvious by placing this code
together at the start of secondary_start_kernel().

Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarLaura Abbott <labbott@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>

Bug: 38331309
Change-Id: I43304d06602216fbb5b968ff83e0face11e238f5
(cherry picked from commit 580efaa7ccfb8c0790dce4396434f0e5ac8d86ee)
Signed-off-by: default avatarZubin Mithra <zsm@google.com>
parent 48dd80cb

arch/arm64/kernel/smp.c

+4 −3
Original line number Diff line number Diff line
@@ -135,7 +135,10 @@ static void smp_store_cpu_info(unsigned int cpuid) 
asmlinkage void secondary_start_kernel(void)

{

	struct mm_struct *mm = &init_mm;

	unsigned int cpu = smp_processor_id();

	unsigned int cpu;



	cpu = task_cpu(current);

	set_my_cpu_offset(per_cpu_offset(cpu));



	/*

	 * All kernel threads share the same mm context; grab a
@@ -144,8 +147,6 @@ asmlinkage void secondary_start_kernel(void) 
	atomic_inc(&mm->mm_count);

	current->active_mm = mm;



	set_my_cpu_offset(per_cpu_offset(smp_processor_id()));



	/*

	 * TTBR0 is only used for the identity mapping at this stage. Make it

	 * point to zero page to avoid speculatively fetching new entries.