arm64: move sp_el0 and tpidr_el1 into cpu_suspend_ctx
authorMark Rutland <mark.rutland@arm.com>
Thu, 3 Nov 2016 20:23:09 +0000 (20:23 +0000)
committerCatalin Marinas <catalin.marinas@arm.com>
Fri, 11 Nov 2016 18:25:44 +0000 (18:25 +0000)
commit623b476fc815464a0241ea7483da7b3580b7d8ac
tree5bfda3f2e218b2dd884f28188def7ba73e8104ed
parent9bbd4c56b0b642f04396da378296e68096d5afca
arm64: move sp_el0 and tpidr_el1 into cpu_suspend_ctx

When returning from idle, we rely on the fact that thread_info lives at
the end of the kernel stack, and restore this by masking the saved stack
pointer. Subsequent patches will sever the relationship between the
stack and thread_info, and to cater for this we must save/restore sp_el0
explicitly, storing it in cpu_suspend_ctx.

As cpu_suspend_ctx must be doubleword aligned, this leaves us with an
extra slot in cpu_suspend_ctx. We can use this to save/restore tpidr_el1
in the same way, which simplifies the code, avoiding pointer chasing on
the restore path (as we no longer need to load thread_info::cpu followed
by the relevant slot in __per_cpu_offset based on this).

This patch stashes both registers in cpu_suspend_ctx.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Cc: James Morse <james.morse@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/include/asm/suspend.h
arch/arm64/kernel/sleep.S
arch/arm64/kernel/suspend.c
arch/arm64/mm/proc.S