From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Tue, 28 Oct 2014 12:43:15 +0000 Subject: [PATCHv4 3/7] arm64: Move cpu_resume into the text section In-Reply-To: References: <1414440752-9411-1-git-send-email-lauraa@codeaurora.org> <1414440752-9411-4-git-send-email-lauraa@codeaurora.org> Message-ID: <20141028124314.GD9796@leverpostej> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Oct 28, 2014 at 08:22:00AM +0000, Ard Biesheuvel wrote: > On 28 October 2014 09:10, Ard Biesheuvel wrote: > > On 27 October 2014 21:12, Laura Abbott wrote: > >> The function cpu_resume currently lives in the .data > >> section. There's no reason for it to be there since > >> we can use relative instructions without a problem. > >> Move it to the text section where it belongs. > >> > >> Reviewed-by: Kees Cook > >> Signed-off-by: Laura Abbott > >> --- > >> arch/arm64/kernel/sleep.S | 12 +++++++----- > >> 1 file changed, 7 insertions(+), 5 deletions(-) > >> > > > > Hi Laura, > > > > Apologies for waiting until v4 to bring this up, but I have some minor comments. > > > >> diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S > >> index a564b44..5762b16 100644 > >> --- a/arch/arm64/kernel/sleep.S > >> +++ b/arch/arm64/kernel/sleep.S > >> @@ -147,12 +147,12 @@ cpu_resume_after_mmu: > >> ret > >> ENDPROC(cpu_resume_after_mmu) > >> > >> - .data > >> ENTRY(cpu_resume) > >> bl el2_setup // if in EL2 drop to EL1 cleanly > >> #ifdef CONFIG_SMP > >> mrs x1, mpidr_el1 > >> - adr x4, mpidr_hash_ptr > >> + adrp x4, mpidr_hash_ptr > >> + add x4, x4, #:lo12:mpidr_hash_ptr > > > > Instead of this change, you could put mpidr_hash_ptr itself in .text as well. > > > > Actually, looking more closely, it appears mpidr_hash_ptr can be > dropped completely: > the address obtained by adrp/add is PC relative, so the whole sequence > could just be > > adrp x8, mpidr_hash > add x8, x8, #:lo12:mpidr_hash // x8 = struct mpidr_hash phys address > > (and the ldr and add below can be dropped, and so can mpidr_hash_ptr at the end) Also, if you update arch/arm64/kernel/suspend.c to drop the extern from sleep_save_sp and sleep_idmap_phys, you can drop all of the .data from sleep.S I gave all of that a go locally and my Juno happily booted to userspace with cpuidle running. I had to apply Marc's timer fix to get cpuidle to work at all with v3.18-rc2, but that should be fixed for -rc3. So with those changes: Reviewed-by: Mark Rutland Tested-by: Mark Rutland Thanks, Mark.