| Message ID | 1393957413-2962-1-git-send-email-lorenzo.pieralisi@arm.com |
|---|---|
| State | New |
| Headers | show |
On Tue, Mar 04 2014 at 6:23:33 pm GMT, Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com> wrote: > On CPUs with virtualization extensions the kernel installs HYP mode > configuration on both primary and secondary cpus upon cold boot. > > On platforms where CPUs are shutdown in idle paths (ie CPU core gating), > when a CPU resumes from low-power states it currently does not execute > code that reinstalls the HYP configuration, which means that the kernel > cannot run eg KVM properly on such machines. > > This patch, mirroring cold-boot behaviour, executes position independent > code that reinstalls HYP configuration and drops to SVC mode safely on > warmboot, so that deep idle states can be enabled in kernel running as > hosts on platforms with power management HW. > > Cc: Christoffer Dall <christoffer.dall@linaro.org> > Cc: Dave Martin <dave.martin@arm.com> > Cc: Marc Zyngier <marc.zyngier@arm.com> > Cc: Nicolas Pitre <nico@linaro.org> > Cc: Russell King <linux@arm.linux.org.uk> > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Look sensible to me. Acked-by: Marc Zyngier <marc.zyngier@arm.com> M. > --- > arch/arm/kernel/sleep.S | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S > index b907d9b..1b880db 100644 > --- a/arch/arm/kernel/sleep.S > +++ b/arch/arm/kernel/sleep.S > @@ -127,6 +127,10 @@ ENDPROC(cpu_resume_after_mmu) > .align > ENTRY(cpu_resume) > ARM_BE8(setend be) @ ensure we are in BE mode > +#ifdef CONFIG_ARM_VIRT_EXT > + bl __hyp_stub_install_secondary > +#endif > + safe_svcmode_maskall r1 > mov r1, #0 > ALT_SMP(mrc p15, 0, r0, c0, c0, 5) > ALT_UP_B(1f) > @@ -144,7 +148,6 @@ ARM_BE8(setend be) @ ensure we are in BE mode > ldr r0, [r0, #SLEEP_SAVE_SP_PHYS] > ldr r0, [r0, r1, lsl #2] > > - setmode PSR_I_BIT | PSR_F_BIT | SVC_MODE, r1 @ set SVC, irqs off > @ load phys pgd, stack, resume fn > ARM( ldmia r0!, {r1, sp, pc} ) > THUMB( ldmia r0!, {r1, r2, r3} )
diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S index b907d9b..1b880db 100644 --- a/arch/arm/kernel/sleep.S +++ b/arch/arm/kernel/sleep.S @@ -127,6 +127,10 @@ ENDPROC(cpu_resume_after_mmu) .align ENTRY(cpu_resume) ARM_BE8(setend be) @ ensure we are in BE mode +#ifdef CONFIG_ARM_VIRT_EXT + bl __hyp_stub_install_secondary +#endif + safe_svcmode_maskall r1 mov r1, #0 ALT_SMP(mrc p15, 0, r0, c0, c0, 5) ALT_UP_B(1f) @@ -144,7 +148,6 @@ ARM_BE8(setend be) @ ensure we are in BE mode ldr r0, [r0, #SLEEP_SAVE_SP_PHYS] ldr r0, [r0, r1, lsl #2] - setmode PSR_I_BIT | PSR_F_BIT | SVC_MODE, r1 @ set SVC, irqs off @ load phys pgd, stack, resume fn ARM( ldmia r0!, {r1, sp, pc} ) THUMB( ldmia r0!, {r1, r2, r3} )
On CPUs with virtualization extensions the kernel installs HYP mode configuration on both primary and secondary cpus upon cold boot. On platforms where CPUs are shutdown in idle paths (ie CPU core gating), when a CPU resumes from low-power states it currently does not execute code that reinstalls the HYP configuration, which means that the kernel cannot run eg KVM properly on such machines. This patch, mirroring cold-boot behaviour, executes position independent code that reinstalls HYP configuration and drops to SVC mode safely on warmboot, so that deep idle states can be enabled in kernel running as hosts on platforms with power management HW. Cc: Christoffer Dall <christoffer.dall@linaro.org> Cc: Dave Martin <dave.martin@arm.com> Cc: Marc Zyngier <marc.zyngier@arm.com> Cc: Nicolas Pitre <nico@linaro.org> Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> --- arch/arm/kernel/sleep.S | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)