| Message ID | 1314021259-31710-1-git-send-email-nbowler@elliptictech.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Aug 22, 2011 at 09:54:19AM -0400, Nick Bowler wrote: > Current Versatile Express CPU hotplug code includes a hardcoded WFI > instruction, in ARM encoding. When the kernel is compiled in Thumb-2 > mode, this is invalid and causes the machine to hang hard when a CPU > is offlined. > > Using the wfi macro (which uses the appropriate assembler mnemonic) > causes the correct instruction to be emitted in either case. As a > consequence of this change, an apparently vestigial "cc" clobber is > dropped from the asm (the macro uses "memory" only). > > Signed-off-by: Nick Bowler <nbowler@elliptictech.com> > --- Reviewed-by: Jamie Iles <jamie@jamieiles.com> if it helps! Jamie
On 2011-08-22 14:59 +0100, Jamie Iles wrote: > On Mon, Aug 22, 2011 at 09:54:19AM -0400, Nick Bowler wrote: > > Current Versatile Express CPU hotplug code includes a hardcoded WFI > > instruction, in ARM encoding. When the kernel is compiled in Thumb-2 > > mode, this is invalid and causes the machine to hang hard when a CPU > > is offlined. > > > > Using the wfi macro (which uses the appropriate assembler mnemonic) > > causes the correct instruction to be emitted in either case. As a > > consequence of this change, an apparently vestigial "cc" clobber is > > dropped from the asm (the macro uses "memory" only). > > > > Signed-off-by: Nick Bowler <nbowler@elliptictech.com> > > --- > > Reviewed-by: Jamie Iles <jamie@jamieiles.com> > > if it helps! Thanks! Since there seem to be no objections, I'll send this off to Russell's tracker. Cheers,
diff --git a/arch/arm/mach-vexpress/hotplug.c b/arch/arm/mach-vexpress/hotplug.c index ea4cbfb..3668cf9 100644 --- a/arch/arm/mach-vexpress/hotplug.c +++ b/arch/arm/mach-vexpress/hotplug.c @@ -13,6 +13,7 @@ #include <linux/smp.h> #include <asm/cacheflush.h> +#include <asm/system.h> extern volatile int pen_release; @@ -62,13 +63,7 @@ static inline void platform_do_lowpower(unsigned int cpu, int *spurious) * code will have already disabled interrupts */ for (;;) { - /* - * here's the WFI - */ - asm(".word 0xe320f003\n" - : - : - : "memory", "cc"); + wfi(); if (pen_release == cpu) { /*
Current Versatile Express CPU hotplug code includes a hardcoded WFI instruction, in ARM encoding. When the kernel is compiled in Thumb-2 mode, this is invalid and causes the machine to hang hard when a CPU is offlined. Using the wfi macro (which uses the appropriate assembler mnemonic) causes the correct instruction to be emitted in either case. As a consequence of this change, an apparently vestigial "cc" clobber is dropped from the asm (the macro uses "memory" only). Signed-off-by: Nick Bowler <nbowler@elliptictech.com> --- arch/arm/mach-vexpress/hotplug.c | 9 ++------- 1 files changed, 2 insertions(+), 7 deletions(-) OK. If this version is acceptable, I'll follow up with patches for the other platforms.