> Date: Sat, 17 Nov 2012 20:40:24 +0200
> From: Paul Irofti <p...@irofti.net>
>
> > 2/ Split the i386 atomic_ucas_32 into two, one that's pcb aware and one
> > that's not. And use the pcb aware one for the futex and the other one
> > for the acpi locking. And of course the amd64 function in the diff
> > bellow will match the non-pcb one from i386.
>
> With the convention that the 'u' in ucas stands for userland (i.e. pcb
> check needed)
Whatever.
this would look something like this:
> diff --git sys/arch/amd64/include/atomic.h sys/arch/amd64/include/atomic.h
> index effbb04..4cf6563 100644
> --- sys/arch/amd64/include/atomic.h
> +++ sys/arch/amd64/include/atomic.h
> @@ -90,6 +90,17 @@ x86_atomic_clearbits_u32(volatile u_int32_t *ptr,
> u_int32_t bits)
> __asm __volatile(LOCK " andl %1,%0" : "=m" (*ptr) : "ir" (~bits));
> }
>
> +static __inline int
> +x86_atomic_cas_int32(volatile int32_t *ptr, int32_t expect, int32_t set)
> +{
> + int res;
> +
> + __asm volatile(LOCK " cmpxchgl %2, %1" : "=a" (res), "=m" (*ptr)
> + : "r" (set), "a" (expect), "m" (*ptr) : "memory");
> +
> + return (res);
> +}
> +
> static __inline u_long
> x86_atomic_cas_ul(volatile u_long *ptr, u_long expect, u_long set)
> {
At least this is consistent with the naming convention currently used.
> diff --git sys/arch/i386/include/atomic.h sys/arch/i386/include/atomic.h
> index fc5408c..d96959c 100644
> --- sys/arch/i386/include/atomic.h
> +++ sys/arch/i386/include/atomic.h
> @@ -99,8 +99,19 @@ i486_atomic_cas_int(volatile u_int *ptr, u_int expect,
> u_int set)
> return (res);
> }
>
> +static __inline int
> +i386_atomic_cas_int32(volatile int32_t *ptr, int32_t expect, int32_t set)
> +{
> + int res;
> +
> + __asm volatile(LOCK " cmpxchgl %2, %1" : "=a" (res), "=m" (*ptr)
> + : "r" (set), "a" (expect), "m" (*ptr) : "memory");
> +
> + return (res);
> +}
> +
However, how are you going to call these functions from the acpi code?
Are you going to add #ifdefs there?
> int ucas_32(volatile int32_t *, int32_t, int32_t);
> -#define atomic_ucas_32 ucas_32
> +#define i386_atomic_ucas_int32 ucas_32
>
> #define atomic_setbits_int i386_atomic_setbits_l
> #define atomic_clearbits_int i386_atomic_clearbits_l
> diff --git sys/compat/linux/linux_futex.c sys/compat/linux/linux_futex.c
> index c8eb1cc..7039be6 100644
> --- sys/compat/linux/linux_futex.c
> +++ sys/compat/linux/linux_futex.c
> @@ -634,7 +634,7 @@ futex_atomic_op(struct proc *p, int encoded_op, void
> *uaddr)
> }
>
> oldval = nval;
> - error = atomic_ucas_32(uaddr, cval, nval);
> + error = i386_atomic_ucas_int32(uaddr, cval, nval);
> if (oldval == cval || error) {
> break;
> }
Well, the Linux compat code *is* effectively i386-only, but I don't
think this makes sense. Just admit that that ucas code is there for
the Linux futex implementation and call it futex_whatever().
