#ifndef __PARISC_LDCW_H #define __PARISC_LDCW_H #ifndef CONFIG_PA20 /* Because kmalloc only guarantees 8-byte alignment for kmalloc'd data, and GCC only guarantees 8-byte alignment for stack locals, we can't be assured of 16-byte alignment for atomic lock data even if we specify "__attribute ((aligned(16)))" in the type declaration. So, we use a struct containing an array of four ints for the atomic lock type and dynamically select the 16-byte aligned int from the array for the semaphore. */ #define __PA_LDCW_ALIGNMENT 16 #define __ldcw_align(a) ({ \ unsigned long __ret = (unsigned long) &(a)->lock[0]; \ __ret = (__ret + __PA_LDCW_ALIGNMENT - 1) \ & ~(__PA_LDCW_ALIGNMENT - 1); \ (volatile unsigned int *) __ret; \ }) #define __LDCW "ldcw" #else /*CONFIG_PA20*/ /* From: "Jim Hull" <jim.hull of hp.com> I've attached a summary of the change, but basically, for PA 2.0, as long as the ",CO" (coherent operation) completer is specified, then the 16-byte alignment requirement for ldcw and ldcd is relaxed, and instead they only require "natural" alignment (4-byte for ldcw, 8-byte for ldcd). */ #define __PA_LDCW_ALIGNMENT 4 #define __ldcw_align(a) (&(a)->slock) #define __LDCW "ldcw,co" #endif /*!CONFIG_PA20*/ /* LDCW, the only atomic read-write operation PA-RISC has. *sigh*. */ #define __ldcw(a) ({ \ unsigned __ret; \ __asm__ __volatile__(__LDCW " 0(%2),%0" \ : "=r" (__ret), "+m" (*(a)) : "r" (a)); \ __ret; \ }) #ifdef CONFIG_SMP # define __lock_aligned __attribute__((__section__(".data..lock_aligned"))) #endif #endif /* __PARISC_LDCW_H */