#ifndef __ASM_SYSTEM_H #define __ASM_SYSTEM_H #include <linux/config.h> #include <linux/kernel.h> #include <asm/segment.h> #include <asm/cpufeature.h> #include <linux/bitops.h> /* for LOCK_PREFIX */ #ifdef __KERNEL__ struct task_struct; /* one of the stranger aspects of C forward declarations.. */ extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struct task_struct *next)); #define switch_to(prev,next,last) do { \ unsigned long esi,edi; \ asm volatile("pushfl\n\t" \ "pushl %%ebp\n\t" \ "movl %%esp,%0\n\t" /* save ESP */ \ "movl %5,%%esp\n\t" /* restore ESP */ \ "movl $1f,%1\n\t" /* save EIP */ \ "pushl %6\n\t" /* restore EIP */ \ "jmp __switch_to\n" \ "1:\t" \ "popl %%ebp\n\t" \ "popfl" \ :"=m" (prev->thread.esp),"=m" (prev->thread.eip), \ "=a" (last),"=S" (esi),"=D" (edi) \ :"m" (next->thread.esp),"m" (next->thread.eip), \ "2" (prev), "d" (next)); \ } while (0) #define _set_base(addr,base) do { unsigned long __pr; \ __asm__ __volatile__ ("movw %%dx,%1\n\t" \ "rorl $16,%%edx\n\t" \ "movb %%dl,%2\n\t" \ "movb %%dh,%3" \ :"=&d" (__pr) \ :"m" (*((addr)+2)), \ "m" (*((addr)+4)), \ "m" (*((addr)+7)), \ "0" (base) \ ); } while(0) #define _set_limit(addr,limit) do { unsigned long __lr; \ __asm__ __volatile__ ("movw %%dx,%1\n\t" \ "rorl $16,%%edx\n\t" \ "movb %2,%%dh\n\t" \ "andb $0xf0,%%dh\n\t" \ "orb %%dh,%%dl\n\t" \ "movb %%dl,%2" \ :"=&d" (__lr) \ :"m" (*(addr)), \ "m" (*((addr)+6)), \ "0" (limit) \ ); } while(0) #define set_base(ldt,base) _set_base( ((char *)&(ldt)) , (base) ) #define set_limit(ldt,limit) _set_limit( ((char *)&(ldt)) , ((limit)-1)>>12 ) static inline unsigned long _get_base(char * addr) { unsigned long __base; __asm__("movb %3,%%dh\n\t" "movb %2,%%dl\n\t" "shll $16,%%edx\n\t" "movw %1,%%dx" :"=&d" (__base) :"m" (*((addr)+2)), "m" (*((addr)+4)), "m" (*((addr)+7))); return __base; } #define get_base(ldt) _get_base( ((char *)&(ldt)) ) /* * Load a segment. Fall back on loading the zero * segment if something goes wrong.. */ #define loadsegment(seg,value) \ asm volatile("\n" \ "1:\t" \ "mov %0,%%" #seg "\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3:\t" \ "pushl $0\n\t" \ "popl %%" #seg "\n\t" \ "jmp 2b\n" \ ".previous\n" \ ".section __ex_table,\"a\"\n\t" \ ".align 4\n\t" \ ".long 1b,3b\n" \ ".previous" \ : :"m" (value)) /* * Save a segment register away */ #define savesegment(seg, value) \ asm volatile("mov %%" #seg ",%0":"=m" (value)) /* * Clear and set 'TS' bit respectively */ #define clts() __asm__ __volatile__ ("clts") #define read_cr0() ({ \ unsigned int __dummy; \ __asm__( \ "movl %%cr0,%0\n\t" \ :"=r" (__dummy)); \ __dummy; \ }) #define write_cr0(x) \ __asm__("movl %0,%%cr0": :"r" (x)); #define read_cr4() ({ \ unsigned int __dummy; \ __asm__( \ "movl %%cr4,%0\n\t" \ :"=r" (__dummy)); \ __dummy; \ }) #define write_cr4(x) \ __asm__("movl %0,%%cr4": :"r" (x)); #define stts() write_cr0(8 | read_cr0()) #endif /* __KERNEL__ */ #define wbinvd() \ __asm__ __volatile__ ("wbinvd": : :"memory"); static inline unsigned long get_limit(unsigned long segment) { unsigned long __limit; __asm__("lsll %1,%0" :"=r" (__limit):"r" (segment)); return __limit+1; } #define nop() __asm__ __volatile__ ("nop") #define xchg(ptr,v) ((__typeof__(*(ptr)))__xchg((unsigned long)(v),(ptr),sizeof(*(ptr)))) #define tas(ptr) (xchg((ptr),1)) struct __xchg_dummy { unsigned long a[100]; }; #define __xg(x) ((struct __xchg_dummy *)(x)) /* * The semantics of XCHGCMP8B are a bit strange, this is why * there is a loop and the loading of %%eax and %%edx has to * be inside. This inlines well in most cases, the cached * cost is around ~38 cycles. (in the future we might want * to do an SIMD/3DNOW!/MMX/FPU 64-bit store here, but that * might have an implicit FPU-save as a cost, so it's not * clear which path to go.) * * cmpxchg8b must be used with the lock prefix here to allow * the instruction to be executed atomically, see page 3-102 * of the instruction set reference 24319102.pdf. We need * the reader side to see the coherent 64bit value. */ static inline void __set_64bit (unsigned long long * ptr, unsigned int low, unsigned int high) { __asm__ __volatile__ ( "\n1:\t" "movl (%0), %%eax\n\t" "movl 4(%0), %%edx\n\t" "lock cmpxchg8b (%0)\n\t" "jnz 1b" : /* no outputs */ : "D"(ptr), "b"(low), "c"(high) : "ax","dx","memory"); } static inline void __set_64bit_constant (unsigned long long *ptr, unsigned long long value) { __set_64bit(ptr,(unsigned int)(value), (unsigned int)((value)>>32ULL)); } #define ll_low(x) *(((unsigned int*)&(x))+0) #define ll_high(x) *(((unsigned int*)&(x))+1) static inline void __set_64bit_var (unsigned long long *ptr, unsigned long long value) { __set_64bit(ptr,ll_low(value), ll_high(value)); } #define set_64bit(ptr,value) \ (__builtin_constant_p(value) ? \ __set_64bit_constant(ptr, value) : \ __set_64bit_var(ptr, value) ) #define _set_64bit(ptr,value) \ (__builtin_constant_p(value) ? \ __set_64bit(ptr, (unsigned int)(value), (unsigned int)((value)>>32ULL) ) : \ __set_64bit(ptr, ll_low(value), ll_high(value)) ) /* * Note: no "lock" prefix even on SMP: xchg always implies lock anyway * Note 2: xchg has side effect, so that attribute volatile is necessary, * but generally the primitive is invalid, *ptr is output argument. --ANK */ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size) { switch (size) { case 1: __asm__ __volatile__("xchgb %b0,%1" :"=q" (x) :"m" (*__xg(ptr)), "0" (x) :"memory"); break; case 2: __asm__ __volatile__("xchgw %w0,%1" :"=r" (x) :"m" (*__xg(ptr)), "0" (x) :"memory"); break; case 4: __asm__ __volatile__("xchgl %0,%1" :"=r" (x) :"m" (*__xg(ptr)), "0" (x) :"memory"); break; } return x; } /* * Atomic compare and exchange. Compare OLD with MEM, if identical, * store NEW in MEM. Return the initial value in MEM. Success is * indicated by comparing RETURN with OLD. */ #ifdef CONFIG_X86_CMPXCHG #define __HAVE_ARCH_CMPXCHG 1 #endif static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size) { unsigned long prev; switch (size) { case 1: __asm__ __volatile__(LOCK_PREFIX "cmpxchgb %b1,%2" : "=a"(prev) : "q"(new), "m"(*__xg(ptr)), "0"(old) : "memory"); return prev; case 2: __asm__ __volatile__(LOCK_PREFIX "cmpxchgw %w1,%2" : "=a"(prev) : "q"(new), "m"(*__xg(ptr)), "0"(old) : "memory"); return prev; case 4: __asm__ __volatile__(LOCK_PREFIX "cmpxchgl %1,%2" : "=a"(prev) : "q"(new), "m"(*__xg(ptr)), "0"(old) : "memory"); return prev; } return old; } #define cmpxchg(ptr,o,n)\ ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\ (unsigned long)(n),sizeof(*(ptr)))) #ifdef __KERNEL__ struct alt_instr { __u8 *instr; /* original instruction */ __u8 *replacement; __u8 cpuid; /* cpuid bit set for replacement */ __u8 instrlen; /* length of original instruction */ __u8 replacementlen; /* length of new instruction, <= instrlen */ __u8 pad; }; #endif /* * Alternative instructions for different CPU types or capabilities. * * This allows to use optimized instructions even on generic binary * kernels. * * length of oldinstr must be longer or equal the length of newinstr * It can be padded with nops as needed. * * For non barrier like inlines please define new variants * without volatile and memory clobber. */ #define alternative(oldinstr, newinstr, feature) \ asm volatile ("661:\n\t" oldinstr "\n662:\n" \ ".section .altinstructions,\"a\"\n" \ " .align 4\n" \ " .long 661b\n" /* label */ \ " .long 663f\n" /* new instruction */ \ " .byte %c0\n" /* feature bit */ \ " .byte 662b-661b\n" /* sourcelen */ \ " .byte 664f-663f\n" /* replacementlen */ \ ".previous\n" \ ".section .altinstr_replacement,\"ax\"\n" \ "663:\n\t" newinstr "\n664:\n" /* replacement */ \ ".previous" :: "i" (feature) : "memory") /* * Alternative inline assembly with input. * * Pecularities: * No memory clobber here. * Argument numbers start with 1. * Best is to use constraints that are fixed size (like (%1) ... "r") * If you use variable sized constraints like "m" or "g" in the * replacement maake sure to pad to the worst case length. */ #define alternative_input(oldinstr, newinstr, feature, input...) \ asm volatile ("661:\n\t" oldinstr "\n662:\n" \ ".section .altinstructions,\"a\"\n" \ " .align 4\n" \ " .long 661b\n" /* label */ \ " .long 663f\n" /* new instruction */ \ " .byte %c0\n" /* feature bit */ \ " .byte 662b-661b\n" /* sourcelen */ \ " .byte 664f-663f\n" /* replacementlen */ \ ".previous\n" \ ".section .altinstr_replacement,\"ax\"\n" \ "663:\n\t" newinstr "\n664:\n" /* replacement */ \ ".previous" :: "i" (feature), ##input) /* * Force strict CPU ordering. * And yes, this is required on UP too when we're talking * to devices. * * For now, "wmb()" doesn't actually do anything, as all * Intel CPU's follow what Intel calls a *Processor Order*, * in which all writes are seen in the program order even * outside the CPU. * * I expect future Intel CPU's to have a weaker ordering, * but I'd also expect them to finally get their act together * and add some real memory barriers if so. * * Some non intel clones support out of order store. wmb() ceases to be a * nop for these. */ /* * Actually only lfence would be needed for mb() because all stores done * by the kernel should be already ordered. But keep a full barrier for now. */ #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2) #define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2) /** * read_barrier_depends - Flush all pending reads that subsequents reads * depend on. * * No data-dependent reads from memory-like regions are ever reordered * over this barrier. All reads preceding this primitive are guaranteed * to access memory (but not necessarily other CPUs' caches) before any * reads following this primitive that depend on the data return by * any of the preceding reads. This primitive is much lighter weight than * rmb() on most CPUs, and is never heavier weight than is * rmb(). * * These ordering constraints are respected by both the local CPU * and the compiler. * * Ordering is not guaranteed by anything other than these primitives, * not even by data dependencies. See the documentation for * memory_barrier() for examples and URLs to more information. * * For example, the following code would force ordering (the initial * value of "a" is zero, "b" is one, and "p" is "&a"): * * <programlisting> * CPU 0 CPU 1 * * b = 2; * memory_barrier(); * p = &b; q = p; * read_barrier_depends(); * d = *q; * </programlisting> * * because the read of "*q" depends on the read of "p" and these * two reads are separated by a read_barrier_depends(). However, * the following code, with the same initial values for "a" and "b": * * <programlisting> * CPU 0 CPU 1 * * a = 2; * memory_barrier(); * b = 3; y = b; * read_barrier_depends(); * x = a; * </programlisting> * * does not enforce ordering, since there is no data dependency between * the read of "a" and the read of "b". Therefore, on some CPUs, such * as Alpha, "y" could be set to 3 and "x" to 0. Use rmb() * in cases like thiswhere there are no data dependencies. **/ #define read_barrier_depends() do { } while(0) #ifdef CONFIG_X86_OOSTORE /* Actually there are no OOO store capable CPUs for now that do SSE, but make it already an possibility. */ #define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM) #else #define wmb() __asm__ __volatile__ ("": : :"memory") #endif #ifdef CONFIG_SMP #define smp_mb() mb() #define smp_rmb() rmb() #define smp_wmb() wmb() #define smp_read_barrier_depends() read_barrier_depends() #define set_mb(var, value) do { xchg(&var, value); } while (0) #else #define smp_mb() barrier() #define smp_rmb() barrier() #define smp_wmb() barrier() #define smp_read_barrier_depends() do { } while(0) #define set_mb(var, value) do { var = value; barrier(); } while (0) #endif #define set_wmb(var, value) do { var = value; wmb(); } while (0) /* interrupt control.. */ #define local_save_flags(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushfl ; popl %0":"=g" (x): /* no input */); } while (0) #define local_irq_restore(x) do { typecheck(unsigned long,x); __asm__ __volatile__("pushl %0 ; popfl": /* no output */ :"g" (x):"memory", "cc"); } while (0) #define local_irq_disable() __asm__ __volatile__("cli": : :"memory") #define local_irq_enable() __asm__ __volatile__("sti": : :"memory") /* used in the idle loop; sti takes one instruction cycle to complete */ #define safe_halt() __asm__ __volatile__("sti; hlt": : :"memory") #define irqs_disabled() \ ({ \ unsigned long flags; \ local_save_flags(flags); \ !(flags & (1<<9)); \ }) /* For spinlocks etc */ #define local_irq_save(x) __asm__ __volatile__("pushfl ; popl %0 ; cli":"=g" (x): /* no input */ :"memory") /* * disable hlt during certain critical i/o operations */ #define HAVE_DISABLE_HLT void disable_hlt(void); void enable_hlt(void); extern int es7000_plat; void cpu_idle_wait(void); extern unsigned long arch_align_stack(unsigned long sp); #endif