#ifndef _ASM_X86_SYSTEM_H #define _ASM_X86_SYSTEM_H #include #include #include #include #include #include #include /* entries in ARCH_DLINFO: */ #ifdef CONFIG_IA32_EMULATION # define AT_VECTOR_SIZE_ARCH 2 #else # define AT_VECTOR_SIZE_ARCH 1 #endif struct task_struct; /* one of the stranger aspects of C forward declarations */ struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *next); struct tss_struct; void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p, struct tss_struct *tss); #ifdef CONFIG_X86_32 #ifdef CONFIG_CC_STACKPROTECTOR #define __switch_canary \ "movl %P[task_canary](%[next]), %%ebx\n\t" \ "movl %%ebx, "__percpu_arg([stack_canary])"\n\t" #define __switch_canary_oparam \ , [stack_canary] "=m" (per_cpu_var(stack_canary)) #define __switch_canary_iparam \ , [task_canary] "i" (offsetof(struct task_struct, stack_canary)) #else /* CC_STACKPROTECTOR */ #define __switch_canary #define __switch_canary_oparam #define __switch_canary_iparam #endif /* CC_STACKPROTECTOR */ /* * Saving eflags is important. It switches not only IOPL between tasks, * it also protects other tasks from NT leaking through sysenter etc. */ #define switch_to(prev, next, last) \ do { \ /* \ * Context-switching clobbers all registers, so we clobber \ * them explicitly, via unused output variables. \ * (EAX and EBP is not listed because EBP is saved/restored \ * explicitly for wchan access and EAX is the return value of \ * __switch_to()) \ */ \ unsigned long ebx, ecx, edx, esi, edi; \ \ asm volatile("pushfl\n\t" /* save flags */ \ "pushl %%ebp\n\t" /* save EBP */ \ "movl %%esp,%[prev_sp]\n\t" /* save ESP */ \ "movl %[next_sp],%%esp\n\t" /* restore ESP */ \ "movl $1f,%[prev_ip]\n\t" /* save EIP */ \ "pushl %[next_ip]\n\t" /* restore EIP */ \ __switch_canary \ "jmp __switch_to\n" /* regparm call */ \ "1:\t" \ "popl %%ebp\n\t" /* restore EBP */ \ "popfl\n" /* restore flags */ \ \ /* output parameters */ \ : [prev_sp] "=m" (prev->thread.sp), \ [prev_ip] "=m" (prev->thread.ip), \ "=a" (last), \ \ /* clobbered output registers: */ \ "=b" (ebx), "=c" (ecx), "=d" (edx), \ "=S" (esi), "=D" (edi) \ \ __switch_canary_oparam \ \ /* input parameters: */ \ : [next_sp] "m" (next->thread.sp), \ [next_ip] "m" (next->thread.ip), \ \ /* regparm parameters for __switch_to(): */ \ [prev] "a" (prev), \ [next] "d" (next) \ \ __switch_canary_iparam \ \ : /* reloaded segment registers */ \ "memory"); \ } while (0) /* * disable hlt during certain critical i/o operations */ #define HAVE_DISABLE_HLT #else #define __SAVE(reg, offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t" #define __RESTORE(reg, offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t" /* frame pointer must be last for get_wchan */ #define SAVE_CONTEXT "pushf ; pushq %%rbp ; movq %%rsi,%%rbp\n\t" #define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popf\t" #define __EXTRA_CLOBBER \ , "rcx", "rbx", "rdx", "r8", "r9", "r10", "r11", \ "r12", "r13", "r14", "r15" #ifdef CONFIG_CC_STACKPROTECTOR #define __switch_canary \ "movq %P[task_canary](%%rsi),%%r8\n\t" \ "movq %%r8,"__percpu_arg([gs_canary])"\n\t" #define __switch_canary_oparam \ , [gs_canary] "=m" (per_cpu_var(irq_stack_union.stack_canary)) #define __switch_canary_iparam \ , [task_canary] "i" (offsetof(struct task_struct, stack_canary)) #else /* CC_STACKPROTECTOR */ #define __switch_canary #define __switch_canary_oparam #define __switch_canary_iparam #endif /* CC_STACKPROTECTOR */ /* Save restore flags to clear handle leaking NT */ #define switch_to(prev, next, last) \ asm volatile(SAVE_CONTEXT \ "movq %%rsp,%P[threadrsp](%[prev])\n\t" /* save RSP */ \ "movq %P[threadrsp](%[next]),%%rsp\n\t" /* restore RSP */ \ "call __switch_to\n\t" \ ".globl thread_return\n" \ "thread_return:\n\t" \ "movq "__percpu_arg([current_task])",%%rsi\n\t" \ __switch_canary \ "movq %P[thread_info](%%rsi),%%r8\n\t" \ "movq %%rax,%%rdi\n\t" \ "testl %[_tif_fork],%P[ti_flags](%%r8)\n\t" \ "jnz ret_from_fork\n\t" \ RESTORE_CONTEXT \ : "=a" (last) \ __switch_canary_oparam \ : [next] "S" (next), [prev] "D" (prev), \ [threadrsp] "i" (offsetof(struct task_struct, thread.sp)), \ [ti_flags] "i" (offsetof(struct thread_info, flags)), \ [_tif_fork] "i" (_TIF_FORK), \ [thread_info] "i" (offsetof(struct task_struct, stack)), \ [current_task] "m" (per_cpu_var(current_task)) \ __switch_canary_iparam \ : "memory", "cc" __EXTRA_CLOBBER) #endif #ifdef __KERNEL__ extern void native_load_gs_index(unsigned); /* * Load a segment. Fall back on loading the zero * segment if something goes wrong.. */ #define loadsegment(seg, value) \ asm volatile("\n" \ "1:\t" \ "movl %k0,%%" #seg "\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3:\t" \ "movl %k1, %%" #seg "\n\t" \ "jmp 2b\n" \ ".previous\n" \ _ASM_EXTABLE(1b,3b) \ : :"r" (value), "r" (0) : "memory") /* * Save a segment register away */ #define savesegment(seg, value) \ asm("mov %%" #seg ",%0":"=r" (value) : : "memory") /* * x86_32 user gs accessors. */ #ifdef CONFIG_X86_32 #ifdef CONFIG_X86_32_LAZY_GS #define get_user_gs(regs) (u16)({unsigned long v; savesegment(gs, v); v;}) #define set_user_gs(regs, v) loadsegment(gs, (unsigned long)(v)) #define task_user_gs(tsk) ((tsk)->thread.gs) #define lazy_save_gs(v) savesegment(gs, (v)) #define lazy_load_gs(v) loadsegment(gs, (v)) #else /* X86_32_LAZY_GS */ #define get_user_gs(regs) (u16)((regs)->gs) #define set_user_gs(regs, v) do { (regs)->gs = (v); } while (0) #define task_user_gs(tsk) (task_pt_regs(tsk)->gs) #define lazy_save_gs(v) do { } while (0) #define lazy_load_gs(v) do { } while (0) #endif /* X86_32_LAZY_GS */ #endif /* X86_32 */ static inline unsigned long get_limit(unsigned long segment) { unsigned long __limit; asm("lsll %1,%0" : "=r" (__limit) : "r" (segment)); return __limit + 1; } static inline void native_clts(void) { asm volatile("clts"); } /* * Volatile isn't enough to prevent the compiler from reordering the * read/write functions for the control registers and messing everything up. * A memory clobber would solve the problem, but would prevent reordering of * all loads stores around it, which can hurt performance. Solution is to * use a variable and mimic reads and writes to it to enforce serialization */ static unsigned long __force_order; static inline unsigned long native_read_cr0(void) { unsigned long val; asm volatile("mov %%cr0,%0\n\t" : "=r" (val), "=m" (__force_order)); return val; } static inline void native_write_cr0(unsigned long val) { asm volatile("mov %0,%%cr0": : "r" (val), "m" (__force_order)); } static inline unsigned long native_read_cr2(void) { unsigned long val; asm volatile("mov %%cr2,%0\n\t" : "=r" (val), "=m" (__force_order)); return val; } static inline void native_write_cr2(unsigned long val) { asm volatile("mov %0,%%cr2": : "r" (val), "m" (__force_order)); } static inline unsigned long native_read_cr3(void) { unsigned long val; asm volatile("mov %%cr3,%0\n\t" : "=r" (val), "=m" (__force_order)); return val; } static inline void native_write_cr3(unsigned long val) { asm volatile("mov %0,%%cr3": : "r" (val), "m" (__force_order)); } static inline unsigned long native_read_cr4(void) { unsigned long val; asm volatile("mov %%cr4,%0\n\t" : "=r" (val), "=m" (__force_order)); return val; } static inline unsigned long native_read_cr4_safe(void) { unsigned long val; /* This could fault if %cr4 does not exist. In x86_64, a cr4 always * exists, so it will never fail. */ #ifdef CONFIG_X86_32 asm volatile("1: mov %%cr4, %0\n" "2:\n" _ASM_EXTABLE(1b, 2b) : "=r" (val), "=m" (__force_order) : "0" (0)); #else val = native_read_cr4(); #endif return val; } static inline void native_write_cr4(unsigned long val) { asm volatile("mov %0,%%cr4": : "r" (val), "m" (__force_order)); } #ifdef CONFIG_X86_64 static inline unsigned long native_read_cr8(void) { unsigned long cr8; asm volatile("movq %%cr8,%0" : "=r" (cr8)); return cr8; } static inline void native_write_cr8(unsigned long val) { asm volatile("movq %0,%%cr8" :: "r" (val) : "memory"); } #endif static inline void native_wbinvd(void) { asm volatile("wbinvd": : :"memory"); } #ifdef CONFIG_PARAVIRT #include #else #define read_cr0() (native_read_cr0()) #define write_cr0(x) (native_write_cr0(x)) #define read_cr2() (native_read_cr2()) #define write_cr2(x) (native_write_cr2(x)) #define read_cr3() (native_read_cr3()) #define write_cr3(x) (native_write_cr3(x)) #define read_cr4() (native_read_cr4()) #define read_cr4_safe() (native_read_cr4_safe()) #define write_cr4(x) (native_write_cr4(x)) #define wbinvd() (native_wbinvd()) #ifdef CONFIG_X86_64 #define read_cr8() (native_read_cr8()) #define write_cr8(x) (native_write_cr8(x)) #define load_gs_index native_load_gs_index #endif /* Clear the 'TS' bit */ #define clts() (native_clts()) #endif/* CONFIG_PARAVIRT */ #define stts() write_cr0(read_cr0() | X86_CR0_TS) #endif /* __KERNEL__ */ static inline void clflush(volatile void *__p) { asm volatile("clflush %0" : "+m" (*(volatile char __force *)__p)); } #define nop() asm volatile ("nop") void disable_hlt(void); void enable_hlt(void); void cpu_idle_wait(void); extern unsigned long arch_align_stack(unsigned long sp); extern void free_init_pages(char *what, unsigned long begin, unsigned long end); void default_idle(void); void stop_this_cpu(void *dummy); /* * Force strict CPU ordering. * And yes, this is required on UP too when we're talking * to devices. */ #ifdef CONFIG_X86_32 /* * Some non-Intel clones support out of order store. wmb() ceases to be a * nop for these. */ #define mb() alternative("lock; addl $0,0(%%esp)", "mfence", X86_FEATURE_XMM2) #define rmb() alternative("lock; addl $0,0(%%esp)", "lfence", X86_FEATURE_XMM2) #define wmb() alternative("lock; addl $0,0(%%esp)", "sfence", X86_FEATURE_XMM) #else #define mb() asm volatile("mfence":::"memory") #define rmb() asm volatile("lfence":::"memory") #define wmb() asm volatile("sfence" ::: "memory") #endif /** * 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"): * * * CPU 0 CPU 1 * * b = 2; * memory_barrier(); * p = &b; q = p; * read_barrier_depends(); * d = *q; * * * 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": * * * CPU 0 CPU 1 * * a = 2; * memory_barrier(); * b = 3; y = b; * read_barrier_depends(); * x = a; * * * 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 this where there are no data dependencies. **/ #define read_barrier_depends() do { } while (0) #ifdef CONFIG_SMP #define smp_mb() mb() #ifdef CONFIG_X86_PPRO_FENCE # define smp_rmb() rmb() #else # define smp_rmb() barrier() #endif #ifdef CONFIG_X86_OOSTORE # define smp_wmb() wmb() #else # define smp_wmb() barrier() #endif #define smp_read_barrier_depends() read_barrier_depends() #define set_mb(var, value) do { (void)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 /* * Stop RDTSC speculation. This is needed when you need to use RDTSC * (or get_cycles or vread that possibly accesses the TSC) in a defined * code region. * * (Could use an alternative three way for this if there was one.) */ static inline void rdtsc_barrier(void) { alternative(ASM_NOP3, "mfence", X86_FEATURE_MFENCE_RDTSC); alternative(ASM_NOP3, "lfence", X86_FEATURE_LFENCE_RDTSC); } #endif /* _ASM_X86_SYSTEM_H */