![Linus Torvalds](/assets/img/avatar_default.png)
(And reset it on new thread creation) It turns out that eflags is important to save and restore not just because of iopl, but due to the magic bits like the NT bit, which we don't want leaking between different threads. Tested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
489 lines
13 KiB
C
489 lines
13 KiB
C
#ifndef __ASM_SYSTEM_H
|
|
#define __ASM_SYSTEM_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));
|
|
|
|
/*
|
|
* 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 { \
|
|
unsigned long esi,edi; \
|
|
asm volatile("pushfl\n\t" /* Save flags */ \
|
|
"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) )
|
|
|
|
/*
|
|
* 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" \
|
|
: :"rm" (value))
|
|
|
|
/*
|
|
* Save a segment register away
|
|
*/
|
|
#define savesegment(seg, value) \
|
|
asm volatile("mov %%" #seg ",%0":"=rm" (value))
|
|
|
|
#define read_cr0() ({ \
|
|
unsigned int __dummy; \
|
|
__asm__ __volatile__( \
|
|
"movl %%cr0,%0\n\t" \
|
|
:"=r" (__dummy)); \
|
|
__dummy; \
|
|
})
|
|
#define write_cr0(x) \
|
|
__asm__ __volatile__("movl %0,%%cr0": :"r" (x))
|
|
|
|
#define read_cr2() ({ \
|
|
unsigned int __dummy; \
|
|
__asm__ __volatile__( \
|
|
"movl %%cr2,%0\n\t" \
|
|
:"=r" (__dummy)); \
|
|
__dummy; \
|
|
})
|
|
#define write_cr2(x) \
|
|
__asm__ __volatile__("movl %0,%%cr2": :"r" (x))
|
|
|
|
#define read_cr3() ({ \
|
|
unsigned int __dummy; \
|
|
__asm__ ( \
|
|
"movl %%cr3,%0\n\t" \
|
|
:"=r" (__dummy)); \
|
|
__dummy; \
|
|
})
|
|
#define write_cr3(x) \
|
|
__asm__ __volatile__("movl %0,%%cr3": :"r" (x))
|
|
|
|
#define read_cr4() ({ \
|
|
unsigned int __dummy; \
|
|
__asm__( \
|
|
"movl %%cr4,%0\n\t" \
|
|
:"=r" (__dummy)); \
|
|
__dummy; \
|
|
})
|
|
#define read_cr4_safe() ({ \
|
|
unsigned int __dummy; \
|
|
/* This could fault if %cr4 does not exist */ \
|
|
__asm__("1: movl %%cr4, %0 \n" \
|
|
"2: \n" \
|
|
".section __ex_table,\"a\" \n" \
|
|
".long 1b,2b \n" \
|
|
".previous \n" \
|
|
: "=r" (__dummy): "0" (0)); \
|
|
__dummy; \
|
|
})
|
|
#define write_cr4(x) \
|
|
__asm__ __volatile__("movl %0,%%cr4": :"r" (x))
|
|
|
|
/*
|
|
* Clear and set 'TS' bit respectively
|
|
*/
|
|
#define clts() __asm__ __volatile__ ("clts")
|
|
#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))
|
|
|
|
|
|
#ifdef CONFIG_X86_CMPXCHG64
|
|
|
|
/*
|
|
* 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)) )
|
|
|
|
#endif
|
|
|
|
/*
|
|
* 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
|
|
#define cmpxchg(ptr,o,n)\
|
|
((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
|
|
(unsigned long)(n),sizeof(*(ptr))))
|
|
#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)
|
|
: "r"(new), "m"(*__xg(ptr)), "0"(old)
|
|
: "memory");
|
|
return prev;
|
|
case 4:
|
|
__asm__ __volatile__(LOCK_PREFIX "cmpxchgl %1,%2"
|
|
: "=a"(prev)
|
|
: "r"(new), "m"(*__xg(ptr)), "0"(old)
|
|
: "memory");
|
|
return prev;
|
|
}
|
|
return old;
|
|
}
|
|
|
|
#ifndef CONFIG_X86_CMPXCHG
|
|
/*
|
|
* Building a kernel capable running on 80386. It may be necessary to
|
|
* simulate the cmpxchg on the 80386 CPU. For that purpose we define
|
|
* a function for each of the sizes we support.
|
|
*/
|
|
|
|
extern unsigned long cmpxchg_386_u8(volatile void *, u8, u8);
|
|
extern unsigned long cmpxchg_386_u16(volatile void *, u16, u16);
|
|
extern unsigned long cmpxchg_386_u32(volatile void *, u32, u32);
|
|
|
|
static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
|
|
unsigned long new, int size)
|
|
{
|
|
switch (size) {
|
|
case 1:
|
|
return cmpxchg_386_u8(ptr, old, new);
|
|
case 2:
|
|
return cmpxchg_386_u16(ptr, old, new);
|
|
case 4:
|
|
return cmpxchg_386_u32(ptr, old, new);
|
|
}
|
|
return old;
|
|
}
|
|
|
|
#define cmpxchg(ptr,o,n) \
|
|
({ \
|
|
__typeof__(*(ptr)) __ret; \
|
|
if (likely(boot_cpu_data.x86 > 3)) \
|
|
__ret = __cmpxchg((ptr), (unsigned long)(o), \
|
|
(unsigned long)(n), sizeof(*(ptr))); \
|
|
else \
|
|
__ret = cmpxchg_386((ptr), (unsigned long)(o), \
|
|
(unsigned long)(n), sizeof(*(ptr))); \
|
|
__ret; \
|
|
})
|
|
#endif
|
|
|
|
#ifdef CONFIG_X86_CMPXCHG64
|
|
|
|
static inline unsigned long long __cmpxchg64(volatile void *ptr, unsigned long long old,
|
|
unsigned long long new)
|
|
{
|
|
unsigned long long prev;
|
|
__asm__ __volatile__(LOCK_PREFIX "cmpxchg8b %3"
|
|
: "=A"(prev)
|
|
: "b"((unsigned long)new),
|
|
"c"((unsigned long)(new >> 32)),
|
|
"m"(*__xg(ptr)),
|
|
"0"(old)
|
|
: "memory");
|
|
return prev;
|
|
}
|
|
|
|
#define cmpxchg64(ptr,o,n)\
|
|
((__typeof__(*(ptr)))__cmpxchg64((ptr),(unsigned long long)(o),\
|
|
(unsigned long long)(n)))
|
|
|
|
#endif
|
|
|
|
/*
|
|
* 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 this where 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 { (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
|
|
|
|
#include <linux/irqflags.h>
|
|
|
|
/*
|
|
* 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);
|
|
|
|
/*
|
|
* On SMP systems, when the scheduler does migration-cost autodetection,
|
|
* it needs a way to flush as much of the CPU's caches as possible:
|
|
*/
|
|
static inline void sched_cacheflush(void)
|
|
{
|
|
wbinvd();
|
|
}
|
|
|
|
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);
|
|
|
|
#endif
|