![Paul Mackerras](/assets/img/avatar_default.png)
This is a patch that I have had in my tree for ages. If init causes an exception that raises a signal, such as a SIGSEGV, SIGILL or SIGFPE, and it hasn't registered a handler for it, we don't deliver the signal, since init doesn't get any signals that it doesn't have a handler for. But that means that we just return to userland and generate the same exception again immediately. With this patch we print a message and kill init in this situation. This is very useful when you have a bug in the kernel that means that init doesn't get as far as executing its first instruction. :) Without this patch the system hangs when it gets to starting the userland init; with it you at least get a message giving you a clue about what has gone wrong. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
214 lines
6.1 KiB
C
214 lines
6.1 KiB
C
/*
|
|
* Copyright (C) 1999 Cort Dougan <cort@cs.nmt.edu>
|
|
*/
|
|
#ifndef __PPC_SYSTEM_H
|
|
#define __PPC_SYSTEM_H
|
|
|
|
#include <linux/config.h>
|
|
#include <linux/kernel.h>
|
|
|
|
#include <asm/atomic.h>
|
|
#include <asm/hw_irq.h>
|
|
|
|
/*
|
|
* Memory barrier.
|
|
* The sync instruction guarantees that all memory accesses initiated
|
|
* by this processor have been performed (with respect to all other
|
|
* mechanisms that access memory). The eieio instruction is a barrier
|
|
* providing an ordering (separately) for (a) cacheable stores and (b)
|
|
* loads and stores to non-cacheable memory (e.g. I/O devices).
|
|
*
|
|
* mb() prevents loads and stores being reordered across this point.
|
|
* rmb() prevents loads being reordered across this point.
|
|
* wmb() prevents stores being reordered across this point.
|
|
* read_barrier_depends() prevents data-dependent loads being reordered
|
|
* across this point (nop on PPC).
|
|
*
|
|
* We can use the eieio instruction for wmb, but since it doesn't
|
|
* give any ordering guarantees about loads, we have to use the
|
|
* stronger but slower sync instruction for mb and rmb.
|
|
*/
|
|
#define mb() __asm__ __volatile__ ("sync" : : : "memory")
|
|
#define rmb() __asm__ __volatile__ ("sync" : : : "memory")
|
|
#define wmb() __asm__ __volatile__ ("eieio" : : : "memory")
|
|
#define read_barrier_depends() do { } while(0)
|
|
|
|
#define set_mb(var, value) do { var = value; mb(); } while (0)
|
|
#define set_wmb(var, value) do { var = value; wmb(); } while (0)
|
|
|
|
#ifdef CONFIG_SMP
|
|
#define smp_mb() mb()
|
|
#define smp_rmb() rmb()
|
|
#define smp_wmb() wmb()
|
|
#define smp_read_barrier_depends() read_barrier_depends()
|
|
#else
|
|
#define smp_mb() barrier()
|
|
#define smp_rmb() barrier()
|
|
#define smp_wmb() barrier()
|
|
#define smp_read_barrier_depends() do { } while(0)
|
|
#endif /* CONFIG_SMP */
|
|
|
|
#ifdef __KERNEL__
|
|
struct task_struct;
|
|
struct pt_regs;
|
|
|
|
extern void print_backtrace(unsigned long *);
|
|
extern void show_regs(struct pt_regs * regs);
|
|
extern void flush_instruction_cache(void);
|
|
extern void hard_reset_now(void);
|
|
extern void poweroff_now(void);
|
|
#ifdef CONFIG_6xx
|
|
extern long _get_L2CR(void);
|
|
extern long _get_L3CR(void);
|
|
extern void _set_L2CR(unsigned long);
|
|
extern void _set_L3CR(unsigned long);
|
|
#else
|
|
#define _get_L2CR() 0L
|
|
#define _get_L3CR() 0L
|
|
#define _set_L2CR(val) do { } while(0)
|
|
#define _set_L3CR(val) do { } while(0)
|
|
#endif
|
|
extern void via_cuda_init(void);
|
|
extern void pmac_nvram_init(void);
|
|
extern void read_rtc_time(void);
|
|
extern void pmac_find_display(void);
|
|
extern void giveup_fpu(struct task_struct *);
|
|
extern void enable_kernel_fp(void);
|
|
extern void enable_kernel_altivec(void);
|
|
extern void giveup_altivec(struct task_struct *);
|
|
extern void load_up_altivec(struct task_struct *);
|
|
extern void giveup_spe(struct task_struct *);
|
|
extern void load_up_spe(struct task_struct *);
|
|
extern int fix_alignment(struct pt_regs *);
|
|
extern void cvt_fd(float *from, double *to, unsigned long *fpscr);
|
|
extern void cvt_df(double *from, float *to, unsigned long *fpscr);
|
|
extern int call_rtas(const char *, int, int, unsigned long *, ...);
|
|
extern void cacheable_memzero(void *p, unsigned int nb);
|
|
extern void *cacheable_memcpy(void *, const void *, unsigned int);
|
|
extern int do_page_fault(struct pt_regs *, unsigned long, unsigned long);
|
|
extern void bad_page_fault(struct pt_regs *, unsigned long, int);
|
|
extern void die(const char *, struct pt_regs *, long);
|
|
extern void _exception(int, struct pt_regs *, int, unsigned long);
|
|
#ifdef CONFIG_BOOKE_WDT
|
|
extern u32 booke_wdt_enabled;
|
|
extern u32 booke_wdt_period;
|
|
#endif /* CONFIG_BOOKE_WDT */
|
|
|
|
struct device_node;
|
|
extern void note_scsi_host(struct device_node *, void *);
|
|
|
|
extern struct task_struct *__switch_to(struct task_struct *,
|
|
struct task_struct *);
|
|
#define switch_to(prev, next, last) ((last) = __switch_to((prev), (next)))
|
|
|
|
struct thread_struct;
|
|
extern struct task_struct *_switch(struct thread_struct *prev,
|
|
struct thread_struct *next);
|
|
|
|
extern unsigned int rtas_data;
|
|
|
|
static __inline__ unsigned long
|
|
xchg_u32(volatile void *p, unsigned long val)
|
|
{
|
|
unsigned long prev;
|
|
|
|
__asm__ __volatile__ ("\n\
|
|
1: lwarx %0,0,%2 \n"
|
|
PPC405_ERR77(0,%2)
|
|
" stwcx. %3,0,%2 \n\
|
|
bne- 1b"
|
|
: "=&r" (prev), "=m" (*(volatile unsigned long *)p)
|
|
: "r" (p), "r" (val), "m" (*(volatile unsigned long *)p)
|
|
: "cc", "memory");
|
|
|
|
return prev;
|
|
}
|
|
|
|
/*
|
|
* This function doesn't exist, so you'll get a linker error
|
|
* if something tries to do an invalid xchg().
|
|
*/
|
|
extern void __xchg_called_with_bad_pointer(void);
|
|
|
|
#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
|
|
#define tas(ptr) (xchg((ptr),1))
|
|
|
|
static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size)
|
|
{
|
|
switch (size) {
|
|
case 4:
|
|
return (unsigned long) xchg_u32(ptr, x);
|
|
#if 0 /* xchg_u64 doesn't exist on 32-bit PPC */
|
|
case 8:
|
|
return (unsigned long) xchg_u64(ptr, x);
|
|
#endif /* 0 */
|
|
}
|
|
__xchg_called_with_bad_pointer();
|
|
return x;
|
|
|
|
|
|
}
|
|
|
|
extern inline void * xchg_ptr(void * m, void * val)
|
|
{
|
|
return (void *) xchg_u32(m, (unsigned long) val);
|
|
}
|
|
|
|
|
|
#define __HAVE_ARCH_CMPXCHG 1
|
|
|
|
static __inline__ unsigned long
|
|
__cmpxchg_u32(volatile unsigned int *p, unsigned int old, unsigned int new)
|
|
{
|
|
unsigned int prev;
|
|
|
|
__asm__ __volatile__ ("\n\
|
|
1: lwarx %0,0,%2 \n\
|
|
cmpw 0,%0,%3 \n\
|
|
bne 2f \n"
|
|
PPC405_ERR77(0,%2)
|
|
" stwcx. %4,0,%2 \n\
|
|
bne- 1b\n"
|
|
#ifdef CONFIG_SMP
|
|
" sync\n"
|
|
#endif /* CONFIG_SMP */
|
|
"2:"
|
|
: "=&r" (prev), "=m" (*p)
|
|
: "r" (p), "r" (old), "r" (new), "m" (*p)
|
|
: "cc", "memory");
|
|
|
|
return prev;
|
|
}
|
|
|
|
/* This function doesn't exist, so you'll get a linker error
|
|
if something tries to do an invalid cmpxchg(). */
|
|
extern void __cmpxchg_called_with_bad_pointer(void);
|
|
|
|
static __inline__ unsigned long
|
|
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new, int size)
|
|
{
|
|
switch (size) {
|
|
case 4:
|
|
return __cmpxchg_u32(ptr, old, new);
|
|
#if 0 /* we don't have __cmpxchg_u64 on 32-bit PPC */
|
|
case 8:
|
|
return __cmpxchg_u64(ptr, old, new);
|
|
#endif /* 0 */
|
|
}
|
|
__cmpxchg_called_with_bad_pointer();
|
|
return old;
|
|
}
|
|
|
|
#define cmpxchg(ptr,o,n) \
|
|
({ \
|
|
__typeof__(*(ptr)) _o_ = (o); \
|
|
__typeof__(*(ptr)) _n_ = (n); \
|
|
(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
|
|
(unsigned long)_n_, sizeof(*(ptr))); \
|
|
})
|
|
|
|
#define arch_align_stack(x) (x)
|
|
|
|
#endif /* __KERNEL__ */
|
|
#endif /* __PPC_SYSTEM_H */
|