diff options
| -rw-r--r-- | drivers/dahdi/dahdi-base.c | 58 |
1 files changed, 54 insertions, 4 deletions
diff --git a/drivers/dahdi/dahdi-base.c b/drivers/dahdi/dahdi-base.c index ac411dc..b29e645 100644 --- a/drivers/dahdi/dahdi-base.c +++ b/drivers/dahdi/dahdi-base.c @@ -289,7 +289,56 @@ static struct dahdi_dialparams global_dialparams = { static int dahdi_chan_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long data, int unit); #if defined(CONFIG_DAHDI_MMX) || defined(ECHO_CAN_FP) +#if (defined(CONFIG_X86) && !defined(CONFIG_X86_64)) || defined(CONFIG_I386) +struct fpu_save_buf { + unsigned long cr0; + unsigned long fpu_buf[128]; +}; + +static DEFINE_PER_CPU(struct fpu_save_buf, fpu_buf); + +/** dahdi_kernel_fpu_begin() - Save floating point registers + * + * This function is similar to kernel_fpu_begin() . However it is + * designed to work in an interrupt context. Restoring must be done with + * dahdi_kernel_fpu_end(). + * + * Furthermore, the whole code between the call to + * dahdi_kernel_fpu_begin() and dahdi_kernel_fpu_end() must reside + * inside a spinlock. Otherwise the context might be restored to the + * wrong process. + * + * Current implementation is x86/ia32-specific and will not even build on + * x86_64) + * */ +static inline void dahdi_kernel_fpu_begin(void) +{ + struct fpu_save_buf *buf = &__get_cpu_var(fpu_buf); + __asm__ __volatile__ ("movl %%cr0,%0; clts" : "=r" (buf->cr0)); + __asm__ __volatile__ ("fnsave %0" : "=m" (buf->fpu_buf)); +} + +/** dahdi_kernel_fpu_end() - restore floating point context + * + * Must be used with context saved by dahdi_kernel_fpu_begin(). See its + * documentation for further information. + */ +static inline void dahdi_kernel_fpu_end(void) +{ + struct fpu_save_buf *buf = &__get_cpu_var(fpu_buf); + __asm__ __volatile__ ("frstor %0" : "=m" (buf->fpu_buf)); + __asm__ __volatile__ ("movl %0,%%cr0" : : "r" (buf->cr0)); +} + +#else /* We haven't fixed FP context saving/restoring yet */ +/* Very strange things can happen when the context is not properly + * restored. OTOH, some people do report success with this. Hence we + * so far just issue a warning */ +#warning CONFIG_DAHDI_MMX may behave randomly on this platform #define dahdi_kernel_fpu_begin kernel_fpu_begin +#define dahdi_kernel_fpu_end kernel_fpu_end +#endif + #endif struct dahdi_timer { @@ -6659,7 +6708,7 @@ static inline void __dahdi_ec_chunk(struct dahdi_chan *ss, unsigned char *rxchun } #if defined(CONFIG_DAHDI_MMX) || defined(ECHO_CAN_FP) - kernel_fpu_end(); + dahdi_kernel_fpu_end(); #endif } spin_unlock_irqrestore(&ss->lock, flags); @@ -6992,6 +7041,7 @@ static inline void __putbuf_chunk(struct dahdi_chan *ss, unsigned char *rxb, int int res; int left, x; + while(bytes) { #if defined(CONFIG_DAHDI_NET) || defined(CONFIG_DAHDI_PPP) skb = NULL; @@ -7553,7 +7603,7 @@ static void __dahdi_transmit_chunk(struct dahdi_chan *chan, unsigned char *buf) #endif __dahdi_process_getaudio_chunk(chan, buf); #ifdef CONFIG_DAHDI_MMX - kernel_fpu_end(); + dahdi_kernel_fpu_end(); #endif } } @@ -7638,7 +7688,7 @@ static void __dahdi_receive_chunk(struct dahdi_chan *chan, unsigned char *buf) #endif __dahdi_process_putaudio_chunk(chan, buf); #ifdef CONFIG_DAHDI_MMX - kernel_fpu_end(); + dahdi_kernel_fpu_end(); #endif } __dahdi_putbuf_chunk(chan, buf); @@ -7860,7 +7910,7 @@ int dahdi_receive(struct dahdi_span *span) } } #ifdef CONFIG_DAHDI_MMX - kernel_fpu_end(); + dahdi_kernel_fpu_end(); #endif } /* do all the pseudo/conferenced channel transmits (putbuf's) */ |