Re: SA_SIGINFO in Linux 2.4.x

From: Aneesh Kumar K.V (aneesh.kumar@digital.com)
Date: Fri Aug 02 2002 - 04:52:16 EST


On Fri, 2002-08-02 at 04:14, Camm Maguire wrote:
> Greetings! The 2.4.x kernels on alpha don't appear to be filling in
> the si_addr element of the siginfo_t structure when a signal handler
> is setup with SA_SIGINFO. Is this right? Any other way to get this
> address in the handler?
>
> Take care,
>
> --
> Camm Maguire camm@enhanced.com

Hi,

 Try the following patch for arch/alpha/mm/fault.c

 -aneesh

--- fault.c Tue Aug 2 12:33:44 2050
+++ fault.c.n Tue Aug 2 12:34:51 2050
@@ -88,6 +88,7 @@
         struct mm_struct *mm = current->mm;
         unsigned int fixup;
         int fault;
+ siginfo_t info;
 
         /* As of EV6, a load into $31/$f31 is a prefetch, and never faults
            (or is suppressed by the PALcode). Support that for older CPUs
@@ -108,6 +109,8 @@
         if (!mm || in_interrupt())
                 goto no_context;
 
+ info.si_code = SEGV_MAPERR;
+
 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
         if (address >= TASK_SIZE)
                 goto vmalloc_fault;
@@ -128,6 +131,7 @@
  * we can handle it..
  */
 good_area:
+ info.si_code = SEGV_ACCERR;
         if (cause < 0) {
                 if (!(vma->vm_flags & VM_EXEC))
                         goto bad_area;
@@ -164,7 +168,12 @@
         up_read(&mm->mmap_sem);
 
         if (user_mode(regs)) {
- force_sig(SIGSEGV, current);
+
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ /* info.si_code has been set above */
+ info.si_addr = (void *)address;
+ force_sig_info(SIGSEGV,&info,current);
                 return;
         }
 
@@ -212,7 +221,12 @@
          * Send a sigbus, regardless of whether we were in kernel
          * or user mode.
          */
- force_sig(SIGBUS, current);
+ info.si_signo = SIGBUS;
+ info.si_errno = 0;
+ /* not sure si_code value here */
+ info.si_code = BUS_ADRERR;
+ info.si_addr = (void *)address;
+ force_sig_info(SIGBUS,&info,current);
         if (!user_mode(regs))
                 goto no_context;
         return;
@@ -220,7 +234,11 @@
 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
 vmalloc_fault:
         if (user_mode(regs)) {
- force_sig(SIGSEGV, current);
+ info.si_signo = SIGSEGV;
+ info.si_errno = 0;
+ /* info.si_code has been set above */
+ info.si_addr = (void *)address;
+ force_sig_info(SIGSEGV,&info,current);
                 return;
         } else {
                 /* Synchronize this task's top level page-table

-
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