Re: accessing Alpha CPU registers from panic()

[Andrea Arcangeli]

On Wed, 15 Dec 1999, Brian Hall wrote:

>I am working on porting the SGI crash tools to Alpha. Since the CPU registers
>aren't available from within the panic() call, I need to grab them directly.
>How do I do this? The equivalent i386 code is:
>
>        /* save the dump specific esp/eip */
>        /* For Alpha, save PC (Program Counter) and RA */
>        __asm__ __volatile__("
>                pushl %%eax\n
>                movl  %%esp, %%eax\n
>                movl  %%eax, %0\n
>                popl  %%eax\n"
>                : "=g" (dump_header.dh_esp)
>        );
>        __asm__ __volatile__("pushl  %eax\n");
>        __dump_save_panic_regs();
>        __asm__ __volatile__("popl   %eax\n");

The above code has nothing to do with eip.

To get sp on alpha you can read $30:

#define get_stack_address()                                     \
({                                                              \
        register unsigned long sp;                              \
        asm("bis $30,$30,%0" : "=r" (sp));                      \
        sp;                                                     \
})

and then:

        unsigned long sp = get_stack_address();

To get EIP just use C:

main()
{
        __label__ here1, here2;

 here1:
        printf("%p %p\n", &&here1, &&here2);
 here2:
}

To write EIP use `goto here1` or `goto here2` 8)

Andrea