Re: Update on wip-arm-bootstrap

[Danny Milosavljevic <dannym@scratchpost.org>]

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> Hmm, I'm not seeing this (I did see something like this before).  You
> *are* on
> 
>     e44b6b7eed squash! commencement: binutils-mesboot0: Support ARM.
> 
> right?

Yes, but your gcc-mesboot.sh hardcoded a specific (older) path.  Sorry.

With updated gcc-mesboot.sh I get:

Program terminated with signal SIGSEGV, Segmentation fault.
(gdb) bt
#0  _IO_setb (f=0x4, b=0x4b <error: Cannot access memory at address 0x4b>, eb=0x4c <error: Cannot access memory at address 0x4c>, a=0) at genops.c:387
#1  0x00008f1c in _IO_doallocbuf (fp=0x4) at genops.c:406
#2  0x0002409c in _IO_new_file_overflow (f=0x6cde0 <_IO_2_1_stdout_>, ch=0) at fileops.c:576
#3  0x000249b0 in _IO_new_file_xsputn (f=0x6cde0 <_IO_2_1_stdout_>, data=0xbecfd313, n=1) at fileops.c:962
#4  0x0001a09c in _IO_vfprintf (s=0x6cde0 <_IO_2_1_stdout_>, format=0xbecfd313 "2\224\323Ͼ\001", 
    ap=<error reading variable: Cannot access memory at address 0xbecfce5c>) at vfprintf.c:1523
#5  0x00008828 in printf (format=0x525f0 "%d\n") at printf.c:33
#6  0x00008214 in main (argc=<error reading variable: Cannot access memory at address 0xbecfd364>, 
    argv=<error reading variable: Cannot access memory at address 0xbecfd360>) at test.c:6

Looks like a NULL pointer for a FILE* ?  Or is gdb just weird?

glibc-2.2.5/libio/genops.c:

void
_IO_setb (f, b, eb, a)
     _IO_FILE *f;
      char *b;
     char *eb;
     int a;
{
  if (f->_IO_buf_base && !(f->_flags & _IO_USER_BUF)) <---------------- here
    FREE_BUF (f->_IO_buf_base, _IO_blen (f));
  f->_IO_buf_base = b;
  f->_IO_buf_end = eb;
  if (a)
    f->_flags &= ~_IO_USER_BUF;
  else
    f->_flags |= _IO_USER_BUF;
}

int
_IO_new_file_overflow (f, ch)
      _IO_FILE *f;
      int ch;
{
  if (f->_flags & _IO_NO_WRITES) /* SET ERROR */
    {
      f->_flags |= _IO_ERR_SEEN;
      __set_errno (EBADF);
      return EOF;
    }
  /* If currently reading or no buffer allocated. */
  if ((f->_flags & _IO_CURRENTLY_PUTTING) == 0 || f->_IO_write_base == 0)
    {
      /* Allocate a buffer if needed. */
      if (f->_IO_write_base == 0)
        {
          _IO_doallocbuf (f); <------------- here
          _IO_setg (f, f->_IO_buf_base, f->_IO_buf_base, f->_IO_buf_base);
        }

Maybe add some debugging statements there?  But printf is broken, so maybe
use write(2, "foo\n", 4) and similar.

(I'm not sure about just defining -D__ARM_EABI__=1 as you are doing--after all,
it entails further stack alignment requirements.  Maybe try


+++ glibc-2.2.5/sysdeps/unix/sysv/linux/arm/sysdep.h    2021-02-22 00:44:43.300906460 +0100
@@ -29,8 +29,8 @@
    of the kernel.  But these symbols do not follow the SYS_* syntax
    so we have to redefine the `SYS_ify' macro here.  */
 #undef SYS_ify
-#define SWI_BASE  (0x900000)
-#define SYS_ify(syscall_name)  (__NR_##syscall_name)
+#define SWI_BASE  (0x000000)
+#define SYS_ify(syscall_name)  (__NR_##syscall_name & 0x8fffff)


as a more minimal patch?  Not sure...)

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