Commit graph

8 commits

Author SHA1 Message Date
Wolfgang Denk
54841ab50c Make sure that argv[] argument pointers are not modified.
The hush shell dynamically allocates (and re-allocates) memory for the
argument strings in the "char *argv[]" argument vector passed to
commands.  Any code that modifies these pointers will cause serious
corruption of the malloc data structures and crash U-Boot, so make
sure the compiler can check that no such modifications are being done
by changing the code into "char * const argv[]".

This modification is the result of debugging a strange crash caused
after adding a new command, which used the following argument
processing code which has been working perfectly fine in all Unix
systems since version 6 - but not so in U-Boot:

int main (int argc, char **argv)
{
	while (--argc > 0 && **++argv == '-') {
/* ====> */	while (*++*argv) {
			switch (**argv) {
			case 'd':
				debug++;
				break;
			...
			default:
				usage ();
			}
		}
	}
	...
}

The line marked "====>" will corrupt the malloc data structures and
usually cause U-Boot to crash when the next command gets executed by
the shell.  With the modification, the compiler will prevent this with
an
	error: increment of read-only location '*argv'

N.B.: The code above can be trivially rewritten like this:

	while (--argc > 0 && **++argv == '-') {
		char *arg = *argv;
		while (*++arg) {
			switch (*arg) {
			...

Signed-off-by: Wolfgang Denk <wd@denx.de>
Acked-by: Mike Frysinger <vapier@gentoo.org>
2010-07-04 23:55:42 +02:00
Thomas Chou
0df01fd3d7 nios2: fix r15 issue for gcc4
The "-ffixed-r15" option doesn't work well for gcc4. Since we
don't use gp for small data with option "-G0", we can use gp
as global data pointer. This allows compiler to use r15. It
is necessary for gcc4 to work properly.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Scott McNutt <smcnutt@psyent.com>
2010-05-28 10:56:03 -04:00
Robin Getz
c4db335c2e Blackfin: change global data register from P5 to P3
Since the Blackfin ABI favors higher scratch registers by default, use the
last scratch register (P3) for global data rather than the first (P5).
This allows the compiler's register allocator to use higher number scratch
P registers, which in turn better matches the Blackfin instruction set,
which reduces the size of U-Boot by more than 1024 bytes...

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2009-09-02 05:14:02 -04:00
Wolfgang Denk
6f99eec3dc Merge branch 'master' of git://www.denx.de/git/u-boot-blackfin
Conflicts:

	Makefile
	doc/README.standalone

Signed-off-by: Wolfgang Denk <wd@denx.de>
2008-02-15 00:06:18 +01:00
Wolfgang Denk
e7670f6c1e PPC: Use r2 instead of r29 as global data pointer
R29 was an unlucky choice as with recent toolchains (gcc-4.2.x) gcc
will refuse to use load/store multiple insns; instead, it issues a
list of simple load/store instructions upon function entry and exit,
resulting in bigger code size, which in turn makes the build for a
few boards fail.

Use r2 instead.

Signed-off-by: Wolfgang Denk <wd@denx.de>
2008-02-14 22:43:22 +01:00
Mike Frysinger
4c58eb5552 add some more Blackfin docs
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
2008-02-04 19:26:54 -05:00
wdenk
7784674852 * Allow crc32 to be used at address 0x000
* Provide consistent interface to standalone applications to access
  the 'global_data' structure
  Provide a doc/README.standalone more useful to users/developers.

* Make IceCube MGT5100 FEC driver work
2003-07-26 08:08:08 +00:00
wdenk
27b207fd0a * Implement new mechanism to export U-Boot's functions to standalone
applications: instead of using (PPC-specific) system calls we now
  use a jump table; please see doc/README.standalone for details

* Patch by Dave Westwood, 24 Jul 2003:
  added support for Unity OS (a proprietary OS)
2003-07-24 23:38:38 +00:00