There is a limitation (or bug?) of nios2 toolchain. The nios2 gcc
didn't generate correct code when the reset vector is passed as a
constant. It just generated a direct "call", which was wrong when
the reset vector was not located in the same 256MB span as u-boot.
The "Nios II Processor Reference Handbook" said,
"call can transfer execution anywhere within the 256 MByte range
determined by PC31..28. The Nios II GNU linker does not automatically
handle cases in which the address is out of this range."
So we have to use registered "callr" instruction to do the job.
Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Scott McNutt <smcnutt@psyent.com>
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>
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>
Global interrupt should be disabled from the beginning.
Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Signed-off-by: Scott McNutt <smcnutt@psyent.com>
