Hi Nemoto-san,
On Fri, 24 Oct 2008, Atsushi Nemoto wrote:
> On Fri, 24 Oct 2008 16:06:28 +0200 (CEST), Geert Uytterhoeven <Geert.Uytterhoeven@xxxxxxxxxxx> wrote:
> > > > | fw_arg0 = 0x80002000
> > > > | fw_arg1 = 0x80001fe0
> > > > | fw_arg2 = 0x2000
> > > > | fw_arg3 = 0x20
> > > >
> > > > So your assumption that bootloaders other than YAMON pass NULL for fw_arg2 is
> > > > apparently wrong.
> > >
> > > Indeed. We should know what sort of value was passed by fw_arg2, and
> > > I hope auto-detection.
> > >
> > > Do you know what value the boot loader passes via fw_arg2? If fw_arg2
> >
> > Unfortunately not. I'll try to Google a bit for it...
>
> BTW, it looks fw_arg0 is not 'argc'. Fortunately current code just
> ignores argv if argc was negative, but it is not intentional
> behaviour, just a luck ;)
Woops...
The memory pointed to by fw_arg0 and fw_arg1 contains just zeroes.
According to the sources, the VxWorks bootloader just jumps to the kernel's
entry point, without passing any parameters in a0-a3 at all. So they're just
leftovers.
> You can put a string starting with "-" in CONFIG_CMDLINE, so that
> fw_arg0 is ignored regardless of its value. Hmm... putting "noenv" or
> something in CONFIG_CMDLINE (and check it in preprocess_cmdline()) can
> be an another workaround for getenv problem...
Prepending my command line in CONFIG_CMDLINE with `-' doesn't help.
prom_getenv() is still called.
So I came up with the patch below.
Subject: [PATCH] txx9: Make firmware parameter passing more robust
When booting Linux on a txx9 board with VxWorks boot loader, it crashes in
prom_getenv(), as VxWorks doesn't pass firmware parameters in a0-a3 (in my
case, the actual leftover values in these registers were 0x80002000,
0x80001fe0, 0x2000, and 0x20).
Make the parsing of argc, argv, and envp a bit more robust by checking if argc
is a number below CKSEG0, and argv/envp point to CKSEG0.
Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@xxxxxxxxxxx>
diff --git a/arch/mips/txx9/generic/setup.c b/arch/mips/txx9/generic/setup.c
index 5526375..f4486a5 100644
--- a/arch/mips/txx9/generic/setup.c
+++ b/arch/mips/txx9/generic/setup.c
@@ -156,11 +156,20 @@ static struct txx9_board_vec *__init find_board_byname(const char *name)
static void __init prom_init_cmdline(void)
{
- int argc = (int)fw_arg0;
- int *argv32 = (int *)fw_arg1;
+ int argc;
+ int *argv32;
int i; /* Always ignore the "-c" at argv[0] */
char builtin[CL_SIZE];
+ if (fw_arg0 >= CKSEG0 || fw_arg1 < CKSEG0) {
+ /* argc is not a valid number, or argv32 is not a valid pointer */
+ argc = 0;
+ argv32 = NULL;
+ } else {
+ argc = (int)fw_arg0;
+ argv32 = (int *)fw_arg1;
+ }
+
/* ignore all built-in args if any f/w args given */
/*
* But if built-in strings was started with '+', append them
@@ -414,10 +423,12 @@ char * __init prom_getcmdline(void)
const char *__init prom_getenv(const char *name)
{
- const s32 *str = (const s32 *)fw_arg2;
+ const s32 *str;
- if (!str)
+ if (fw_arg2 < CKSEG0)
return NULL;
+
+ str = (const s32 *)fw_arg2;
/* YAMON style ("name", "value" pairs) */
while (str[0] && str[1]) {
if (!strcmp((const char *)(unsigned long)str[0], name))
With kind regards,
Geert Uytterhoeven
Software Architect
Sony Techsoft Centre Europe
The Corporate Village · Da Vincilaan 7-D1 · B-1935 Zaventem · Belgium
Phone: +32 (0)2 700 8453
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E-mail: Geert.Uytterhoeven@xxxxxxxxxxx
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