r584 - coreboot-v3/arch/x86

Author: hailfinger
Date: 2008-02-10 17:44:32 +0100 (Sun, 10 Feb 2008)
New Revision: 584

Modified:
   coreboot-v3/arch/x86/mc146818rtc.c
Log:
I found another bug in LAR handling of the option table by staring at
the logs. (Yes, I read logs.)
Looking at the log of a qemu x86 boot with a 1024 kB image, I'd say
something is really broken. Excerpts of my log quoted below:
> [...]
> LAR: Attempting to open 'fallback/initram/segment0'.
> LAR: Start 0xfff00000 len 0x100000
> LAR: seen member normal/option_table
> LAR: seen member normal/stage2/segment0
> LAR: seen member normal/stage2/segment1
> LAR: seen member normal/stage2/segment2
> LAR: seen member normal/initram/segment0
> LAR: seen member bootblock
> LAR: File not found!
> [...]
> LAR: Attempting to open 'normal/initram/segment0'.
> LAR: Start 0xfff00000 len 0x100000
> LAR: seen member normal/option_table
> LAR: seen member normal/stage2/segment0
> LAR: seen member normal/stage2/segment1
> LAR: seen member normal/stage2/segment2
> LAR: seen member normal/initram/segment0
> LAR: CHECK normal/initram/segment0 @ 0xfff040d0
> [...]
> LAR: Attempting to open 'normal/option_table'.
> LAR: Start 0xfffc0000 len 0x3c000

WTF?!? This start address is obviously very wrong.
> LAR: seen member bootblock
> LAR: File not found!

Which results in not finding the option table.
> [...]
> LAR: Attempting to open 'normal/payload'.
> LAR: Start 0xfff00000 len 0x100000
> LAR: seen member normal/option_table
> LAR: seen member normal/stage2/segment0
> LAR: seen member normal/stage2/segment1
> LAR: seen member normal/stage2/segment2
> LAR: seen member normal/initram/segment0
> LAR: seen member bootblock
> LAR: File not found!
> [...]

The bug is in arch/x86/mc146818rtc.c:
> struct cmos_option_table *get_option_table(void)
> {
>     struct mem_file result, archive;
>     int ret;
> // FIXME - i want to be dynamic.
> archive.len=(CONFIG_COREBOOT_ROMSIZE_KB-16)*1024;

We can't calculate len like that. Reasons:
- We can't know at compile time how big the archive is going to be.
- Subtracting 16 kB from the ROM size was needed when the bootblock
  was not part of the LAR.  These times are long gone.
> archive.start=(void *)(0UL-(CONFIG_COREBOOT_ROMSIZE_KB*1024)); 

Since the len calculation above is invalid, start is wrong as well.
> ret = find_file(&archive, "normal/option_table", &result);
> if (ret) {
>         printk(BIOS_ERR, "No such file '%s'.\n",
>                         "normal/option_table");
>         return (struct cmos_option_table *)NULL;
> }
> return (struct cmos_option_table *) result.start;
>
> }

Use the existing init_archive function to find the LAR in memory.
This fixes the case where the option table was not found depending
on a few unrelated parameters.

Signed-off-by: Carl-Daniel Hailfinger 
Acked-by: Stefan Reinauer

Modified: coreboot-v3/arch/x86/mc146818rtc.c
===================================================================
--- coreboot-v3/arch/x86/mc146818rtc.c	2008-02-09 21:16:42 UTC (rev 583)
+++ coreboot-v3/arch/x86/mc146818rtc.c	2008-02-10 16:44:32 UTC (rev 584)
@@ -183,9 +183,7 @@
    struct mem_file result, archive;
    int ret;

-	// FIXME - i want to be dynamic.
-	archive.len=(CONFIG_COREBOOT_ROMSIZE_KB-16)*1024;
-	archive.start=(void *)(0UL-(CONFIG_COREBOOT_ROMSIZE_KB*1024)); 
+	init_archive(&archive);

ret = find_file(&archive, "normal/option_table", &result);
    if (ret) {