* Re: reed solomon breaks larger pxe images
2010-12-27 4:30 reed solomon breaks larger pxe images Seth Goldberg
@ 2010-12-27 5:06 ` Vladimir 'φ-coder/phcoder' Serbinenko
0 siblings, 0 replies; 2+ messages in thread
From: Vladimir 'φ-coder/phcoder' Serbinenko @ 2010-12-27 5:06 UTC (permalink / raw)
To: grub-devel
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On 12/27/2010 05:30 AM, Seth Goldberg wrote:
> Hi,
>
> While trying to test pxe booting, I noticed that creating a pxe
> image larger than around 100k causes the system hard-hang after
> control is transferred to pxegrub. I narrowed it down to an unknown
> problem in grub_reed_solomon_recover (called from startup.S).
> Unconditionally jumping over the call allows the system to continue to
> proceed to the menu. So, if you're trying to build a pxe image with a
> lot of modules, and you get a hard hang, try this:
>
Attached patch should fix the problem.
> === modified file 'grub-core/kern/i386/pc/startup.S'
> --- grub-core/kern/i386/pc/startup.S 2010-12-24 06:29:28 +0000
> +++ grub-core/kern/i386/pc/startup.S 2010-12-27 04:26:25 +0000
> @@ -147,6 +147,8 @@
> incl %eax
> call grub_gate_a20
>
> + jmp post_reed_solomon
> +
> movl EXT_C(grub_compressed_size), %edx
> addl $(GRUB_KERNEL_MACHINE_RAW_SIZE -
> GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART), %edx
> movl reed_solomon_redundancy, %ecx
>
>
>
> --S
>
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> http://lists.gnu.org/mailman/listinfo/grub-devel
>
--
Regards
Vladimir 'φ-coder/phcoder' Serbinenko
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=== modified file 'grub-core/kern/i386/pc/startup.S'
--- grub-core/kern/i386/pc/startup.S 2010-12-04 16:19:26 +0000
+++ grub-core/kern/i386/pc/startup.S 2010-12-27 04:51:59 +0000
@@ -151,8 +151,6 @@
addl $(GRUB_KERNEL_MACHINE_RAW_SIZE - GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART), %edx
movl reed_solomon_redundancy, %ecx
leal _start + GRUB_KERNEL_I386_PC_NO_REED_SOLOMON_PART, %eax
- testl %edx, %edx
- jz post_reed_solomon
call EXT_C (grub_reed_solomon_recover)
jmp post_reed_solomon
=== modified file 'grub-core/lib/reed_solomon.c'
--- grub-core/lib/reed_solomon.c 2010-12-21 16:51:08 +0000
+++ grub-core/lib/reed_solomon.c 2010-12-27 05:06:01 +0000
@@ -372,6 +372,10 @@
grub_size_t rr = (rs + SECTOR_SIZE - 1 - i) / SECTOR_SIZE;
gf_single_t m[ds + rr];
+ /* Nothing to do. */
+ if (!ds || !rr)
+ continue;
+
for (j = 0; j < (int) ds; j++)
m[j] = ptr[SECTOR_SIZE * j + i];
for (j = 0; j < (int) rr; j++)
@@ -414,6 +418,10 @@
gf_single_t *ptr = buffer;
gf_single_t *rptr = ptr + s;
+ /* Nothing to do. */
+ if (!rs)
+ return;
+
while (s > 0)
{
grub_size_t tt;
@@ -441,6 +449,10 @@
gf_single_t *ptr = ptr_;
gf_single_t *rptr = ptr + s;
+ /* Nothing to do. */
+ if (!rs)
+ return;
+
#if defined (STANDALONE)
init_inverts ();
#endif
@@ -454,8 +466,8 @@
tt = cs + crs;
if (tt > MAX_BLOCK_SIZE)
{
- cs = cs * MAX_BLOCK_SIZE / tt;
- crs = crs * MAX_BLOCK_SIZE / tt;
+ cs = (cs * MAX_BLOCK_SIZE) / tt;
+ crs = (crs * MAX_BLOCK_SIZE) / tt;
}
decode_block (ptr, cs, rptr, crs);
ptr += cs;
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