Re: [patch 14/23] x86 microcode: dont check the size

Shaohua,

this one seems appropriate for 2.4 too. It is OK for you if I merge it ?

Thanks,
Willy

On Wed, Nov 29, 2006 at 02:00:25PM -0800, Chris Wright wrote:
-stable review patch. If anyone has any objections, please let us know.
------------------

From: Shaohua Li <shaohua.li@xxxxxxxxx>

IA32 manual says if micorcode update's size is 0, then the size is
default size (2048 bytes). But this doesn't suggest all microcode
update's size should be above 2048 bytes to me. We actually had a
microcode update whose size is 1024 bytes. The patch just removed the
check.

Backported to 2.6.18 by Daniel Drake.

Signed-off-by: Daniel Drake <dsd@xxxxxxxxxx>
Signed-off-by: Chris Wright <chrisw@xxxxxxxxxxxx>
---
arch/i386/kernel/microcode.c | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)

--- linux-2.6.18.4.orig/arch/i386/kernel/microcode.c
+++ linux-2.6.18.4/arch/i386/kernel/microcode.c
@@ -250,14 +250,14 @@ static int find_matching_ucodes (void)
}

total_size = get_totalsize(&mc_header);
- if ((cursor + total_size > user_buffer_size) || (total_size < DEFAULT_UCODE_TOTALSIZE)) {
+ if (cursor + total_size > user_buffer_size) {
printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
error = -EINVAL;
goto out;
}

data_size = get_datasize(&mc_header);
- if ((data_size + MC_HEADER_SIZE > total_size) || (data_size < DEFAULT_UCODE_DATASIZE)) {
+ if (data_size + MC_HEADER_SIZE > total_size) {
printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
error = -EINVAL;
goto out;
@@ -460,11 +460,6 @@ static ssize_t microcode_write (struct f
{
ssize_t ret;

- if (len < DEFAULT_UCODE_TOTALSIZE) {
- printk(KERN_ERR "microcode: not enough data\n");
- return -EINVAL;
- }
-
if ((len >> PAGE_SHIFT) > num_physpages) {
printk(KERN_ERR "microcode: too much data (max %ld pages)\n", num_physpages);
return -EINVAL;

--
-
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