Re: [PATCH 4/4] ide: preserve Host Protected Area by default

Bartlomiej Zolnierkiewicz
2009-06-01T21:59:00Z

On Sunday 31 May 2009 16:39:39 Bartlomiej Zolnierkiewicz wrote:
> From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
> Subject: [PATCH] ide: preserve Host Protected Area by default
>
> From the perspective of most users of recent systems, disabling Host
> Protected Area (HPA) can break vendor RAID formats, GPT partitions and
> risks corrupting firmware or overwriting vendor system recovery tools.
>
> Unfortunately the original (kernels < 2.6.30) behavior (unconditionally
> disabling HPA and using full disk capacity) was introduced at the time
> when the main use of HPA was to make the drive look small enough for the
> BIOS to allow the system to boot with large capacity drives.
>
> Thus to allow the maximum compatibility with the existing setups (using
> HPA and partitioned with HPA disabled) we automatically disable HPA if
> any partitions overlapping HPA are detected. Additionally HPA can also
> be disabled using the "nohpa" module parameter (i.e. "ide_core.nohpa=0.0"
> to disable HPA on /dev/hda).
>
> While at it:
> - remove stale "idebus=" entry from Documentation/kernel-parameters.txt
>
> Cc: Robert Hancock <hancockrwd@gmail.com>
> Cc: Frans Pop <elendil@planet.nl>
> Cc: "Andries E. Brouwer" <Andries.Brouwer@cwi.nl>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> [patch description was based on input from Alan Cox and Frans Pop]
> Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

v2 interdiff

v2:
Fix ->resume HPA support.
---
ide-disk.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff -u b/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
--- b/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -433,8 +433,11 @@
goto out;

set = ide_disk_hpa_set_capacity(drive, set, lba48);
- if (set)
+ if (set) {
+ /* needed for ->resume to disable HPA */
+ drive->dev_flags |= IDE_DFLAG_NOHPA;
return set;
+ }
out:
return drive->capacity64;
}