2010-01-16 09:40:06

by Luca Barbieri

Subject: [PATCH] Fix broken mmiotrace due to dr6 by reference change

Commit 62edab9056a6cf0c9207339c8892c923a5217e45 (from June 2009 but merged
in 2.6.33) changes notify_die to pass dr6 by reference.

However, it forgets to fix the check for DR_STEP in kmmio.c, breaking
mmiotrace. It also passes a wrong value to the post handler.

This simple fix makes mmiotrace work again.

Please send to Linus for inclusion in 2.6.33

Signed-off-by: Luca Barbieri <[email protected]>
---
arch/x86/mm/kmmio.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index c0f6198..536fb68 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -538,14 +538,15 @@ static int
kmmio_die_notifier(struct notifier_block *nb, unsigned long val, void *args)
{
struct die_args *arg = args;
+ unsigned long* dr6_p = (unsigned long *)ERR_PTR(arg->err);

- if (val == DIE_DEBUG && (arg->err & DR_STEP))
- if (post_kmmio_handler(arg->err, arg->regs) == 1) {
+ if (val == DIE_DEBUG && (*dr6_p & DR_STEP))
+ if (post_kmmio_handler(*dr6_p, arg->regs) == 1) {
/*
* Reset the BS bit in dr6 (pointed by args->err) to
* denote completion of processing
*/
- (*(unsigned long *)ERR_PTR(arg->err)) &= ~DR_STEP;
+ *dr6_p &= ~DR_STEP;
return NOTIFY_STOP;
}

--
1.6.3.3

2010-01-16 19:58:39

by K.Prasad

Subject: Re: [PATCH] Fix broken mmiotrace due to dr6 by reference change

On Sat, Jan 16, 2010 at 10:39:30AM +0100, Luca Barbieri wrote:
> Commit 62edab9056a6cf0c9207339c8892c923a5217e45 (from June 2009 but merged
> in 2.6.33) changes notify_die to pass dr6 by reference.
>
> However, it forgets to fix the check for DR_STEP in kmmio.c, breaking
> mmiotrace. It also passes a wrong value to the post handler.
>

Yes, looks like I missed it...must have hunted down all those registered
to the die notifier...to propagate the fix.

> This simple fix makes mmiotrace work again.
>
> Please send to Linus for inclusion in 2.6.33
>
> Signed-off-by: Luca Barbieri <[email protected]>
Acked-by: K.Prasad <[email protected]>

Thanks,
K.Prasad

> ---
> arch/x86/mm/kmmio.c | 7 ++++---
> 1 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
> index c0f6198..536fb68 100644
> --- a/arch/x86/mm/kmmio.c
> +++ b/arch/x86/mm/kmmio.c
> @@ -538,14 +538,15 @@ static int
> kmmio_die_notifier(struct notifier_block *nb, unsigned long val, void *args)
> {
> struct die_args *arg = args;
> + unsigned long* dr6_p = (unsigned long *)ERR_PTR(arg->err);
>
> - if (val == DIE_DEBUG && (arg->err & DR_STEP))
> - if (post_kmmio_handler(arg->err, arg->regs) == 1) {
> + if (val == DIE_DEBUG && (*dr6_p & DR_STEP))
> + if (post_kmmio_handler(*dr6_p, arg->regs) == 1) {
> /*
> * Reset the BS bit in dr6 (pointed by args->err) to
> * denote completion of processing
> */
> - (*(unsigned long *)ERR_PTR(arg->err)) &= ~DR_STEP;
> + *dr6_p &= ~DR_STEP;
> return NOTIFY_STOP;
> }
>
> --
> 1.6.3.3
>

2010-01-16 20:29:45

by Luca Barbieri

Subject: Re: [PATCH] Fix broken mmiotrace due to dr6 by reference change

It seems kgdb needs to be fixed too.

2010-01-17 18:31:49

by Luca Barbieri

Subject: [tip:perf/urgent] hw-breakpoints, perf: Fix broken mmiotrace due to dr6 by reference change

Commit-ID: 0bb7a95f5455cd87e6a69e5818bc1f509a98d187
Gitweb: http://git.kernel.org/tip/0bb7a95f5455cd87e6a69e5818bc1f509a98d187
Author: Luca Barbieri <[email protected]>
AuthorDate: Sat, 16 Jan 2010 10:39:30 +0100
Committer: Ingo Molnar <[email protected]>
CommitDate: Sun, 17 Jan 2010 08:01:44 +0100

hw-breakpoints, perf: Fix broken mmiotrace due to dr6 by reference change

Commit 62edab9056a6cf0c9207339c8892c923a5217e45 (from June 2009
but merged in 2.6.33) changes notify_die to pass dr6 by
reference.

However, it forgets to fix the check for DR_STEP in kmmio.c,
breaking mmiotrace. It also passes a wrong value to the post
handler.

This simple fix makes mmiotrace work again.

Signed-off-by: Luca Barbieri <[email protected]>
Acked-by: K.Prasad <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
---
arch/x86/mm/kmmio.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index c0f6198..536fb68 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -538,14 +538,15 @@ static int
kmmio_die_notifier(struct notifier_block *nb, unsigned long val, void *args)
{
struct die_args *arg = args;
+ unsigned long* dr6_p = (unsigned long *)ERR_PTR(arg->err);

- if (val == DIE_DEBUG && (arg->err & DR_STEP))
- if (post_kmmio_handler(arg->err, arg->regs) == 1) {
+ if (val == DIE_DEBUG && (*dr6_p & DR_STEP))
+ if (post_kmmio_handler(*dr6_p, arg->regs) == 1) {
/*
* Reset the BS bit in dr6 (pointed by args->err) to
* denote completion of processing
*/
- (*(unsigned long *)ERR_PTR(arg->err)) &= ~DR_STEP;
+ *dr6_p &= ~DR_STEP;
return NOTIFY_STOP;
}