Re: [tpmdd-devel] [PATCH] - TPM save state before suspending to ram

From: David Smith
Date: Fri Jan 04 2008 - 23:55:12 EST


> On Fri 2008-01-04 14:09:01, Kent Yoder wrote:
> > On Jan 4, 2008 10:39 AM, Pavel Machek <pavel@xxxxxx> wrote:
> > > On Thu 2008-01-03 21:44:15, Marcel Selhorst wrote:
> > > > Dear list,
> > > >
> > > > this patch fixes a bug, that prevents the TPM chip to resume
> > > > correctly from a suspended state.
> > > >
> > > > Signed-off-by: Marcel Selhorst <tpm@xxxxxxxxxxxx>
> >
> > [cut]
> >
> > > I'm not sure if we want to use variable-size array on stack. What
> > > hacks are you doing with max_t/max?
> > >
> > > Pavel
> >
> > Hi Pavel,
> >
> > Here's an alternate solution from David, signoffs pending --
> >
> > commit 058f1e3c4d4e2de5a7188608a1c2e0722498fd4b
> > Author: David Smith <davidsmith@xxxxxxx>
> > Date: Fri Jan 4 03:33:11 2008 +0900
> >
> > Fix for TPM suspend/resume failure
> >
> > diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
> > index 9bb5429..79d2fd5 100644
> > --- a/drivers/char/tpm/tpm.c
> > +++ b/drivers/char/tpm/tpm.c
> > @@ -1046,12 +1046,6 @@ void tpm_remove_hardware(struct device *dev)
> > }
> > EXPORT_SYMBOL_GPL(tpm_remove_hardware);
> >
> > -static u8 savestate[] = {
> > - 0, 193, /* TPM_TAG_RQU_COMMAND */
> > - 0, 0, 0, 10, /* blob length (in bytes) */
> > - 0, 0, 0, 152 /* TPM_ORD_SaveState */
> > -};
> > -
> > /*
> > * We are about to suspend. Save the TPM state
> > * so that it can be restored.
> > @@ -1059,8 +1053,14 @@ static u8 savestate[] = {
> > int tpm_pm_suspend(struct device *dev, pm_message_t pm_state)
> > {
> > struct tpm_chip *chip = dev_get_drvdata(dev);
> > + u8 savestate[] = {
> > + 0, 193, /* TPM_TAG_RQU_COMMAND */
> > + 0, 0, 0, 10, /* blob length (in bytes) */
> > + 0, 0, 0, 152 /* TPM_ORD_SaveState */
> > + };
> > +
> > if (chip == NULL)
> > - return -ENODEV;
> > + return -ENODEV;
> >
> > tpm_transmit(chip, savestate, sizeof(savestate));
> > return 0;
>
> Yep, but please fix the whitespace.
> Pavel

OK, attached.
--
man perl | tail -6 | head -2
commit a17f28b93a6e11097ea806d576eb317263aa8768
Author: David Smith <dds@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Date: Fri Jan 4 16:12:58 2008 +0900

Fix TPM suspend and resume failure.

The savestate command structure was being overwritten by the
result of running the TPM_SaveState command after one run, so
make it a local variable to the function instead of a global
variable that gets overwritten.

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 9bb5429..4f18ddf 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -1046,12 +1046,6 @@ void tpm_remove_hardware(struct device *dev)
}
EXPORT_SYMBOL_GPL(tpm_remove_hardware);

-static u8 savestate[] = {
- 0, 193, /* TPM_TAG_RQU_COMMAND */
- 0, 0, 0, 10, /* blob length (in bytes) */
- 0, 0, 0, 152 /* TPM_ORD_SaveState */
-};
-
/*
* We are about to suspend. Save the TPM state
* so that it can be restored.
@@ -1059,6 +1053,12 @@ static u8 savestate[] = {
int tpm_pm_suspend(struct device *dev, pm_message_t pm_state)
{
struct tpm_chip *chip = dev_get_drvdata(dev);
+ u8 savestate[] = {
+ 0, 193, /* TPM_TAG_RQU_COMMAND */
+ 0, 0, 0, 10, /* blob length (in bytes) */
+ 0, 0, 0, 152 /* TPM_ORD_SaveState */
+ };
+
if (chip == NULL)
return -ENODEV;

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