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

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Message-ID: <499d6ed30801041209o4da54b3bw39335f3342e528f0@mail.gmail.com>
Date:	Fri, 4 Jan 2008 14:09:01 -0600
From:	"Kent Yoder" <shpedoikal@...il.com>
To:	"Pavel Machek" <pavel@....cz>
Cc:	"Marcel Selhorst" <tpm@...horst.net>,
	"Andrew Morton" <akpm@...l.org>,
	"TPM Device Driver List" <tpmdd-devel@...ts.sourceforge.net>,
	linux-kernel@...r.kernel.org, "David Smith" <davidsmith@....org>
Subject: Re: [tpmdd-devel] [PATCH] - TPM save state before suspending to ram

On Jan 4, 2008 10:39 AM, Pavel Machek <pavel@....cz> 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@...horst.net>
[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@....org>
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;


Kent

-- 
Kent Yoder
IBM LTC Security Dev.
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