Re: [PATCH] tpm, tpm_tis: Acquire locality in tpm_tis_gen_interrupt() and tpm_get_timeouts()

[Jarkko Sakkinen <jarkko@kernel.org>]

On Tue, Jun 15, 2021 at 01:19:56PM +0200, Laurent Bigonville wrote:
> Le 14/06/21 à 22:40, Jarkko Sakkinen a écrit :
> > On Thu, Jun 10, 2021 at 04:00:27PM +0200, Laurent Bigonville wrote:
> > > Le 10/06/21 à 14:29, Jarkko Sakkinen a écrit :
> > > > On Thu, Jun 10, 2021 at 01:35:47PM +0200, Laurent Bigonville wrote:
> > > > > # dmesg |grep -i tpm
> > > > > 
> > > > > [   13.019986] tpm_tis 00:06: 1.2 TPM (device-id 0x6871, rev-id 1)
> > > > > [   15.016198] tpm tpm0: tpm_try_transmit: send(): error -62
> > > > > [   15.016208] tpm tpm0: A TPM error (-62) occurred attempting to determine
> > > > > the timeouts
> > > > > [   15.016239] tpm_tis: probe of 00:06 failed with error -62
> > > > > [   15.053255] tpm_inf_pnp 00:06: Found TPM with ID IFX0102
> > > > If possible, can you check what happens when you apply the attached patch.
> > > > I'm not proposing it as a bug fix but it just simplifies the flow a lot,
> > > > and might help to observe something.
> > > > 
> > > With the patch on the top of HEAD of master and the patch from your branch,
> > > I'm getting this:
> > > 
> > > [   13.140548] tpm tpm0: invalid TPM_STS.x 0xa0, dumping stack for forensics
> > > [   13.140617] CPU: 4 PID: 462 Comm: systemd-udevd Tainted: G          I
> > > E     5.13.0-rc5+ #7
> > > [   13.140621] Hardware name: System manufacturer System Product Name/P6T
> > > DELUXE V2, BIOS 0406    04/24/2009
> > > [   13.140623] Call Trace:
> > > [   13.140628]  dump_stack+0x76/0x94
> > > [   13.140637]  tpm_tis_status.cold+0x19/0x20 [tpm_tis_core]
> > > [   13.140643]  tpm_transmit+0x15f/0x3d0 [tpm]
> > > [   13.140657]  tpm_transmit_cmd+0x25/0x90 [tpm]
> > > [   13.140666]  tpm2_probe+0xe2/0x140 [tpm]
> > It's weird because it's the first transaction with the TPM, not likely
> > to have any sort of mismatch in power gating.
> > 
> > I'm suspecting this:
> > 
> > 	if (wait_startup(chip, 0) != 0) {
> > 		rc = -ENODEV;
> > 		goto out_err;
> > 	}
> > 
> > I did not find anything from [*] stating that reading Access Register,
> > could cause any change in the burstCount (0xa0) but still might be worth
> > of testing to couple that with
> > 
> > 	release_locality(chip, 0);
> > 
> > I.e. add that just after the first snippet.
> > 
> You mean this, right?
> 
> diff --git a/drivers/char/tpm/tpm_tis_core.c
> b/drivers/char/tpm/tpm_tis_core.c
> index 3b5a03f9efce..857ea790e9d3 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -969,6 +969,7 @@ int tpm_tis_core_init(struct device *dev, struct
> tpm_tis_data *priv, int irq,
>                 rc = -ENODEV;
>                 goto out_err;
>         }
> +       release_locality(chip, 0);
> 
>         /* Take control of the TPM's interrupt hardware and shut it off */
>         rc = tpm_tis_read32(priv, TPM_INT_ENABLE(priv->locality), &intmask);
> 
> 
> With this change (and with or without "tpm_tis: Use request_locality()
> before calling tpm2_probe()"), I get the following:
> 
> [   13.420485] tpm tpm0: invalid TPM_STS.x 0xff, dumping stack for forensics
> [   13.420494] CPU: 5 PID: 461 Comm: systemd-udevd Tainted: G          I
> E     5.13.0-rc6+ #8
> [   13.420498] Hardware name: System manufacturer System Product Name/P6T
> DELUXE V2, BIOS 0406    04/24/2009
> [   13.420500] Call Trace:
> [   13.420505]  dump_stack+0x76/0x94
> [   13.420512]  tpm_tis_status.cold+0x19/0x20 [tpm_tis_core]
> [   13.420519]  wait_for_tpm_stat+0x49/0x200 [tpm_tis_core]
> [   13.420524]  ? get_page_from_freelist+0x228/0xed0
> [   13.420530]  ? tpm_tcg_read_bytes+0x30/0x50 [tpm_tis]
> [   13.420536]  tpm_tis_send_data+0x90/0x250 [tpm_tis_core]
> [   13.420542]  tpm_tis_send_main+0x2e/0xf0 [tpm_tis_core]
> [   13.420547]  tpm_transmit+0xd8/0x3d0 [tpm]
> [   13.420559]  tpm_transmit_cmd+0x25/0x90 [tpm]
> [   13.420567]  tpm2_probe+0xe2/0x140 [tpm]
> [   13.420577]  tpm_tis_core_init+0x1fd/0x2e0 [tpm_tis_core]
> [   13.420582]  ? tpm_tis_init.part.0+0x130/0x130 [tpm_tis]
> [   13.420587]  tpm_tis_pnp_init+0xe1/0x110 [tpm_tis]
> [   13.420594]  pnp_device_probe+0xaf/0x140
> [   13.420600]  really_probe+0xf2/0x460
> [   13.420606]  driver_probe_device+0xe8/0x160
> [   13.420610]  device_driver_attach+0xa1/0xb0
> [   13.420614]  __driver_attach+0x8f/0x150
> [   13.420618]  ? device_driver_attach+0xb0/0xb0
> [   13.420621]  ? device_driver_attach+0xb0/0xb0
> [   13.420624]  bus_for_each_dev+0x78/0xc0
> [   13.420628]  bus_add_driver+0x12b/0x1e0
> [   13.420632]  driver_register+0x8b/0xe0
> [   13.420636]  ? 0xffffffffc1413000
> [   13.420639]  init_tis+0xa0/0x1000 [tpm_tis]
> [   13.420646]  do_one_initcall+0x44/0x1d0
> [   13.420652]  ? kmem_cache_alloc_trace+0x119/0x240
> [   13.420657]  do_init_module+0x5c/0x260
> [   13.420662]  __do_sys_finit_module+0xb1/0x110
> [   13.420668]  do_syscall_64+0x40/0xb0
> [   13.420673]  entry_SYSCALL_64_after_hwframe+0x44/0xae
> [   13.420678] RIP: 0033:0x7f15fe84e9b9
> [   13.420681] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48
> 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48>
> 3d 01 f0 ff ff 73 01 c3 48 8b 0d a7 54 0c 00 f7 d8 64 89 01 48
> [   13.420685] RSP: 002b:00007fffc3aca668 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000139
> [   13.420689] RAX: ffffffffffffffda RBX: 00005561627275b0 RCX:
> 00007f15fe84e9b9
> [   13.420692] RDX: 0000000000000000 RSI: 00007f15fe9d9e2d RDI:
> 0000000000000012
> [   13.420694] RBP: 0000000000020000 R08: 0000000000000000 R09:
> 0000556161c2f330
> [   13.420696] R10: 0000000000000012 R11: 0000000000000246 R12:
> 00007f15fe9d9e2d
> [   13.420698] R13: 0000000000000000 R14: 000055616271dab0 R15:
> 00005561627275b0
> [...]
> [   14.185406] tpm tpm0: tpm_try_transmit: send(): error -62
> [   14.185422] tpm_tis 00:06: 1.2 TPM (device-id 0x6871, rev-id 1)
> [   15.021233] tpm tpm0: tpm_try_transmit: send(): error -62
> [   24.381575] tpm tpm0: tpm_try_transmit: send(): error -62
> [...]
> 
> But now the /dev/tpm0 device appears (but doesn't seem to work)

I'm sorry, I made a mistake: release_locality() call should be exactly
right before tpm_chip_start(). The reason is that we access TPM_INT_ENABLE,
i.e. locality is released too early.

In summary, I think I would try this:

	tpm_chip_stop(chip);

	rc = tpm_chip_start(chip);
	if (rc)
		goto out_err;
	rc = tpm2_probe(chip);
	tpm_chip_stop(chip);
	if (rc)
		goto out_err;

tpm_chip_stop() is makes more sense it takes care also of disabling
clk_enable.

I.e. TPM should be shut down right after intmask mangling...

/Jarkko