Re: [PATCH v3] tpm_tis: Add missing tpm_request/relinquish_locality calls

From: Jarkko Sakkinen
Date: Tue Feb 02 2021 - 16:50:10 EST

On Tue, Feb 02, 2021 at 04:51:39PM +0100, Lukasz Majczak wrote:
> There are missing calls to tpm_request_locality before the calls to
> the tpm_get_timeouts() and tpm_tis_probe_irq_single() - both functions
> internally send commands to the tpm. As the current
> approach might work for tpm2, it fails for tpm1.x - in that case
> call to tpm_get_timeouts() or tpm_tis_probe_irq_single()
> without acquired locality fails and in turn causes tpm_tis_core_init()
> to fail, it can be observed in the log with the following warning
> trace:

I said earlier about proper capitalizations of the acronyms.

E.g. "tpm1.x" has no meaning. TPM 1.x has. There's also a few other
similar examples.

>
> [ 4.324298] TPM returned invalid status
> [ 4.324806] WARNING: CPU: 2 PID: 1 at drivers/char/tpm/tpm_tis_core.c:275 tpm_tis_status+0x86/0x8f

To make the commit message shorter you could snip from here.

> [ 4.325888] Modules linked in:
> [ 4.326287] CPU: 2 PID: 1 Comm: swapper/0 Tainted: G W 5.11.0-rc6-next-20210201-00003-g214461adb2e8 #43
> [ 4.327406] Hardware name: Google Caroline/Caroline, BIOS Google_Caroline.7820.430.0 07/20/2018
> [ 4.327918] RIP: 0010:tpm_tis_status+0x86/0x8f
> [ 4.328323] Code: 28 00 00 00 48 3b 45 f0 75 24 89 d8 48 83 c4 10 5b 5d c3 c6 05 58 d9 28 01 01 31 db 48 c7 c7 73 52 98 9c 31 c0 e8 c2 17 b0 ff <0f> 0b eb cd e8 cf 4f 55 00 0f 1f 44 00 00 55 48 89 e56
> [ 4.330592] RSP: 0000:ffff88810092f7a0 EFLAGS: 00010246
> [ 4.331223] RAX: 691ee151166db100 RBX: 0000000000000000 RCX: 0000000000000001
> [ 4.331860] RDX: 0000000000000006 RSI: ffffffff9c96d302 RDI: 00000000ffffffff
> [ 4.332272] RBP: ffff88810092f7b8 R08: dffffc0000000000 R09: fffffbfff39c96ce
> [ 4.332683] R10: fffffbfff39c96ce R11: 0000000000000001 R12: ffff8881053e2000
> [ 4.333109] R13: 0000000065000000 R14: ffff888105d71000 R15: ffff888105cd2628
> [ 4.333738] FS: 0000000000000000(0000) GS:ffff88842f200000(0000) knlGS:0000000000000000
> [ 4.334432] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 4.334783] CR2: 0000000000000000 CR3: 0000000037828001 CR4: 00000000003706e0
> [ 4.335196] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> [ 4.335886] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> [ 4.336793] Call Trace:
> [ 4.337107] tpm_tis_send_data+0x3d/0x22f
> [ 4.337506] tpm_tis_send_main+0x30/0xf5
> [ 4.337746] tpm_transmit+0xbf/0x327
> [ 4.338042] ? __alloc_pages_nodemask+0x261/0x36d
> [ 4.338615] tpm_transmit_cmd+0x2c/0x93
> [ 4.339109] tpm1_getcap+0x232/0x285
> [ 4.339578] tpm1_get_timeouts+0x48/0x47d
> [ 4.339964] ? lockdep_init_map_type+0x71/0x257
> [ 4.340256] ? lockdep_init_map_type+0x71/0x257
> [ 4.340719] ? __raw_spin_lock_init+0x40/0x69
> [ 4.341208] tpm_tis_core_init+0x402/0x5ee
> [ 4.341629] tpm_tis_init+0x11d/0x1a2
> [ 4.341867] tpm_tis_pnp_init+0x91/0xb5
> [ 4.342101] ? tis_int_handler+0x15f/0x15f
> [ 4.342466] pnp_device_probe+0x79/0x9f
> [ 4.342941] really_probe+0x149/0x4a8
> [ 4.343412] driver_probe_device+0xd6/0x144
> [ 4.343968] device_driver_attach+0x42/0x5b
> [ 4.344382] __driver_attach+0xca/0x139
> [ 4.344617] ? driver_attach+0x1f/0x1f
> [ 4.344860] bus_for_each_dev+0x85/0xb7
> [ 4.345096] bus_add_driver+0x12b/0x228
> [ 4.345330] driver_register+0x64/0xed
> [ 4.345560] init_tis+0xa5/0xeb
> [ 4.345784] ? lock_is_held_type+0x100/0x141
> [ 4.346044] ? tpm_init+0x106/0x106
> [ 4.346259] ? rcu_read_lock_sched_held+0x41/0x7e
> [ 4.346542] ? tpm_init+0x106/0x106
> [ 4.346678] battery: ACPI: Battery Slot [BAT0] (battery present)
> [ 4.346754] do_one_initcall+0x1b9/0x43d
> [ 4.346776] ? asm_sysvec_apic_timer_interrupt+0x12/0x20
> [ 4.347659] ? lockdep_hardirqs_on+0x8e/0x12e
> [ 4.347937] ? lock_is_held_type+0x100/0x141
> [ 4.348196] ? rcu_read_lock_sched_held+0x41/0x7e
> [ 4.348477] do_initcall_level+0x99/0xa9
> [ 4.348717] ? kernel_init+0xe/0x10a
> [ 4.348954] do_initcalls+0x4e/0x79
> [ 4.349170] kernel_init_freeable+0x15a/0x1ae
> [ 4.349434] ? rest_init+0x1d6/0x1d6
> [ 4.349655] kernel_init+0xe/0x10a
> [ 4.349882] ret_from_fork+0x22/0x30
> [ 4.350103] irq event stamp: 700039
> [ 4.350318] hardirqs last enabled at (700047): [<ffffffff9b735265>] console_unlock+0x4be/0x538
> [ 4.350836] hardirqs last disabled at (700056): [<ffffffff9b734e84>] console_unlock+0xdd/0x538
> [ 4.351331] softirqs last enabled at (699522): [<ffffffff9c4004ec>] __do_softirq+0x4ec/0x539
> [ 4.351835] softirqs last disabled at (699517): [<ffffffff9c200f62>] asm_call_irq_on_stack+0x12/0x20
>
> Following the trace one can also notice a comment in the tpm_tis_status():
>
> /*
> * If this trips, the chances are the read is
> * returning 0xff because the locality hasn't been
> * acquired. Usually because tpm_try_get_ops() hasn't
> * been called before doing a TPM operation.
> */
> In this case we don't have to call tpm_try_get_ops()

Do not use "we". Write in imperative term.

> as both calls (tpm_get_timeouts() and tpm_tis_probe_irq_single()) are
> in the tpm_tis_core_init function and don't require any locking or clock
> enablement. Similar usage is in the probe_itpm() function also called
> inside tpm_tis_core_init().

You use parentheses incosistently here. E.g. tpm_tis_core_init has them
in some sentences, and in some it doesn't.

> Tested on Samsung Chromebook Pro (Caroline).
>
> Signed-off-by: Lukasz Majczak <lma@xxxxxxxxxxxx>
> ---
> Hi Jarkko
>
> I have checked the linux-next with James patches, also followed Dirk
> suggestion applying remaining ones, although without any luck -
> a warning trace was still present. As Guneter mentioned earlier, this
> patch[1] doesn't address a lack of acquired locality in the
> tpm_get_timeouts() and does it only for tpm_tis_probe_irq_single() but
> also without a call to tpm_relinquish_locality().
>
> Here are my logs from the clean linux-next master branch [2]
> (with two James' patches present) and with my
> patch applied[3]
>
> Best regards,
> Lukasz

Ok. Please also take care fixing the cosmetic things, which you
clearly haven't done (like writing acronyms correctly).

> [1] https://lore.kernel.org/linux-integrity/20201001180925.13808-5-James.Bottomley@xxxxxxxxxxxxxxxxxxxxx/
> [2] https://gist.github.com/semihalf-majczak-lukasz/f588c0684a6cc7d983bb9c4eb4bda586
> [3] https://gist.github.com/semihalf-majczak-lukasz/88ede933bc7d28d806e3532850a04054
>
> v2 -> v3:
> - Added braces around if part of if/else statements
> - Rebased to linux-next
> - Updated commit message
>
> drivers/char/tpm/tpm-chip.c | 4 ++--
> drivers/char/tpm/tpm-interface.c | 13 ++++++++++---
> drivers/char/tpm/tpm.h | 2 ++
> drivers/char/tpm/tpm_tis_core.c | 14 +++++++++++---
> 4 files changed, 25 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index ddaeceb7e109..5351963a4b19 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -32,7 +32,7 @@ struct class *tpm_class;
> struct class *tpmrm_class;
> dev_t tpm_devt;
>
> -static int tpm_request_locality(struct tpm_chip *chip)
> +int tpm_request_locality(struct tpm_chip *chip)
> {
> int rc;
>
> @@ -47,7 +47,7 @@ static int tpm_request_locality(struct tpm_chip *chip)
> return 0;
> }
>
> -static void tpm_relinquish_locality(struct tpm_chip *chip)
> +void tpm_relinquish_locality(struct tpm_chip *chip)
> {
> int rc;

You need to export the symbols.

> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> index 1621ce818705..2a9001d329f2 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -241,10 +241,17 @@ int tpm_get_timeouts(struct tpm_chip *chip)
> if (chip->flags & TPM_CHIP_FLAG_HAVE_TIMEOUTS)
> return 0;
>
> - if (chip->flags & TPM_CHIP_FLAG_TPM2)
> + if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> return tpm2_get_timeouts(chip);
> - else
> - return tpm1_get_timeouts(chip);
> + } else {
> + ssize_t ret = tpm_request_locality(chip);
> +
> + if (ret)
> + return ret;
> + ret = tpm1_get_timeouts(chip);
> + tpm_relinquish_locality(chip);
> + return ret;
> + }
> }
> EXPORT_SYMBOL_GPL(tpm_get_timeouts);
>
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 947d1db0a5cc..8c13008437dd 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -193,6 +193,8 @@ static inline void tpm_msleep(unsigned int delay_msec)
>
> int tpm_chip_start(struct tpm_chip *chip);
> void tpm_chip_stop(struct tpm_chip *chip);
> +int tpm_request_locality(struct tpm_chip *chip);
> +void tpm_relinquish_locality(struct tpm_chip *chip);
> struct tpm_chip *tpm_find_get_ops(struct tpm_chip *chip);
> __must_check int tpm_try_get_ops(struct tpm_chip *chip);
> void tpm_put_ops(struct tpm_chip *chip);
> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 431919d5f48a..d4f381d6356e 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -708,11 +708,19 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
> u32 cap2;
> cap_t cap;
>
> - if (chip->flags & TPM_CHIP_FLAG_TPM2)
> + if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> return tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
> - else
> - return tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc,
> + } else {
> + ssize_t ret = tpm_request_locality(chip);
> +
> + if (ret)
> + return ret;
> + ret = tpm1_getcap(chip, TPM_CAP_PROP_TIS_TIMEOUT, &cap, desc,
> 0);
> + tpm_relinquish_locality(chip);
> + return ret;
> + }

Why this and nost just call tpm_chip_start()?

> +
> }
>
> /* Register the IRQ and issue a command that will cause an interrupt. If an
> --
> 2.25.1
>
>

/Jarkko