Re: [PATCH v7 15/17] tpm: introduce tpm_chip_start() and tpm_chip_stop()

From: Stefan Berger
Date: Tue Nov 13 2018 - 17:35:07 EST

On 11/13/18 1:36 PM, Jarkko Sakkinen wrote:
Encapsulate power gating and locality functionality to tpm_chip_start()
and tpm_chip_stop() in order to clean up the branching mess in
tpm_transmit().


I ran the vtpm proxy test suite on this series and got this error when running it with 'make check-j5' (https://github.com/stefanberger/linux-vtpm-tests).

It's was actually difficult to hit this bug since I ran it with -j1 , -j2 and so on before.


[ 3003.838138] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000
[ 3003.838806] PGD 0 P4D 0
[ 3003.838806] Oops: 0010 [#1] SMP PTI
[ 3003.840394] CPU: 3 PID: 111 Comm: kworker/3:1 Not tainted 4.20.0-rc2+ #6
[ 3003.840394] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-50-g14221cd-dirty-20181018_164544-sbct-4.pok.ibm.com 04/01/2014
[ 3003.840394] Workqueue: tpm-vtpm vtpm_proxy_work
[ 3003.840394] RIP: 0010:ÂÂÂÂÂÂÂÂÂ (null)
[ 3003.840394] Code: Bad RIP value.
[ 3003.840394] RSP: 0018:ffffa6e6816d7e10 EFLAGS: 00010246
[ 3003.840394] RAX: 00000000ffffffe0 RBX: ffff9698077ad000 RCX: 0000000000000006
[ 3003.840394] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9698077ad000
[ 3003.840394] RBP: ffff9698077ad000 R08: fffff59bc6172d08 R09: 0000000000000000
[ 3003.840394] R10: 0000000000000000 R11: 0000000000000000 R12: ffff9698b78f0700
[ 3003.840394] R13: ffff9698b78fbc00 R14: 0000000000000000 R15: ffff9697f8ea10f8
[ 3003.840394] FS:Â 0000000000000000(0000) GS:ffff9698b78c0000(0000) knlGS:0000000000000000
[ 3003.840394] CS:Â 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3003.840394] CR2: ffffffffffffffd6 CR3: 0000000190606000 CR4: 00000000000006e0
[ 3003.840394] Call Trace:
[ 3003.840394]Â ? tpm_chip_start+0xb8/0xe0
[ 3003.840394]Â ? tpm_chip_register+0x15/0x240
[ 3003.840394]Â ? vtpm_proxy_work+0x15/0x30
[ 3003.840394]Â ? process_one_work+0x237/0x5c0
[ 3003.840394]Â ? worker_thread+0x1d5/0x390
[ 3003.840394]Â ? process_one_work+0x5c0/0x5c0
[ 3003.840394]Â ? kthread+0x11e/0x140
[ 3003.840394]Â ? kthread_park+0x90/0x90
[ 3003.840394]Â ? ret_from_fork+0x3a/0x50
[ 3003.840394] Modules linked in: xt_CHECKSUM ipt_MASQUERADE tun nf_conntrack_netbios_ns nf_conntrack_broadcast xt_CT ip6t_rpfilter ip6t_REJECT nf_reject_ipv6 xt_conntrack ip_set nfnetlink ebtable_nat ebtable_broute bridge stp llc ip6table_nat nf_nat_ipv6 ip6table_mangle ip6table_raw ip6table_security iptable_nat nf_nat_ipv4 nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 libcrc32c iptable_mangle iptable_raw iptable_security ebtable_filter ebtables ip6table_filter ip6_tables sunrpc virtio_gpu ttm drm_kms_helper drm joydev syscopyarea sysfillrect sysimgblt pcspkr virtio_balloon i2c_piix4 fb_sys_fops virtio_net net_failover virtio_console failover virtio_blk crc32c_intel virtio_pci serio_raw ata_generic virtio_ring virtio pata_acpi floppy qemu_fw_cfg
[ 3003.840394] CR2: 0000000000000000
[ 3003.840394] ---[ end trace 29e5990b605a7ccb ]---
[ 3003.840394] RIP: 0010:ÂÂÂÂÂÂÂÂÂ (null)
[ 3003.840394] Code: Bad RIP value.
[ 3003.840394] RSP: 0018:ffffa6e6816d7e10 EFLAGS: 00010246
[ 3003.840394] RAX: 00000000ffffffe0 RBX: ffff9698077ad000 RCX: 0000000000000006
[ 3003.840394] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff9698077ad000
[ 3003.840394] RBP: ffff9698077ad000 R08: fffff59bc6172d08 R09: 0000000000000000
[ 3003.840394] R10: 0000000000000000 R11: 0000000000000000 R12: ffff9698b78f0700
[ 3003.840394] R13: ffff9698b78fbc00 R14: 0000000000000000 R15: ffff9697f8ea10f8
[ 3003.840394] FS:Â 0000000000000000(0000) GS:ffff9698b78c0000(0000) knlGS:0000000000000000
[ 3003.840394] CS:Â 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3003.840394] CR2: ffffffffffffffd6 CR3: 0000000190606000 CR4: 00000000000006e0
[ 3003.840394] BUG: sleeping function called from invalid context at ./include/linux/percpu-rwsem.h:34
[ 3003.840394] in_atomic(): 0, irqs_disabled(): 1, pid: 111, name: kworker/3:1
[ 3003.840394] INFO: lockdep is turned off.
[ 3003.840394] irq event stamp: 165206
[ 3003.840394] hardirqs last enabled at (165205): [<ffffffff8b220113>] free_unref_page+0xf3/0x1f0
[ 3003.840394] hardirqs last disabled at (165206): [<ffffffff8b0019ee>] trace_hardirqs_off_thunk+0x1a/0x1c
[ 3003.840394] softirqs last enabled at (165182): [<ffffffff8b785e01>] peernet2id+0x41/0x50
[ 3003.840394] softirqs last disabled at (165180): [<ffffffff8b785de2>] peernet2id+0x22/0x50
[ 3003.840394] CPU: 3 PID: 111 Comm: kworker/3:1 Tainted: G DÂÂÂÂÂÂÂÂÂÂ 4.20.0-rc2+ #6
[ 3003.840394] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.0-50-g14221cd-dirty-20181018_164544-sbct-4.pok.ibm.com 04/01/2014
[ 3003.840394] Workqueue: tpm-vtpm vtpm_proxy_work
[ 3003.840394] Call Trace:
[ 3003.840394]Â dump_stack+0x67/0x9b
[ 3003.840394]Â ___might_sleep+0x149/0x230
[ 3003.840394]Â exit_signals+0x20/0x210
[ 3003.840394]Â ? worker_thread+0x1d5/0x390
[ 3003.840394]Â do_exit+0xa0/0xc70
[ 3003.840394]Â ? process_one_work+0x5c0/0x5c0
[ 3003.840394]Â ? kthread+0x11e/0x140
[ 3003.840394]Â rewind_stack_do_exit+0x17/0x20
[ 3004.389582] tpm tpm1803: tpm_try_transmit: tpm_send: error -14



Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
drivers/char/tpm/tpm-chip.c | 110 +++++++++++++++++++++++++++++++
drivers/char/tpm/tpm-interface.c | 87 +-----------------------
drivers/char/tpm/tpm.h | 2 +
3 files changed, 115 insertions(+), 84 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 157505b0f755..65f1561eba81 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -37,6 +37,116 @@ struct class *tpm_class;
struct class *tpmrm_class;
dev_t tpm_devt;

+static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
+{
+ int rc;
+
+ if (flags & TPM_TRANSMIT_NESTED)
+ return 0;
+
+ if (!chip->ops->request_locality)
+ return 0;
+
+ rc = chip->ops->request_locality(chip, 0);
+ if (rc < 0)
+ return rc;
+
+ chip->locality = rc;
+ return 0;
+}
+
+static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
+{
+ int rc;
+
+ if (flags & TPM_TRANSMIT_NESTED)
+ return;
+
+ if (!chip->ops->relinquish_locality)
+ return;
+
+ rc = chip->ops->relinquish_locality(chip, chip->locality);
+ if (rc)
+ dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
+
+ chip->locality = -1;
+}
+
+static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
+{
+ if (flags & TPM_TRANSMIT_NESTED)
+ return 0;
+
+ if (!chip->ops->cmd_ready)
+ return 0;
+
+ return chip->ops->cmd_ready(chip);
+}
+
+static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
+{
+ if (flags & TPM_TRANSMIT_NESTED)
+ return 0;
+
+ if (!chip->ops->go_idle)
+ return 0;
+
+ return chip->ops->go_idle(chip);
+}
+
+/**
+ * tpm_chip_start() - power on the TPM
+ * @chip: a TPM chip to use
+ * @flags: TPM transmit flags
+ *
+ * Return:
+ * * The response length - OK
+ * * -errno - A system error
+ */
+int tpm_chip_start(struct tpm_chip *chip, unsigned int flags)
+{
+ int ret;
+
+ if (chip->ops->clk_enable)
+ chip->ops->clk_enable(chip, true);
+
+ if (chip->locality == -1) {
+ ret = tpm_request_locality(chip, flags);
+ if (ret) {
+ chip->ops->clk_enable(chip, false);
+ return ret;
+ }
+ }
+
+ ret = tpm_cmd_ready(chip, flags);
+ if (ret) {
+ tpm_relinquish_locality(chip, flags);
+ if (chip->ops->clk_enable)
+ chip->ops->clk_enable(chip, false);
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * tpm_chip_stop() - power off the TPM
+ * @chip: a TPM chip to use
+ * @flags: TPM transmit flags
+ *
+ * Return:
+ * * The response length - OK
+ * * -errno - A system error
+ */
+void tpm_chip_stop(struct tpm_chip *chip, unsigned int flags)
+{
+ tpm_go_idle(chip, flags);
+ tpm_relinquish_locality(chip, flags);
+ if (chip->ops->clk_enable)
+ chip->ops->clk_enable(chip, false);
+}
+
+
/**
* tpm_try_get_ops() - Get a ref to the tpm_chip
* @chip: Chip to ref
diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 5865b9671d20..888c9923fca1 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -62,64 +62,6 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal)
}
EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);

-static int tpm_request_locality(struct tpm_chip *chip, unsigned int flags)
-{
- int rc;
-
- if (flags & TPM_TRANSMIT_NESTED)
- return 0;
-
- if (!chip->ops->request_locality)
- return 0;
-
- rc = chip->ops->request_locality(chip, 0);
- if (rc < 0)
- return rc;
-
- chip->locality = rc;
-
- return 0;
-}
-
-static void tpm_relinquish_locality(struct tpm_chip *chip, unsigned int flags)
-{
- int rc;
-
- if (flags & TPM_TRANSMIT_NESTED)
- return;
-
- if (!chip->ops->relinquish_locality)
- return;
-
- rc = chip->ops->relinquish_locality(chip, chip->locality);
- if (rc)
- dev_err(&chip->dev, "%s: : error %d\n", __func__, rc);
-
- chip->locality = -1;
-}
-
-static int tpm_cmd_ready(struct tpm_chip *chip, unsigned int flags)
-{
- if (flags & TPM_TRANSMIT_NESTED)
- return 0;
-
- if (!chip->ops->cmd_ready)
- return 0;
-
- return chip->ops->cmd_ready(chip);
-}
-
-static int tpm_go_idle(struct tpm_chip *chip, unsigned int flags)
-{
- if (flags & TPM_TRANSMIT_NESTED)
- return 0;
-
- if (!chip->ops->go_idle)
- return 0;
-
- return chip->ops->go_idle(chip);
-}
-
static ssize_t tpm_try_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
unsigned int flags)
{
@@ -212,7 +154,6 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
/* space for header and handles */
u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];
unsigned int delay_msec = TPM2_DURATION_SHORT;
- bool has_locality = false;
u32 rc = 0;
ssize_t ret;
const size_t save_size = min(sizeof(save), bufsiz);
@@ -227,34 +168,12 @@ ssize_t tpm_transmit(struct tpm_chip *chip, u8 *buf, size_t bufsiz,
memcpy(save, buf, save_size);

for (;;) {
- if (chip->ops->clk_enable != NULL)
- chip->ops->clk_enable(chip, true);
-
- if (chip->locality == -1) {
- ret = tpm_request_locality(chip, flags);
- if (ret)
- goto out_locality;
- has_locality = true;
- }
-
- ret = tpm_cmd_ready(chip, flags);
+ ret = tpm_chip_start(chip, flags);
if (ret)
- goto out_locality;
-
+ return ret;
ret = tpm_try_transmit(chip, buf, bufsiz, flags);
+ tpm_chip_stop(chip, flags);

- /* This may fail but do not override ret. */
- tpm_go_idle(chip, flags);
-
-out_locality:
- if (has_locality)
- tpm_relinquish_locality(chip, flags);
-
- if (chip->ops->clk_enable != NULL)
- chip->ops->clk_enable(chip, false);
-
- if (ret < 0)
- break;
rc = be32_to_cpu(header->return_code);
if (rc != TPM2_RC_RETRY && rc != TPM2_RC_TESTING)
break;
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index c7c06de651a0..c42a75710b70 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -523,6 +523,8 @@ static inline void tpm_msleep(unsigned int delay_msec)
delay_msec * 1000);
};

+int tpm_chip_start(struct tpm_chip *chip, unsigned int flags);
+void tpm_chip_stop(struct tpm_chip *chip, unsigned int flags);
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);