[PATCH v8] tpm: Map the ACPI provided event log

[Jarkko Sakkinen <jarkko@kernel.org>]

The following failure was reported:

[   10.693310][    T1] tpm_tis STM0925:00: 2.0 TPM (device-id 0x3, rev-id 0)
[   10.848132][    T1] ------------[ cut here ]------------
[   10.853559][    T1] WARNING: CPU: 59 PID: 1 at mm/page_alloc.c:4727 __alloc_pages_noprof+0x2ca/0x330
[   10.862827][    T1] Modules linked in:
[   10.866671][    T1] CPU: 59 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-lp155.2.g52785e2-default #1 openSUSE Tumbleweed (unreleased) 588cd98293a7c9eba9013378d807364c088c9375
[   10.882741][    T1] Hardware name: HPE ProLiant DL320 Gen12/ProLiant DL320 Gen12, BIOS 1.20 10/28/2024
[   10.892170][    T1] RIP: 0010:__alloc_pages_noprof+0x2ca/0x330
[   10.898103][    T1] Code: 24 08 e9 4a fe ff ff e8 34 36 fa ff e9 88 fe ff ff 83 fe 0a 0f 86 b3 fd ff ff 80 3d 01 e7 ce 01 00 75 09 c6 05 f8 e6 ce 01 01 <0f> 0b 45 31 ff e9 e5 fe ff ff f7 c2 00 00 08 00 75 42 89 d9 80 e1
[   10.917750][    T1] RSP: 0000:ffffb7cf40077980 EFLAGS: 00010246
[   10.923777][    T1] RAX: 0000000000000000 RBX: 0000000000040cc0 RCX: 0000000000000000
[   10.931727][    T1] RDX: 0000000000000000 RSI: 000000000000000c RDI: 0000000000040cc0

Above shows that ACPI pointed a 16 MiB buffer for the log events because
RSI maps to the 'order' parameter of __alloc_pages_noprof(). Address the
bug with kvmalloc() and devm_add_action_or_reset().

Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Cc: stable@vger.kernel.org # v2.6.16+
Fixes: 55a82ab3181b ("[PATCH] tpm: add bios measurement log")
Reported-by: Andy Liang <andy.liang@hpe.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219495
Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
---
v8:
* Reduced to only to this quick fix. Let HPE reserve 16 MiB if they want
  to. We have mapping approach backed up in lore.
v7:
* Use devm_add_action_or_reset().
* Fix tags.
v6:
* A new patch.
---
 drivers/char/tpm/eventlog/acpi.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/char/tpm/eventlog/acpi.c b/drivers/char/tpm/eventlog/acpi.c
index 69533d0bfb51..394c8302cefd 100644
--- a/drivers/char/tpm/eventlog/acpi.c
+++ b/drivers/char/tpm/eventlog/acpi.c
@@ -63,6 +63,11 @@ static bool tpm_is_tpm2_log(void *bios_event_log, u64 len)
 	return n == 0;
 }
 
+static void tpm_bios_log_free(void *data)
+{
+	kvfree(data);
+}
+
 /* read binary bios log */
 int tpm_read_log_acpi(struct tpm_chip *chip)
 {
@@ -136,10 +141,16 @@ int tpm_read_log_acpi(struct tpm_chip *chip)
 	}
 
 	/* malloc EventLog space */
-	log->bios_event_log = devm_kmalloc(&chip->dev, len, GFP_KERNEL);
+	log->bios_event_log = kvmalloc(len, GFP_KERNEL);
 	if (!log->bios_event_log)
 		return -ENOMEM;
 
+	ret = devm_add_action_or_reset(&chip->dev, tpm_bios_log_free, log->bios_event_log);
+	if (ret) {
+		log->bios_event_log = NULL;
+		return ret;
+	}
+
 	log->bios_event_log_end = log->bios_event_log + len;
 
 	virt = acpi_os_map_iomem(start, len);
-- 
2.47.1