[PATCH 1/4] platform/x86/intel/pmt: crashlog binary file endpoint

[Michael J. Ruhl]

The export API added a requirement for end point data to be
used by the intel_pmt_read() function to access mmio data.

Without the ep, the call causes a NULL pointer exception.

BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: Oops: 0000 [#1] SMP NOPTI
CPU: 12 UID: 0 PID: 5721 Comm: cat Tainted: G           OE       6.15.0-rc4+ #3 PREEMPT(voluntary)
Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 1641 02/21/2024
RIP: 0010:intel_pmt_read+0x3b/0x70 [pmt_class]
Code:
RSP: 0018:ffffb19981ebba18 EFLAGS: 00010246
RAX: ffffffffc0ef8e08 RBX: 0000000000000800 RCX: 0000000000000800
RDX: ffff99aee03af450 RSI: ffff99ae86552000 RDI: 0000000000000000
RBP: ffffb19981ebba58 R08: 0000000000000000 R09: 0000000000000800
R10: 000000000e2f8200 R11: 0000000000000000 R12: 0000000000000000
R13: ffff99aee03af450 R14: ffff99ae8a4bbc00 R15: ffff99ae86a35a40
FS:  00007f097dd88740(0000) GS:ffff99b62fbe8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000198860005 CR4: 0000000000f72ef0
PKRU: 55555554
Call Trace:
 <TASK>
 ? sysfs_kf_bin_read+0xc0/0xe0
 kernfs_fop_read_iter+0xac/0x1a0
 vfs_read+0x26d/0x350
 ksys_read+0x6b/0xe0
 __x64_sys_read+0x1d/0x30
 x64_sys_call+0x1bc8/0x1d70
 do_syscall_64+0x6d/0x110
 ? __mod_memcg_lruvec_state+0xe7/0x240
 ? __lruvec_stat_mod_folio+0x8f/0xe0
 ? set_ptes.isra.0+0x3b/0x80
 ? do_anonymous_page+0x101/0x9c0
 ? ___pte_offset_map+0x20/0x180
 ? __handle_mm_fault+0xba3/0x1010
 ? __count_memcg_events+0xca/0x190
 ? count_memcg_events.constprop.0+0x1e/0x40
 ? handle_mm_fault+0x1a8/0x2b0
 ? do_user_addr_fault+0x2f6/0x7b0
 ? irqentry_exit_to_user_mode+0x33/0x170
 ? irqentry_exit+0x3f/0x50
 ? exc_page_fault+0x94/0x1b0
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x7f097db25701

Add the endpoint information to the crashlog driver to avoid
the NULL pointer exception.

Two minor white space issues are addressed as well.

Fixes: 416eeb2e1fc7 ("platform/x86/intel/pmt: telemetry: Export API to read telemetry")
Signed-off-by: Michael J. Ruhl <michael.j.ruhl at intel.com>
---
 drivers/platform/x86/intel/pmt/crashlog.c | 38 ++++++++++++++++++++---
 1 file changed, 34 insertions(+), 4 deletions(-)

diff --git a/drivers/platform/x86/intel/pmt/crashlog.c b/drivers/platform/x86/intel/pmt/crashlog.c
index 6a9eb3c4b313..952bfe341f53 100644
--- a/drivers/platform/x86/intel/pmt/crashlog.c
+++ b/drivers/platform/x86/intel/pmt/crashlog.c
@@ -143,7 +143,7 @@ enable_show(struct device *dev, struct device_attribute *attr, char *buf)
 
 static ssize_t
 enable_store(struct device *dev, struct device_attribute *attr,
-	    const char *buf, size_t count)
+	     const char *buf, size_t count)
 {
 	struct crashlog_entry *entry;
 	bool enabled;
@@ -177,7 +177,7 @@ trigger_show(struct device *dev, struct device_attribute *attr, char *buf)
 
 static ssize_t
 trigger_store(struct device *dev, struct device_attribute *attr,
-	    const char *buf, size_t count)
+	      const char *buf, size_t count)
 {
 	struct crashlog_entry *entry;
 	bool trigger;
@@ -222,6 +222,31 @@ static const struct attribute_group pmt_crashlog_group = {
 	.attrs	= pmt_crashlog_attrs,
 };
 
+static int pmt_crashlog_add_endpoint(struct intel_vsec_device *ivdev,
+				     struct intel_pmt_entry *entry)
+{
+	struct telem_endpoint *ep;
+
+	/* Endpoint lifetimes are managed by kref, not devres */
+	entry->ep = kzalloc(sizeof(*entry->ep), GFP_KERNEL);
+	if (!entry->ep)
+		return -ENOMEM;
+
+	ep = entry->ep;
+	ep->pcidev = ivdev->pcidev;
+	ep->header.access_type = entry->header.access_type;
+	ep->header.guid = entry->header.guid;
+	ep->header.base_offset = entry->header.base_offset;
+	ep->header.size = entry->header.size;
+	ep->base = entry->base;
+	ep->present = true;
+	ep->cb = ivdev->priv_data;
+
+	kref_init(&ep->kref);
+
+	return 0;
+}
+
 static int pmt_crashlog_header_decode(struct intel_pmt_entry *entry,
 				      struct device *dev)
 {
@@ -252,6 +277,7 @@ static struct intel_pmt_namespace pmt_crashlog_ns = {
 	.xa = &crashlog_array,
 	.attr_grp = &pmt_crashlog_group,
 	.pmt_header_decode = pmt_crashlog_header_decode,
+	.pmt_add_endpoint = pmt_crashlog_add_endpoint,
 };
 
 /*
@@ -262,8 +288,12 @@ static void pmt_crashlog_remove(struct auxiliary_device *auxdev)
 	struct pmt_crashlog_priv *priv = auxiliary_get_drvdata(auxdev);
 	int i;
 
-	for (i = 0; i < priv->num_entries; i++)
-		intel_pmt_dev_destroy(&priv->entry[i].entry, &pmt_crashlog_ns);
+	for (i = 0; i < priv->num_entries; i++) {
+		struct intel_pmt_entry *entry = &priv->entry[i].entry;
+
+		kfree(entry->ep);
+		intel_pmt_dev_destroy(entry, &pmt_crashlog_ns);
+	}
 }
 
 static int pmt_crashlog_probe(struct auxiliary_device *auxdev,
-- 
2.49.0