From 2dd6f63be51cf8415b34a211c3ce7f54a4e35788 Mon Sep 17 00:00:00 2001
From: Johnny Shaw <johnny.shaw@live.com>
Date: Thu, 9 Jan 2025 17:17:47 -0700
Subject: [PATCH] firmware remove agressive smbios caching

---
 phlib/firmware.c | 40 +++++++++++++++++++++-------------------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/phlib/firmware.c b/phlib/firmware.c
index 691a92da7d44..10c3a66e3c8c 100644
--- a/phlib/firmware.c
+++ b/phlib/firmware.c
@@ -129,27 +129,29 @@ NTSTATUS PhEnumSMBIOS(
     _In_opt_ PVOID Context
     )
 {
-    static PH_INITONCE initOnce = PH_INITONCE_INIT;
-    static NTSTATUS status;
-    static ULONG length;
-    static PSYSTEM_FIRMWARE_TABLE_INFORMATION info;
+    static volatile ULONG cachedLength = sizeof(PSYSTEM_FIRMWARE_TABLE_INFORMATION) + 64;
+    NTSTATUS status;
+    ULONG length;
+    PSYSTEM_FIRMWARE_TABLE_INFORMATION info;
 
-    if (PhBeginInitOnce(&initOnce))
-    {
-        SYSTEM_FIRMWARE_TABLE_INFORMATION initInfo;
+    length = (ULONG)ReadAcquire((volatile LONG*)&cachedLength);
 
-        initInfo.ProviderSignature = 'RSMB';
-        initInfo.TableID = 0;
-        initInfo.Action = SystemFirmwareTableGet;
-        initInfo.TableBufferLength = 0;
+    info = PhAllocateZero(length);
 
-        NtQuerySystemInformation(
-            SystemFirmwareTableInformation,
-            &initInfo,
-            sizeof(SYSTEM_FIRMWARE_TABLE_INFORMATION),
-            &length
-            );
+    info->ProviderSignature = 'RSMB';
+    info->TableID = 0;
+    info->Action = SystemFirmwareTableGet;
+    info->TableBufferLength = length - sizeof(PSYSTEM_FIRMWARE_TABLE_INFORMATION);
 
+    status = NtQuerySystemInformation(
+        SystemFirmwareTableInformation,
+        info,
+        length,
+        &length
+        );
+    if (status == STATUS_BUFFER_TOO_SMALL)
+    {
+        PhFree(info);
         info = PhAllocateZero(length);
 
         info->ProviderSignature = 'RSMB';
@@ -163,8 +165,8 @@ NTSTATUS PhEnumSMBIOS(
             length,
             &length
             );
-
-        PhEndInitOnce(&initOnce);
+        if (NT_SUCCESS(status))
+            WriteRelease((volatile LONG*)&cachedLength, (LONG)length);
     }
 
     if (NT_SUCCESS(status))