[PATCH 3/4] ntdll: Fill in SYSTEM_CPU_INFORMATION.MaximumCpus

[Alex Henrie]

Signed-off-by: Alex Henrie 
---
https://www.geoffchappell.com/studies/windows/km/ntoskrnl/api/ex/sysinfo/pro...
---
 dlls/ntdll/unix/system.c | 29 +++++++++++++++++++++++++++++
 include/winternl.h       |  2 +-
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/dlls/ntdll/unix/system.c b/dlls/ntdll/unix/system.c
index a889b2e020c..d34a3229816 100644
--- a/dlls/ntdll/unix/system.c
+++ b/dlls/ntdll/unix/system.c
@@ -170,6 +170,31 @@ struct smbios_boot_info

static SYSTEM_CPU_INFORMATION cpu_info;

+static int get_possible_cpus(void)
+{
+    int ret = NtCurrentTeb()->Peb->NumberOfProcessors;
+#ifdef linux
+    FILE *f = fopen("/sys/devices/system/cpu/possible", "r");
+    char line[32];
+    char *value;
+    if (f)
+    {
+        if (fgets(line, sizeof(line), f))
+        {
+            value = strchr(line, '-');
+            if (value)
+            {
+                *value = 0;
+                value++;
+                ret = atoi(value) - atoi(line) + 1;
+            }
+        }
+        fclose(f);
+    }
+#endif
+    return ret;
+}
+
 /*******************************************************************************
  * Architecture specific feature detection for CPUs
  *
@@ -267,6 +292,8 @@ static void get_cpuinfo( SYSTEM_CPU_INFORMATION *info )
     info->Architecture = PROCESSOR_ARCHITECTURE_AMD64;
 #endif

+    info->MaximumCpus = get_possible_cpus();
+
     /* We're at least a 386 */
     info->FeatureSet = CPU_FEATURE_VME | CPU_FEATURE_X86 | CPU_FEATURE_PGE;
     info->Level = 3;
@@ -415,6 +442,7 @@ static inline void get_cpuinfo( SYSTEM_CPU_INFORMATION *info )
     FIXME("CPU Feature detection not implemented.\n");
 #endif
     info->Architecture = PROCESSOR_ARCHITECTURE_ARM;
+    info->MaximumCpus = get_possible_cpus();
 }

#elif defined(__aarch64__)
@@ -463,6 +491,7 @@ static void get_cpuinfo( SYSTEM_CPU_INFORMATION *info )
 #endif
     info->Level = max(info->Level, 8);
     info->Architecture = PROCESSOR_ARCHITECTURE_ARM64;
+    info->MaximumCpus = get_possible_cpus();
 }

#endif /* End architecture specific feature detection for CPUs */
diff --git a/include/winternl.h b/include/winternl.h
index a7b0e04aade..4d207f9cd17 100644
--- a/include/winternl.h
+++ b/include/winternl.h
@@ -1691,7 +1691,7 @@ typedef struct _SYSTEM_CPU_INFORMATION {
     WORD Architecture;
     WORD Level;
     WORD Revision;       /* combination of CPU model and stepping */
-    WORD Reserved;       /* always zero */
+    WORD MaximumCpus;    /* number of CPUs if as many as possible are hot-added */
     DWORD FeatureSet;    /* see bit flags below */
 } SYSTEM_CPU_INFORMATION, *PSYSTEM_CPU_INFORMATION;