From ea08eeccae9297f7aabd2ef7f0c2517ac4549acc Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:18:26 +0000
Subject: [PATCH] write in 30M

---
 kernel/drivers/acpi/pptt.c |  155 +++++++++++++++++++++++++++++++++++----------------
 1 files changed, 106 insertions(+), 49 deletions(-)

diff --git a/kernel/drivers/acpi/pptt.c b/kernel/drivers/acpi/pptt.c
index 9dbf86a..4ae9335 100644
--- a/kernel/drivers/acpi/pptt.c
+++ b/kernel/drivers/acpi/pptt.c
@@ -98,11 +98,11 @@
  *
  * Return: The cache structure and the level we terminated with.
  */
-static int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
-				int local_level,
-				struct acpi_subtable_header *res,
-				struct acpi_pptt_cache **found,
-				int level, int type)
+static unsigned int acpi_pptt_walk_cache(struct acpi_table_header *table_hdr,
+					 unsigned int local_level,
+					 struct acpi_subtable_header *res,
+					 struct acpi_pptt_cache **found,
+					 unsigned int level, int type)
 {
 	struct acpi_pptt_cache *cache;
 
@@ -119,7 +119,7 @@
 			if (*found != NULL && cache != *found)
 				pr_warn("Found duplicate cache level/type unable to determine uniqueness\n");
 
-			pr_debug("Found cache @ level %d\n", level);
+			pr_debug("Found cache @ level %u\n", level);
 			*found = cache;
 			/*
 			 * continue looking at this node's resource list
@@ -132,16 +132,17 @@
 	return local_level;
 }
 
-static struct acpi_pptt_cache *acpi_find_cache_level(struct acpi_table_header *table_hdr,
-						     struct acpi_pptt_processor *cpu_node,
-						     int *starting_level, int level,
-						     int type)
+static struct acpi_pptt_cache *
+acpi_find_cache_level(struct acpi_table_header *table_hdr,
+		      struct acpi_pptt_processor *cpu_node,
+		      unsigned int *starting_level, unsigned int level,
+		      int type)
 {
 	struct acpi_subtable_header *res;
-	int number_of_levels = *starting_level;
+	unsigned int number_of_levels = *starting_level;
 	int resource = 0;
 	struct acpi_pptt_cache *ret = NULL;
-	int local_level;
+	unsigned int local_level;
 
 	/* walk down from processor node */
 	while ((res = acpi_get_pptt_resource(table_hdr, cpu_node, resource))) {
@@ -164,7 +165,7 @@
 }
 
 /**
- * acpi_count_levels() - Given a PPTT table, and a cpu node, count the caches
+ * acpi_count_levels() - Given a PPTT table, and a CPU node, count the caches
  * @table_hdr: Pointer to the head of the PPTT table
  * @cpu_node: processor node we wish to count caches for
  *
@@ -209,6 +210,9 @@
 	struct acpi_pptt_processor *cpu_node;
 	u32 proc_sz;
 
+	if (table_hdr->revision > 1)
+		return (node->flags & ACPI_PPTT_ACPI_LEAF_NODE);
+
 	table_end = (unsigned long)table_hdr + table_hdr->length;
 	node_entry = ACPI_PTR_DIFF(node, table_hdr);
 	entry = ACPI_ADD_PTR(struct acpi_subtable_header, table_hdr,
@@ -232,7 +236,7 @@
 /**
  * acpi_find_processor_node() - Given a PPTT table find the requested processor
  * @table_hdr:  Pointer to the head of the PPTT table
- * @acpi_cpu_id: cpu we are searching for
+ * @acpi_cpu_id: CPU we are searching for
  *
  * Find the subtable entry describing the provided processor.
  * This is done by iterating the PPTT table looking for processor nodes
@@ -318,12 +322,12 @@
 						    unsigned int level,
 						    struct acpi_pptt_processor **node)
 {
-	int total_levels = 0;
+	unsigned int total_levels = 0;
 	struct acpi_pptt_cache *found = NULL;
 	struct acpi_pptt_processor *cpu_node;
 	u8 acpi_type = acpi_cache_type(type);
 
-	pr_debug("Looking for CPU %d's level %d cache type %d\n",
+	pr_debug("Looking for CPU %d's level %u cache type %d\n",
 		 acpi_cpu_id, level, acpi_type);
 
 	cpu_node = acpi_find_processor_node(table_hdr, acpi_cpu_id);
@@ -429,17 +433,40 @@
 	}
 }
 
+static bool flag_identical(struct acpi_table_header *table_hdr,
+			   struct acpi_pptt_processor *cpu)
+{
+	struct acpi_pptt_processor *next;
+
+	/* heterogeneous machines must use PPTT revision > 1 */
+	if (table_hdr->revision < 2)
+		return false;
+
+	/* Locate the last node in the tree with IDENTICAL set */
+	if (cpu->flags & ACPI_PPTT_ACPI_IDENTICAL) {
+		next = fetch_pptt_node(table_hdr, cpu->parent);
+		if (!(next && next->flags & ACPI_PPTT_ACPI_IDENTICAL))
+			return true;
+	}
+
+	return false;
+}
+
 /* Passing level values greater than this will result in search termination */
 #define PPTT_ABORT_PACKAGE 0xFF
 
-static struct acpi_pptt_processor *acpi_find_processor_package_id(struct acpi_table_header *table_hdr,
-								  struct acpi_pptt_processor *cpu,
-								  int level, int flag)
+static struct acpi_pptt_processor *acpi_find_processor_tag(struct acpi_table_header *table_hdr,
+							   struct acpi_pptt_processor *cpu,
+							   int level, int flag)
 {
 	struct acpi_pptt_processor *prev_node;
 
 	while (cpu && level) {
-		if (cpu->flags & flag)
+		/* special case the identical flag to find last identical */
+		if (flag == ACPI_PPTT_ACPI_IDENTICAL) {
+			if (flag_identical(table_hdr, cpu))
+				break;
+		} else if (cpu->flags & flag)
 			break;
 		pr_debug("level %d\n", level);
 		prev_node = fetch_pptt_node(table_hdr, cpu->parent);
@@ -451,18 +478,23 @@
 	return cpu;
 }
 
+static void acpi_pptt_warn_missing(void)
+{
+	pr_warn_once("No PPTT table found, CPU and cache topology may be inaccurate\n");
+}
+
 /**
  * topology_get_acpi_cpu_tag() - Find a unique topology value for a feature
  * @table: Pointer to the head of the PPTT table
- * @cpu: Kernel logical cpu number
+ * @cpu: Kernel logical CPU number
  * @level: A level that terminates the search
  * @flag: A flag which terminates the search
  *
- * Get a unique value given a cpu, and a topology level, that can be
+ * Get a unique value given a CPU, and a topology level, that can be
  * matched to determine which cpus share common topological features
  * at that level.
  *
- * Return: Unique value, or -ENOENT if unable to locate cpu
+ * Return: Unique value, or -ENOENT if unable to locate CPU
  */
 static int topology_get_acpi_cpu_tag(struct acpi_table_header *table,
 				     unsigned int cpu, int level, int flag)
@@ -472,8 +504,8 @@
 
 	cpu_node = acpi_find_processor_node(table, acpi_cpu_id);
 	if (cpu_node) {
-		cpu_node = acpi_find_processor_package_id(table, cpu_node,
-							  level, flag);
+		cpu_node = acpi_find_processor_tag(table, cpu_node,
+						   level, flag);
 		/*
 		 * As per specification if the processor structure represents
 		 * an actual processor, then ACPI processor ID must be valid.
@@ -498,11 +530,11 @@
 
 	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 	if (ACPI_FAILURE(status)) {
-		pr_warn_once("No PPTT table found, cpu topology may be inaccurate\n");
+		acpi_pptt_warn_missing();
 		return -ENOENT;
 	}
 	retval = topology_get_acpi_cpu_tag(table, cpu, level, flag);
-	pr_debug("Topology Setup ACPI cpu %d, level %d ret = %d\n",
+	pr_debug("Topology Setup ACPI CPU %d, level %d ret = %d\n",
 		 cpu, level, retval);
 	acpi_put_table(table);
 
@@ -532,7 +564,7 @@
 
 	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 	if (ACPI_FAILURE(status)) {
-		pr_warn_once("No PPTT table found, cpu topology may be inaccurate\n");
+		acpi_pptt_warn_missing();
 		return ret;
 	}
 
@@ -549,9 +581,9 @@
 
 /**
  * acpi_find_last_cache_level() - Determines the number of cache levels for a PE
- * @cpu: Kernel logical cpu number
+ * @cpu: Kernel logical CPU number
  *
- * Given a logical cpu number, returns the number of levels of cache represented
+ * Given a logical CPU number, returns the number of levels of cache represented
  * in the PPTT. Errors caused by lack of a PPTT table, or otherwise, return 0
  * indicating we didn't find any cache levels.
  *
@@ -564,12 +596,12 @@
 	int number_of_levels = 0;
 	acpi_status status;
 
-	pr_debug("Cache Setup find last level cpu=%d\n", cpu);
+	pr_debug("Cache Setup find last level CPU=%d\n", cpu);
 
 	acpi_cpu_id = get_acpi_id_for_cpu(cpu);
 	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 	if (ACPI_FAILURE(status)) {
-		pr_warn_once("No PPTT table found, cache topology may be inaccurate\n");
+		acpi_pptt_warn_missing();
 	} else {
 		number_of_levels = acpi_find_cache_levels(table, acpi_cpu_id);
 		acpi_put_table(table);
@@ -581,14 +613,14 @@
 
 /**
  * cache_setup_acpi() - Override CPU cache topology with data from the PPTT
- * @cpu: Kernel logical cpu number
+ * @cpu: Kernel logical CPU number
  *
  * Updates the global cache info provided by cpu_get_cacheinfo()
  * when there are valid properties in the acpi_pptt_cache nodes. A
  * successful parse may not result in any updates if none of the
- * cache levels have any valid flags set.  Futher, a unique value is
+ * cache levels have any valid flags set.  Further, a unique value is
  * associated with each known CPU cache entry. This unique value
- * can be used to determine whether caches are shared between cpus.
+ * can be used to determine whether caches are shared between CPUs.
  *
  * Return: -ENOENT on failure to find table, or 0 on success
  */
@@ -597,11 +629,11 @@
 	struct acpi_table_header *table;
 	acpi_status status;
 
-	pr_debug("Cache Setup ACPI cpu %d\n", cpu);
+	pr_debug("Cache Setup ACPI CPU %d\n", cpu);
 
 	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 	if (ACPI_FAILURE(status)) {
-		pr_warn_once("No PPTT table found, cache topology may be inaccurate\n");
+		acpi_pptt_warn_missing();
 		return -ENOENT;
 	}
 
@@ -626,8 +658,8 @@
 }
 
 /**
- * find_acpi_cpu_topology() - Determine a unique topology value for a given cpu
- * @cpu: Kernel logical cpu number
+ * find_acpi_cpu_topology() - Determine a unique topology value for a given CPU
+ * @cpu: Kernel logical CPU number
  * @level: The topological level for which we would like a unique ID
  *
  * Determine a topology unique ID for each thread/core/cluster/mc_grouping
@@ -640,7 +672,7 @@
  * other levels beyond this use a generated value to uniquely identify
  * a topological feature.
  *
- * Return: -ENOENT if the PPTT doesn't exist, or the cpu cannot be found.
+ * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
  * Otherwise returns a value which represents a unique topological feature.
  */
 int find_acpi_cpu_topology(unsigned int cpu, int level)
@@ -650,12 +682,12 @@
 
 /**
  * find_acpi_cpu_cache_topology() - Determine a unique cache topology value
- * @cpu: Kernel logical cpu number
+ * @cpu: Kernel logical CPU number
  * @level: The cache level for which we would like a unique ID
  *
  * Determine a unique ID for each unified cache in the system
  *
- * Return: -ENOENT if the PPTT doesn't exist, or the cpu cannot be found.
+ * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
  * Otherwise returns a value which represents a unique topological feature.
  */
 int find_acpi_cpu_cache_topology(unsigned int cpu, int level)
@@ -669,7 +701,7 @@
 
 	status = acpi_get_table(ACPI_SIG_PPTT, 0, &table);
 	if (ACPI_FAILURE(status)) {
-		pr_warn_once("No PPTT table found, topology may be inaccurate\n");
+		acpi_pptt_warn_missing();
 		return -ENOENT;
 	}
 
@@ -685,22 +717,47 @@
 	return ret;
 }
 
-
 /**
- * find_acpi_cpu_topology_package() - Determine a unique cpu package value
- * @cpu: Kernel logical cpu number
+ * find_acpi_cpu_topology_package() - Determine a unique CPU package value
+ * @cpu: Kernel logical CPU number
  *
- * Determine a topology unique package ID for the given cpu.
+ * Determine a topology unique package ID for the given CPU.
  * This ID can then be used to group peers, which will have matching ids.
  *
  * The search terminates when either a level is found with the PHYSICAL_PACKAGE
  * flag set or we reach a root node.
  *
- * Return: -ENOENT if the PPTT doesn't exist, or the cpu cannot be found.
- * Otherwise returns a value which represents the package for this cpu.
+ * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
+ * Otherwise returns a value which represents the package for this CPU.
  */
 int find_acpi_cpu_topology_package(unsigned int cpu)
 {
 	return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
 					  ACPI_PPTT_PHYSICAL_PACKAGE);
 }
+
+/**
+ * find_acpi_cpu_topology_hetero_id() - Get a core architecture tag
+ * @cpu: Kernel logical CPU number
+ *
+ * Determine a unique heterogeneous tag for the given CPU. CPUs with the same
+ * implementation should have matching tags.
+ *
+ * The returned tag can be used to group peers with identical implementation.
+ *
+ * The search terminates when a level is found with the identical implementation
+ * flag set or we reach a root node.
+ *
+ * Due to limitations in the PPTT data structure, there may be rare situations
+ * where two cores in a heterogeneous machine may be identical, but won't have
+ * the same tag.
+ *
+ * Return: -ENOENT if the PPTT doesn't exist, or the CPU cannot be found.
+ * Otherwise returns a value which represents a group of identical cores
+ * similar to this CPU.
+ */
+int find_acpi_cpu_topology_hetero_id(unsigned int cpu)
+{
+	return find_acpi_cpu_topology_tag(cpu, PPTT_ABORT_PACKAGE,
+					  ACPI_PPTT_ACPI_IDENTICAL);
+}

--
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