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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-26 06:04:14 +08:00
linux-next/arch/sparc/kernel/cpumap.c
Greg Kroah-Hartman b24413180f License cleanup: add SPDX GPL-2.0 license identifier to files with no license
Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier.  The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
 - file had no licensing information it it.
 - file was a */uapi/* one with no licensing information in it,
 - file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne.  Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed.  Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
 - Files considered eligible had to be source code files.
 - Make and config files were included as candidates if they contained >5
   lines of source
 - File already had some variant of a license header in it (even if <5
   lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

 - when both scanners couldn't find any license traces, file was
   considered to have no license information in it, and the top level
   COPYING file license applied.

   For non */uapi/* files that summary was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0                                              11139

   and resulted in the first patch in this series.

   If that file was a */uapi/* path one, it was "GPL-2.0 WITH
   Linux-syscall-note" otherwise it was "GPL-2.0".  Results of that was:

   SPDX license identifier                            # files
   ---------------------------------------------------|-------
   GPL-2.0 WITH Linux-syscall-note                        930

   and resulted in the second patch in this series.

 - if a file had some form of licensing information in it, and was one
   of the */uapi/* ones, it was denoted with the Linux-syscall-note if
   any GPL family license was found in the file or had no licensing in
   it (per prior point).  Results summary:

   SPDX license identifier                            # files
   ---------------------------------------------------|------
   GPL-2.0 WITH Linux-syscall-note                       270
   GPL-2.0+ WITH Linux-syscall-note                      169
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause)    21
   ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause)    17
   LGPL-2.1+ WITH Linux-syscall-note                      15
   GPL-1.0+ WITH Linux-syscall-note                       14
   ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause)    5
   LGPL-2.0+ WITH Linux-syscall-note                       4
   LGPL-2.1 WITH Linux-syscall-note                        3
   ((GPL-2.0 WITH Linux-syscall-note) OR MIT)              3
   ((GPL-2.0 WITH Linux-syscall-note) AND MIT)             1

   and that resulted in the third patch in this series.

 - when the two scanners agreed on the detected license(s), that became
   the concluded license(s).

 - when there was disagreement between the two scanners (one detected a
   license but the other didn't, or they both detected different
   licenses) a manual inspection of the file occurred.

 - In most cases a manual inspection of the information in the file
   resulted in a clear resolution of the license that should apply (and
   which scanner probably needed to revisit its heuristics).

 - When it was not immediately clear, the license identifier was
   confirmed with lawyers working with the Linux Foundation.

 - If there was any question as to the appropriate license identifier,
   the file was flagged for further research and to be revisited later
   in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights.  The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
 - a full scancode scan run, collecting the matched texts, detected
   license ids and scores
 - reviewing anything where there was a license detected (about 500+
   files) to ensure that the applied SPDX license was correct
 - reviewing anything where there was no detection but the patch license
   was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
   SPDX license was correct

This produced a worksheet with 20 files needing minor correction.  This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg.  Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected.  This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.)  Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-02 11:10:55 +01:00

441 lines
11 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* cpumap.c: used for optimizing CPU assignment
*
* Copyright (C) 2009 Hong H. Pham <hong.pham@windriver.com>
*/
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/cpumask.h>
#include <linux/spinlock.h>
#include <asm/cpudata.h>
#include "cpumap.h"
enum {
CPUINFO_LVL_ROOT = 0,
CPUINFO_LVL_NODE,
CPUINFO_LVL_CORE,
CPUINFO_LVL_PROC,
CPUINFO_LVL_MAX,
};
enum {
ROVER_NO_OP = 0,
/* Increment rover every time level is visited */
ROVER_INC_ON_VISIT = 1 << 0,
/* Increment parent's rover every time rover wraps around */
ROVER_INC_PARENT_ON_LOOP = 1 << 1,
};
struct cpuinfo_node {
int id;
int level;
int num_cpus; /* Number of CPUs in this hierarchy */
int parent_index;
int child_start; /* Array index of the first child node */
int child_end; /* Array index of the last child node */
int rover; /* Child node iterator */
};
struct cpuinfo_level {
int start_index; /* Index of first node of a level in a cpuinfo tree */
int end_index; /* Index of last node of a level in a cpuinfo tree */
int num_nodes; /* Number of nodes in a level in a cpuinfo tree */
};
struct cpuinfo_tree {
int total_nodes;
/* Offsets into nodes[] for each level of the tree */
struct cpuinfo_level level[CPUINFO_LVL_MAX];
struct cpuinfo_node nodes[0];
};
static struct cpuinfo_tree *cpuinfo_tree;
static u16 cpu_distribution_map[NR_CPUS];
static DEFINE_SPINLOCK(cpu_map_lock);
/* Niagara optimized cpuinfo tree traversal. */
static const int niagara_iterate_method[] = {
[CPUINFO_LVL_ROOT] = ROVER_NO_OP,
/* Strands (or virtual CPUs) within a core may not run concurrently
* on the Niagara, as instruction pipeline(s) are shared. Distribute
* work to strands in different cores first for better concurrency.
* Go to next NUMA node when all cores are used.
*/
[CPUINFO_LVL_NODE] = ROVER_INC_ON_VISIT|ROVER_INC_PARENT_ON_LOOP,
/* Strands are grouped together by proc_id in cpuinfo_sparc, i.e.
* a proc_id represents an instruction pipeline. Distribute work to
* strands in different proc_id groups if the core has multiple
* instruction pipelines (e.g. the Niagara 2/2+ has two).
*/
[CPUINFO_LVL_CORE] = ROVER_INC_ON_VISIT,
/* Pick the next strand in the proc_id group. */
[CPUINFO_LVL_PROC] = ROVER_INC_ON_VISIT,
};
/* Generic cpuinfo tree traversal. Distribute work round robin across NUMA
* nodes.
*/
static const int generic_iterate_method[] = {
[CPUINFO_LVL_ROOT] = ROVER_INC_ON_VISIT,
[CPUINFO_LVL_NODE] = ROVER_NO_OP,
[CPUINFO_LVL_CORE] = ROVER_INC_PARENT_ON_LOOP,
[CPUINFO_LVL_PROC] = ROVER_INC_ON_VISIT|ROVER_INC_PARENT_ON_LOOP,
};
static int cpuinfo_id(int cpu, int level)
{
int id;
switch (level) {
case CPUINFO_LVL_ROOT:
id = 0;
break;
case CPUINFO_LVL_NODE:
id = cpu_to_node(cpu);
break;
case CPUINFO_LVL_CORE:
id = cpu_data(cpu).core_id;
break;
case CPUINFO_LVL_PROC:
id = cpu_data(cpu).proc_id;
break;
default:
id = -EINVAL;
}
return id;
}
/*
* Enumerate the CPU information in __cpu_data to determine the start index,
* end index, and number of nodes for each level in the cpuinfo tree. The
* total number of cpuinfo nodes required to build the tree is returned.
*/
static int enumerate_cpuinfo_nodes(struct cpuinfo_level *tree_level)
{
int prev_id[CPUINFO_LVL_MAX];
int i, n, num_nodes;
for (i = CPUINFO_LVL_ROOT; i < CPUINFO_LVL_MAX; i++) {
struct cpuinfo_level *lv = &tree_level[i];
prev_id[i] = -1;
lv->start_index = lv->end_index = lv->num_nodes = 0;
}
num_nodes = 1; /* Include the root node */
for (i = 0; i < num_possible_cpus(); i++) {
if (!cpu_online(i))
continue;
n = cpuinfo_id(i, CPUINFO_LVL_NODE);
if (n > prev_id[CPUINFO_LVL_NODE]) {
tree_level[CPUINFO_LVL_NODE].num_nodes++;
prev_id[CPUINFO_LVL_NODE] = n;
num_nodes++;
}
n = cpuinfo_id(i, CPUINFO_LVL_CORE);
if (n > prev_id[CPUINFO_LVL_CORE]) {
tree_level[CPUINFO_LVL_CORE].num_nodes++;
prev_id[CPUINFO_LVL_CORE] = n;
num_nodes++;
}
n = cpuinfo_id(i, CPUINFO_LVL_PROC);
if (n > prev_id[CPUINFO_LVL_PROC]) {
tree_level[CPUINFO_LVL_PROC].num_nodes++;
prev_id[CPUINFO_LVL_PROC] = n;
num_nodes++;
}
}
tree_level[CPUINFO_LVL_ROOT].num_nodes = 1;
n = tree_level[CPUINFO_LVL_NODE].num_nodes;
tree_level[CPUINFO_LVL_NODE].start_index = 1;
tree_level[CPUINFO_LVL_NODE].end_index = n;
n++;
tree_level[CPUINFO_LVL_CORE].start_index = n;
n += tree_level[CPUINFO_LVL_CORE].num_nodes;
tree_level[CPUINFO_LVL_CORE].end_index = n - 1;
tree_level[CPUINFO_LVL_PROC].start_index = n;
n += tree_level[CPUINFO_LVL_PROC].num_nodes;
tree_level[CPUINFO_LVL_PROC].end_index = n - 1;
return num_nodes;
}
/* Build a tree representation of the CPU hierarchy using the per CPU
* information in __cpu_data. Entries in __cpu_data[0..NR_CPUS] are
* assumed to be sorted in ascending order based on node, core_id, and
* proc_id (in order of significance).
*/
static struct cpuinfo_tree *build_cpuinfo_tree(void)
{
struct cpuinfo_tree *new_tree;
struct cpuinfo_node *node;
struct cpuinfo_level tmp_level[CPUINFO_LVL_MAX];
int num_cpus[CPUINFO_LVL_MAX];
int level_rover[CPUINFO_LVL_MAX];
int prev_id[CPUINFO_LVL_MAX];
int n, id, cpu, prev_cpu, last_cpu, level;
n = enumerate_cpuinfo_nodes(tmp_level);
new_tree = kzalloc(sizeof(struct cpuinfo_tree) +
(sizeof(struct cpuinfo_node) * n), GFP_ATOMIC);
if (!new_tree)
return NULL;
new_tree->total_nodes = n;
memcpy(&new_tree->level, tmp_level, sizeof(tmp_level));
prev_cpu = cpu = cpumask_first(cpu_online_mask);
/* Initialize all levels in the tree with the first CPU */
for (level = CPUINFO_LVL_PROC; level >= CPUINFO_LVL_ROOT; level--) {
n = new_tree->level[level].start_index;
level_rover[level] = n;
node = &new_tree->nodes[n];
id = cpuinfo_id(cpu, level);
if (unlikely(id < 0)) {
kfree(new_tree);
return NULL;
}
node->id = id;
node->level = level;
node->num_cpus = 1;
node->parent_index = (level > CPUINFO_LVL_ROOT)
? new_tree->level[level - 1].start_index : -1;
node->child_start = node->child_end = node->rover =
(level == CPUINFO_LVL_PROC)
? cpu : new_tree->level[level + 1].start_index;
prev_id[level] = node->id;
num_cpus[level] = 1;
}
for (last_cpu = (num_possible_cpus() - 1); last_cpu >= 0; last_cpu--) {
if (cpu_online(last_cpu))
break;
}
while (++cpu <= last_cpu) {
if (!cpu_online(cpu))
continue;
for (level = CPUINFO_LVL_PROC; level >= CPUINFO_LVL_ROOT;
level--) {
id = cpuinfo_id(cpu, level);
if (unlikely(id < 0)) {
kfree(new_tree);
return NULL;
}
if ((id != prev_id[level]) || (cpu == last_cpu)) {
prev_id[level] = id;
node = &new_tree->nodes[level_rover[level]];
node->num_cpus = num_cpus[level];
num_cpus[level] = 1;
if (cpu == last_cpu)
node->num_cpus++;
/* Connect tree node to parent */
if (level == CPUINFO_LVL_ROOT)
node->parent_index = -1;
else
node->parent_index =
level_rover[level - 1];
if (level == CPUINFO_LVL_PROC) {
node->child_end =
(cpu == last_cpu) ? cpu : prev_cpu;
} else {
node->child_end =
level_rover[level + 1] - 1;
}
/* Initialize the next node in the same level */
n = ++level_rover[level];
if (n <= new_tree->level[level].end_index) {
node = &new_tree->nodes[n];
node->id = id;
node->level = level;
/* Connect node to child */
node->child_start = node->child_end =
node->rover =
(level == CPUINFO_LVL_PROC)
? cpu : level_rover[level + 1];
}
} else
num_cpus[level]++;
}
prev_cpu = cpu;
}
return new_tree;
}
static void increment_rover(struct cpuinfo_tree *t, int node_index,
int root_index, const int *rover_inc_table)
{
struct cpuinfo_node *node = &t->nodes[node_index];
int top_level, level;
top_level = t->nodes[root_index].level;
for (level = node->level; level >= top_level; level--) {
node->rover++;
if (node->rover <= node->child_end)
return;
node->rover = node->child_start;
/* If parent's rover does not need to be adjusted, stop here. */
if ((level == top_level) ||
!(rover_inc_table[level] & ROVER_INC_PARENT_ON_LOOP))
return;
node = &t->nodes[node->parent_index];
}
}
static int iterate_cpu(struct cpuinfo_tree *t, unsigned int root_index)
{
const int *rover_inc_table;
int level, new_index, index = root_index;
switch (sun4v_chip_type) {
case SUN4V_CHIP_NIAGARA1:
case SUN4V_CHIP_NIAGARA2:
case SUN4V_CHIP_NIAGARA3:
case SUN4V_CHIP_NIAGARA4:
case SUN4V_CHIP_NIAGARA5:
case SUN4V_CHIP_SPARC_M6:
case SUN4V_CHIP_SPARC_M7:
case SUN4V_CHIP_SPARC_M8:
case SUN4V_CHIP_SPARC_SN:
case SUN4V_CHIP_SPARC64X:
rover_inc_table = niagara_iterate_method;
break;
default:
rover_inc_table = generic_iterate_method;
}
for (level = t->nodes[root_index].level; level < CPUINFO_LVL_MAX;
level++) {
new_index = t->nodes[index].rover;
if (rover_inc_table[level] & ROVER_INC_ON_VISIT)
increment_rover(t, index, root_index, rover_inc_table);
index = new_index;
}
return index;
}
static void _cpu_map_rebuild(void)
{
int i;
if (cpuinfo_tree) {
kfree(cpuinfo_tree);
cpuinfo_tree = NULL;
}
cpuinfo_tree = build_cpuinfo_tree();
if (!cpuinfo_tree)
return;
/* Build CPU distribution map that spans all online CPUs. No need
* to check if the CPU is online, as that is done when the cpuinfo
* tree is being built.
*/
for (i = 0; i < cpuinfo_tree->nodes[0].num_cpus; i++)
cpu_distribution_map[i] = iterate_cpu(cpuinfo_tree, 0);
}
/* Fallback if the cpuinfo tree could not be built. CPU mapping is linear
* round robin.
*/
static int simple_map_to_cpu(unsigned int index)
{
int i, end, cpu_rover;
cpu_rover = 0;
end = index % num_online_cpus();
for (i = 0; i < num_possible_cpus(); i++) {
if (cpu_online(cpu_rover)) {
if (cpu_rover >= end)
return cpu_rover;
cpu_rover++;
}
}
/* Impossible, since num_online_cpus() <= num_possible_cpus() */
return cpumask_first(cpu_online_mask);
}
static int _map_to_cpu(unsigned int index)
{
struct cpuinfo_node *root_node;
if (unlikely(!cpuinfo_tree)) {
_cpu_map_rebuild();
if (!cpuinfo_tree)
return simple_map_to_cpu(index);
}
root_node = &cpuinfo_tree->nodes[0];
#ifdef CONFIG_HOTPLUG_CPU
if (unlikely(root_node->num_cpus != num_online_cpus())) {
_cpu_map_rebuild();
if (!cpuinfo_tree)
return simple_map_to_cpu(index);
}
#endif
return cpu_distribution_map[index % root_node->num_cpus];
}
int map_to_cpu(unsigned int index)
{
int mapped_cpu;
unsigned long flag;
spin_lock_irqsave(&cpu_map_lock, flag);
mapped_cpu = _map_to_cpu(index);
#ifdef CONFIG_HOTPLUG_CPU
while (unlikely(!cpu_online(mapped_cpu)))
mapped_cpu = _map_to_cpu(index);
#endif
spin_unlock_irqrestore(&cpu_map_lock, flag);
return mapped_cpu;
}
EXPORT_SYMBOL(map_to_cpu);
void cpu_map_rebuild(void)
{
unsigned long flag;
spin_lock_irqsave(&cpu_map_lock, flag);
_cpu_map_rebuild();
spin_unlock_irqrestore(&cpu_map_lock, flag);
}