add dts config

hc

2023-12-06 08f87f769b595151be1afeff53e144f543faa614

 kernel/arch/powerpc/platforms/pseries/dtl.c
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..
@@ -1,23 +1,10 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /*
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  * Virtual Processor Dispatch Trace Log
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  *
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  * (C) Copyright IBM Corporation 2009
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  *
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  * Author: Jeremy Kerr <jk@ozlabs.org>
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- *
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- * This program is free software; you can redistribute it and/or modify
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- * it under the terms of the GNU General Public License as published by
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- * the Free Software Foundation; either version 2, or (at your option)
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- * any later version.
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- *
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- * This program is distributed in the hope that it will be useful,
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- * but WITHOUT ANY WARRANTY; without even the implied warranty of
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- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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- * GNU General Public License for more details.
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- *
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- * You should have received a copy of the GNU General Public License
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- * along with this program; if not, write to the Free Software
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- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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  */
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9
 
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10
 #include <linux/slab.h>
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..
@@ -25,6 +12,7 @@
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12
 #include <asm/smp.h>
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 #include <linux/uaccess.h>
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14
 #include <asm/firmware.h>
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+#include <asm/dtl.h>
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 #include <asm/lppaca.h>
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 #include <asm/debugfs.h>
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 #include <asm/plpar_wrappers.h>
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..
@@ -32,7 +20,6 @@
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20
 
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 struct dtl {
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 	struct dtl_entry	*buf;
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-	struct dentry		*file;
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 	int			cpu;
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 	int			buf_entries;
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 	u64			last_idx;
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..
@@ -40,13 +27,7 @@
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 };
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 static DEFINE_PER_CPU(struct dtl, cpu_dtl);
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29
 
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-/*
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- * Dispatch trace log event mask:
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- * 0x7: 0x1: voluntary virtual processor waits
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- *      0x2: time-slice preempts
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- *      0x4: virtual partition memory page faults
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- */
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-static u8 dtl_event_mask = 0x7;
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+static u8 dtl_event_mask = DTL_LOG_ALL;
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31
 
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32
 
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 /*
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..
@@ -61,7 +42,6 @@
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 	struct dtl_entry *write_ptr;
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 	struct dtl_entry *buf;
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 	struct dtl_entry *buf_end;
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-	u8	saved_dtl_mask;
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45
 };
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46
 
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 static DEFINE_PER_CPU(struct dtl_ring, dtl_rings);
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..
@@ -111,7 +91,6 @@
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 	dtlr->write_ptr = dtl->buf;
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92
 
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 	/* enable event logging */
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-	dtlr->saved_dtl_mask = lppaca_of(dtl->cpu).dtl_enable_mask;
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 	lppaca_of(dtl->cpu).dtl_enable_mask |= dtl_event_mask;
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95
 
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 	dtl_consumer = consume_dtle;
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..
@@ -129,7 +108,7 @@
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108
 	dtlr->buf = NULL;
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109
 
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 	/* restore dtl_enable_mask */
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-	lppaca_of(dtl->cpu).dtl_enable_mask = dtlr->saved_dtl_mask;
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+	lppaca_of(dtl->cpu).dtl_enable_mask = DTL_LOG_PREEMPT;
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112
 
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 	if (atomic_dec_and_test(&dtl_count))
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114
 		dtl_consumer = NULL;
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@@ -201,11 +180,16 @@
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 	if (dtl->buf)
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 		return -EBUSY;
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182
 
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+	/* ensure there are no other conflicting dtl users */
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+	if (!read_trylock(&dtl_access_lock))
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+		return -EBUSY;
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+
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 	n_entries = dtl_buf_entries;
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 	buf = kmem_cache_alloc_node(dtl_cache, GFP_KERNEL, cpu_to_node(dtl->cpu));
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 	if (!buf) {
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 		printk(KERN_WARNING "%s: buffer alloc failed for cpu %d\n",
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 				__func__, dtl->cpu);
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+		read_unlock(&dtl_access_lock);
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 		return -ENOMEM;
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 	}
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195
 
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@@ -222,8 +206,11 @@
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206
 	}
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 	spin_unlock(&dtl->lock);
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208
 
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-	if (rc)
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+	if (rc) {
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+		read_unlock(&dtl_access_lock);
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211
 		kmem_cache_free(dtl_cache, buf);
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+	}
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+
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 	return rc;
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 }
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@@ -235,6 +222,7 @@
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 	dtl->buf = NULL;
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 	dtl->buf_entries = 0;
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 	spin_unlock(&dtl->lock);
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+	read_unlock(&dtl_access_lock);
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 }
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227
 
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 /* file interface */
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@@ -332,46 +320,28 @@
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320
 
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 static struct dentry *dtl_dir;
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322
 
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-static int dtl_setup_file(struct dtl *dtl)
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+static void dtl_setup_file(struct dtl *dtl)
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 {
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 	char name[10];
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326
 
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 	sprintf(name, "cpu-%d", dtl->cpu);
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328
 
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-	dtl->file = debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops);
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-	if (!dtl->file)
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-		return -ENOMEM;
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-
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-	return 0;
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+	debugfs_create_file(name, 0400, dtl_dir, dtl, &dtl_fops);
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 }
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 static int dtl_init(void)
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 {
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-	struct dentry *event_mask_file, *buf_entries_file;
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-	int rc, i;
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+	int i;
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 	if (!firmware_has_feature(FW_FEATURE_SPLPAR))
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 		return -ENODEV;
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338
 
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 	/* set up common debugfs structure */
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340
 
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-	rc = -ENOMEM;
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 	dtl_dir = debugfs_create_dir("dtl", powerpc_debugfs_root);
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-	if (!dtl_dir) {
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-		printk(KERN_WARNING "%s: can't create dtl root dir\n",
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-				__func__);
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-		goto err;
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-	}
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-	event_mask_file = debugfs_create_x8("dtl_event_mask", 0600,
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-				dtl_dir, &dtl_event_mask);
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-	buf_entries_file = debugfs_create_u32("dtl_buf_entries", 0400,
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-				dtl_dir, &dtl_buf_entries);
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-
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-	if (!event_mask_file || !buf_entries_file) {
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-		printk(KERN_WARNING "%s: can't create dtl files\n", __func__);
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-		goto err_remove_dir;
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-	}
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+	debugfs_create_x8("dtl_event_mask", 0600, dtl_dir, &dtl_event_mask);
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+	debugfs_create_u32("dtl_buf_entries", 0400, dtl_dir, &dtl_buf_entries);
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345
 
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 	/* set up the per-cpu log structures */
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 	for_each_possible_cpu(i) {
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@@ -379,16 +349,9 @@
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 		spin_lock_init(&dtl->lock);
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 		dtl->cpu = i;
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351
 
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-		rc = dtl_setup_file(dtl);
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-		if (rc)
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-			goto err_remove_dir;
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+		dtl_setup_file(dtl);
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 	}
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354
 
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 	return 0;
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-
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-err_remove_dir:
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-	debugfs_remove_recursive(dtl_dir);
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-err:
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-	return rc;
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 }
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 machine_arch_initcall(pseries, dtl_init);