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7644d5819c
powerpc_debugfs_root is the dentry representing the root of the "powerpc" directory tree in debugfs. Currently it sits in asm/debug.h, a long with some other things that have "debug" in the name, but are otherwise unrelated. Pull it out into a separate header, which also includes linux/debugfs.h, and convert all the users to include debugfs.h instead of debug.h. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
395 lines
8.5 KiB
C
395 lines
8.5 KiB
C
/*
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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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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <asm/smp.h>
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#include <linux/uaccess.h>
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#include <asm/firmware.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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#include <asm/machdep.h>
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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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spinlock_t lock;
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};
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static DEFINE_PER_CPU(struct dtl, cpu_dtl);
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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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/*
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* Size of per-cpu log buffers. Firmware requires that the buffer does
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* not cross a 4k boundary.
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*/
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static int dtl_buf_entries = N_DISPATCH_LOG;
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
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struct dtl_ring {
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u64 write_index;
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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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};
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static DEFINE_PER_CPU(struct dtl_ring, dtl_rings);
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static atomic_t dtl_count;
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/*
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* The cpu accounting code controls the DTL ring buffer, and we get
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* given entries as they are processed.
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*/
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static void consume_dtle(struct dtl_entry *dtle, u64 index)
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{
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struct dtl_ring *dtlr = this_cpu_ptr(&dtl_rings);
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struct dtl_entry *wp = dtlr->write_ptr;
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struct lppaca *vpa = local_paca->lppaca_ptr;
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if (!wp)
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return;
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*wp = *dtle;
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barrier();
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/* check for hypervisor ring buffer overflow, ignore this entry if so */
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if (index + N_DISPATCH_LOG < be64_to_cpu(vpa->dtl_idx))
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return;
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++wp;
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if (wp == dtlr->buf_end)
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wp = dtlr->buf;
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dtlr->write_ptr = wp;
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/* incrementing write_index makes the new entry visible */
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smp_wmb();
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++dtlr->write_index;
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}
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static int dtl_start(struct dtl *dtl)
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{
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struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu);
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dtlr->buf = dtl->buf;
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dtlr->buf_end = dtl->buf + dtl->buf_entries;
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dtlr->write_index = 0;
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/* setting write_ptr enables logging into our buffer */
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smp_wmb();
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dtlr->write_ptr = dtl->buf;
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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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dtl_consumer = consume_dtle;
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atomic_inc(&dtl_count);
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return 0;
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}
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static void dtl_stop(struct dtl *dtl)
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{
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struct dtl_ring *dtlr = &per_cpu(dtl_rings, dtl->cpu);
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dtlr->write_ptr = NULL;
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smp_wmb();
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dtlr->buf = NULL;
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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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if (atomic_dec_and_test(&dtl_count))
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dtl_consumer = NULL;
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}
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static u64 dtl_current_index(struct dtl *dtl)
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{
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return per_cpu(dtl_rings, dtl->cpu).write_index;
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}
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#else /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
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static int dtl_start(struct dtl *dtl)
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{
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unsigned long addr;
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int ret, hwcpu;
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/* Register our dtl buffer with the hypervisor. The HV expects the
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* buffer size to be passed in the second word of the buffer */
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((u32 *)dtl->buf)[1] = DISPATCH_LOG_BYTES;
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hwcpu = get_hard_smp_processor_id(dtl->cpu);
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addr = __pa(dtl->buf);
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ret = register_dtl(hwcpu, addr);
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if (ret) {
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printk(KERN_WARNING "%s: DTL registration for cpu %d (hw %d) "
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"failed with %d\n", __func__, dtl->cpu, hwcpu, ret);
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return -EIO;
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}
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/* set our initial buffer indices */
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lppaca_of(dtl->cpu).dtl_idx = 0;
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/* ensure that our updates to the lppaca fields have occurred before
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* we actually enable the logging */
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smp_wmb();
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/* enable event logging */
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lppaca_of(dtl->cpu).dtl_enable_mask = dtl_event_mask;
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return 0;
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}
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static void dtl_stop(struct dtl *dtl)
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{
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int hwcpu = get_hard_smp_processor_id(dtl->cpu);
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lppaca_of(dtl->cpu).dtl_enable_mask = 0x0;
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unregister_dtl(hwcpu);
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}
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static u64 dtl_current_index(struct dtl *dtl)
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{
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return lppaca_of(dtl->cpu).dtl_idx;
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}
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#endif /* CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
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static int dtl_enable(struct dtl *dtl)
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{
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long int n_entries;
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long int rc;
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struct dtl_entry *buf = NULL;
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if (!dtl_cache)
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return -ENOMEM;
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/* only allow one reader */
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if (dtl->buf)
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return -EBUSY;
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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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return -ENOMEM;
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}
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spin_lock(&dtl->lock);
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rc = -EBUSY;
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if (!dtl->buf) {
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/* store the original allocation size for use during read */
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dtl->buf_entries = n_entries;
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dtl->buf = buf;
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dtl->last_idx = 0;
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rc = dtl_start(dtl);
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if (rc)
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dtl->buf = NULL;
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}
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spin_unlock(&dtl->lock);
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if (rc)
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kmem_cache_free(dtl_cache, buf);
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return rc;
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}
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static void dtl_disable(struct dtl *dtl)
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{
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spin_lock(&dtl->lock);
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dtl_stop(dtl);
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kmem_cache_free(dtl_cache, dtl->buf);
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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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}
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/* file interface */
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static int dtl_file_open(struct inode *inode, struct file *filp)
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{
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struct dtl *dtl = inode->i_private;
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int rc;
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rc = dtl_enable(dtl);
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if (rc)
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return rc;
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filp->private_data = dtl;
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return 0;
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}
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static int dtl_file_release(struct inode *inode, struct file *filp)
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{
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struct dtl *dtl = inode->i_private;
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dtl_disable(dtl);
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return 0;
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}
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static ssize_t dtl_file_read(struct file *filp, char __user *buf, size_t len,
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loff_t *pos)
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{
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long int rc, n_read, n_req, read_size;
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struct dtl *dtl;
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u64 cur_idx, last_idx, i;
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if ((len % sizeof(struct dtl_entry)) != 0)
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return -EINVAL;
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dtl = filp->private_data;
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/* requested number of entries to read */
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n_req = len / sizeof(struct dtl_entry);
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/* actual number of entries read */
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n_read = 0;
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spin_lock(&dtl->lock);
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cur_idx = dtl_current_index(dtl);
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last_idx = dtl->last_idx;
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if (last_idx + dtl->buf_entries <= cur_idx)
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last_idx = cur_idx - dtl->buf_entries + 1;
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if (last_idx + n_req > cur_idx)
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n_req = cur_idx - last_idx;
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if (n_req > 0)
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dtl->last_idx = last_idx + n_req;
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spin_unlock(&dtl->lock);
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if (n_req <= 0)
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return 0;
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i = last_idx % dtl->buf_entries;
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/* read the tail of the buffer if we've wrapped */
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if (i + n_req > dtl->buf_entries) {
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read_size = dtl->buf_entries - i;
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rc = copy_to_user(buf, &dtl->buf[i],
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read_size * sizeof(struct dtl_entry));
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if (rc)
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return -EFAULT;
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i = 0;
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n_req -= read_size;
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n_read += read_size;
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buf += read_size * sizeof(struct dtl_entry);
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}
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/* .. and now the head */
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rc = copy_to_user(buf, &dtl->buf[i], n_req * sizeof(struct dtl_entry));
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if (rc)
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return -EFAULT;
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n_read += n_req;
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return n_read * sizeof(struct dtl_entry);
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}
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static const struct file_operations dtl_fops = {
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.open = dtl_file_open,
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.release = dtl_file_release,
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.read = dtl_file_read,
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.llseek = no_llseek,
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};
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static struct dentry *dtl_dir;
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static int dtl_setup_file(struct dtl *dtl)
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{
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char name[10];
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sprintf(name, "cpu-%d", dtl->cpu);
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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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return 0;
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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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if (!firmware_has_feature(FW_FEATURE_SPLPAR))
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return -ENODEV;
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/* set up common debugfs structure */
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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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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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/* set up the per-cpu log structures */
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for_each_possible_cpu(i) {
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struct dtl *dtl = &per_cpu(cpu_dtl, i);
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spin_lock_init(&dtl->lock);
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dtl->cpu = i;
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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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}
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return 0;
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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);
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