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/******************************************************************************
* common/trace.c
*
* Xen Trace Buffer
*
* Copyright (C) 2004 by Intel Research Cambridge
*
* Author: Mark Williamson, mark.a.williamson@intel.com
* Date: January 2004
*
* The trace buffer code is designed to allow debugging traces of Xen to be
* generated on UP / SMP machines. Each trace entry is timestamped so that
* it's possible to reconstruct a chronological record of trace events.
*
* See also include/xen/trace.h and the dom0 op in
* include/hypervisor-ifs/dom0_ops.h
*/
#include <xen/config.h>
#include <asm/types.h>
#include <asm/io.h>
#include <xen/lib.h>
#include <xen/sched.h>
#include <xen/slab.h>
#include <xen/smp.h>
#include <xen/trace.h>
#include <xen/errno.h>
#include <asm/atomic.h>
#include <hypervisor-ifs/dom0_ops.h>
/* Pointers to the meta-data objects for all system trace buffers */
struct t_buf *t_bufs[NR_CPUS];
/* a flag recording whether initialisation has been done */
int tb_init_done = 0;
/**
* init_trace_bufs - performs initialisation of the per-cpu trace buffers.
*
* This function is called at start of day in order to initialise the per-cpu
* trace buffers. The trace buffers are then available for debugging use, via
* the %TRACE_xD macros exported in <xen/trace.h>.
*/
void init_trace_bufs(void)
{
extern int opt_tbuf_size;
int i, order;
unsigned long nr_pages;
char *rawbuf;
struct t_buf *buf;
struct domain *dom0;
if ( opt_tbuf_size == 0 )
{
printk("Xen trace buffers: disabled\n");
return;
}
nr_pages = smp_num_cpus * opt_tbuf_size;
order = get_order(nr_pages * PAGE_SIZE);
if ( (rawbuf = (char *)alloc_xenheap_pages(order)) == NULL )
{
printk("Xen trace buffers: memory allocation failed\n");
return;
}
/* Share pages so that xentrace can map them. */
dom0 = find_domain_by_id(0);
for( i = 0; i < nr_pages; i++)
SHARE_PFN_WITH_DOMAIN(virt_to_page(rawbuf+(i*PAGE_SIZE)), dom0);
put_domain(dom0);
for ( i = 0; i < smp_num_cpus; i++ )
{
buf = t_bufs[i] = (struct t_buf *)&rawbuf[i*opt_tbuf_size*PAGE_SIZE];
/* For use in Xen. */
buf->vdata = (struct t_rec *)(buf+1);
buf->head_ptr = buf->vdata;
/* For use in user space. */
buf->data = __pa(buf->vdata);
buf->head = 0;
/* For use in both. */
buf->size = (opt_tbuf_size * PAGE_SIZE - sizeof(struct t_buf))
/ sizeof(struct t_rec);
}
printk("Xen trace buffers: initialised\n");
wmb(); /* above must be visible before tb_init_done flag set */
tb_init_done = 1;
}
/**
* get_tb_info - get trace buffer details
* @st: a pointer to a dom0_gettbufs_t to be filled out
*
* Called by the %DOM0_GETTBUFS dom0 op to fetch the machine address of the
* trace buffers.
*/
int get_tb_info(dom0_gettbufs_t *st)
{
if(tb_init_done)
{
extern unsigned int opt_tbuf_size;
st->mach_addr = __pa(t_bufs[0]);
st->size = opt_tbuf_size * PAGE_SIZE;
return 0;
}
else
{
st->mach_addr = 0;
st->size = 0;
return -ENODATA;
}
}
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