xen: xensyms support

Export Xen symbols to dom0 via /proc/xen/xensyms (similar to
/proc/kallsyms).

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
This commit is contained in:
Boris Ostrovsky 2015-08-10 16:34:32 -04:00 committed by David Vrabel
parent cb3eb85013
commit a11f4f0a4e
6 changed files with 183 additions and 0 deletions

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@ -280,4 +280,12 @@ config XEN_ACPI
def_bool y
depends on X86 && ACPI
config XEN_SYMS
bool "Xen symbols"
depends on X86 && XEN_DOM0 && XENFS
default y if KALLSYMS
help
Exports hypervisor symbols (along with their types and addresses) via
/proc/xen/xensyms file, similar to /proc/kallsyms
endmenu

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@ -2,3 +2,4 @@ obj-$(CONFIG_XENFS) += xenfs.o
xenfs-y = super.o
xenfs-$(CONFIG_XEN_DOM0) += xenstored.o
xenfs-$(CONFIG_XEN_SYMS) += xensyms.o

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@ -57,6 +57,9 @@ static int xenfs_fill_super(struct super_block *sb, void *data, int silent)
{ "privcmd", &xen_privcmd_fops, S_IRUSR|S_IWUSR },
{ "xsd_kva", &xsd_kva_file_ops, S_IRUSR|S_IWUSR},
{ "xsd_port", &xsd_port_file_ops, S_IRUSR|S_IWUSR},
#ifdef CONFIG_XEN_SYMS
{ "xensyms", &xensyms_ops, S_IRUSR},
#endif
{""},
};

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@ -3,5 +3,6 @@
extern const struct file_operations xsd_kva_file_ops;
extern const struct file_operations xsd_port_file_ops;
extern const struct file_operations xensyms_ops;
#endif /* _XENFS_XENBUS_H */

152
drivers/xen/xenfs/xensyms.c Normal file
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@ -0,0 +1,152 @@
#include <linux/module.h>
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <xen/interface/platform.h>
#include <asm/xen/hypercall.h>
#include <xen/xen-ops.h>
#include "xenfs.h"
#define XEN_KSYM_NAME_LEN 127 /* Hypervisor may have different name length */
struct xensyms {
struct xen_platform_op op;
char *name;
uint32_t namelen;
};
/* Grab next output page from the hypervisor */
static int xensyms_next_sym(struct xensyms *xs)
{
int ret;
struct xenpf_symdata *symdata = &xs->op.u.symdata;
uint64_t symnum;
memset(xs->name, 0, xs->namelen);
symdata->namelen = xs->namelen;
symnum = symdata->symnum;
ret = HYPERVISOR_dom0_op(&xs->op);
if (ret < 0)
return ret;
/*
* If hypervisor's symbol didn't fit into the buffer then allocate
* a larger buffer and try again.
*/
if (unlikely(symdata->namelen > xs->namelen)) {
kfree(xs->name);
xs->namelen = symdata->namelen;
xs->name = kzalloc(xs->namelen, GFP_KERNEL);
if (!xs->name)
return -ENOMEM;
set_xen_guest_handle(symdata->name, xs->name);
symdata->symnum--; /* Rewind */
ret = HYPERVISOR_dom0_op(&xs->op);
if (ret < 0)
return ret;
}
if (symdata->symnum == symnum)
/* End of symbols */
return 1;
return 0;
}
static void *xensyms_start(struct seq_file *m, loff_t *pos)
{
struct xensyms *xs = (struct xensyms *)m->private;
xs->op.u.symdata.symnum = *pos;
if (xensyms_next_sym(xs))
return NULL;
return m->private;
}
static void *xensyms_next(struct seq_file *m, void *p, loff_t *pos)
{
struct xensyms *xs = (struct xensyms *)m->private;
xs->op.u.symdata.symnum = ++(*pos);
if (xensyms_next_sym(xs))
return NULL;
return p;
}
static int xensyms_show(struct seq_file *m, void *p)
{
struct xensyms *xs = (struct xensyms *)m->private;
struct xenpf_symdata *symdata = &xs->op.u.symdata;
seq_printf(m, "%016llx %c %s\n", symdata->address,
symdata->type, xs->name);
return 0;
}
static void xensyms_stop(struct seq_file *m, void *p)
{
}
static const struct seq_operations xensyms_seq_ops = {
.start = xensyms_start,
.next = xensyms_next,
.show = xensyms_show,
.stop = xensyms_stop,
};
static int xensyms_open(struct inode *inode, struct file *file)
{
struct seq_file *m;
struct xensyms *xs;
int ret;
ret = seq_open_private(file, &xensyms_seq_ops,
sizeof(struct xensyms));
if (ret)
return ret;
m = file->private_data;
xs = (struct xensyms *)m->private;
xs->namelen = XEN_KSYM_NAME_LEN + 1;
xs->name = kzalloc(xs->namelen, GFP_KERNEL);
if (!xs->name) {
seq_release_private(inode, file);
return -ENOMEM;
}
set_xen_guest_handle(xs->op.u.symdata.name, xs->name);
xs->op.cmd = XENPF_get_symbol;
xs->op.u.symdata.namelen = xs->namelen;
return 0;
}
static int xensyms_release(struct inode *inode, struct file *file)
{
struct seq_file *m = file->private_data;
struct xensyms *xs = (struct xensyms *)m->private;
kfree(xs->name);
return seq_release_private(inode, file);
}
const struct file_operations xensyms_ops = {
.open = xensyms_open,
.read = seq_read,
.llseek = seq_lseek,
.release = xensyms_release
};

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@ -474,6 +474,23 @@ struct xenpf_core_parking {
};
DEFINE_GUEST_HANDLE_STRUCT(xenpf_core_parking);
#define XENPF_get_symbol 63
struct xenpf_symdata {
/* IN/OUT variables */
uint32_t namelen; /* size of 'name' buffer */
/* IN/OUT variables */
uint32_t symnum; /* IN: Symbol to read */
/* OUT: Next available symbol. If same as IN */
/* then we reached the end */
/* OUT variables */
GUEST_HANDLE(char) name;
uint64_t address;
char type;
};
DEFINE_GUEST_HANDLE_STRUCT(xenpf_symdata);
struct xen_platform_op {
uint32_t cmd;
uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
@ -495,6 +512,7 @@ struct xen_platform_op {
struct xenpf_cpu_hotadd cpu_add;
struct xenpf_mem_hotadd mem_add;
struct xenpf_core_parking core_parking;
struct xenpf_symdata symdata;
uint8_t pad[128];
} u;
};