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5c4e79e29a
The interface specifies the symnum field as an input and output; the
hypervisor sets it to the next sequential symbol's index. xensyms_next()
incrementing the position explicitly (and xensyms_next_sym()
decrementing it to "rewind") is only correct as long as the sequence of
symbol indexes is non-sparse. Use the hypervisor-supplied value instead
to update the position in xensyms_next(), and use the saved incoming
index in xensyms_next_sym().
Cc: stable@kernel.org
Fixes: a11f4f0a4e ("xen: xensyms support")
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Message-ID: <15d5e7fa-ec5d-422f-9319-d28bed916349@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
152 lines
3 KiB
C
152 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/init.h>
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#include <linux/seq_file.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/proc_fs.h>
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#include <linux/slab.h>
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#include <xen/interface/platform.h>
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#include <asm/xen/hypercall.h>
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#include <xen/xen-ops.h>
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#include "xenfs.h"
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#define XEN_KSYM_NAME_LEN 127 /* Hypervisor may have different name length */
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struct xensyms {
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struct xen_platform_op op;
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char *name;
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uint32_t namelen;
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};
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/* Grab next output page from the hypervisor */
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static int xensyms_next_sym(struct xensyms *xs)
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{
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int ret;
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struct xenpf_symdata *symdata = &xs->op.u.symdata;
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uint64_t symnum;
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memset(xs->name, 0, xs->namelen);
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symdata->namelen = xs->namelen;
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symnum = symdata->symnum;
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ret = HYPERVISOR_platform_op(&xs->op);
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if (ret < 0)
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return ret;
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/*
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* If hypervisor's symbol didn't fit into the buffer then allocate
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* a larger buffer and try again.
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*/
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if (unlikely(symdata->namelen > xs->namelen)) {
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kfree(xs->name);
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xs->namelen = symdata->namelen;
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xs->name = kzalloc(xs->namelen, GFP_KERNEL);
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if (!xs->name)
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return -ENOMEM;
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set_xen_guest_handle(symdata->name, xs->name);
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symdata->symnum = symnum; /* Rewind */
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ret = HYPERVISOR_platform_op(&xs->op);
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if (ret < 0)
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return ret;
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}
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if (symdata->symnum == symnum)
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/* End of symbols */
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return 1;
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return 0;
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}
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static void *xensyms_start(struct seq_file *m, loff_t *pos)
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{
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struct xensyms *xs = m->private;
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xs->op.u.symdata.symnum = *pos;
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if (xensyms_next_sym(xs))
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return NULL;
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return m->private;
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}
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static void *xensyms_next(struct seq_file *m, void *p, loff_t *pos)
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{
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struct xensyms *xs = m->private;
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*pos = xs->op.u.symdata.symnum;
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if (xensyms_next_sym(xs))
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return NULL;
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return p;
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}
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static int xensyms_show(struct seq_file *m, void *p)
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{
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struct xensyms *xs = m->private;
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struct xenpf_symdata *symdata = &xs->op.u.symdata;
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seq_printf(m, "%016llx %c %s\n", symdata->address,
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symdata->type, xs->name);
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return 0;
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}
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static void xensyms_stop(struct seq_file *m, void *p)
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{
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}
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static const struct seq_operations xensyms_seq_ops = {
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.start = xensyms_start,
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.next = xensyms_next,
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.show = xensyms_show,
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.stop = xensyms_stop,
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};
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static int xensyms_open(struct inode *inode, struct file *file)
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{
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struct seq_file *m;
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struct xensyms *xs;
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int ret;
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ret = seq_open_private(file, &xensyms_seq_ops,
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sizeof(struct xensyms));
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if (ret)
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return ret;
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m = file->private_data;
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xs = m->private;
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xs->namelen = XEN_KSYM_NAME_LEN + 1;
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xs->name = kzalloc(xs->namelen, GFP_KERNEL);
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if (!xs->name) {
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seq_release_private(inode, file);
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return -ENOMEM;
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}
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set_xen_guest_handle(xs->op.u.symdata.name, xs->name);
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xs->op.cmd = XENPF_get_symbol;
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xs->op.u.symdata.namelen = xs->namelen;
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return 0;
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}
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static int xensyms_release(struct inode *inode, struct file *file)
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{
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struct seq_file *m = file->private_data;
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struct xensyms *xs = m->private;
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kfree(xs->name);
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return seq_release_private(inode, file);
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}
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const struct file_operations xensyms_ops = {
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.open = xensyms_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = xensyms_release
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};
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