Re: [Xen-devel] [PATCH v2 1/6] xen: xensyms support

[Dietmar Hahn <dietmar.hahn@xxxxxxxxxxxxxx>]

Am Freitag 06 Juni 2014, 13:44:41 schrieb Boris Ostrovsky:
> Export Xen symbols to dom0 via /proc/xen/xensyms (similar to /proc/kallsyms).
> 
> Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> ---
>  drivers/xen/Kconfig              |   5 ++
>  drivers/xen/xenfs/Makefile       |   1 +
>  drivers/xen/xenfs/super.c        |   3 +
>  drivers/xen/xenfs/xenfs.h        |   1 +
>  drivers/xen/xenfs/xensyms.c      | 124 
> +++++++++++++++++++++++++++++++++++++++
>  include/xen/interface/platform.h |  19 ++++++
>  6 files changed, 153 insertions(+)
>  create mode 100644 drivers/xen/xenfs/xensyms.c
> 
> diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
> index 38fb36e..b3d1da7 100644
> --- a/drivers/xen/Kconfig
> +++ b/drivers/xen/Kconfig
> @@ -240,4 +240,9 @@ config XEN_MCE_LOG
>  config XEN_HAVE_PVMMU
>         bool
>  
> +config XEN_SYMS
> +       bool "Xen symbols"
> +       depends on XEN_DOM0 && XENFS
> +       default y if KALLSYMS
> +
>  endmenu
> diff --git a/drivers/xen/xenfs/Makefile b/drivers/xen/xenfs/Makefile
> index b019865..1a83010 100644
> --- a/drivers/xen/xenfs/Makefile
> +++ b/drivers/xen/xenfs/Makefile
> @@ -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
> diff --git a/drivers/xen/xenfs/super.c b/drivers/xen/xenfs/super.c
> index 06092e0..8559a71 100644
> --- a/drivers/xen/xenfs/super.c
> +++ b/drivers/xen/xenfs/super.c
> @@ -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
>               {""},
>       };
>  
> diff --git a/drivers/xen/xenfs/xenfs.h b/drivers/xen/xenfs/xenfs.h
> index 6b80c77..2c5934e 100644
> --- a/drivers/xen/xenfs/xenfs.h
> +++ b/drivers/xen/xenfs/xenfs.h
> @@ -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 */
> diff --git a/drivers/xen/xenfs/xensyms.c b/drivers/xen/xenfs/xensyms.c
> new file mode 100644
> index 0000000..748948c
> --- /dev/null
> +++ b/drivers/xen/xenfs/xensyms.c
> @@ -0,0 +1,124 @@
> +#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 */
> +
> +
> +/* Grab next output page from the hypervisor */
> +static int xensyms_next_sym(struct xen_platform_op *op)
> +{
> +     int ret;
> +     uint64_t symnum = op->u.symdata.symnum;
> +
> +     memset(op->u.symdata.name, 0, XEN_KSYM_NAME_LEN + 1);
> +
> +     ret = HYPERVISOR_dom0_op(op);
> +     if (ret < 0)
> +             return ret;
> +
> +     if (op->u.symdata.symnum == symnum)
> +             /* End of symbols */
> +             return 1;
> +
> +     return 0;
> +}
> +
> +static void *xensyms_start(struct seq_file *m, loff_t *pos)
> +{
> +     struct xen_platform_op *op = (struct xen_platform_op *)m->private;
> +
> +     if (op->u.symdata.symnum != *pos)
> +             op->u.symdata.symnum = *pos;
> +
> +     if (xensyms_next_sym(op))
> +             return NULL;
> +
> +     return m->private;
> +}
> +
> +static void *xensyms_next(struct seq_file *m, void *p, loff_t *pos)
> +{
> +     struct xen_platform_op *op = (struct xen_platform_op *)m->private;
> +
> +     (*pos)++;
> +
> +     if (op->u.symdata.symnum != *pos)
> +             op->u.symdata.symnum = *pos;
> +
> +     if (xensyms_next_sym(op))
> +             return NULL;
> +
> +     return p;
> +}
> +
> +static int xensyms_show(struct seq_file *m, void *p)
> +{
> +     struct xen_platform_op *op = (struct xen_platform_op *)m->private;
> +
> +     seq_printf(m, "%016llx %c %s\n", op->u.symdata.address,
> +                op->u.symdata.type, op->u.symdata.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 xen_platform_op *op;
> +     char *buf;
> +     int ret;
> +
> +     buf = kzalloc(XEN_KSYM_NAME_LEN + 1, GFP_KERNEL);
> +     if (!buf)
> +             return -ENOMEM;
> +
> +     ret = seq_open_private(file, &xensyms_seq_ops,
> +             sizeof(struct xen_platform_op));
> +     if (ret)
> +             return ret;

kfree(buf) in error case?

Dietmar.

> +     m = file->private_data;
> +     op = (struct xen_platform_op *)m->private;
> +     set_xen_guest_handle(op->u.symdata.name, buf);
> +     op->cmd = XENPF_get_symbol;
> +     op->u.symdata.namelen = XEN_KSYM_NAME_LEN + 1;
> +
> +     return 0;
> +}
> +
> +static int xensyms_release(struct inode *inode, struct file *file)
> +{
> +     struct seq_file *m = file->private_data;
> +     struct xen_platform_op *op = (struct xen_platform_op *)m->private;
> +
> +     kfree(op->u.symdata.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
> +};
> diff --git a/include/xen/interface/platform.h 
> b/include/xen/interface/platform.h
> index f1331e3..792e29a 100644
> --- a/include/xen/interface/platform.h
> +++ b/include/xen/interface/platform.h
> @@ -352,6 +352,24 @@ struct xenpf_core_parking {
>  };
>  DEFINE_GUEST_HANDLE_STRUCT(xenpf_core_parking);
>  
> +#define XENPF_get_symbol      61
> +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 */
> +     char type;
> +     uint64_t address;
> +     GUEST_HANDLE(char) name;
> +};
> +DEFINE_GUEST_HANDLE_STRUCT(xenpf_symdata);
> +
> +
>  struct xen_platform_op {
>       uint32_t cmd;
>       uint32_t interface_version; /* XENPF_INTERFACE_VERSION */
> @@ -372,6 +390,7 @@ 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;
>  };
> 

-- 
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