arch/i386/kernel/vsyscall-note.S

   1 /*
   2  * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text.
   3  * Here we can supply some information useful to userland.
   4  */
   5
   6 #include <linux/version.h>
   7 #include <linux/elfnote.h>
   8
   9 /* Ideally this would use UTS_NAME, but using a quoted string here
  10    doesn't work. Remember to change this when changing the
  11    kernel's name. */
  12 ELFNOTE_START(Linux, 0, "a")
  13         .long LINUX_VERSION_CODE
  14 ELFNOTE_END
  15
  16 #ifdef CONFIG_XEN
  17
  18 /*
  19  * Add a special note telling glibc's dynamic linker a fake hardware
  20  * flavor that it will use to choose the search path for libraries in the
  21  * same way it uses real hardware capabilities like "mmx".
  22  * We supply "nosegneg" as the fake capability, to indicate that we
  23  * do not like negative offsets in instructions using segment overrides,
  24  * since we implement those inefficiently.  This makes it possible to
  25  * install libraries optimized to avoid those access patterns in someplace
  26  * like /lib/i686/tls/nosegneg.  Note that an /etc/ld.so.conf.d/file
  27  * corresponding to the bits here is needed to make ldconfig work right.
  28  * It should contain:
  29  *      hwcap 1 nosegneg
  30  * to match the mapping of bit to name that we give here.
  31  */
  32
  33 /* Bit used for the pseudo-hwcap for non-negative segments.  We use
  34    bit 1 to avoid bugs in some versions of glibc when bit 0 is
  35    used; the choice is otherwise arbitrary. */
  36 #define VDSO_NOTE_NONEGSEG_BIT  1
  37
  38 ELFNOTE_START(GNU, 2, "a")
  39         .long 1, 1<<VDSO_NOTE_NONEGSEG_BIT              /* ncaps, mask */
  40         .byte VDSO_NOTE_NONEGSEG_BIT; .asciz "nosegneg" /* bit, name */
  41 ELFNOTE_END
  42 #endif