direct-io.hg

view linux-2.6-xen-sparse/arch/i386/kernel/vsyscall-note-xen.S @ 14421:98eacf1b075c

Fix up nosegneg vsyscall elfnote.
Signed-off-by: Keir Fraser <keir@xensource.com>
author Keir Fraser <keir@xensource.com>
date Sat Mar 17 12:24:32 2007 +0000 (2007-03-17)
parents fd9b2c1bb577
children
line source
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 * First we get the vanilla i386 note that supplies the kernel version info.
5 */
7 #include "vsyscall-note.S"
9 /*
10 * Now we add a special note telling glibc's dynamic linker a fake hardware
11 * flavor that it will use to choose the search path for libraries in the
12 * same way it uses real hardware capabilities like "mmx".
13 * We supply "nosegneg" as the fake capability, to indicate that we
14 * do not like negative offsets in instructions using segment overrides,
15 * since we implement those inefficiently. This makes it possible to
16 * install libraries optimized to avoid those access patterns in someplace
17 * like /lib/i686/tls/nosegneg. Note that an /etc/ld.so.conf.d/file
18 * corresponding to the bits here is needed to make ldconfig work right.
19 * It should contain:
20 * hwcap 0 nosegneg
21 * to match the mapping of bit to name that we give here.
22 */
23 #define NOTE_KERNELCAP_BEGIN(ncaps, mask) \
24 ASM_ELF_NOTE_BEGIN(".note.kernelcap", "a", "GNU", 2) \
25 .long ncaps, mask
26 #define NOTE_KERNELCAP(bit, name) \
27 .byte bit; .asciz name
28 #define NOTE_KERNELCAP_END ASM_ELF_NOTE_END
30 NOTE_KERNELCAP_BEGIN(1, 1)
31 NOTE_KERNELCAP(0, "nosegneg")
32 NOTE_KERNELCAP_END