diff options
Diffstat (limited to 'kernel/arch/x86/vdso/vdso32/note.S')
-rw-r--r-- | kernel/arch/x86/vdso/vdso32/note.S | 44 |
1 files changed, 44 insertions, 0 deletions
diff --git a/kernel/arch/x86/vdso/vdso32/note.S b/kernel/arch/x86/vdso/vdso32/note.S new file mode 100644 index 000000000..c83f25734 --- /dev/null +++ b/kernel/arch/x86/vdso/vdso32/note.S @@ -0,0 +1,44 @@ +/* + * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text. + * Here we can supply some information useful to userland. + */ + +#include <linux/version.h> +#include <linux/elfnote.h> + +/* Ideally this would use UTS_NAME, but using a quoted string here + doesn't work. Remember to change this when changing the + kernel's name. */ +ELFNOTE_START(Linux, 0, "a") + .long LINUX_VERSION_CODE +ELFNOTE_END + +#ifdef CONFIG_XEN +/* + * Add a special note telling glibc's dynamic linker a fake hardware + * flavor that it will use to choose the search path for libraries in the + * same way it uses real hardware capabilities like "mmx". + * We supply "nosegneg" as the fake capability, to indicate that we + * do not like negative offsets in instructions using segment overrides, + * since we implement those inefficiently. This makes it possible to + * install libraries optimized to avoid those access patterns in someplace + * like /lib/i686/tls/nosegneg. Note that an /etc/ld.so.conf.d/file + * corresponding to the bits here is needed to make ldconfig work right. + * It should contain: + * hwcap 1 nosegneg + * to match the mapping of bit to name that we give here. + * + * At runtime, the fake hardware feature will be considered to be present + * if its bit is set in the mask word. So, we start with the mask 0, and + * at boot time we set VDSO_NOTE_NONEGSEG_BIT if running under Xen. + */ + +#include "../../xen/vdso.h" /* Defines VDSO_NOTE_NONEGSEG_BIT. */ + +ELFNOTE_START(GNU, 2, "a") + .long 1 /* ncaps */ +VDSO32_NOTE_MASK: /* Symbol used by arch/x86/xen/setup.c */ + .long 0 /* mask */ + .byte VDSO_NOTE_NONEGSEG_BIT; .asciz "nosegneg" /* bit, name */ +ELFNOTE_END +#endif |