1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text. 4 * Here we can supply some information useful to userland. 5 */ 6 7 #include <linux/build-salt.h> 8 #include <linux/version.h> 9 #include <linux/elfnote.h> 10 11 /* Ideally this would use UTS_NAME, but using a quoted string here 12 doesn't work. Remember to change this when changing the 13 kernel's name. */ 14 ELFNOTE_START(Linux, 0, "a") 15 .long LINUX_VERSION_CODE 16 ELFNOTE_END 17 18 BUILD_SALT 19 20 #ifdef CONFIG_XEN 21 /* 22 * Add a special note telling glibc's dynamic linker a fake hardware 23 * flavor that it will use to choose the search path for libraries in the 24 * same way it uses real hardware capabilities like "mmx". 25 * We supply "nosegneg" as the fake capability, to indicate that we 26 * do not like negative offsets in instructions using segment overrides, 27 * since we implement those inefficiently. This makes it possible to 28 * install libraries optimized to avoid those access patterns in someplace 29 * like /lib/i686/tls/nosegneg. Note that an /etc/ld.so.conf.d/file 30 * corresponding to the bits here is needed to make ldconfig work right. 31 * It should contain: 32 * hwcap 1 nosegneg 33 * to match the mapping of bit to name that we give here. 34 * 35 * At runtime, the fake hardware feature will be considered to be present 36 * if its bit is set in the mask word. So, we start with the mask 0, and 37 * at boot time we set VDSO_NOTE_NONEGSEG_BIT if running under Xen. 38 */ 39 40 #include "../../xen/vdso.h" /* Defines VDSO_NOTE_NONEGSEG_BIT. */ 41 42 ELFNOTE_START(GNU, 2, "a") 43 .long 1 /* ncaps */ 44 VDSO32_NOTE_MASK: /* Symbol used by arch/x86/xen/setup.c */ 45 .long 0 /* mask */ 46 .byte VDSO_NOTE_NONEGSEG_BIT; .asciz "nosegneg" /* bit, name */ 47 ELFNOTE_END 48 #endif