Messages in this thread Patch in this message | | | Subject | [patch 065/198] i386 vDSO: add PT_NOTE segment | From | akpm@osdl ... | Date | Tue, 12 Apr 2005 03:31:37 -0700 |
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From: Roland McGrath <roland@redhat.com>
This patch adds an ELF note to the vDSO giving the LINUX_VERSION_CODE value. Having this in the vDSO lets the dynamic linker avoid the `uname' syscall it now always does at startup to ascertain the kernel ABI available.
Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> ---
25-akpm/arch/i386/kernel/Makefile | 6 ++++-- 25-akpm/arch/i386/kernel/vsyscall-note.S | 25 +++++++++++++++++++++++++ 25-akpm/arch/i386/kernel/vsyscall.lds.S | 3 ++- 3 files changed, 31 insertions(+), 3 deletions(-)
diff -puN arch/i386/kernel/Makefile~i386-vdso-add-pt_note-segment arch/i386/kernel/Makefile --- 25/arch/i386/kernel/Makefile~i386-vdso-add-pt_note-segment 2005-04-12 03:21:18.982251160 -0700 +++ 25-akpm/arch/i386/kernel/Makefile 2005-04-12 03:21:18.986250552 -0700 @@ -56,7 +56,8 @@ SYSCFLAGS_vsyscall-sysenter.so = $(vsysc SYSCFLAGS_vsyscall-int80.so = $(vsyscall-flags) $(obj)/vsyscall-int80.so $(obj)/vsyscall-sysenter.so: \ -$(obj)/vsyscall-%.so: $(src)/vsyscall.lds $(obj)/vsyscall-%.o FORCE +$(obj)/vsyscall-%.so: $(src)/vsyscall.lds \ + $(obj)/vsyscall-%.o $(obj)/vsyscall-note.o FORCE $(call if_changed,syscall) # We also create a special relocatable object that should mirror the symbol @@ -67,5 +68,6 @@ $(obj)/built-in.o: $(obj)/vsyscall-syms. $(obj)/built-in.o: ld_flags += -R $(obj)/vsyscall-syms.o SYSCFLAGS_vsyscall-syms.o = -r -$(obj)/vsyscall-syms.o: $(src)/vsyscall.lds $(obj)/vsyscall-sysenter.o FORCE +$(obj)/vsyscall-syms.o: $(src)/vsyscall.lds \ + $(obj)/vsyscall-sysenter.o $(obj)/vsyscall-note.o FORCE $(call if_changed,syscall) diff -puN arch/i386/kernel/vsyscall.lds.S~i386-vdso-add-pt_note-segment arch/i386/kernel/vsyscall.lds.S --- 25/arch/i386/kernel/vsyscall.lds.S~i386-vdso-add-pt_note-segment 2005-04-12 03:21:18.983251008 -0700 +++ 25-akpm/arch/i386/kernel/vsyscall.lds.S 2005-04-12 03:21:18.987250400 -0700 @@ -23,7 +23,7 @@ SECTIONS . = VSYSCALL_BASE + 0x400; .text : { *(.text) } :text =0x90909090 - + .note : { *(.note.*) } :text :note .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr .eh_frame : { KEEP (*(.eh_frame)) } :text .dynamic : { *(.dynamic) } :text :dynamic @@ -43,6 +43,7 @@ PHDRS { text PT_LOAD FILEHDR PHDRS FLAGS(5); /* PF_R|PF_X */ dynamic PT_DYNAMIC FLAGS(4); /* PF_R */ + note PT_NOTE FLAGS(4); /* PF_R */ eh_frame_hdr 0x6474e550; /* PT_GNU_EH_FRAME, but ld doesn't match the name */ } diff -puN /dev/null arch/i386/kernel/vsyscall-note.S --- /dev/null 2003-09-15 06:40:47.000000000 -0700 +++ 25-akpm/arch/i386/kernel/vsyscall-note.S 2005-04-12 03:21:18.987250400 -0700 @@ -0,0 +1,25 @@ +/* + * 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/uts.h> +#include <linux/version.h> + +#define ASM_ELF_NOTE_BEGIN(name, flags, vendor, type) \ + .section name, flags; \ + .balign 4; \ + .long 1f - 0f; /* name length */ \ + .long 3f - 2f; /* data length */ \ + .long type; /* note type */ \ +0: .asciz vendor; /* vendor name */ \ +1: .balign 4; \ +2: + +#define ASM_ELF_NOTE_END \ +3: .balign 4; /* pad out section */ \ + .previous + + ASM_ELF_NOTE_BEGIN(".note.kernel-version", "a", UTS_SYSNAME, 0) + .long LINUX_VERSION_CODE + ASM_ELF_NOTE_END _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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