Differential D25211 Diff 72932 lib/csu/common/crtbrand.c

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lib/csu/common/crtbrand.c

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	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT			* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF			* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.			* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/			*/

	#include <sys/cdefs.h>			#include <sys/cdefs.h>
	__FBSDID("$FreeBSD$");			__FBSDID("$FreeBSD$");

	#include <sys/param.h>			#include <sys/param.h>
				jhbAuthorUnsubmitted Done Inline Actions This seemed less work than getting it added into ACFLAGS in various places at least as a hack, but I'd be fine moving this out to ACFLAGS if that is preferred. jhb: This seemed less work than getting it added into ACFLAGS in various places at least as a hack…
	#include <sys/elf_common.h>			#include <sys/elf_common.h>
	#include "notes.h"

	/*			/*
	* Special ".note" entry specifying the ABI version. See			* Special ".note" entry specifying the ABI version. See
	* http://www.netbsd.org/Documentation/kernel/elf-notes.html			* http://www.netbsd.org/Documentation/kernel/elf-notes.html
	* for more information.			* for more information.
	*
	* For all arches except sparc, gcc emits the section directive for the
	* following struct with a PROGBITS type. However, newer versions of binutils
	* (after 2.16.90) require the section to be of NOTE type, to guarantee that the
	* .note.ABI-tag section correctly ends up in the first page of the final
	* executable.
	*
	* Unfortunately, there is no clean way to tell gcc to use another section type,
	* so this C file (or the C file that includes it) must be compiled in multiple
	* steps:
	*
	* - Compile the .c file to a .s file.
	* - Edit the .s file to change the 'progbits' type to 'note', for the section
	* directive that defines the .note.ABI-tag section.
	* - Compile the .s file to an object file.
	*
	* These steps are done in the invididual Makefiles for each applicable arch.
	*/			*/
	static const struct {			__asm(
	int32_t namesz;			" .section .note.tag,\"a\",@note\n"
	int32_t descsz;			" .p2align 2\n"
	int32_t type;			" .word 8\n"
	char name[sizeof(NOTE_FREEBSD_VENDOR)];			" .word 4\n"
	int32_t desc;			" .word " __XSTRING(NT_FREEBSD_ABI_TAG) "\n"
	} abitag __attribute__ ((section (NOTE_SECTION), aligned(4))) __used = {			" .asciz \"FreeBSD\"\n"
				jrtc27Unsubmitted Not Done Inline Actions I would be explicit with the NULs to be clear this is exactly 8 bytes as we need to ensure 4-byte alignment of the following word (and to match the namesz above). jrtc27: I would be explicit with the NULs to be clear this is exactly 8 bytes as we need to ensure 4…
				jhbAuthorUnsubmitted Done Inline Actions The alternative might be to throw in a `.p2align 2` to enforce the padding? jhb: The alternative might be to throw in a `.p2align 2` to enforce the padding?
				jrtc27Unsubmitted Not Done Inline Actions Then it's less clear that namesz is correct. jrtc27: Then it's less clear that namesz is correct.
				jhbAuthorUnsubmitted Done Inline Actions So I could use labels to derive namesz (and perhaps even descsz) as the NetBSD webpage suggests. jhb: So I could use labels to derive namesz (and perhaps even descsz) as the NetBSD webpage suggests.
				jrtc27Unsubmitted Not Done Inline Actions Ah yes, that would work. jrtc27: Ah yes, that would work.
				emasteUnsubmitted Not Done Inline Actions Sounds good to me. emaste: Sounds good to me.
	.namesz = sizeof(NOTE_FREEBSD_VENDOR),			" .p2align 2\n"
	.descsz = sizeof(int32_t),			" .word " __XSTRING(__FreeBSD_version));
	.type = NT_FREEBSD_ABI_TAG,
	.name = NOTE_FREEBSD_VENDOR,
	.desc = __FreeBSD_version
	};

	static const struct {			__asm(
	int32_t namesz;			" .section .note.tag,\"a\",@note\n"
	int32_t descsz;			" .p2align 2\n"
	int32_t type;			" .word 8\n"
	char name[sizeof(NOTE_FREEBSD_VENDOR)];			" .word 4\n"
	uint32_t desc[1];			" .word " __XSTRING(NT_FREEBSD_FEATURE_CTL) "\n"
	} crt_feature_ctl __attribute__ ((section (NOTE_SECTION),			" .asciz \"FreeBSD\"\n"
	aligned(4))) __used = {			" .p2align 2\n"
	.namesz = sizeof(NOTE_FREEBSD_VENDOR),			" .word 0");
	.descsz = sizeof(uint32_t),
	.type = NT_FREEBSD_FEATURE_CTL,
	.name = NOTE_FREEBSD_VENDOR,
	.desc = { 0 }
	};