arch/powerpc/boot/addnote.c

Source file repositories/reference/linux-study-clean/arch/powerpc/boot/addnote.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/boot/addnote.c
Extension
.c
Size
6965 bytes
Lines
249
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

if (GET_32(ph + PH_TYPE) == PT_NOTE) {
			fprintf(stderr, "%s already has a note entry\n",
				av[1]);
			exit(0);
		}
		ph += ps;
	}

	/* XXX check that the area we want to use is all zeroes */
	for (i = 0; i < 2 * ps + nnote + nnote2; ++i)
		if (buf[ph + i] != 0)
			goto nospace;

	/* fill in the program header entry */
	ns = ph + 2 * ps;
	PUT_32(ph + PH_TYPE, PT_NOTE);
	if (e_class == ELFCLASS32)
		PUT_32(ph + PH_OFFSET, ns);
	else
		PUT_64(ph + PH_OFFSET, ns);

	if (e_class == ELFCLASS32)
		PUT_32(ph + PH_FILESZ, nnote);
	else
		PUT_64(ph + PH_FILESZ, nnote);

	/* fill in the note area we point to */
	/* XXX we should probably make this a proper section */
	PUT_32(ns, strlen(arch) + 1);
	PUT_32(ns + 4, N_DESCR * 4);
	PUT_32(ns + 8, 0x1275);
	strcpy((char *) &buf[ns + 12], arch);
	ns += 12 + strlen(arch) + 1;
	for (i = 0; i < N_DESCR; ++i, ns += 4)
		PUT_32BE(ns, descr[i]);

	/* fill in the second program header entry and the RPA note area */
	ph += ps;
	PUT_32(ph + PH_TYPE, PT_NOTE);
	if (e_class == ELFCLASS32)
		PUT_32(ph + PH_OFFSET, ns);
	else
		PUT_64(ph + PH_OFFSET, ns);

	if (e_class == ELFCLASS32)
		PUT_32(ph + PH_FILESZ, nnote);
	else
		PUT_64(ph + PH_FILESZ, nnote2);

	/* fill in the note area we point to */
	PUT_32(ns, strlen(rpaname) + 1);
	PUT_32(ns + 4, sizeof(rpanote));
	PUT_32(ns + 8, 0x12759999);
	strcpy((char *) &buf[ns + 12], rpaname);
	ns += 12 + ROUNDUP(strlen(rpaname) + 1);
	for (i = 0; i < N_RPA_DESCR; ++i, ns += 4)
		PUT_32BE(ns, rpanote[i]);

	/* Update the number of program headers */
	PUT_16(E_PHNUM, np + 2);

	/* write back */
	i = lseek(fd, (long) 0, SEEK_SET);
	if (i < 0) {
		perror("lseek");
		exit(1);
	}
	i = write(fd, buf, n);
	if (i < 0) {
		perror("write");
		exit(1);
	}
	if (i < n) {
		fprintf(stderr, "%s: write truncated\n", av[1]);
		exit(1);
	}

	exit(0);

 notelf:
	fprintf(stderr, "%s does not appear to be an ELF file\n", av[1]);
	exit(1);

 nospace:
	fprintf(stderr, "sorry, I can't find space in %s to put the note\n",
		av[1]);
	exit(1);
}

Annotation

Implementation Notes