Commit add4eed0 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by H. Peter Anvin
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x86/vdso, build: Fix cross-compilation from big-endian architectures 



This adds a macro GET(x) to convert x from big-endian to
little-endian.  Hopefully I put it everywhere it needs to go and got
all the cases needed for everyone's linux/elf.h.

Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/2cf258df123cb24bad63c274c8563c050547d99d.1401464755.git.luto@amacapital.net


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 01156183

arch/x86/vdso/vdso2c.c

+15 −0
Original line number Diff line number Diff line
@@ -51,6 +51,21 @@ static void fail(const char *format, ...) 
	va_end(ap);

}



/*

 * Evil macros to do a little-endian read.

 */

#define __GET_TYPE(x, type, bits, ifnot)				\

	__builtin_choose_expr(						\

		__builtin_types_compatible_p(typeof(x), type),		\

		le##bits##toh((x)), ifnot)



extern void bad_get(uint64_t);



#define GET(x)								\

	__GET_TYPE((x), __u32, 32, __GET_TYPE((x), __u64, 64,		\

	__GET_TYPE((x), __s32, 32, __GET_TYPE((x), __s64, 64,		\

	__GET_TYPE((x), __u16, 16, bad_get(x))))))



#define NSYMS (sizeof(required_syms) / sizeof(required_syms[0]))



#define BITS 64

arch/x86/vdso/vdso2c.h

+35 −28
Original line number Diff line number Diff line
@@ -18,25 +18,27 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) 
	const char *secstrings;

	uint64_t syms[NSYMS] = {};



	Elf_Phdr *pt = (Elf_Phdr *)(addr + hdr->e_phoff);

	Elf_Phdr *pt = (Elf_Phdr *)(addr + GET(hdr->e_phoff));



	/* Walk the segment table. */

	for (i = 0; i < hdr->e_phnum; i++) {

		if (pt[i].p_type == PT_LOAD) {

	for (i = 0; i < GET(hdr->e_phnum); i++) {

		if (GET(pt[i].p_type) == PT_LOAD) {

			if (found_load)

				fail("multiple PT_LOAD segs\n");



			if (pt[i].p_offset != 0 || pt[i].p_vaddr != 0)

			if (GET(pt[i].p_offset) != 0 ||

			    GET(pt[i].p_vaddr) != 0)

				fail("PT_LOAD in wrong place\n");



			if (pt[i].p_memsz != pt[i].p_filesz)

			if (GET(pt[i].p_memsz) != GET(pt[i].p_filesz))

				fail("cannot handle memsz != filesz\n");



			load_size = pt[i].p_memsz;

			load_size = GET(pt[i].p_memsz);

			found_load = 1;

		} else if (pt[i].p_type == PT_DYNAMIC) {

			dyn = addr + pt[i].p_offset;

			dyn_end = addr + pt[i].p_offset + pt[i].p_memsz;

		} else if (GET(pt[i].p_type) == PT_DYNAMIC) {

			dyn = addr + GET(pt[i].p_offset);

			dyn_end = addr + GET(pt[i].p_offset) +

				GET(pt[i].p_memsz);

		}

	}

	if (!found_load)
@@ -44,43 +46,48 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) 
	data_size = (load_size + 4095) / 4096 * 4096;



	/* Walk the dynamic table */

	for (i = 0; dyn + i < dyn_end && dyn[i].d_tag != DT_NULL; i++) {

		if (dyn[i].d_tag == DT_REL || dyn[i].d_tag == DT_RELSZ ||

		    dyn[i].d_tag == DT_RELENT || dyn[i].d_tag == DT_TEXTREL)

	for (i = 0; dyn + i < dyn_end && GET(dyn[i].d_tag) != DT_NULL; i++) {

		typeof(dyn[i].d_tag) tag = GET(dyn[i].d_tag);

		if (tag == DT_REL || tag == DT_RELSZ ||

		    tag == DT_RELENT || tag == DT_TEXTREL)

			fail("vdso image contains dynamic relocations\n");

	}



	/* Walk the section table */

	secstrings_hdr = addr + hdr->e_shoff + hdr->e_shentsize*hdr->e_shstrndx;

	secstrings = addr + secstrings_hdr->sh_offset;

	for (i = 0; i < hdr->e_shnum; i++) {

		Elf_Shdr *sh = addr + hdr->e_shoff + hdr->e_shentsize * i;

		if (sh->sh_type == SHT_SYMTAB)

	secstrings_hdr = addr + GET(hdr->e_shoff) +

		GET(hdr->e_shentsize)*GET(hdr->e_shstrndx);

	secstrings = addr + GET(secstrings_hdr->sh_offset);

	for (i = 0; i < GET(hdr->e_shnum); i++) {

		Elf_Shdr *sh = addr + GET(hdr->e_shoff) +

			GET(hdr->e_shentsize) * i;

		if (GET(sh->sh_type) == SHT_SYMTAB)

			symtab_hdr = sh;



		if (!strcmp(secstrings + sh->sh_name, ".altinstructions"))

		if (!strcmp(secstrings + GET(sh->sh_name), ".altinstructions"))

			alt_sec = sh;

	}



	if (!symtab_hdr)

		fail("no symbol table\n");



	strtab_hdr = addr + hdr->e_shoff +

		hdr->e_shentsize * symtab_hdr->sh_link;

	strtab_hdr = addr + GET(hdr->e_shoff) +

		GET(hdr->e_shentsize) * GET(symtab_hdr->sh_link);



	/* Walk the symbol table */

	for (i = 0; i < symtab_hdr->sh_size / symtab_hdr->sh_entsize; i++) {

	for (i = 0; i < GET(symtab_hdr->sh_size) / GET(symtab_hdr->sh_entsize);

	     i++) {

		int k;

		Elf_Sym *sym = addr + symtab_hdr->sh_offset +

			symtab_hdr->sh_entsize * i;

		const char *name = addr + strtab_hdr->sh_offset + sym->st_name;

		Elf_Sym *sym = addr + GET(symtab_hdr->sh_offset) +

			GET(symtab_hdr->sh_entsize) * i;

		const char *name = addr + GET(strtab_hdr->sh_offset) +

			GET(sym->st_name);

		for (k = 0; k < NSYMS; k++) {

			if (!strcmp(name, required_syms[k])) {

				if (syms[k]) {

					fail("duplicate symbol %s\n",

					     required_syms[k]);

				}

				syms[k] = sym->st_value;

				syms[k] = GET(sym->st_value);

			}

		}

	}
@@ -106,7 +113,7 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) 
	hdr->e_shoff = 0;

	hdr->e_shentsize = 0;

	hdr->e_shnum = 0;

	hdr->e_shstrndx = SHN_UNDEF;

	hdr->e_shstrndx = htole16(SHN_UNDEF);



	if (!name) {

		fwrite(addr, load_size, 1, outfile);
@@ -140,9 +147,9 @@ static void GOFUNC(void *addr, size_t len, FILE *outfile, const char *name) 
	fprintf(outfile, "\t},\n");

	if (alt_sec) {

		fprintf(outfile, "\t.alt = %lu,\n",

			(unsigned long)alt_sec->sh_offset);

			(unsigned long)GET(alt_sec->sh_offset));

		fprintf(outfile, "\t.alt_len = %lu,\n",

			(unsigned long)alt_sec->sh_size);

			(unsigned long)GET(alt_sec->sh_size));

	}

	for (i = 0; i < NSYMS; i++) {

		if (syms[i])

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