fix Darwin cross-compile for x86 4.14.x kernel

target/linux/patches/4.14.44/vdso2.patch

@@ -0,0 +1,290 @@
+diff -Nur linux-4.14.44.orig/arch/x86/entry/vdso/vdso2c.c linux-4.14.44/arch/x86/entry/vdso/vdso2c.c
+--- linux-4.14.44.orig/arch/x86/entry/vdso/vdso2c.c	2018-05-25 16:18:02.000000000 +0200
++++ linux-4.14.44/arch/x86/entry/vdso/vdso2c.c	2018-05-31 02:09:00.000000000 +0200
+@@ -64,7 +64,15 @@
+ #include <tools/le_byteshift.h>
+ 
+ #include <linux/elf.h>
++#ifdef __linux__
+ #include <linux/types.h>
++#else
++typedef _Bool			bool;
++enum {
++        false   = 0,
++        true    = 1
++};
++#endif
+ 
+ const char *outfilename;
+ 
+@@ -86,6 +94,7 @@
+ 	sym_hvclock_page,
+ };
+ 
++
+ struct vdso_sym {
+ 	const char *name;
+ 	bool export;
+diff -Nur linux-4.14.44.orig/arch/x86/entry/vdso/vdso2c.c.orig linux-4.14.44/arch/x86/entry/vdso/vdso2c.c.orig
+--- linux-4.14.44.orig/arch/x86/entry/vdso/vdso2c.c.orig	1970-01-01 01:00:00.000000000 +0100
++++ linux-4.14.44/arch/x86/entry/vdso/vdso2c.c.orig	2018-05-25 16:18:02.000000000 +0200
+@@ -0,0 +1,259 @@
++/*
++ * vdso2c - A vdso image preparation tool
++ * Copyright (c) 2014 Andy Lutomirski and others
++ * Licensed under the GPL v2
++ *
++ * vdso2c requires stripped and unstripped input.  It would be trivial
++ * to fully strip the input in here, but, for reasons described below,
++ * we need to write a section table.  Doing this is more or less
++ * equivalent to dropping all non-allocatable sections, but it's
++ * easier to let objcopy handle that instead of doing it ourselves.
++ * If we ever need to do something fancier than what objcopy provides,
++ * it would be straightforward to add here.
++ *
++ * We're keep a section table for a few reasons:
++ *
++ * The Go runtime had a couple of bugs: it would read the section
++ * table to try to figure out how many dynamic symbols there were (it
++ * shouldn't have looked at the section table at all) and, if there
++ * were no SHT_SYNDYM section table entry, it would use an
++ * uninitialized value for the number of symbols.  An empty DYNSYM
++ * table would work, but I see no reason not to write a valid one (and
++ * keep full performance for old Go programs).  This hack is only
++ * needed on x86_64.
++ *
++ * The bug was introduced on 2012-08-31 by:
++ * https://code.google.com/p/go/source/detail?r=56ea40aac72b
++ * and was fixed on 2014-06-13 by:
++ * https://code.google.com/p/go/source/detail?r=fc1cd5e12595
++ *
++ * Binutils has issues debugging the vDSO: it reads the section table to
++ * find SHT_NOTE; it won't look at PT_NOTE for the in-memory vDSO, which
++ * would break build-id if we removed the section table.  Binutils
++ * also requires that shstrndx != 0.  See:
++ * https://sourceware.org/bugzilla/show_bug.cgi?id=17064
++ *
++ * elfutils might not look for PT_NOTE if there is a section table at
++ * all.  I don't know whether this matters for any practical purpose.
++ *
++ * For simplicity, rather than hacking up a partial section table, we
++ * just write a mostly complete one.  We omit non-dynamic symbols,
++ * though, since they're rather large.
++ *
++ * Once binutils gets fixed, we might be able to drop this for all but
++ * the 64-bit vdso, since build-id only works in kernel RPMs, and
++ * systems that update to new enough kernel RPMs will likely update
++ * binutils in sync.  build-id has never worked for home-built kernel
++ * RPMs without manual symlinking, and I suspect that no one ever does
++ * that.
++ */
++
++#include <inttypes.h>
++#include <stdint.h>
++#include <unistd.h>
++#include <stdarg.h>
++#include <stdlib.h>
++#include <stdio.h>
++#include <string.h>
++#include <fcntl.h>
++#include <err.h>
++
++#include <sys/mman.h>
++#include <sys/types.h>
++
++#include <tools/le_byteshift.h>
++
++#include <linux/elf.h>
++#include <linux/types.h>
++
++const char *outfilename;
++
++/* Symbols that we need in vdso2c. */
++enum {
++	sym_vvar_start,
++	sym_vvar_page,
++	sym_hpet_page,
++	sym_pvclock_page,
++	sym_hvclock_page,
++	sym_VDSO_FAKE_SECTION_TABLE_START,
++	sym_VDSO_FAKE_SECTION_TABLE_END,
++};
++
++const int special_pages[] = {
++	sym_vvar_page,
++	sym_hpet_page,
++	sym_pvclock_page,
++	sym_hvclock_page,
++};
++
++struct vdso_sym {
++	const char *name;
++	bool export;
++};
++
++struct vdso_sym required_syms[] = {
++	[sym_vvar_start] = {"vvar_start", true},
++	[sym_vvar_page] = {"vvar_page", true},
++	[sym_hpet_page] = {"hpet_page", true},
++	[sym_pvclock_page] = {"pvclock_page", true},
++	[sym_hvclock_page] = {"hvclock_page", true},
++	[sym_VDSO_FAKE_SECTION_TABLE_START] = {
++		"VDSO_FAKE_SECTION_TABLE_START", false
++	},
++	[sym_VDSO_FAKE_SECTION_TABLE_END] = {
++		"VDSO_FAKE_SECTION_TABLE_END", false
++	},
++	{"VDSO32_NOTE_MASK", true},
++	{"__kernel_vsyscall", true},
++	{"__kernel_sigreturn", true},
++	{"__kernel_rt_sigreturn", true},
++	{"int80_landing_pad", true},
++};
++
++__attribute__((format(printf, 1, 2))) __attribute__((noreturn))
++static void fail(const char *format, ...)
++{
++	va_list ap;
++	va_start(ap, format);
++	fprintf(stderr, "Error: ");
++	vfprintf(stderr, format, ap);
++	if (outfilename)
++		unlink(outfilename);
++	exit(1);
++	va_end(ap);
++}
++
++/*
++ * Evil macros for little-endian reads and writes
++ */
++#define GLE(x, bits, ifnot)						\
++	__builtin_choose_expr(						\
++		(sizeof(*(x)) == bits/8),				\
++		(__typeof__(*(x)))get_unaligned_le##bits(x), ifnot)
++
++extern void bad_get_le(void);
++#define LAST_GLE(x)							\
++	__builtin_choose_expr(sizeof(*(x)) == 1, *(x), bad_get_le())
++
++#define GET_LE(x)							\
++	GLE(x, 64, GLE(x, 32, GLE(x, 16, LAST_GLE(x))))
++
++#define PLE(x, val, bits, ifnot)					\
++	__builtin_choose_expr(						\
++		(sizeof(*(x)) == bits/8),				\
++		put_unaligned_le##bits((val), (x)), ifnot)
++
++extern void bad_put_le(void);
++#define LAST_PLE(x, val)						\
++	__builtin_choose_expr(sizeof(*(x)) == 1, *(x) = (val), bad_put_le())
++
++#define PUT_LE(x, val)					\
++	PLE(x, val, 64, PLE(x, val, 32, PLE(x, val, 16, LAST_PLE(x, val))))
++
++
++#define NSYMS (sizeof(required_syms) / sizeof(required_syms[0]))
++
++#define BITSFUNC3(name, bits, suffix) name##bits##suffix
++#define BITSFUNC2(name, bits, suffix) BITSFUNC3(name, bits, suffix)
++#define BITSFUNC(name) BITSFUNC2(name, ELF_BITS, )
++
++#define INT_BITS BITSFUNC2(int, ELF_BITS, _t)
++
++#define ELF_BITS_XFORM2(bits, x) Elf##bits##_##x
++#define ELF_BITS_XFORM(bits, x) ELF_BITS_XFORM2(bits, x)
++#define ELF(x) ELF_BITS_XFORM(ELF_BITS, x)
++
++#define ELF_BITS 64
++#include "vdso2c.h"
++#undef ELF_BITS
++
++#define ELF_BITS 32
++#include "vdso2c.h"
++#undef ELF_BITS
++
++static void go(void *raw_addr, size_t raw_len,
++	       void *stripped_addr, size_t stripped_len,
++	       FILE *outfile, const char *name)
++{
++	Elf64_Ehdr *hdr = (Elf64_Ehdr *)raw_addr;
++
++	if (hdr->e_ident[EI_CLASS] == ELFCLASS64) {
++		go64(raw_addr, raw_len, stripped_addr, stripped_len,
++		     outfile, name);
++	} else if (hdr->e_ident[EI_CLASS] == ELFCLASS32) {
++		go32(raw_addr, raw_len, stripped_addr, stripped_len,
++		     outfile, name);
++	} else {
++		fail("unknown ELF class\n");
++	}
++}
++
++static void map_input(const char *name, void **addr, size_t *len, int prot)
++{
++	off_t tmp_len;
++
++	int fd = open(name, O_RDONLY);
++	if (fd == -1)
++		err(1, "%s", name);
++
++	tmp_len = lseek(fd, 0, SEEK_END);
++	if (tmp_len == (off_t)-1)
++		err(1, "lseek");
++	*len = (size_t)tmp_len;
++
++	*addr = mmap(NULL, tmp_len, prot, MAP_PRIVATE, fd, 0);
++	if (*addr == MAP_FAILED)
++		err(1, "mmap");
++
++	close(fd);
++}
++
++int main(int argc, char **argv)
++{
++	size_t raw_len, stripped_len;
++	void *raw_addr, *stripped_addr;
++	FILE *outfile;
++	char *name, *tmp;
++	int namelen;
++
++	if (argc != 4) {
++		printf("Usage: vdso2c RAW_INPUT STRIPPED_INPUT OUTPUT\n");
++		return 1;
++	}
++
++	/*
++	 * Figure out the struct name.  If we're writing to a .so file,
++	 * generate raw output insted.
++	 */
++	name = strdup(argv[3]);
++	namelen = strlen(name);
++	if (namelen >= 3 && !strcmp(name + namelen - 3, ".so")) {
++		name = NULL;
++	} else {
++		tmp = strrchr(name, '/');
++		if (tmp)
++			name = tmp + 1;
++		tmp = strchr(name, '.');
++		if (tmp)
++			*tmp = '\0';
++		for (tmp = name; *tmp; tmp++)
++			if (*tmp == '-')
++				*tmp = '_';
++	}
++
++	map_input(argv[1], &raw_addr, &raw_len, PROT_READ);
++	map_input(argv[2], &stripped_addr, &stripped_len, PROT_READ);
++
++	outfilename = argv[3];
++	outfile = fopen(outfilename, "w");
++	if (!outfile)
++		err(1, "%s", argv[2]);
++
++	go(raw_addr, raw_len, stripped_addr, stripped_len, outfile, name);
++
++	munmap(raw_addr, raw_len);
++	munmap(stripped_addr, stripped_len);
++	fclose(outfile);
++
++	return 0;
++}