Make musl initialization work with unikraft

Work around some syscalls not being implemented in unikraft.

Signed-off-by: Cyril Soldani <[email protected]>

Author: cffs

patches/0013-init-no-mprotect.patch

@@ -0,0 +1,14 @@
+--- a/src/thread/pthread_create.c	2020-11-06 14:30:42.098195850 +0100
++++ b/src/thread/pthread_create.c	2020-11-06 14:41:51.039515090 +0100
+@@ -244,11 +244,6 @@
+ 		if (guard) {
+ 			map = __mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANON, -1, 0);
+ 			if (map == MAP_FAILED) goto fail;
+-			if (__mprotect(map+guard, size-guard, PROT_READ|PROT_WRITE)
+-			    && errno != ENOSYS) {
+-				__munmap(map, size);
+-				goto fail;
+-			}
+ 		} else {
+ 			map = __mmap(0, size, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
+ 			if (map == MAP_FAILED) goto fail;

patches/0014-mmap-alloc.patch

@@ -0,0 +1,37 @@
+--- a/src/mman/mmap.c	2020-11-06 14:33:14.588895081 +0100
++++ b/src/mman/mmap.c	2020-11-06 14:54:26.393274709 +0100
+@@ -6,6 +6,9 @@
+ #include "syscall.h"
+ #include "libc.h"
+ 
++#include <uk/alloc.h>
++#include <uk/assert.h>
++
+ static void dummy(void) { }
+ weak_alias(dummy, __vm_wait);
+ 
+@@ -26,11 +29,22 @@
+ 	if (flags & MAP_FIXED) {
+ 		__vm_wait();
+ 	}
++        if (start == NULL && fd == -1 && (flags & MAP_ANON)) {
++            start = NULL;
++            uk_posix_memalign(
++                    uk_alloc_get_default(),
++                    &start,
++                    4096, // TODO read actual page size
++                    len);
++            UK_ASSERT(start != NULL);
++            ret = (long) start;
++        } else {
+ #ifdef SYS_mmap2
+-	ret = __syscall(SYS_mmap2, start, len, prot, flags, fd, off/UNIT);
++            ret = __syscall(SYS_mmap2, start, len, prot, flags, fd, off/UNIT);
+ #else
+-	ret = __syscall(SYS_mmap, start, len, prot, flags, fd, off);
++            ret = __syscall(SYS_mmap, start, len, prot, flags, fd, off);
+ #endif
++        }
+ 	/* Fixup incorrect EPERM from kernel. */
+ 	if (ret == -EPERM && !start && (flags&MAP_ANON) && !(flags&MAP_FIXED))
+ 		ret = -ENOMEM;

patches/0015-avoid-mmap-in-init_tls.patch

@@ -0,0 +1,36 @@
+--- a/src/env/__init_tls.c	2020-11-06 14:11:05.226052792 +0100
++++ b/src/env/__init_tls.c	2020-11-06 14:37:32.885073260 +0100
+@@ -8,6 +8,9 @@
+ #include "atomic.h"
+ #include "syscall.h"
+ 
++#include <uk/alloc.h>
++#include <uk/assert.h>
++
+ int __init_tp(void *p)
+ {
+ 	pthread_t td = p;
+@@ -114,16 +117,13 @@
+ 		+ MIN_TLS_ALIGN-1 & -MIN_TLS_ALIGN;
+ 
+ 	if (libc.tls_size > sizeof builtin_tls) {
+-#ifndef SYS_mmap2
+-#define SYS_mmap2 SYS_mmap
+-#endif
+-		mem = (void *)__syscall(
+-			SYS_mmap2,
+-			0, libc.tls_size, PROT_READ|PROT_WRITE,
+-			MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
+-		/* -4095...-1 cast to void * will crash on dereference anyway,
+-		 * so don't bloat the init code checking for error codes and
+-		 * explicitly calling a_crash(). */
++                mem = NULL;
++                uk_posix_memalign(
++                        uk_alloc_get_default(),
++                        &mem,
++                        4096, // TODO read actual page size
++                        libc.tls_size);
++                UK_ASSERT(mem != NULL);
+ 	} else {
+ 		mem = builtin_tls;
+ 	}

patches/0016-avoid-arch_prctl.patch

@@ -0,0 +1,13 @@
+--- a/src/thread/x86_64/__set_thread_area.s	2018-02-22 19:39:19.000000000 +0100
++++ b/src/thread/x86_64/__set_thread_area.s	2020-11-13 12:26:36.600544392 +0100
+@@ -3,8 +3,6 @@
+ .global __set_thread_area
+ .type __set_thread_area,@function
+ __set_thread_area:
+-	mov %rdi,%rsi           /* shift for syscall */
+-	movl $0x1002,%edi       /* SET_FS register */
+-	movl $158,%eax          /* set fs segment to */
+-	syscall                 /* arch_prctl(SET_FS, arg)*/
++	wrfsbase %rdi
++       movq $0,%rax
+ 	ret