Added detailed mapping of bss.

.data and .text now needs to be 4K apart.
removed an early copy of test0 called test1

tasks/mm0/src/lib/elf/elf.c

@@ -5,6 +5,7 @@
  */
 #include <memory.h>
 #include <vm_area.h>
+#include <l4/api/errno.h>
 #include <lib/elf/elf.h>
 #include <lib/elf/elfprg.h>
 #include <lib/elf/elfsym.h>
@@ -39,6 +40,7 @@ int elf_test_expand_segment(struct elf_section_header *section,
 	    (section->sh_flags & sec_flmask) == sec_flags) {
 		/* Set new section */
 		if (!*start) {
+			BUG_ON(*offset || *end);
 			*offset = section->sh_offset;
 			*start = section->sh_addr;
 			*end = section->sh_addr + section->sh_size;
@@ -49,13 +51,11 @@ int elf_test_expand_segment(struct elf_section_header *section,
 
 	return 0;
 }
+
 /*
  * Sift through sections and copy their marks to tcb and efd
- * if they are recognised and loadable sections.
+ * if they are recognised and loadable sections. Test the
- *
+ * assigned segment marks and return an error if they're invalid.
- * NOTE: There may be multiple sections of same kind, in
- * consecutive address regions. Then we need to increase
- * that region's marks.
  */
 int elf_mark_segments(struct elf_section_header *sect_header, int nsections,
 		      struct tcb *task, struct exec_file_desc *efd)
@@ -64,24 +64,45 @@ int elf_mark_segments(struct elf_section_header *sect_header, int nsections,
 		struct elf_section_header *section = &sect_header[i];
 
 		/* Text + read-only data segments */
-		elf_test_expand_segment(section, SHT_PROGBITS, SHF_ALLOC,
+		elf_test_expand_segment(section, SHT_PROGBITS,
-					SHF_ALLOC | SHF_WRITE, &task->text_start,
+					SHF_ALLOC, SHF_ALLOC | SHF_WRITE,
-					&task->text_end, &efd->text_offset);
+					&task->text_start, &task->text_end,
+					&efd->text_offset);
 
 		/* Data segment */
-		elf_test_expand_segment(section, SHT_PROGBITS, SHF_ALLOC | SHF_WRITE,
+		elf_test_expand_segment(section, SHT_PROGBITS, SHF_ALLOC |
-					SHF_ALLOC | SHF_WRITE, &task->data_start,
+					SHF_WRITE, SHF_ALLOC | SHF_WRITE,
-					&task->data_end, &efd->data_offset);
+					&task->data_start, &task->data_end,
+					&efd->data_offset);
 
 		/* Bss segment */
-		elf_test_expand_segment(section, SHT_NOBITS, SHF_ALLOC | SHF_WRITE,
+		elf_test_expand_segment(section, SHT_NOBITS, SHF_ALLOC |
-					SHF_ALLOC | SHF_WRITE, &task->bss_start,
+					SHF_WRITE, SHF_ALLOC | SHF_WRITE,
-					&task->bss_end, &efd->bss_offset);
+					&task->bss_start, &task->bss_end,
+					&efd->bss_offset);
 	}
 
-	if (!task->text_start || !task->data_start || !task->bss_start) {
+	/* Test anomalies with the mappings */
-		printf("%s: NOTE: Could not find one of text, data or "
+
-		       "bss segments in elf file.\n", __FUNCTION__);
+	/* No text */
+	if (!task->text_start) {
+		printf("%s: Error: Could not find a text "
+		       "segment in ELF file.\n", __FUNCTION__);
+		return -ENOEXEC;
+	}
+
+	/* Warn if no data or bss but it's not an error */
+	if (!task->data_start || !task->bss_start) {
+		printf("%s: NOTE: Could not find a data and/or "
+		       "bss segment in ELF file.\n", __FUNCTION__);
+	}
+
+	/* Data and text are less than page apart */
+	if ((task->data_start - task->text_start) < PAGE_SIZE) {
+		printf("%s: Error: Distance between data and text"
+		       " sections are less than page size (4K)\n",
+		      __FUNCTION__);
+		return -ENOEXEC;
 	}
 
 	return 0;
@@ -105,7 +126,7 @@ int elf_parse_executable(struct tcb *task, struct vm_file *file,
 	struct elf_section_header *sect_header;
 	unsigned long sect_offset, sect_size;
 	unsigned long prg_offset, prg_size;
-	int err;
+	int err = 0;
 
 	/* Test that it is a valid elf file */
 	if ((err = elf_probe(elf_headerp)) < 0)
@@ -138,7 +159,8 @@ int elf_parse_executable(struct tcb *task, struct vm_file *file,
 	sect_header = (struct elf_section_header *)
 		      pager_map_file_range(file, sect_offset, sect_size);
 
-	elf_mark_segments(sect_header, elf_header.e_shnum, task, efd);
+	/* Copy segment marks from ELF file to task + efd. Return errors */
+	err = elf_mark_segments(sect_header, elf_header.e_shnum, task, efd);
 
 	/* Unmap program header table */
 	pager_unmap_pages(prg_header_start, __pfn(page_align_up(prg_size)));
@@ -146,6 +168,6 @@ int elf_parse_executable(struct tcb *task, struct vm_file *file,
 	/* Unmap section header table */
 	pager_unmap_pages(sect_header, __pfn(page_align_up(sect_size)));
 
-	return 0;
+	return err;
 }
 

tasks/mm0/src/task.c

@@ -16,6 +16,7 @@
 #include <l4lib/arch/utcb.h>
 #include <l4lib/ipcdefs.h>
 #include <l4lib/exregs.h>
+#include <l4/lib/math.h>
 #include <lib/addr.h>
 #include <lib/malloc.h>
 #include <init.h>
@@ -342,12 +343,79 @@ struct tcb *task_create(struct tcb *parent, struct task_ids *ids,
 	return task;
 }
 
+/*
+ * If bss comes consecutively after the data section, prefault the
+ * last page of the data section and zero out the bit that contains
+ * the beginning of bss. If bss spans into more pages, then map those
+ * pages as anonymous pages which are mapped by the devzero file.
+ */
+int task_map_bss(struct vm_file *f, struct exec_file_desc *efd, struct tcb *task)
+{
+	unsigned long bss_mmap_start;
+	void *mapped;
+
+	/*
+	 * Test if bss starts right from the end of data,
+	 * and not on a new page boundary.
+	 */
+	if ((task->data_end == task->bss_start) &&
+	    !is_page_aligned(task->bss_start)) {
+		unsigned long bss_size = task->bss_end - task->bss_start;
+		struct page *last_data_page;
+		void *pagebuf, *bss;
+
+		/* Prefault the last data page */
+		BUG_ON(prefault_page(task, task->data_end,
+				     VM_READ | VM_WRITE) < 0);
+		/* Get the page */
+		last_data_page = task_virt_to_page(task, task->data_end);
+
+		/* Map the page */
+		pagebuf = l4_map_helper((void *)page_to_phys(last_data_page), 1);
+
+		/* Find the bss offset */
+		bss = (void *)((unsigned long)pagebuf |
+			       (PAGE_MASK & task->bss_start));
+
+		/*
+		 * Zero out the part that is bss. This is minimum of either
+		 * end of bss or until the end of page, whichever is met first.
+		 */
+		memset((void *)bss, 0, min(TILL_PAGE_ENDS(task->data_end),
+		       (int)bss_size));
+
+		/* Unmap the page */
+		l4_unmap_helper(pagebuf, 1);
+
+		/* Push bss mmap start to next page */
+		bss_mmap_start = page_align_up(task->bss_start);
+	} else	/* Otherwise bss mmap start is same as bss_start */
+		bss_mmap_start = task->bss_start;
+
+	/*
+	 * Now if there are more pages covering bss,
+	 * map those as anonymous zero pages
+	 */
+	if (task->bss_end > bss_mmap_start) {
+		if (IS_ERR(mapped = do_mmap(0, 0, task, task->bss_start,
+					    VM_READ | VM_WRITE |
+					    VMA_PRIVATE | VMA_ANONYMOUS,
+					    __pfn(page_align_up(task->bss_end) -
+						  page_align(task->bss_start))))) {
+			printf("do_mmap: Mapping environment failed with %d.\n",
+			       (int)mapped);
+			return (int)mapped;
+		}
+	}
+
+	return 0;
+}
+
 int task_mmap_segments(struct tcb *task, struct vm_file *file, struct exec_file_desc *efd)
 {
 	void *mapped;
 	struct vm_file *shm;
-
+	int err;
-	/* Set up heap as one page after bss */
 
 	/* mmap task's text to task's address space. */
 	if (IS_ERR(mapped = do_mmap(file, efd->text_offset, task, task->text_start,
@@ -368,14 +436,12 @@ int task_mmap_segments(struct tcb *task, struct vm_file *file, struct exec_file_
 	}
 
 	/* mmap task's bss as anonymous memory. */
-	if (IS_ERR(mapped = do_mmap(0, 0, task, task->bss_start,
+	if ((err = task_map_bss(file, efd, task)) < 0) {
-				    VM_READ | VM_WRITE |
+		printf("%s: Mapping bss has failed.\n",
-				    VMA_PRIVATE | VMA_ANONYMOUS,
+		       __FUNCTION__);
-				    __pfn(task->bss_end - task->bss_start)))) {
+		return err;
-		printf("do_mmap: Mapping environment failed with %d.\n",
-		       (int)mapped);
-		return (int)mapped;
 	}
+
 	/* mmap task's environment as anonymous memory. */
 	if (IS_ERR(mapped = do_mmap(0, 0, task, task->env_start,
 				    VM_READ | VM_WRITE |

tasks/test0/include/linker.lds

@@ -30,9 +30,10 @@ SECTIONS
 	/* rodata is needed else your strings will link at physical! */
 	.rodata : AT (ADDR(.rodata) - offset) { *(.rodata) }
 	.rodata1 : AT (ADDR(.rodata1) - offset) { *(.rodata1) }
+
+	. = ALIGN(4K);
 	.data : AT (ADDR(.data) - offset)
 	{
-		. = ALIGN(4K);
 		_start_test1 = .;
 		*(.test1)
 		_end_test1 = .;

tasks/test1/SConstruct

@@ -1,78 +0,0 @@
-#
-# User space application build script
-#
-# Copyright (C) 2007 Bahadir Balban
-#
-import os
-import sys
-import shutil
-from os.path import join
-from glob import glob
-
-task_name = "test1"
-
-# The root directory of the repository where this file resides:
-project_root = "../.."
-tools_root = join(project_root, "tools")
-prev_image = join(project_root, "tasks/test0/test0.axf")
-libs_path = join(project_root, "libs")
-ld_script = "include/linker.lds"
-physical_base_ld_script = "include/physical_base.lds"
-
-# Libc situation:
-# Libposix has uClibc (and therefore posix) headers.
-# NICTA libc implements printf for us for now.
-# Libposix implements posix calls for us, e.g. mmap.
-# In conclusion nicta libc and libposix complement each other
-# they should not clash. In future libposix will be part of uclibc
-# and uclibc will be used.
-
-# libc paths:
-libc_variant = "userspace"
-libc_libpath = join(libs_path, "c/build/%s" % libc_variant)
-libc_incpath = join(libc_libpath, "include")
-libc_crt0 = join(libs_path, "c/build/crt/sys-userspace/arch-arm/crt0.o")
-libc_name = "c-%s" % libc_variant
-
-# libposix paths:
-libposix_libpath = "../libposix"
-libposix_incpath = "../libposix/include/posix"
-
-# libl4 paths:
-libl4_path = "../libl4"
-libl4_incpath = join(libl4_path, "include")
-
-# kernel paths:
-kernel_incpath = join(project_root, "include")
-
-# If crt0 is in its library path, it becomes hard to link with it.
-# For instance the linker script must use an absolute path for it.
-def copy_crt0(source, target, env):
-	os.system("cp " + str(source[0]) + " " + str(target[0]))
-
-def get_physical_base(source, target, env):
-	os.system(join(tools_root, "pyelf/readelf.py --first-free-page " + \
-		  prev_image + " >> " + physical_base_ld_script))
-
-# The kernel build environment:
-env = Environment(CC = 'arm-none-linux-gnueabi-gcc',
-		  # We don't use -nostdinc because sometimes we need standard headers,
-		  # such as stdarg.h e.g. for variable args, as in printk().
-		  CCFLAGS = ['-g', '-nostdlib', '-ffreestanding', '-std=gnu99', '-Wall', '-Werror'],
-		  LINKFLAGS = ['-nostdlib', '-T' + ld_script, "-L" + libc_libpath, "-L" + libl4_path, \
-				  '-L' + libposix_libpath],
-		  ASFLAGS = ['-D__ASSEMBLY__'],
-		  PROGSUFFIX = '.axf',			# The suffix to use for final executable
-		  ENV = {'PATH' : os.environ['PATH']},	# Inherit shell path
-		  LIBS = [libc_name, 'gcc', libc_name, 'libl4', 'libposix'],
-		  CPPFLAGS = "-D__USERSPACE__",
-		  CPPPATH = ['#include', libl4_incpath, libposix_incpath, kernel_incpath])
-
-src = [glob("src/*.c"), glob("*.c"), glob("src/arch/arm/*.c")]
-objs = env.Object(src)
-physical_base = env.Command(physical_base_ld_script, prev_image, get_physical_base)
-crt0_copied = env.Command("crt0.o", libc_crt0, copy_crt0)
-
-task = env.Program(task_name, objs + [crt0_copied])
-env.Alias(task_name, task)
-env.Depends(task, physical_base)

tasks/test1/include/.gitignore

@@ -1 +0,0 @@
-physical_base.lds

tasks/test1/include/linker.lds

@@ -1,36 +0,0 @@
-/*
- * Simple linker script for userspace or svc tasks.
- *
- * Copyright (C) 2007 Bahadir Balban
- */
-
-/*
- * The only catch with this linker script is that everything
- * is linked starting at virtual_base, and loaded starting
- * at physical_base. virtual_base is the predefined region
- * of virtual memory for userland applications. physical_base
- * is determined at build-time, it is one of the subsequent pages
- * that come after the kernel image's load area.
- */
-/* USER_AREA_START, see memlayout.h */
-virtual_base = 0x10000000;
-__stack = 0x20000000;
-INCLUDE "include/physical_base.lds"
-
-/* physical_base = 0x228000; */
-offset = virtual_base - physical_base;
-
-ENTRY(_start)
-
-SECTIONS
-{
-	. = virtual_base;
-	_start_text = .;
-	.text : AT (ADDR(.text) - offset) { crt0.o(.text) *(.text) }
-	/* rodata is needed else your strings will link at physical! */
-	.rodata : AT (ADDR(.rodata) - offset) { *(.rodata) }
-	.rodata1 : AT (ADDR(.rodata1) - offset) { *(.rodata1) }
-	.data : AT (ADDR(.data) - offset) { *(.data) }
-	.bss : AT (ADDR(.bss) - offset) { *(.bss) }
-	_end = .;
-}

tasks/test1/include/tests.h

@@ -1,7 +0,0 @@
-#ifndef __TEST0_TESTS_H__
-#define __TEST0_TESTS_H__
-
-int shmtest(void);
-int mmaptest(void);
-
-#endif /* __TEST0_TESTS_H__ */

tasks/test1/main.c

@@ -1,36 +0,0 @@
-/*
- * Some tests for posix syscalls.
- *
- * Copyright (C) 2007 Bahadir Balban
- */
-#include <stdio.h>
-#include <string.h>
-#include <l4lib/arch/message.h>
-#include <l4lib/arch/syslib.h>
-#include <l4lib/kip.h>
-#include <l4lib/utcb.h>
-#include <l4/api/ipc.h>
-#include <tests.h>
-
-#define __TASKNAME__			"test0"
-
-void wait_pager(l4id_t partner)
-{
-	u32 tag = L4_IPC_TAG_WAIT;
-	printf("%s: Syncing with pager.\n", __TASKNAME__);
-	l4_send(partner, tag);
-	printf("Pager synced with us.\n");
-}
-
-void main(void)
-{
-	/* Sync with pager */
-	wait_pager(0);
-
-	/* Check mmap/munmap */
-	mmaptest();
-
-	/* Check shmget/shmat/shmdt */
-	shmtest();
-}
-

tasks/test1/src/mmaptest.c

@@ -1,60 +0,0 @@
-/*
- * Test mmap/munmap posix calls.
- *
- * Copyright (C) 2007 - 2008 Bahadir Balban
- */
-#include <sys/ipc.h>
-#include <sys/shm.h>
-#include <sys/types.h>
-#include <sys/mman.h>
-#include <sys/types.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <tests.h>
-
-#define PAGE_SIZE		0x1000
-
-int mmaptest(void)
-{
-	int fd;
-	void *base;
-	int x = 0x1000;
-
-	if ((fd = open("./newfile.txt", O_CREAT | O_TRUNC | O_RDWR, S_IRWXU)) < 0)
-		perror("open:");
-	else
-		printf("open: Success.\n");
-
-	/* Extend the file */
-	if ((int)lseek(fd, PAGE_SIZE*16, SEEK_SET) < 0)
-		perror("lseek");
-	else
-		printf("lseek: Success.\n");
-
-	if (write(fd, &x, sizeof(x)) < 0)
-		perror("write");
-	else
-		printf("write: Success.\n");
-
-	if ((int)(base = mmap(0, PAGE_SIZE*16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) < 0)
-		perror("mmap");
-	else
-		printf("mmap: Success: %p\n", base);
-
-	*(unsigned int *)(base + PAGE_SIZE*2) = 0x1000;
-	if (msync(base + PAGE_SIZE*2, PAGE_SIZE, MS_SYNC) < 0)
-		perror("msync");
-	else
-		printf("msync: Success: %p\n", base);
-
-	if (munmap(base + PAGE_SIZE*2, PAGE_SIZE) < 0)
-		perror("munmap");
-	else
-		printf("munmap: Success: %p\n", base);
-	*(unsigned int *)(base + PAGE_SIZE*3) = 0x1000;
-	*(unsigned int *)(base + PAGE_SIZE*1) = 0x1000;
-
-	return 0;
-}

tasks/test1/src/mmaptest.c.orig

@@ -1,60 +0,0 @@
-/*
- * Test mmap/munmap posix calls.
- *
- * Copyright (C) 2007 - 2008 Bahadir Balban
- */
-#include <sys/ipc.h>
-#include <sys/shm.h>
-#include <sys/types.h>
-#include <sys/mman.h>
-#include <sys/types.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <tests.h>
-
-#define PAGE_SIZE		0x1000
-
-int mmaptest(void)
-{
-	int fd;
-	void *base;
-	int x = 0x1000;
-
-	if ((fd = open("./newfile.txt", O_CREAT | O_TRUNC | O_RDWR, S_IRWXU)) < 0)
-		perror("open:");
-	else
-		printf("open: Success.\n");
-
-	/* Extend the file */
-	if ((int)lseek(fd, PAGE_SIZE*16, SEEK_SET) < 0)
-		perror("lseek");
-	else
-		printf("lseek: Success.\n");
-
-	if (write(fd, &x, sizeof(x)) < 0)
-		perror("write");
-	else
-		printf("write: Success.\n");
-
-	if ((int)(base = mmap(0, PAGE_SIZE*16, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0)) < 0)
-		perror("mmap");
-	else
-		printf("mmap: Success: %p\n", base);
-
-	*(unsigned int *)(base + PAGE_SIZE*2) = 0x1000;
-	if (msync(base + PAGE_SIZE*2, PAGE_SIZE, MS_SYNC) < 0)
-		perror("msync");
-	else
-		printf("msync: Success: %p\n", base);
-
-	if (munmap(base + PAGE_SIZE*2, PAGE_SIZE) < 0)
-		perror("munmap");
-	else
-		printf("munmap: Success: %p\n", base);
-	*(unsigned int *)(base + PAGE_SIZE*3) = 0x1000;
-	*(unsigned int *)(base + PAGE_SIZE*1) = 0x1000;
-
-	return 0;
-}

tasks/test1/src/shmtest.c

@@ -1,51 +0,0 @@
-/*
- * Test shmget/shmat/shmdt posix calls.
- *
- * Copyright (C) 2007 - 2008 Bahadir Balban
- */
-#include <sys/ipc.h>
-#include <sys/shm.h>
-#include <sys/types.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <tests.h>
-
-int shmtest(void)
-{
-	//key_t keys[2] = { 5, 10000 };
-	key_t keys[2] = { 2, 3 };
-	void *bases[2] = { 0 , 0 };
-	int shmids[2];
-
-	printf("Initiating shmget()\n");
-	for (int i = 0; i < 2; i++) {
-		if ((shmids[i] = shmget(keys[i], 27, IPC_CREAT | 0666)) < 0) {
-			printf("Call failed.\n");
-			perror("SHMGET");
-		} else
-			printf("SHMID returned: %d\n", shmids[i]);
-	}
-	printf("Now shmat()\n");
-	for (int i = 0; i < 2; i++) {
-		if ((int)(bases[i] = shmat(shmids[i], NULL, 0)) == -1)
-			perror("SHMAT");
-		else
-			printf("SHM base address returned: %p\n", bases[i]);
-	}
-	printf("Now shmdt()\n");
-	for (int i = 0; i < 2; i++) {
-		if (shmdt(bases[i]) < 0)
-			perror("SHMDT");
-		else
-			printf("SHM detached OK.\n");
-	}
-	printf("Now shmat() again\n");
-	for (int i = 0; i < 2; i++) {
-		if ((int)(bases[i] = shmat(shmids[i], NULL, 0)) == -1)
-			perror("SHMAT");
-		else
-			printf("SHM base address returned: %p\n", bases[i]);
-	}
-
-	return 0;
-}

tasks/test1/tools/generate_bootdesc.py

@@ -1,27 +0,0 @@
-#!/usr/bin/python
-import os
-import sys
-
-compiler_prefix = "arm-linux-"
-objdump = "objdump"
-command = "-t"
-image_name = "roottask.axf"
-linkoutput_file_suffix = "-linkinfo.txt"
-linkoutput_file = image_name + linkoutput_file_suffix
-def generate_bootdesc():
-	command = compiler_prefix + objdump + " -t " + image_name + " > " + linkoutput_file
-	print command
-	os.system(command)
-	f = open(linkoutput_file, "r")
-
-	while True:
-		line = f.readline()
-		if len(line) is 0:
-			break
-		if "_start" in line or "_end" in line:
-			print line
-	f.close()
-
-if __name__ == "__main__":
-	generate_bootdesc()
-