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Modified task initialisation so that stack now comes beneath the environment

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Environment is backed by a special per-task file maintained by mm0 for each task.
This file is filled in by the env pager, by simple copying of env data into the
faulty page upon a fault. UTCB and all anon regions (stack) could use the same
scheme.

Fixed IS_ERR(x) to accept negative values that are above -1000 for errors. This
protects against false positives for pointers such as 0xE0000000.

	modified:   include/l4/generic/scheduler.h
	modified:   include/l4/macros.h
	modified:   src/arch/arm/exception.c
	modified:   tasks/fs0/include/linker.lds
	modified:   tasks/libl4/src/init.c
	modified:   tasks/libposix/shm.c
	new file:   tasks/mm0/include/env.h
	modified:   tasks/mm0/include/file.h
	new file:   tasks/mm0/include/lib/addr.h
	deleted:    tasks/mm0/include/lib/vaddr.h
	modified:   tasks/mm0/include/task.h
	new file:   tasks/mm0/include/utcb.h
	new file:   tasks/mm0/src/env.c
	modified:   tasks/mm0/src/fault.c
	modified:   tasks/mm0/src/file.c
	modified:   tasks/mm0/src/init.c
	new file:   tasks/mm0/src/lib/addr.c
	modified:   tasks/mm0/src/lib/idpool.c
	deleted:    tasks/mm0/src/lib/vaddr.c
	modified:   tasks/mm0/src/mmap.c
	modified:   tasks/mm0/src/shm.c
	modified:   tasks/mm0/src/task.c
	new file:   tasks/mm0/src/utcb.c
	modified:   tasks/test0/include/linker.lds
This commit is contained in:
Bahadir Balban
2008-02-29 01:43:56 +00:00
parent 5b7bb88008
commit 617d24b4f0
24 changed files with 316 additions and 144 deletions
Download Patch File Download Diff File Expand all files Collapse all files

40
tasks/mm0/src/fault.c
View File

@@ -108,8 +108,10 @@ int do_file_page(struct fault_data *fault)
* Read the page. (Simply read into the faulty area that's
* now mapped using a newly allocated page.)
*/
fault->vma->owner->pager->ops.read_page(fault->vma->owner,
f_offset, vaddr);
if (fault->vma->owner->pager->ops.read_page(fault->vma->owner,
f_offset,
vaddr) < 0)
BUG();
/* Remove temporary mapping */
l4_unmap(vaddr, 1, self_tid());
@@ -221,8 +223,10 @@ int do_file_page(struct fault_data *fault)
* Read the page. (Simply read into the faulty area that's
* now mapped using a newly allocated page.)
*/
fault->vma->owner->pager->ops.read_page(fault->vma->owner,
f_offset, vaddr);
if (fault->vma->owner->pager->ops.read_page(fault->vma->owner,
f_offset,
vaddr) < 0)
BUG();
/* Unmap from self */
l4_unmap(vaddr, 1, self_tid());
@@ -252,26 +256,6 @@ int do_file_page(struct fault_data *fault)
return 0;
}
/* Check if faulty page has environment and argument information */
int is_env_arg_page(struct fault_data *fault)
{
return fault->address >= page_align(fault->task->stack_end);
}
int fill_env_arg_info(struct fault_data *fault, void *vaddr)
{
/* Get the env start offset in the page */
unsigned long env_offset = fault->task->env_start & PAGE_MASK;
/* Write the environment information */
*(unsigned long *)(vaddr + env_offset) = fault->task->utcb_address;
printf("%s: Written env value 0x%x, to task address 0x%x\n",
__TASKNAME__, fault->task->utcb_address,
page_align(fault->address) + env_offset);
return 0;
}
/*
* Handles any page allocation or file ownership change for anonymous pages.
* For read accesses initialises a wired-in zero page and for write accesses
@@ -303,7 +287,7 @@ int do_anon_page(struct fault_data *fault)
/* For non-existant pages just map the zero page, unless it is the
* beginning of stack which requires environment and argument data. */
if (fault->reason & VM_READ && is_env_arg_page(fault)) {
if (fault->reason & VM_READ) {
/*
* Zero page is a special wired-in page that is mapped
* many times in many tasks. Just update its count field.
@@ -315,7 +299,7 @@ int do_anon_page(struct fault_data *fault)
}
/* Write faults require a real zero initialised page */
if (fault->reason & VM_WRITE || is_env_arg_page(fault)) {
if (fault->reason & VM_WRITE) {
paddr = alloc_page(1);
vaddr = phys_to_virt(paddr);
page = phys_to_page(paddr);
@@ -333,10 +317,6 @@ int do_anon_page(struct fault_data *fault)
/* Clear the page */
memset((void *)vaddr, 0, PAGE_SIZE);
/* If its the env/arg page on stack, fill that information */
if (is_env_arg_page(fault))
fill_env_arg_info(fault, vaddr);
/* Remove temporary mapping */
l4_unmap((void *)vaddr, 1, self_tid());