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[PATCH] uml: maintain own LDT entries

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Patch imlements full LDT handling in SKAS:
 * UML holds it's own LDT table, used to deliver data on
   modify_ldt(READ)
 * UML disables the default_ldt, inherited from the host (SKAS3)
   or resets LDT entries, set by host's clib and inherited in
   SKAS0
 * A new global variable skas_needs_stub is inserted, that
   can be used to decide, whether stub-pages must be supported
   or not.
 * Uses the syscall-stub to replace missing PTRACE_LDT (therefore,
   write_ldt_entry needs to be modified)

Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Bodo Stroesser
2005-11-07 00:58:55 -08:00
committed by Linus Torvalds
parent e763b793f7
commit 858259cf7d
13 changed files with 724 additions and 141 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
arch/um/kernel/skas/include/mmu-skas.h
View File

@@ -8,6 +8,7 @@
#include "linux/config.h"
#include "mm_id.h"
#include "asm/ldt.h"
struct mmu_context_skas {
struct mm_id id;
@@ -15,6 +16,7 @@ struct mmu_context_skas {
#ifdef CONFIG_3_LEVEL_PGTABLES
unsigned long last_pmd;
#endif
uml_ldt_t ldt;
};
extern void switch_mm_skas(struct mm_id * mm_idp);

3
arch/um/kernel/skas/include/skas.h
View File

@@ -10,7 +10,8 @@
#include "sysdep/ptrace.h"
extern int userspace_pid[];
extern int proc_mm, ptrace_faultinfo;
extern int proc_mm, ptrace_faultinfo, ptrace_ldt;
extern int skas_needs_stub;
extern void switch_threads(void *me, void *next);
extern void thread_wait(void *sw, void *fb);

2
arch/um/kernel/skas/mem.c
View File

@@ -20,7 +20,7 @@ unsigned long set_task_sizes_skas(int arg, unsigned long *host_size_out,
*task_size_out = CONFIG_HOST_TASK_SIZE;
#else
*host_size_out = top;
if (proc_mm && ptrace_faultinfo)
if (!skas_needs_stub)
*task_size_out = top;
else *task_size_out = CONFIG_STUB_START & PGDIR_MASK;
#endif

44
arch/um/kernel/skas/mmu.c
View File

@@ -15,6 +15,7 @@
#include "asm/mmu.h"
#include "asm/pgalloc.h"
#include "asm/pgtable.h"
#include "asm/ldt.h"
#include "os.h"
#include "skas.h"
@@ -74,13 +75,12 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
int init_new_context_skas(struct task_struct *task, struct mm_struct *mm)
{
struct mm_struct *cur_mm = current->mm;
struct mm_id *cur_mm_id = &cur_mm->context.skas.id;
struct mm_id *mm_id = &mm->context.skas.id;
struct mmu_context_skas *from_mm = NULL;
struct mmu_context_skas *to_mm = &mm->context.skas;
unsigned long stack = 0;
int from, ret = -ENOMEM;
int from_fd, ret = -ENOMEM;
if(!proc_mm || !ptrace_faultinfo){
if(skas_needs_stub){
stack = get_zeroed_page(GFP_KERNEL);
if(stack == 0)
goto out;
@@ -102,33 +102,43 @@ int init_new_context_skas(struct task_struct *task, struct mm_struct *mm)
mm->nr_ptes--;
}
mm_id->stack = stack;
to_mm->id.stack = stack;
if(current->mm != NULL && current->mm != &init_mm)
from_mm = &current->mm->context.skas;
if(proc_mm){
if((cur_mm != NULL) && (cur_mm != &init_mm))
from = cur_mm_id->u.mm_fd;
else from = -1;
if(from_mm)
from_fd = from_mm->id.u.mm_fd;
else from_fd = -1;
ret = new_mm(from, stack);
ret = new_mm(from_fd, stack);
if(ret < 0){
printk("init_new_context_skas - new_mm failed, "
"errno = %d\n", ret);
goto out_free;
}
mm_id->u.mm_fd = ret;
to_mm->id.u.mm_fd = ret;
}
else {
if((cur_mm != NULL) && (cur_mm != &init_mm))
mm_id->u.pid = copy_context_skas0(stack,
cur_mm_id->u.pid);
else mm_id->u.pid = start_userspace(stack);
if(from_mm)
to_mm->id.u.pid = copy_context_skas0(stack,
from_mm->id.u.pid);
else to_mm->id.u.pid = start_userspace(stack);
}
ret = init_new_ldt(to_mm, from_mm);
if(ret < 0){
printk("init_new_context_skas - init_ldt"
" failed, errno = %d\n", ret);
goto out_free;
}
return 0;
out_free:
if(mm_id->stack != 0)
free_page(mm_id->stack);
if(to_mm->id.stack != 0)
free_page(to_mm->id.stack);
out:
return ret;
}

6
arch/um/kernel/skas/process.c
View File

@@ -381,9 +381,9 @@ int copy_context_skas0(unsigned long new_stack, int pid)
}
/*
* This is used only, if proc_mm is available, while PTRACE_FAULTINFO
* isn't. Opening /proc/mm creates a new mm_context, which lacks the stub-pages
* Thus, we map them using /proc/mm-fd
* This is used only, if stub pages are needed, while proc_mm is
* availabl. Opening /proc/mm creates a new mm_context, which lacks
* the stub-pages. Thus, we map them using /proc/mm-fd
*/
void map_stub_pages(int fd, unsigned long code,
unsigned long data, unsigned long stack)

2
arch/um/kernel/skas/process_kern.c
View File

@@ -145,7 +145,7 @@ int new_mm(int from, unsigned long stack)
"err = %d\n", -n);
}
if(!ptrace_faultinfo)
if(skas_needs_stub)
map_stub_pages(fd, CONFIG_STUB_CODE, CONFIG_STUB_DATA, stack);
return(fd);