[uml-devel] 2.6-specific UML patches (modules, modversions, various other stuff)

[BlaisorBlade <blaisorblade_spam@yahoo.it>]

Hi! I'm happy to hear again from you.

I don't remember if you answered when I posted this URL:
http://web.tiscali.it/no-redirect-tiscali/blaisorblade/

There you will find a number of patches for UML 2.6. Some are mine and some 
come from Ingo and M A Young; I've included everything Ingo posted minus the 
speedup - breakage for 2.4 host. That is, MM_COPY_SEGMENTS is still called by 
UML but if the host is a 2.6 that is a no-op.

Only use the v8! In the Readme there is a careful description of each patch - 
ask for more comments if you need.

They are tested enough (at least for building UML; the resulting patch should 
work even on i386, and at least it compiles). Maybe you already have in your 
tree some of the patches; they apply onto vanilla linux kernel. The -test9 
patch has been split: the change for tty_init has been removed, and the 
change to mm/memory.c has been replaced. You can find the two patches to move 
out here, as A-03* and A-04*:

http://web.tiscali.it/no-redirect-tiscali/blaisorblade/linux/archives/UML/v6/A-Orig/

The replacements are in the B directory. About the A-04 patch, and this hunk 
in particular(it goes to mm/memory.c):

@@ -700,19 +719,8 @@

                vma = find_extend_vma(mm, start);

-#ifdef FIXADDR_USER_START
-               if (!vma &&
-                   start >= FIXADDR_USER_START && start < FIXADDR_USER_END) {
-                       static struct vm_area_struct fixmap_vma = {
-                               /* Catch users - if there are any valid
-                                  ones, we can make this be "&init_mm" or
-                                  something.  */
-                               .vm_mm = NULL,
-                               .vm_start = FIXADDR_USER_START,
-                               .vm_end = FIXADDR_USER_END,
-                               .vm_page_prot = PAGE_READONLY,
-                               .vm_flags = VM_READ | VM_EXEC,
-                       };
+#ifdef FIXADDR_START
+               if (!vma && start >= FIXADDR_START && start < FIXADDR_TOP) {
                        unsigned long pg = start & PAGE_MASK;
                        pgd_t *pgd;
                        pmd_t *pmd;
Did you have any reason for replacing FIXADDR_USER_START with FIXADDR_START?
I've looked in older patches and saw that FIXADDR_USER_START didn't exist, so 
I thought that you simply didn't see the change happened in mainline; even 
because I've maybe understood what code does, and there is no need to map 
anything in a process's address space except for the VSYSCALL page. Am I 
right?

I must admit that with my replacement for that patch, I've got one 
non-repeatable segfault, in the early boot process. I've never had it any 
more, so maybe it's elsewhere.

For the makefile patches, they haven't still been accepted by Kbuild 
developers :-(. But everything is open (kbuild mail list is not that active, 
actually...)

Bye
-- 
cat <<EOSIGN
Paolo Giarrusso, aka Blaisorblade
Linux Kernel 2.4.23/2.6.0 on an i686; Linux registered user n. 292729
EOSIGN



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