On Tue, 24 Dec 2002, Linus Torvalds wrote:
> Ingo, would you mind taking a look at the patch, to see if you see any
> paths where we don't follow the new segment register rules. It looks
> like swsuspend isn't properly saving and restoring segment register
> contents. so that will need double-checking (it wasn't correct before
> either, so this doesn't make it any worse, at least).
this reminds me of another related matter that is not fixed yet, which bug
caused XFree86 to crash if it was linked against the new libpthreads - in
vm86 mode we did not save/restore %gs [and %fs] properly, which breaks
new-style threading. The attached patch is against the 2.4 backport of the
threading stuff, i'll do a 2.5 patch after christmas eve :-)
Ingo
--- linux/include/asm-i386/processor.h.orig 2002-12-06 11:49:24.000000000 +0100
+++ linux/include/asm-i386/processor.h 2002-12-06 11:52:39.000000000 +0100
@@ -388,6 +388,7 @@
struct vm86_struct * vm86_info;
unsigned long screen_bitmap;
unsigned long v86flags, v86mask, saved_esp0;
+ unsigned int saved_fs, saved_gs;
/* IO permissions */
int ioperm;
unsigned long io_bitmap[IO_BITMAP_SIZE+1];
--- linux/arch/i386/kernel/vm86.c.orig 2002-12-06 11:50:26.000000000 +0100
+++ linux/arch/i386/kernel/vm86.c 2002-12-06 11:53:40.000000000 +0100
@@ -113,6 +113,8 @@
tss = init_tss + smp_processor_id();
tss->esp0 = current->thread.esp0 = current->thread.saved_esp0;
current->thread.saved_esp0 = 0;
+ loadsegment(fs, current->thread.saved_fs);
+ loadsegment(gs, current->thread.saved_gs);
ret = KVM86->regs32;
return ret;
}
@@ -277,6 +279,9 @@
*/
info->regs32->eax = 0;
tsk->thread.saved_esp0 = tsk->thread.esp0;
+ asm volatile("movl %%fs,%0":"=m" (tsk->thread.saved_fs));
+ asm volatile("movl %%gs,%0":"=m" (tsk->thread.saved_gs));
+
tss = init_tss + smp_processor_id();
tss->esp0 = tsk->thread.esp0 = (unsigned long) &info->VM86_TSS_ESP0;
-
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This archive was generated by hypermail 2b29 : Tue Dec 31 2002 - 22:00:07 EST