Date: Thu, 5 Mar 1998 16:14:43 +1100 From: Bruce Evans <bde@zeta.org.au> To: adkin003@tc.umn.edu, Tor.Egge@idi.ntnu.no Cc: smp@FreeBSD.ORG Subject: Re: Current SMP kernel panics on booting Message-ID: <199803050514.QAA02534@godzilla.zeta.org.au>
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>Please try a kernel with the NO_F00F_HACK option. f00f_hack() is
>broken, since it causes further calls to setidt() to have very little
>effect.
Here are my (very old :-() fixes for this. I think you only want the
first hunk. Only one page is necessary for the buggy version and for
a version that maps the page read-write in setidt(), so I'm saving
some space and preparing for a better setidt() by only allocating one.
The other changes are mostly style fixes.
This should all be done differently, perhaps by allocating a page or
two of physical memory earlier as in NetBSD. It would have been better
to allocate one idt without padding in the text section and mapping it
read/write in setidt(), but the 4MB page breaks the read-onlyness of
the text section.
Bruce
diff -c2 machdep.c~ machdep.c
*** machdep.c~ Tue Mar 3 12:58:07 1998
--- machdep.c Tue Mar 3 12:58:10 1998
***************
*** 1056,1061 ****
int selec;
{
! struct gate_descriptor *ip = idt + idx;
ip->gd_looffset = (int)func;
ip->gd_selector = selec;
--- 1119,1129 ----
int selec;
{
! struct gate_descriptor *ip;
+ #if defined(I586_CPU) && !defined(NO_F00F_HACK)
+ ip = (t_idt != NULL ? t_idt : idt) + idx;
+ #else
+ ip = idt + idx;
+ #endif
ip->gd_looffset = (int)func;
ip->gd_selector = selec;
***************
*** 1560,1593 ****
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
! static void f00f_hack(void *unused);
! SYSINIT(f00f_hack, SI_SUB_INTRINSIC, SI_ORDER_FIRST, f00f_hack, NULL);
static void
! f00f_hack(void *unused) {
struct region_descriptor r_idt;
vm_offset_t tmp;
- int i;
if (!has_f00f_bug)
return;
!
! printf("Intel Pentium F00F detected, installing workaround\n");
!
! r_idt.rd_limit = sizeof(idt) - 1;
!
tmp = kmem_alloc(kernel_map, PAGE_SIZE * 2);
if (tmp == 0)
panic("kmem_alloc returned 0");
! if (((unsigned int)tmp & (PAGE_SIZE-1)) != 0)
! panic("kmem_alloc returned non-page-aligned memory");
! /* Put the first seven entries in the lower page */
! t_idt = (struct gate_descriptor*)(tmp + PAGE_SIZE - (7*8));
bcopy(idt, t_idt, sizeof(idt));
! r_idt.rd_base = (int)t_idt;
! lidt(&r_idt);
! if (vm_map_protect(kernel_map, tmp, tmp + PAGE_SIZE,
! VM_PROT_READ, FALSE) != KERN_SUCCESS)
panic("vm_map_protect failed");
! return;
}
#endif /* defined(I586_CPU) && !NO_F00F_HACK */
--- 1623,1662 ----
#if defined(I586_CPU) && !defined(NO_F00F_HACK)
! static void f00f_hack __P((void *unused));
! SYSINIT(f00f_hack, SI_SUB_INTRINSIC, SI_ORDER_FIRST, f00f_hack, NULL)
static void
! f00f_hack(unused)
! void *unused;
! {
struct region_descriptor r_idt;
vm_offset_t tmp;
if (!has_f00f_bug)
return;
! printf("Intel Pentium detected, installing workaround for F00F bug\n");
! #if 0
tmp = kmem_alloc(kernel_map, PAGE_SIZE * 2);
+ #else
+ tmp = kmem_alloc(kernel_map, PAGE_SIZE * 1);
+ #endif
if (tmp == 0)
panic("kmem_alloc returned 0");
!
! /* Put the problematic entry (#6) at the end of the lower page. */
! t_idt = (struct gate_descriptor *)
! #if 0
! (tmp + PAGE_SIZE - 7 * sizeof(struct gate_descriptor));
! #else
! tmp;
! #endif
!
bcopy(idt, t_idt, sizeof(idt));
! if (vm_map_protect(kernel_map, tmp, tmp + PAGE_SIZE, VM_PROT_READ,
! FALSE) != KERN_SUCCESS)
panic("vm_map_protect failed");
! r_idt.rd_limit = sizeof(idt) - 1;
! r_idt.rd_base = (unsigned)t_idt;
! lidt(&r_idt);
}
#endif /* defined(I586_CPU) && !NO_F00F_HACK */
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