Fatal trap 12: page fault on Acer Chromebook 720 (peppy)
Konstantin Belousov
kostikbel at gmail.com
Wed Aug 22 21:15:40 UTC 2018
On Wed, Aug 22, 2018 at 10:03:54PM +0200, Michael Gmelin wrote:
>
>
> > On 22. Aug 2018, at 17:46, Konstantin Belousov <kostikbel at gmail.com> wrote:
> >
> >> On Tue, Aug 21, 2018 at 12:14:35AM +0200, Michael Gmelin wrote:
> >>
> >>
> >>>> On 20. Aug 2018, at 17:09, Konstantin Belousov <kostikbel at gmail.com> wrote:
> >>>>
> >>>> On Mon, Aug 20, 2018 at 12:45:12AM +0200, Michael Gmelin wrote:
> >>>>
> >>>> See here for a screenshot (also including the output of "show pte
> >>>> 0xfffff80001000000"):
> >>>>
> >>>> https://gist.github.com/grembo/78d0f2a100dd4f16775b85a118769658#file-ddb1-png
> >>> It is too early for ddb routines to register.
> >>> Ok can you try the following debugging patch, to verify my guess ?
> >>>
> >>> diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
> >>> index 18777d23f09..cd05fdb763f 100644
> >>> --- a/sys/amd64/amd64/pmap.c
> >>> +++ b/sys/amd64/amd64/pmap.c
> >>> @@ -1052,8 +1052,7 @@ create_pagetables(vm_paddr_t *firstaddr)
> >>> pd_p = (pd_entry_t *)DMPDkernphys;
> >>> for (i = 0; i < (NPDEPG * nkdmpde); i++)
> >>> pd_p[i] = (i << PDRSHIFT) | X86_PG_V | PG_PS | pg_g |
> >>> - X86_PG_M | X86_PG_A | pg_nx |
> >>> - bootaddr_rwx(i << PDRSHIFT);
> >>> + X86_PG_M | X86_PG_A | pg_nx | X86_PG_RW;
> >>> for (i = 0; i < nkdmpde; i++)
> >>> pdp_p[i] = (DMPDkernphys + ptoa(i)) | X86_PG_RW |
> >>> X86_PG_V;
> >>
> >> With this change it boots okay (mptramp_pagetables is 0x1000000, as expected).
> >
> > Can you apply the following on top of the previous debugging patch and show
> > me the line printed ?
> >
> > diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
> > index 3d70532b7fd..613fa9f2165 100644
> > --- a/sys/amd64/amd64/pmap.c
> > +++ b/sys/amd64/amd64/pmap.c
> > @@ -2662,6 +2662,7 @@ pmap_pinit0(pmap_t pmap)
> > pmap->pm_pcids[i].pm_gen = 1;
> > }
> > pmap_activate_boot(pmap);
> > +printf("bootaddr addr %#lx rwx %#lx btext %#lx _end %#lx brwsection %#lx etext %#lx KERNBASE %#lx\n", 0x1000000UL, bootaddr_rwx(0x1000000UL), (uintptr_t)btext, (uintptr_t)_end, (uintptr_t)brwsection, (uintptr_t)etext, (uintptr_t)KERNBASE);
> > }
> >
> > void
>
> bootaddr addr 0x1000000 rwx 0 btext 0xffffffff80342000 _end 0xffffffff823cf840 brwsection #ffffffff81a00000 etext 0xffffffff812041e4 KERNBASE 0xffffffff80000000
>
Try this, please. Revert all debugging pmap.c patches that I provided
before.
diff --git a/sys/amd64/amd64/mp_machdep.c b/sys/amd64/amd64/mp_machdep.c
index 4ca2e07e578..2ee8f862854 100644
--- a/sys/amd64/amd64/mp_machdep.c
+++ b/sys/amd64/amd64/mp_machdep.c
@@ -87,6 +87,8 @@ __FBSDID("$FreeBSD$");
#define GiB(v) (v ## ULL << 30)
+#define AP_BOOTPT_SZ (PAGE_SIZE * 3)
+
extern struct pcpu __pcpu[];
/* Temporary variables for init_secondary() */
@@ -101,45 +103,78 @@ char *dbg_stack;
static int start_ap(int apic_id);
+static bool
+is_kernel_paddr(vm_paddr_t pa)
+{
+
+ return (pa >= trunc_2mpage(btext - KERNBASE) &&
+ pa < round_page(_end - KERNBASE));
+}
+
+static bool
+is_mpboot_good(vm_paddr_t start, vm_paddr_t end)
+{
+
+ return (start + AP_BOOTPT_SZ <= GiB(4) &&
+ end >= start + AP_BOOTPT_SZ && atop(end) < Maxmem);
+}
+
/*
* Calculate usable address in base memory for AP trampoline code.
*/
void
mp_bootaddress(vm_paddr_t *physmap, unsigned int *physmap_idx)
{
+ vm_paddr_t start, end;
unsigned int i;
bool allocated;
alloc_ap_trampoline(physmap, physmap_idx);
+ /*
+ * Find a memory region big enough below the 4GB boundary to
+ * store the initial page tables. Region must be mapped by
+ * the direct map.
+ *
+ * Note that it needs to be aligned to a page boundary.
+ */
allocated = false;
for (i = *physmap_idx; i <= *physmap_idx; i -= 2) {
/*
- * Find a memory region big enough below the 4GB
- * boundary to store the initial page tables. Region
- * must be mapped by the direct map.
- *
- * Note that it needs to be aligned to a page
- * boundary.
+ * First, try to chomp at the start of the physmap region.
+ * Kernel binary might claim it already.
+ */
+ start = round_page(physmap[i]);
+ end = trunc_page(physmap[i + 1]);
+ if (is_mpboot_good(start, end) &&
+ !is_kernel_paddr(start) && !is_kernel_paddr(end - 1)) {
+ allocated = true;
+ physmap[i] = start + AP_BOOTPT_SZ;
+ break;
+ }
+
+ /*
+ * Second, try to chomp at the end. Again, check
+ * against kernel.
*/
- if (physmap[i] >= GiB(4) || physmap[i + 1] -
- round_page(physmap[i]) < PAGE_SIZE * 3 ||
- atop(physmap[i + 1]) > Maxmem)
- continue;
-
- allocated = true;
- mptramp_pagetables = round_page(physmap[i]);
- physmap[i] = round_page(physmap[i]) + (PAGE_SIZE * 3);
+ end = trunc_page(physmap[i + 1]);
+ start = end - AP_BOOTPT_SZ;
+ if (start >= physmap[i] && is_mpboot_good(start, end) &&
+ !is_kernel_paddr(start) && !is_kernel_paddr(end - 1)) {
+ allocated = true;
+ physmap[i + 1] = start;
+ break;
+ }
+ }
+ if (allocated) {
+ mptramp_pagetables = start;
if (physmap[i] == physmap[i + 1] && *physmap_idx != 0) {
memmove(&physmap[i], &physmap[i + 2],
sizeof(*physmap) * (*physmap_idx - i + 2));
*physmap_idx -= 2;
}
- break;
- }
-
- if (!allocated) {
- mptramp_pagetables = trunc_page(boot_address) - (PAGE_SIZE * 3);
+ } else {
+ mptramp_pagetables = trunc_page(boot_address) - AP_BOOTPT_SZ;
if (bootverbose)
printf(
"Cannot find enough space for the initial AP page tables, placing them at %#x",
More information about the freebsd-current
mailing list