Nate Lawson wrote:
Julian Elischer wrote:
Nate Lawson wrote:
njl 2007-03-14 22:30:02 UTC
FreeBSD src repository
Modified files:
sys/i386/acpica acpi_wakeup.c sys/i386/i386 pmap.c
Log:
Create an identity mapping (V=P) super page for the low memory
region on
boot. Then, just switch to the kernel pmap when suspending instead of
allocating/freeing our own mapping every time. This should solve a
panic
of pmap_remove() being called with interrupts disabled. Thanks to Alan
Cox for developing this patch.
Note: this means that ACPI requires super page (PG_PS) support in
the CPU.
This has been present since the Pentium and first documented in the
Pentium Pro. However, it may need to be revisited later.
I thought we were still supporting 486 class machines.
if so, shouldn't this be somehow ifdef'd?
Yes, that part needs to be covered although an ifdef is not necessary
(PG_PS is defined for even 486's so this will compile).
Index: src/sys/i386/i386/pmap.c
diff -u src/sys/i386/i386/pmap.c:1.582 src/sys/i386/i386/pmap.c:1.583
--- src/sys/i386/i386/pmap.c:1.582 Mon Mar 5 21:40:10 2007
+++ src/sys/i386/i386/pmap.c Wed Mar 14 22:30:02 2007
@@ -422,6 +422,13 @@
/* Turn on PG_G on kernel page(s) */
pmap_set_pg();
+
+ /*
+ * Create an identity mapping (virt == phys) for the low 1 MB
+ * physical memory region that is used by the ACPI wakeup code.
+ * This mapping must not have PG_G set. + */
+ kernel_pmap->pm_pdir[0] = PG_PS | PG_RW | PG_V;
}
/*
I propose conditionalizing this code on "if (pseflag)". Of course, the
acpi suspend code will fail on 486's but we disable acpi entirely if the
bios date < 1999/1/1 and acpi isn't supported on the 486.
as long as you are keeping this in mind,
I have no objection as to how you tackle it..
so if someone uses a 486 based embedded system (low power etc.)
they can definitely not have any acpi support in the bios?
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