Author: nwhitehorn
Date: Sun Mar 4 04:49:09 2018
New Revision: 330371
URL: https://svnweb.freebsd.org/changeset/base/330371
Log:
Where we can, pass the kernel an FDT facsimile of the OF device tree rather
than a pointer to Open Firmware by default. This eliminates a number of
potentially unsafe calls to firmware from the kernel and provides better
performance.
This feature is meant to be expanded until it is on by default
unconditionally and, ideally, we can then garbage-collect the
nightmare pile of hacks required to call into Open Firmware from a live
kernel.
Reviewed by: jhibbits
Modified:
head/stand/powerpc/ofw/main.c
Modified: head/stand/powerpc/ofw/main.c
==============================================================================
--- head/stand/powerpc/ofw/main.c Sun Mar 4 03:23:19 2018
(r330370)
+++ head/stand/powerpc/ofw/main.c Sun Mar 4 04:49:09 2018
(r330371)
@@ -33,6 +33,8 @@ __FBSDID("$FreeBSD$");
#include "libofw.h"
#include "bootstrap.h"
+#include <machine/psl.h>
+
struct arch_switch archsw; /* MI/MD interface boundary */
extern char end[];
@@ -47,6 +49,16 @@ static char heap[HEAP_SIZE]; // In BSS, so uses no spa
#define OF_puts(fd, text) OF_write(fd, text, strlen(text))
+static __inline register_t
+mfmsr(void)
+{
+ register_t value;
+
+ __asm __volatile ("mfmsr %0" : "=r"(value));
+
+ return (value);
+}
+
void
init_heap(void)
{
@@ -144,6 +156,15 @@ main(int (*openfirm)(void *))
env_setenv("loaddev", EV_VOLATILE, bootpath, env_noset,
env_nounset);
setenv("LINES", "24", 1); /* optional */
+
+ /*
+ * On non-Apple hardware, where it works reliably, pass flattened
+ * device trees to the kernel by default instead of OF CI pointers.
+ * Apple hardware is the only virtual-mode OF implementation in
+ * existence, so far as I am aware, so use that as a flag.
+ */
+ if (!(mfmsr() & PSL_DR))
+ setenv("usefdt", "1", 1);
archsw.arch_getdev = ofw_getdev;
archsw.arch_copyin = ofw_copyin;
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