freebsd-dev/stand/powerpc/ofw/main.c
Leandro Lupori 83e356c3c9 [PPC64] Implement CAS
Guest PPC OSs running under a hypervisor may communicate the features they
support, in order for the hypervisor to expose a virtualized machine in the way
the client (guest OS) expects (see LoPAPR 1.1 - B.6.2.3).

This is done by calling the "/ibm,client-architecture-support" (CAS) method,
informing supported features in option vectors.  Until now, FreeBSD wasn't
using CAS, but instead relied on hypervisor/QEMU's defaults.

The problem is that, without CAS, it is very inconvenient to run POWER9 VMs on
a POWER9 host running with radix enabled.  This happens because, in this case,
the QEMU default is to present the guest OS a dual MMU (HPT/RPT), instead of
presenting a regular HPT MMU, as FreeBSD expects, resulting in an early panic.
The known workarounds required either changing the host to disable radix or
passing a flag to QEMU to run in a POWER8 compatible mode.

With CAS, FreeBSD is now able to communicate that it wants an HPT MMU,
independent of the host setup, which now makes FreeBSD work on POWER9/pseries,
with KVM enabled and without hugepages (support added in a previous commit).

As CAS is invoked through OpenFirmware's call-method interface, it needs to be
performed early, when OpenFirmware is still operational. Besides, now that FDT
is the default way to inspect the device tree on PPC, OFW call-method feature
will be unavailable by default, when control is passed to the kernel. Because
of this, the call to CAS is being performed at the loader, instead of at the
kernel.

To avoid regressions with old platforms, this change uses CAS only on
POWER8/POWER9.

Reviewed by:	jhibbits
Differential Revision:	https://reviews.freebsd.org/D20827
2019-07-31 20:31:36 +00:00

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5.1 KiB
C

/*-
* Copyright (c) 2000 Benno Rice <benno@jeamland.net>
* Copyright (c) 2000 Stephane Potvin <sepotvin@videotron.ca>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <stand.h>
#include "openfirm.h"
#include "libofw.h"
#include "bootstrap.h"
#include <machine/psl.h>
struct arch_switch archsw; /* MI/MD interface boundary */
extern char end[];
uint32_t acells, scells;
static char bootargs[128];
#define HEAP_SIZE 0x800000
static char heap[HEAP_SIZE]; // In BSS, so uses no space
#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)
{
bzero(heap, HEAP_SIZE);
setheap(heap, (void *)((int)heap + HEAP_SIZE));
}
uint64_t
memsize(void)
{
phandle_t memoryp;
cell_t reg[24];
int i, sz;
uint64_t memsz;
memsz = 0;
memoryp = OF_instance_to_package(memory);
sz = OF_getprop(memoryp, "reg", &reg, sizeof(reg));
sz /= sizeof(reg[0]);
for (i = 0; i < sz; i += (acells + scells)) {
if (scells > 1)
memsz += (uint64_t)reg[i + acells] << 32;
memsz += reg[i + acells + scells - 1];
}
return (memsz);
}
#ifdef CAS
extern int ppc64_cas(void);
static int
ppc64_autoload(void)
{
const char *cas;
if ((cas = getenv("cas")) && cas[0] == '1')
if (ppc64_cas() != 0)
return (-1);
return (ofw_autoload());
}
#endif
int
main(int (*openfirm)(void *))
{
phandle_t root;
int i;
char bootpath[64];
char *ch;
int bargc;
char **bargv;
/*
* Initialise the Open Firmware routines by giving them the entry point.
*/
OF_init(openfirm);
root = OF_finddevice("/");
scells = acells = 1;
OF_getprop(root, "#address-cells", &acells, sizeof(acells));
OF_getprop(root, "#size-cells", &scells, sizeof(scells));
/*
* Initialise the heap as early as possible. Once this is done,
* alloc() is usable. The stack is buried inside us, so this is
* safe.
*/
init_heap();
/*
* Set up console.
*/
cons_probe();
/*
* March through the device switch probing for things.
*/
for (i = 0; devsw[i] != NULL; i++)
if (devsw[i]->dv_init != NULL)
(devsw[i]->dv_init)();
printf("\n%s", bootprog_info);
printf("Memory: %lldKB\n", memsize() / 1024);
OF_getprop(chosen, "bootpath", bootpath, 64);
ch = strchr(bootpath, ':');
*ch = '\0';
printf("Booted from: %s\n", bootpath);
printf("\n");
/*
* Only parse the first bootarg if present. It should
* be simple to handle extra arguments
*/
OF_getprop(chosen, "bootargs", bootargs, sizeof(bootargs));
bargc = 0;
parse(&bargc, &bargv, bootargs);
if (bargc == 1)
env_setenv("currdev", EV_VOLATILE, bargv[0], ofw_setcurrdev,
env_nounset);
else
env_setenv("currdev", EV_VOLATILE, bootpath,
ofw_setcurrdev, env_nounset);
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;
archsw.arch_copyout = ofw_copyout;
archsw.arch_readin = ofw_readin;
#ifdef CAS
setenv("cas", "1", 0);
archsw.arch_autoload = ppc64_autoload;
#else
archsw.arch_autoload = ofw_autoload;
#endif
interact(); /* doesn't return */
OF_exit();
return 0;
}
COMMAND_SET(halt, "halt", "halt the system", command_halt);
static int
command_halt(int argc, char *argv[])
{
OF_exit();
return (CMD_OK);
}
COMMAND_SET(memmap, "memmap", "print memory map", command_memmap);
int
command_memmap(int argc, char **argv)
{
ofw_memmap(acells);
return (CMD_OK);
}