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powerpc/powernv: Add OPAL takeover from PowerVM

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On machines supporting the OPAL firmware version 1, the system
is initially booted under pHyp. We then use a special hypercall
to verify if OPAL is available and if it is, we then trigger
a "takeover" which disables pHyp and loads the OPAL runtime
firmware, giving control to the kernel in hypervisor mode.

This patch add the necessary code to detect that the OPAL takeover
capability is present when running under PowerVM (aka pHyp) and
perform said takeover to get hypervisor control of the processor.

To perform the takeover, we must first use RTAS (within Open
Firmware runtime environment) to start all processors & threads,
in order to give control to OPAL on all of them. We then call
the takeover hypercall on everybody, OPAL will re-enter the kernel
main entry point passing it a flat device-tree.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Benjamin Herrenschmidt 2011-09-19 18:27:58 +00:00
parent 344eb010b2
commit 27f4488872
6 changed files with 419 additions and 19 deletions
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50
arch/powerpc/include/asm/opal.h Normal file
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@ -0,0 +1,50 @@
/*
* PowerNV OPAL definitions.
*
* Copyright 2011 IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef __OPAL_H
#define __OPAL_H
/****** Takeover interface ********/
/* PAPR H-Call used to querty the HAL existence and/or instanciate
* it from within pHyp (tech preview only).
*
* This is exclusively used in prom_init.c
*/
#ifndef __ASSEMBLY__
struct opal_takeover_args {
u64 k_image; /* r4 */
u64 k_size; /* r5 */
u64 k_entry; /* r6 */
u64 k_entry2; /* r7 */
u64 hal_addr; /* r8 */
u64 rd_image; /* r9 */
u64 rd_size; /* r10 */
u64 rd_loc; /* r11 */
};
extern long opal_query_takeover(u64 *hal_size, u64 *hal_align);
extern long opal_do_takeover(struct opal_takeover_args *args);
extern int opal_enter_rtas(struct rtas_args *args,
unsigned long data,
unsigned long entry);
#endif /* __ASSEMBLY__ */
/****** OPAL APIs ******/
#endif /* __OPAL_H */

4
arch/powerpc/kernel/head_64.S
View File

@ -51,6 +51,10 @@
* For pSeries or server processors:
* 1. The MMU is off & open firmware is running in real mode.
* 2. The kernel is entered at __start
* -or- For OPAL entry:
* 1. The MMU is off, processor in HV mode, primary CPU enters at 0
* with device-tree in gpr3
* 2. Secondary processors enter at 0x60 with PIR in gpr3
*
* For iSeries:
* 1. The MMU is on (as it always is for iSeries)

239
arch/powerpc/kernel/prom_init.c
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@ -43,6 +43,7 @@
#include <asm/btext.h>
#include <asm/sections.h>
#include <asm/machdep.h>
#include <asm/opal.h>
#include <linux/linux_logo.h>
@ -185,6 +186,7 @@ static unsigned long __initdata prom_tce_alloc_end;
#define PLATFORM_LPAR 0x0001
#define PLATFORM_POWERMAC 0x0400
#define PLATFORM_GENERIC 0x0500
#define PLATFORM_OPAL 0x0600
static int __initdata of_platform;
@ -644,7 +646,7 @@ static void __init early_cmdline_parse(void)
}
}
#ifdef CONFIG_PPC_PSERIES
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
/*
* There are two methods for telling firmware what our capabilities are.
* Newer machines have an "ibm,client-architecture-support" method on the
@ -1274,6 +1276,195 @@ static void __init prom_init_mem(void)
prom_printf(" ram_top : %x\n", RELOC(ram_top));
}
static void __init prom_close_stdin(void)
{
struct prom_t *_prom = &RELOC(prom);
ihandle val;
if (prom_getprop(_prom->chosen, "stdin", &val, sizeof(val)) > 0)
call_prom("close", 1, 0, val);
}
#ifdef CONFIG_PPC_POWERNV
static u64 __initdata prom_opal_size;
static u64 __initdata prom_opal_align;
static int __initdata prom_rtas_start_cpu;
static u64 __initdata prom_rtas_data;
static u64 __initdata prom_rtas_entry;
/* XXX Don't change this structure without updating opal-takeover.S */
static struct opal_secondary_data {
s64 ack; /* 0 */
u64 go; /* 8 */
struct opal_takeover_args args; /* 16 */
} opal_secondary_data;
extern char opal_secondary_entry;
static void prom_query_opal(void)
{
long rc;
prom_printf("Querying for OPAL presence... ");
rc = opal_query_takeover(&RELOC(prom_opal_size),
&RELOC(prom_opal_align));
prom_debug("(rc = %ld) ", rc);
if (rc != 0) {
prom_printf("not there.\n");
return;
}
RELOC(of_platform) = PLATFORM_OPAL;
prom_printf(" there !\n");
prom_debug(" opal_size = 0x%lx\n", RELOC(prom_opal_size));
prom_debug(" opal_align = 0x%lx\n", RELOC(prom_opal_align));
if (RELOC(prom_opal_align) < 0x10000)
RELOC(prom_opal_align) = 0x10000;
}
static int prom_rtas_call(int token, int nargs, int nret, int *outputs, ...)
{
struct rtas_args rtas_args;
va_list list;
int i;
rtas_args.token = token;
rtas_args.nargs = nargs;
rtas_args.nret = nret;
rtas_args.rets = (rtas_arg_t *)&(rtas_args.args[nargs]);
va_start(list, outputs);
for (i = 0; i < nargs; ++i)
rtas_args.args[i] = va_arg(list, rtas_arg_t);
va_end(list);
for (i = 0; i < nret; ++i)
rtas_args.rets[i] = 0;
opal_enter_rtas(&rtas_args, RELOC(prom_rtas_data),
RELOC(prom_rtas_entry));
if (nret > 1 && outputs != NULL)
for (i = 0; i < nret-1; ++i)
outputs[i] = rtas_args.rets[i+1];
return (nret > 0)? rtas_args.rets[0]: 0;
}
static void __init prom_opal_hold_cpus(void)
{
int i, cnt, cpu, rc;
long j;
phandle node;
char type[64];
u32 servers[8];
struct prom_t *_prom = &RELOC(prom);
void *entry = (unsigned long *)&RELOC(opal_secondary_entry);
struct opal_secondary_data *data = &RELOC(opal_secondary_data);
prom_debug("prom_opal_hold_cpus: start...\n");
prom_debug(" - entry = 0x%x\n", entry);
prom_debug(" - data = 0x%x\n", data);
data->ack = -1;
data->go = 0;
/* look for cpus */
for (node = 0; prom_next_node(&node); ) {
type[0] = 0;
prom_getprop(node, "device_type", type, sizeof(type));
if (strcmp(type, RELOC("cpu")) != 0)
continue;
/* Skip non-configured cpus. */
if (prom_getprop(node, "status", type, sizeof(type)) > 0)
if (strcmp(type, RELOC("okay")) != 0)
continue;
cnt = prom_getprop(node, "ibm,ppc-interrupt-server#s", servers,
sizeof(servers));
if (cnt == PROM_ERROR)
break;
cnt >>= 2;
for (i = 0; i < cnt; i++) {
cpu = servers[i];
prom_debug("CPU %d ... ", cpu);
if (cpu == _prom->cpu) {
prom_debug("booted !\n");
continue;
}
prom_debug("starting ... ");
/* Init the acknowledge var which will be reset by
* the secondary cpu when it awakens from its OF
* spinloop.
*/
data->ack = -1;
rc = prom_rtas_call(RELOC(prom_rtas_start_cpu), 3, 1,
NULL, cpu, entry, data);
prom_debug("rtas rc=%d ...", rc);
for (j = 0; j < 100000000 && data->ack == -1; j++) {
HMT_low();
mb();
}
HMT_medium();
if (data->ack != -1)
prom_debug("done, PIR=0x%x\n", data->ack);
else
prom_debug("timeout !\n");
}
}
prom_debug("prom_opal_hold_cpus: end...\n");
}
static void prom_opal_takeover(void)
{
struct opal_secondary_data *data = &RELOC(opal_secondary_data);
struct opal_takeover_args *args = &data->args;
u64 align = RELOC(prom_opal_align);
u64 top_addr, opal_addr;
args->k_image = (u64)RELOC(_stext);
args->k_size = _end - _stext;
args->k_entry = 0;
args->k_entry2 = 0x60;
top_addr = _ALIGN_UP(args->k_size, align);
if (RELOC(prom_initrd_start) != 0) {
args->rd_image = RELOC(prom_initrd_start);
args->rd_size = RELOC(prom_initrd_end) - args->rd_image;
args->rd_loc = top_addr;
top_addr = _ALIGN_UP(args->rd_loc + args->rd_size, align);
}
/* Pickup an address for the HAL. We want to go really high
* up to avoid problem with future kexecs. On the other hand
* we don't want to be all over the TCEs on P5IOC2 machines
* which are going to be up there too. We assume the machine
* has plenty of memory, and we ask for the HAL for now to
* be just below the 1G point, or above the initrd
*/
opal_addr = _ALIGN_DOWN(0x40000000 - RELOC(prom_opal_size), align);
if (opal_addr < top_addr)
opal_addr = top_addr;
args->hal_addr = opal_addr;
prom_debug(" k_image = 0x%lx\n", args->k_image);
prom_debug(" k_size = 0x%lx\n", args->k_size);
prom_debug(" k_entry = 0x%lx\n", args->k_entry);
prom_debug(" k_entry2 = 0x%lx\n", args->k_entry2);
prom_debug(" hal_addr = 0x%lx\n", args->hal_addr);
prom_debug(" rd_image = 0x%lx\n", args->rd_image);
prom_debug(" rd_size = 0x%lx\n", args->rd_size);
prom_debug(" rd_loc = 0x%lx\n", args->rd_loc);
prom_printf("Performing OPAL takeover,this can take a few minutes..\n");
prom_close_stdin();
mb();
data->go = 1;
for (;;)
opal_do_takeover(args);
}
#endif /* CONFIG_PPC_POWERNV */
/*
* Allocate room for and instantiate RTAS
@ -1326,6 +1517,12 @@ static void __init prom_instantiate_rtas(void)
prom_setprop(rtas_node, "/rtas", "linux,rtas-entry",
&entry, sizeof(entry));
#ifdef CONFIG_PPC_POWERNV
/* PowerVN takeover hack */
RELOC(prom_rtas_data) = base;
RELOC(prom_rtas_entry) = entry;
prom_getprop(rtas_node, "start-cpu", &RELOC(prom_rtas_start_cpu), 4);
#endif
prom_debug("rtas base = 0x%x\n", base);
prom_debug("rtas entry = 0x%x\n", entry);
prom_debug("rtas size = 0x%x\n", (long)size);
@ -1543,7 +1740,7 @@ static void __init prom_hold_cpus(void)
*acknowledge = (unsigned long)-1;
if (reg != _prom->cpu) {
/* Primary Thread of non-boot cpu */
/* Primary Thread of non-boot cpu or any thread */
prom_printf("starting cpu hw idx %lu... ", reg);
call_prom("start-cpu", 3, 0, node,
secondary_hold, reg);
@ -1652,15 +1849,6 @@ static void __init prom_init_stdout(void)
prom_setprop(val, path, "linux,boot-display", NULL, 0);
}
static void __init prom_close_stdin(void)
{
struct prom_t *_prom = &RELOC(prom);
ihandle val;
if (prom_getprop(_prom->chosen, "stdin", &val, sizeof(val)) > 0)
call_prom("close", 1, 0, val);
}
static int __init prom_find_machine_type(void)
{
struct prom_t *_prom = &RELOC(prom);
@ -2504,6 +2692,7 @@ static void __init prom_check_initrd(unsigned long r3, unsigned long r4)
#endif /* CONFIG_BLK_DEV_INITRD */
}
/*
* We enter here early on, when the Open Firmware prom is still
* handling exceptions and the MMU hash table for us.
@ -2565,7 +2754,7 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
*/
prom_check_initrd(r3, r4);
#ifdef CONFIG_PPC_PSERIES
#if defined(CONFIG_PPC_PSERIES) || defined(CONFIG_PPC_POWERNV)
/*
* On pSeries, inform the firmware about our capabilities
*/
@ -2611,14 +2800,30 @@ unsigned long __init prom_init(unsigned long r3, unsigned long r4,
#endif
/*
* On non-powermacs, try to instantiate RTAS and puts all CPUs
* in spin-loops. PowerMacs don't have a working RTAS and use
* a different way to spin CPUs
* On non-powermacs, try to instantiate RTAS. PowerMacs don't
* have a usable RTAS implementation.
*/
if (RELOC(of_platform) != PLATFORM_POWERMAC) {
if (RELOC(of_platform) != PLATFORM_POWERMAC)
prom_instantiate_rtas();
prom_hold_cpus();
#ifdef CONFIG_PPC_POWERNV
/* Detect HAL and try instanciating it & doing takeover */
if (RELOC(of_platform) == PLATFORM_PSERIES_LPAR) {
prom_query_opal();
if (RELOC(of_platform) == PLATFORM_OPAL) {
prom_opal_hold_cpus();
prom_opal_takeover();
}
}
#endif
/*
* On non-powermacs, put all CPUs in spin-loops.
*
* PowerMacs use a different mechanism to spin CPUs
*/
if (RELOC(of_platform) != PLATFORM_POWERMAC)
prom_hold_cpus();
/*
* Fill in some infos for use by the kernel later on

3
arch/powerpc/kernel/prom_init_check.sh
View File

@ -20,7 +20,8 @@ WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
_end enter_prom memcpy memset reloc_offset __secondary_hold
__secondary_hold_acknowledge __secondary_hold_spinloop __start
strcmp strcpy strlcpy strlen strncmp strstr logo_linux_clut224
reloc_got2 kernstart_addr memstart_addr linux_banner"
reloc_got2 kernstart_addr memstart_addr linux_banner _stext
opal_query_takeover opal_do_takeover opal_enter_rtas opal_secondary_entry"
NM="$1"
OBJ="$2"

2
arch/powerpc/platforms/powernv/Makefile
View File

@ -1,2 +1,2 @@
obj-y += setup.o
obj-y += setup.o opal-takeover.o
obj-$(CONFIG_SMP) += smp.o

140
arch/powerpc/platforms/powernv/opal-takeover.S Normal file
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@ -0,0 +1,140 @@
/*
* PowerNV OPAL takeover assembly code, for use by prom_init.c
*
* Copyright 2011 IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <asm/ppc_asm.h>
#include <asm/hvcall.h>
#include <asm/asm-offsets.h>
#include <asm/opal.h>
#define STK_PARAM(i) (48 + ((i)-3)*8)
#define H_HAL_TAKEOVER 0x5124
#define H_HAL_TAKEOVER_QUERY_MAGIC -1
.text
_GLOBAL(opal_query_takeover)
mfcr r0
stw r0,8(r1)
std r3,STK_PARAM(r3)(r1)
std r4,STK_PARAM(r4)(r1)
li r3,H_HAL_TAKEOVER
li r4,H_HAL_TAKEOVER_QUERY_MAGIC
HVSC
ld r10,STK_PARAM(r3)(r1)
std r4,0(r10)
ld r10,STK_PARAM(r4)(r1)
std r5,0(r10)
lwz r0,8(r1)
mtcrf 0xff,r0
blr
_GLOBAL(opal_do_takeover)
mfcr r0
stw r0,8(r1)
mflr r0
std r0,16(r1)
bl __opal_do_takeover
ld r0,16(r1)
mtlr r0
lwz r0,8(r1)
mtcrf 0xff,r0
blr
__opal_do_takeover:
ld r4,0(r3)
ld r5,0x8(r3)
ld r6,0x10(r3)
ld r7,0x18(r3)
ld r8,0x20(r3)
ld r9,0x28(r3)
ld r10,0x30(r3)
ld r11,0x38(r3)
li r3,H_HAL_TAKEOVER
HVSC
blr
.globl opal_secondary_entry
opal_secondary_entry:
mr r31,r3
mfmsr r11
li r12,(MSR_SF | MSR_ISF)@highest
sldi r12,r12,48
or r11,r11,r12
mtmsrd r11
isync
mfspr r4,SPRN_PIR
std r4,0(r3)
1: HMT_LOW
ld r4,8(r3)
cmpli cr0,r4,0
beq 1b
HMT_MEDIUM
1: addi r3,r31,16
bl __opal_do_takeover
b 1b
_GLOBAL(opal_enter_rtas)
mflr r0
std r0,16(r1)
stdu r1,-PROM_FRAME_SIZE(r1) /* Save SP and create stack space */
/* Because PROM is running in 32b mode, it clobbers the high order half
* of all registers that it saves. We therefore save those registers
* PROM might touch to the stack. (r0, r3-r13 are caller saved)
*/
SAVE_GPR(2, r1)
SAVE_GPR(13, r1)
SAVE_8GPRS(14, r1)
SAVE_10GPRS(22, r1)
mfcr r10
mfmsr r11
std r10,_CCR(r1)
std r11,_MSR(r1)
/* Get the PROM entrypoint */
mtlr r5
/* Switch MSR to 32 bits mode
*/
li r12,1
rldicr r12,r12,MSR_SF_LG,(63-MSR_SF_LG)
andc r11,r11,r12
li r12,1
rldicr r12,r12,MSR_ISF_LG,(63-MSR_ISF_LG)
andc r11,r11,r12
mtmsrd r11
isync
/* Enter RTAS here... */
blrl
/* Just make sure that r1 top 32 bits didn't get
* corrupt by OF
*/
rldicl r1,r1,0,32
/* Restore the MSR (back to 64 bits) */
ld r0,_MSR(r1)
MTMSRD(r0)
isync
/* Restore other registers */
REST_GPR(2, r1)
REST_GPR(13, r1)
REST_8GPRS(14, r1)
REST_10GPRS(22, r1)
ld r4,_CCR(r1)
mtcr r4
addi r1,r1,PROM_FRAME_SIZE
ld r0,16(r1)
mtlr r0
blr