powerpc/powernv: Add OPAL takeover from PowerVM
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>
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index a909f4e..9369287 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -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 @@
#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 @@
}
}
-#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 @@
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 @@
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 @@
*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 @@
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 @@
#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 @@
*/
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 @@
#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