Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2088 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
new file mode 100644
index 0000000000..87d65bdd3e
--- /dev/null
+++ b/arch/powerpc/kernel/rtas.c
@@ -0,0 +1,2088 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * Procedures for interfacing to the RTAS on CHRP machines.
+ *
+ * Peter Bergner, IBM	March 2001.
+ * Copyright (C) 2001 IBM.
+ */
+
+#define pr_fmt(fmt)	"rtas: " fmt
+
+#include <linux/bsearch.h>
+#include <linux/capability.h>
+#include <linux/delay.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/kconfig.h>
+#include <linux/kernel.h>
+#include <linux/lockdep.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/reboot.h>
+#include <linux/sched.h>
+#include <linux/security.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/stdarg.h>
+#include <linux/syscalls.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/xarray.h>
+
+#include <asm/delay.h>
+#include <asm/firmware.h>
+#include <asm/interrupt.h>
+#include <asm/machdep.h>
+#include <asm/mmu.h>
+#include <asm/page.h>
+#include <asm/rtas-work-area.h>
+#include <asm/rtas.h>
+#include <asm/time.h>
+#include <asm/trace.h>
+#include <asm/udbg.h>
+
+struct rtas_filter {
+	/* Indexes into the args buffer, -1 if not used */
+	const int buf_idx1;
+	const int size_idx1;
+	const int buf_idx2;
+	const int size_idx2;
+	/*
+	 * Assumed buffer size per the spec if the function does not
+	 * have a size parameter, e.g. ibm,errinjct. 0 if unused.
+	 */
+	const int fixed_size;
+};
+
+/**
+ * struct rtas_function - Descriptor for RTAS functions.
+ *
+ * @token: Value of @name if it exists under the /rtas node.
+ * @name: Function name.
+ * @filter: If non-NULL, invoking this function via the rtas syscall is
+ *          generally allowed, and @filter describes constraints on the
+ *          arguments. See also @banned_for_syscall_on_le.
+ * @banned_for_syscall_on_le: Set when call via sys_rtas is generally allowed
+ *                            but specifically restricted on ppc64le. Such
+ *                            functions are believed to have no users on
+ *                            ppc64le, and we want to keep it that way. It does
+ *                            not make sense for this to be set when @filter
+ *                            is NULL.
+ */
+struct rtas_function {
+	s32 token;
+	const bool banned_for_syscall_on_le:1;
+	const char * const name;
+	const struct rtas_filter *filter;
+};
+
+static struct rtas_function rtas_function_table[] __ro_after_init = {
+	[RTAS_FNIDX__CHECK_EXCEPTION] = {
+		.name = "check-exception",
+	},
+	[RTAS_FNIDX__DISPLAY_CHARACTER] = {
+		.name = "display-character",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__EVENT_SCAN] = {
+		.name = "event-scan",
+	},
+	[RTAS_FNIDX__FREEZE_TIME_BASE] = {
+		.name = "freeze-time-base",
+	},
+	[RTAS_FNIDX__GET_POWER_LEVEL] = {
+		.name = "get-power-level",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__GET_SENSOR_STATE] = {
+		.name = "get-sensor-state",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__GET_TERM_CHAR] = {
+		.name = "get-term-char",
+	},
+	[RTAS_FNIDX__GET_TIME_OF_DAY] = {
+		.name = "get-time-of-day",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_ACTIVATE_FIRMWARE] = {
+		.name = "ibm,activate-firmware",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_CBE_START_PTCAL] = {
+		.name = "ibm,cbe-start-ptcal",
+	},
+	[RTAS_FNIDX__IBM_CBE_STOP_PTCAL] = {
+		.name = "ibm,cbe-stop-ptcal",
+	},
+	[RTAS_FNIDX__IBM_CHANGE_MSI] = {
+		.name = "ibm,change-msi",
+	},
+	[RTAS_FNIDX__IBM_CLOSE_ERRINJCT] = {
+		.name = "ibm,close-errinjct",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_CONFIGURE_BRIDGE] = {
+		.name = "ibm,configure-bridge",
+	},
+	[RTAS_FNIDX__IBM_CONFIGURE_CONNECTOR] = {
+		.name = "ibm,configure-connector",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 0, .size_idx1 = -1,
+			.buf_idx2 = 1, .size_idx2 = -1,
+			.fixed_size = 4096,
+		},
+	},
+	[RTAS_FNIDX__IBM_CONFIGURE_KERNEL_DUMP] = {
+		.name = "ibm,configure-kernel-dump",
+	},
+	[RTAS_FNIDX__IBM_CONFIGURE_PE] = {
+		.name = "ibm,configure-pe",
+	},
+	[RTAS_FNIDX__IBM_CREATE_PE_DMA_WINDOW] = {
+		.name = "ibm,create-pe-dma-window",
+	},
+	[RTAS_FNIDX__IBM_DISPLAY_MESSAGE] = {
+		.name = "ibm,display-message",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 0, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_ERRINJCT] = {
+		.name = "ibm,errinjct",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 2, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+			.fixed_size = 1024,
+		},
+	},
+	[RTAS_FNIDX__IBM_EXTI2C] = {
+		.name = "ibm,exti2c",
+	},
+	[RTAS_FNIDX__IBM_GET_CONFIG_ADDR_INFO] = {
+		.name = "ibm,get-config-addr-info",
+	},
+	[RTAS_FNIDX__IBM_GET_CONFIG_ADDR_INFO2] = {
+		.name = "ibm,get-config-addr-info2",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_GET_DYNAMIC_SENSOR_STATE] = {
+		.name = "ibm,get-dynamic-sensor-state",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_GET_INDICES] = {
+		.name = "ibm,get-indices",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 2, .size_idx1 = 3,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_GET_RIO_TOPOLOGY] = {
+		.name = "ibm,get-rio-topology",
+	},
+	[RTAS_FNIDX__IBM_GET_SYSTEM_PARAMETER] = {
+		.name = "ibm,get-system-parameter",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 1, .size_idx1 = 2,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_GET_VPD] = {
+		.name = "ibm,get-vpd",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 0, .size_idx1 = -1,
+			.buf_idx2 = 1, .size_idx2 = 2,
+		},
+	},
+	[RTAS_FNIDX__IBM_GET_XIVE] = {
+		.name = "ibm,get-xive",
+	},
+	[RTAS_FNIDX__IBM_INT_OFF] = {
+		.name = "ibm,int-off",
+	},
+	[RTAS_FNIDX__IBM_INT_ON] = {
+		.name = "ibm,int-on",
+	},
+	[RTAS_FNIDX__IBM_IO_QUIESCE_ACK] = {
+		.name = "ibm,io-quiesce-ack",
+	},
+	[RTAS_FNIDX__IBM_LPAR_PERFTOOLS] = {
+		.name = "ibm,lpar-perftools",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 2, .size_idx1 = 3,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_MANAGE_FLASH_IMAGE] = {
+		.name = "ibm,manage-flash-image",
+	},
+	[RTAS_FNIDX__IBM_MANAGE_STORAGE_PRESERVATION] = {
+		.name = "ibm,manage-storage-preservation",
+	},
+	[RTAS_FNIDX__IBM_NMI_INTERLOCK] = {
+		.name = "ibm,nmi-interlock",
+	},
+	[RTAS_FNIDX__IBM_NMI_REGISTER] = {
+		.name = "ibm,nmi-register",
+	},
+	[RTAS_FNIDX__IBM_OPEN_ERRINJCT] = {
+		.name = "ibm,open-errinjct",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_OPEN_SRIOV_ALLOW_UNFREEZE] = {
+		.name = "ibm,open-sriov-allow-unfreeze",
+	},
+	[RTAS_FNIDX__IBM_OPEN_SRIOV_MAP_PE_NUMBER] = {
+		.name = "ibm,open-sriov-map-pe-number",
+	},
+	[RTAS_FNIDX__IBM_OS_TERM] = {
+		.name = "ibm,os-term",
+	},
+	[RTAS_FNIDX__IBM_PARTNER_CONTROL] = {
+		.name = "ibm,partner-control",
+	},
+	[RTAS_FNIDX__IBM_PHYSICAL_ATTESTATION] = {
+		.name = "ibm,physical-attestation",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 0, .size_idx1 = 1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_PLATFORM_DUMP] = {
+		.name = "ibm,platform-dump",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 4, .size_idx1 = 5,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_POWER_OFF_UPS] = {
+		.name = "ibm,power-off-ups",
+	},
+	[RTAS_FNIDX__IBM_QUERY_INTERRUPT_SOURCE_NUMBER] = {
+		.name = "ibm,query-interrupt-source-number",
+	},
+	[RTAS_FNIDX__IBM_QUERY_PE_DMA_WINDOW] = {
+		.name = "ibm,query-pe-dma-window",
+	},
+	[RTAS_FNIDX__IBM_READ_PCI_CONFIG] = {
+		.name = "ibm,read-pci-config",
+	},
+	[RTAS_FNIDX__IBM_READ_SLOT_RESET_STATE] = {
+		.name = "ibm,read-slot-reset-state",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_READ_SLOT_RESET_STATE2] = {
+		.name = "ibm,read-slot-reset-state2",
+	},
+	[RTAS_FNIDX__IBM_REMOVE_PE_DMA_WINDOW] = {
+		.name = "ibm,remove-pe-dma-window",
+	},
+	[RTAS_FNIDX__IBM_RESET_PE_DMA_WINDOWS] = {
+		.name = "ibm,reset-pe-dma-windows",
+	},
+	[RTAS_FNIDX__IBM_SCAN_LOG_DUMP] = {
+		.name = "ibm,scan-log-dump",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 0, .size_idx1 = 1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_SET_DYNAMIC_INDICATOR] = {
+		.name = "ibm,set-dynamic-indicator",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 2, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_SET_EEH_OPTION] = {
+		.name = "ibm,set-eeh-option",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_SET_SLOT_RESET] = {
+		.name = "ibm,set-slot-reset",
+	},
+	[RTAS_FNIDX__IBM_SET_SYSTEM_PARAMETER] = {
+		.name = "ibm,set-system-parameter",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_SET_XIVE] = {
+		.name = "ibm,set-xive",
+	},
+	[RTAS_FNIDX__IBM_SLOT_ERROR_DETAIL] = {
+		.name = "ibm,slot-error-detail",
+	},
+	[RTAS_FNIDX__IBM_SUSPEND_ME] = {
+		.name = "ibm,suspend-me",
+		.banned_for_syscall_on_le = true,
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__IBM_TUNE_DMA_PARMS] = {
+		.name = "ibm,tune-dma-parms",
+	},
+	[RTAS_FNIDX__IBM_UPDATE_FLASH_64_AND_REBOOT] = {
+		.name = "ibm,update-flash-64-and-reboot",
+	},
+	[RTAS_FNIDX__IBM_UPDATE_NODES] = {
+		.name = "ibm,update-nodes",
+		.banned_for_syscall_on_le = true,
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 0, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+			.fixed_size = 4096,
+		},
+	},
+	[RTAS_FNIDX__IBM_UPDATE_PROPERTIES] = {
+		.name = "ibm,update-properties",
+		.banned_for_syscall_on_le = true,
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = 0, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+			.fixed_size = 4096,
+		},
+	},
+	[RTAS_FNIDX__IBM_VALIDATE_FLASH_IMAGE] = {
+		.name = "ibm,validate-flash-image",
+	},
+	[RTAS_FNIDX__IBM_WRITE_PCI_CONFIG] = {
+		.name = "ibm,write-pci-config",
+	},
+	[RTAS_FNIDX__NVRAM_FETCH] = {
+		.name = "nvram-fetch",
+	},
+	[RTAS_FNIDX__NVRAM_STORE] = {
+		.name = "nvram-store",
+	},
+	[RTAS_FNIDX__POWER_OFF] = {
+		.name = "power-off",
+	},
+	[RTAS_FNIDX__PUT_TERM_CHAR] = {
+		.name = "put-term-char",
+	},
+	[RTAS_FNIDX__QUERY_CPU_STOPPED_STATE] = {
+		.name = "query-cpu-stopped-state",
+	},
+	[RTAS_FNIDX__READ_PCI_CONFIG] = {
+		.name = "read-pci-config",
+	},
+	[RTAS_FNIDX__RTAS_LAST_ERROR] = {
+		.name = "rtas-last-error",
+	},
+	[RTAS_FNIDX__SET_INDICATOR] = {
+		.name = "set-indicator",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__SET_POWER_LEVEL] = {
+		.name = "set-power-level",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__SET_TIME_FOR_POWER_ON] = {
+		.name = "set-time-for-power-on",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__SET_TIME_OF_DAY] = {
+		.name = "set-time-of-day",
+		.filter = &(const struct rtas_filter) {
+			.buf_idx1 = -1, .size_idx1 = -1,
+			.buf_idx2 = -1, .size_idx2 = -1,
+		},
+	},
+	[RTAS_FNIDX__START_CPU] = {
+		.name = "start-cpu",
+	},
+	[RTAS_FNIDX__STOP_SELF] = {
+		.name = "stop-self",
+	},
+	[RTAS_FNIDX__SYSTEM_REBOOT] = {
+		.name = "system-reboot",
+	},
+	[RTAS_FNIDX__THAW_TIME_BASE] = {
+		.name = "thaw-time-base",
+	},
+	[RTAS_FNIDX__WRITE_PCI_CONFIG] = {
+		.name = "write-pci-config",
+	},
+};
+
+/*
+ * Nearly all RTAS calls need to be serialized. All uses of the
+ * default rtas_args block must hold rtas_lock.
+ *
+ * Exceptions to the RTAS serialization requirement (e.g. stop-self)
+ * must use a separate rtas_args structure.
+ */
+static DEFINE_RAW_SPINLOCK(rtas_lock);
+static struct rtas_args rtas_args;
+
+/**
+ * rtas_function_token() - RTAS function token lookup.
+ * @handle: Function handle, e.g. RTAS_FN_EVENT_SCAN.
+ *
+ * Context: Any context.
+ * Return: the token value for the function if implemented by this platform,
+ *         otherwise RTAS_UNKNOWN_SERVICE.
+ */
+s32 rtas_function_token(const rtas_fn_handle_t handle)
+{
+	const size_t index = handle.index;
+	const bool out_of_bounds = index >= ARRAY_SIZE(rtas_function_table);
+
+	if (WARN_ONCE(out_of_bounds, "invalid function index %zu", index))
+		return RTAS_UNKNOWN_SERVICE;
+	/*
+	 * Various drivers attempt token lookups on non-RTAS
+	 * platforms.
+	 */
+	if (!rtas.dev)
+		return RTAS_UNKNOWN_SERVICE;
+
+	return rtas_function_table[index].token;
+}
+EXPORT_SYMBOL_GPL(rtas_function_token);
+
+static int rtas_function_cmp(const void *a, const void *b)
+{
+	const struct rtas_function *f1 = a;
+	const struct rtas_function *f2 = b;
+
+	return strcmp(f1->name, f2->name);
+}
+
+/*
+ * Boot-time initialization of the function table needs the lookup to
+ * return a non-const-qualified object. Use rtas_name_to_function()
+ * in all other contexts.
+ */
+static struct rtas_function *__rtas_name_to_function(const char *name)
+{
+	const struct rtas_function key = {
+		.name = name,
+	};
+	struct rtas_function *found;
+
+	found = bsearch(&key, rtas_function_table, ARRAY_SIZE(rtas_function_table),
+			sizeof(rtas_function_table[0]), rtas_function_cmp);
+
+	return found;
+}
+
+static const struct rtas_function *rtas_name_to_function(const char *name)
+{
+	return __rtas_name_to_function(name);
+}
+
+static DEFINE_XARRAY(rtas_token_to_function_xarray);
+
+static int __init rtas_token_to_function_xarray_init(void)
+{
+	int err = 0;
+
+	for (size_t i = 0; i < ARRAY_SIZE(rtas_function_table); ++i) {
+		const struct rtas_function *func = &rtas_function_table[i];
+		const s32 token = func->token;
+
+		if (token == RTAS_UNKNOWN_SERVICE)
+			continue;
+
+		err = xa_err(xa_store(&rtas_token_to_function_xarray,
+				      token, (void *)func, GFP_KERNEL));
+		if (err)
+			break;
+	}
+
+	return err;
+}
+arch_initcall(rtas_token_to_function_xarray_init);
+
+/*
+ * For use by sys_rtas(), where the token value is provided by user
+ * space and we don't want to warn on failed lookups.
+ */
+static const struct rtas_function *rtas_token_to_function_untrusted(s32 token)
+{
+	return xa_load(&rtas_token_to_function_xarray, token);
+}
+
+/*
+ * Reverse lookup for deriving the function descriptor from a
+ * known-good token value in contexts where the former is not already
+ * available. @token must be valid, e.g. derived from the result of a
+ * prior lookup against the function table.
+ */
+static const struct rtas_function *rtas_token_to_function(s32 token)
+{
+	const struct rtas_function *func;
+
+	if (WARN_ONCE(token < 0, "invalid token %d", token))
+		return NULL;
+
+	func = rtas_token_to_function_untrusted(token);
+
+	if (WARN_ONCE(!func, "unexpected failed lookup for token %d", token))
+		return NULL;
+
+	return func;
+}
+
+/* This is here deliberately so it's only used in this file */
+void enter_rtas(unsigned long);
+
+static void __do_enter_rtas(struct rtas_args *args)
+{
+	enter_rtas(__pa(args));
+	srr_regs_clobbered(); /* rtas uses SRRs, invalidate */
+}
+
+static void __do_enter_rtas_trace(struct rtas_args *args)
+{
+	const char *name = NULL;
+
+	if (args == &rtas_args)
+		lockdep_assert_held(&rtas_lock);
+	/*
+	 * If the tracepoints that consume the function name aren't
+	 * active, avoid the lookup.
+	 */
+	if ((trace_rtas_input_enabled() || trace_rtas_output_enabled())) {
+		const s32 token = be32_to_cpu(args->token);
+		const struct rtas_function *func = rtas_token_to_function(token);
+
+		name = func->name;
+	}
+
+	trace_rtas_input(args, name);
+	trace_rtas_ll_entry(args);
+
+	__do_enter_rtas(args);
+
+	trace_rtas_ll_exit(args);
+	trace_rtas_output(args, name);
+}
+
+static void do_enter_rtas(struct rtas_args *args)
+{
+	const unsigned long msr = mfmsr();
+	/*
+	 * Situations where we want to skip any active tracepoints for
+	 * safety reasons:
+	 *
+	 * 1. The last code executed on an offline CPU as it stops,
+	 *    i.e. we're about to call stop-self. The tracepoints'
+	 *    function name lookup uses xarray, which uses RCU, which
+	 *    isn't valid to call on an offline CPU.  Any events
+	 *    emitted on an offline CPU will be discarded anyway.
+	 *
+	 * 2. In real mode, as when invoking ibm,nmi-interlock from
+	 *    the pseries MCE handler. We cannot count on trace
+	 *    buffers or the entries in rtas_token_to_function_xarray
+	 *    to be contained in the RMO.
+	 */
+	const unsigned long mask = MSR_IR | MSR_DR;
+	const bool can_trace = likely(cpu_online(raw_smp_processor_id()) &&
+				      (msr & mask) == mask);
+	/*
+	 * Make sure MSR[RI] is currently enabled as it will be forced later
+	 * in enter_rtas.
+	 */
+	BUG_ON(!(msr & MSR_RI));
+
+	BUG_ON(!irqs_disabled());
+
+	hard_irq_disable(); /* Ensure MSR[EE] is disabled on PPC64 */
+
+	if (can_trace)
+		__do_enter_rtas_trace(args);
+	else
+		__do_enter_rtas(args);
+}
+
+struct rtas_t rtas;
+
+DEFINE_SPINLOCK(rtas_data_buf_lock);
+EXPORT_SYMBOL_GPL(rtas_data_buf_lock);
+
+char rtas_data_buf[RTAS_DATA_BUF_SIZE] __aligned(SZ_4K);
+EXPORT_SYMBOL_GPL(rtas_data_buf);
+
+unsigned long rtas_rmo_buf;
+
+/*
+ * If non-NULL, this gets called when the kernel terminates.
+ * This is done like this so rtas_flash can be a module.
+ */
+void (*rtas_flash_term_hook)(int);
+EXPORT_SYMBOL_GPL(rtas_flash_term_hook);
+
+/*
+ * call_rtas_display_status and call_rtas_display_status_delay
+ * are designed only for very early low-level debugging, which
+ * is why the token is hard-coded to 10.
+ */
+static void call_rtas_display_status(unsigned char c)
+{
+	unsigned long flags;
+
+	if (!rtas.base)
+		return;
+
+	raw_spin_lock_irqsave(&rtas_lock, flags);
+	rtas_call_unlocked(&rtas_args, 10, 1, 1, NULL, c);
+	raw_spin_unlock_irqrestore(&rtas_lock, flags);
+}
+
+static void call_rtas_display_status_delay(char c)
+{
+	static int pending_newline = 0;  /* did last write end with unprinted newline? */
+	static int width = 16;
+
+	if (c == '\n') {	
+		while (width-- > 0)
+			call_rtas_display_status(' ');
+		width = 16;
+		mdelay(500);
+		pending_newline = 1;
+	} else {
+		if (pending_newline) {
+			call_rtas_display_status('\r');
+			call_rtas_display_status('\n');
+		} 
+		pending_newline = 0;
+		if (width--) {
+			call_rtas_display_status(c);
+			udelay(10000);
+		}
+	}
+}
+
+void __init udbg_init_rtas_panel(void)
+{
+	udbg_putc = call_rtas_display_status_delay;
+}
+
+#ifdef CONFIG_UDBG_RTAS_CONSOLE
+
+/* If you think you're dying before early_init_dt_scan_rtas() does its
+ * work, you can hard code the token values for your firmware here and
+ * hardcode rtas.base/entry etc.
+ */
+static unsigned int rtas_putchar_token = RTAS_UNKNOWN_SERVICE;
+static unsigned int rtas_getchar_token = RTAS_UNKNOWN_SERVICE;
+
+static void udbg_rtascon_putc(char c)
+{
+	int tries;
+
+	if (!rtas.base)
+		return;
+
+	/* Add CRs before LFs */
+	if (c == '\n')
+		udbg_rtascon_putc('\r');
+
+	/* if there is more than one character to be displayed, wait a bit */
+	for (tries = 0; tries < 16; tries++) {
+		if (rtas_call(rtas_putchar_token, 1, 1, NULL, c) == 0)
+			break;
+		udelay(1000);
+	}
+}
+
+static int udbg_rtascon_getc_poll(void)
+{
+	int c;
+
+	if (!rtas.base)
+		return -1;
+
+	if (rtas_call(rtas_getchar_token, 0, 2, &c))
+		return -1;
+
+	return c;
+}
+
+static int udbg_rtascon_getc(void)
+{
+	int c;
+
+	while ((c = udbg_rtascon_getc_poll()) == -1)
+		;
+
+	return c;
+}
+
+
+void __init udbg_init_rtas_console(void)
+{
+	udbg_putc = udbg_rtascon_putc;
+	udbg_getc = udbg_rtascon_getc;
+	udbg_getc_poll = udbg_rtascon_getc_poll;
+}
+#endif /* CONFIG_UDBG_RTAS_CONSOLE */
+
+void rtas_progress(char *s, unsigned short hex)
+{
+	struct device_node *root;
+	int width;
+	const __be32 *p;
+	char *os;
+	static int display_character, set_indicator;
+	static int display_width, display_lines, form_feed;
+	static const int *row_width;
+	static DEFINE_SPINLOCK(progress_lock);
+	static int current_line;
+	static int pending_newline = 0;  /* did last write end with unprinted newline? */
+
+	if (!rtas.base)
+		return;
+
+	if (display_width == 0) {
+		display_width = 0x10;
+		if ((root = of_find_node_by_path("/rtas"))) {
+			if ((p = of_get_property(root,
+					"ibm,display-line-length", NULL)))
+				display_width = be32_to_cpu(*p);
+			if ((p = of_get_property(root,
+					"ibm,form-feed", NULL)))
+				form_feed = be32_to_cpu(*p);
+			if ((p = of_get_property(root,
+					"ibm,display-number-of-lines", NULL)))
+				display_lines = be32_to_cpu(*p);
+			row_width = of_get_property(root,
+					"ibm,display-truncation-length", NULL);
+			of_node_put(root);
+		}
+		display_character = rtas_function_token(RTAS_FN_DISPLAY_CHARACTER);
+		set_indicator = rtas_function_token(RTAS_FN_SET_INDICATOR);
+	}
+
+	if (display_character == RTAS_UNKNOWN_SERVICE) {
+		/* use hex display if available */
+		if (set_indicator != RTAS_UNKNOWN_SERVICE)
+			rtas_call(set_indicator, 3, 1, NULL, 6, 0, hex);
+		return;
+	}
+
+	spin_lock(&progress_lock);
+
+	/*
+	 * Last write ended with newline, but we didn't print it since
+	 * it would just clear the bottom line of output. Print it now
+	 * instead.
+	 *
+	 * If no newline is pending and form feed is supported, clear the
+	 * display with a form feed; otherwise, print a CR to start output
+	 * at the beginning of the line.
+	 */
+	if (pending_newline) {
+		rtas_call(display_character, 1, 1, NULL, '\r');
+		rtas_call(display_character, 1, 1, NULL, '\n');
+		pending_newline = 0;
+	} else {
+		current_line = 0;
+		if (form_feed)
+			rtas_call(display_character, 1, 1, NULL,
+				  (char)form_feed);
+		else
+			rtas_call(display_character, 1, 1, NULL, '\r');
+	}
+ 
+	if (row_width)
+		width = row_width[current_line];
+	else
+		width = display_width;
+	os = s;
+	while (*os) {
+		if (*os == '\n' || *os == '\r') {
+			/* If newline is the last character, save it
+			 * until next call to avoid bumping up the
+			 * display output.
+			 */
+			if (*os == '\n' && !os[1]) {
+				pending_newline = 1;
+				current_line++;
+				if (current_line > display_lines-1)
+					current_line = display_lines-1;
+				spin_unlock(&progress_lock);
+				return;
+			}
+ 
+			/* RTAS wants CR-LF, not just LF */
+ 
+			if (*os == '\n') {
+				rtas_call(display_character, 1, 1, NULL, '\r');
+				rtas_call(display_character, 1, 1, NULL, '\n');
+			} else {
+				/* CR might be used to re-draw a line, so we'll
+				 * leave it alone and not add LF.
+				 */
+				rtas_call(display_character, 1, 1, NULL, *os);
+			}
+ 
+			if (row_width)
+				width = row_width[current_line];
+			else
+				width = display_width;
+		} else {
+			width--;
+			rtas_call(display_character, 1, 1, NULL, *os);
+		}
+ 
+		os++;
+ 
+		/* if we overwrite the screen length */
+		if (width <= 0)
+			while ((*os != 0) && (*os != '\n') && (*os != '\r'))
+				os++;
+	}
+ 
+	spin_unlock(&progress_lock);
+}
+EXPORT_SYMBOL_GPL(rtas_progress);		/* needed by rtas_flash module */
+
+int rtas_token(const char *service)
+{
+	const struct rtas_function *func;
+	const __be32 *tokp;
+
+	if (rtas.dev == NULL)
+		return RTAS_UNKNOWN_SERVICE;
+
+	func = rtas_name_to_function(service);
+	if (func)
+		return func->token;
+	/*
+	 * The caller is looking up a name that is not known to be an
+	 * RTAS function. Either it's a function that needs to be
+	 * added to the table, or they're misusing rtas_token() to
+	 * access non-function properties of the /rtas node. Warn and
+	 * fall back to the legacy behavior.
+	 */
+	WARN_ONCE(1, "unknown function `%s`, should it be added to rtas_function_table?\n",
+		  service);
+
+	tokp = of_get_property(rtas.dev, service, NULL);
+	return tokp ? be32_to_cpu(*tokp) : RTAS_UNKNOWN_SERVICE;
+}
+EXPORT_SYMBOL_GPL(rtas_token);
+
+int rtas_service_present(const char *service)
+{
+	return rtas_token(service) != RTAS_UNKNOWN_SERVICE;
+}
+
+#ifdef CONFIG_RTAS_ERROR_LOGGING
+
+static u32 rtas_error_log_max __ro_after_init = RTAS_ERROR_LOG_MAX;
+
+/*
+ * Return the firmware-specified size of the error log buffer
+ *  for all rtas calls that require an error buffer argument.
+ *  This includes 'check-exception' and 'rtas-last-error'.
+ */
+int rtas_get_error_log_max(void)
+{
+	return rtas_error_log_max;
+}
+
+static void __init init_error_log_max(void)
+{
+	static const char propname[] __initconst = "rtas-error-log-max";
+	u32 max;
+
+	if (of_property_read_u32(rtas.dev, propname, &max)) {
+		pr_warn("%s not found, using default of %u\n",
+			propname, RTAS_ERROR_LOG_MAX);
+		max = RTAS_ERROR_LOG_MAX;
+	}
+
+	if (max > RTAS_ERROR_LOG_MAX) {
+		pr_warn("%s = %u, clamping max error log size to %u\n",
+			propname, max, RTAS_ERROR_LOG_MAX);
+		max = RTAS_ERROR_LOG_MAX;
+	}
+
+	rtas_error_log_max = max;
+}
+
+
+static char rtas_err_buf[RTAS_ERROR_LOG_MAX];
+
+/** Return a copy of the detailed error text associated with the
+ *  most recent failed call to rtas.  Because the error text
+ *  might go stale if there are any other intervening rtas calls,
+ *  this routine must be called atomically with whatever produced
+ *  the error (i.e. with rtas_lock still held from the previous call).
+ */
+static char *__fetch_rtas_last_error(char *altbuf)
+{
+	const s32 token = rtas_function_token(RTAS_FN_RTAS_LAST_ERROR);
+	struct rtas_args err_args, save_args;
+	u32 bufsz;
+	char *buf = NULL;
+
+	lockdep_assert_held(&rtas_lock);
+
+	if (token == -1)
+		return NULL;
+
+	bufsz = rtas_get_error_log_max();
+
+	err_args.token = cpu_to_be32(token);
+	err_args.nargs = cpu_to_be32(2);
+	err_args.nret = cpu_to_be32(1);
+	err_args.args[0] = cpu_to_be32(__pa(rtas_err_buf));
+	err_args.args[1] = cpu_to_be32(bufsz);
+	err_args.args[2] = 0;
+
+	save_args = rtas_args;
+	rtas_args = err_args;
+
+	do_enter_rtas(&rtas_args);
+
+	err_args = rtas_args;
+	rtas_args = save_args;
+
+	/* Log the error in the unlikely case that there was one. */
+	if (unlikely(err_args.args[2] == 0)) {
+		if (altbuf) {
+			buf = altbuf;
+		} else {
+			buf = rtas_err_buf;
+			if (slab_is_available())
+				buf = kmalloc(RTAS_ERROR_LOG_MAX, GFP_ATOMIC);
+		}
+		if (buf)
+			memmove(buf, rtas_err_buf, RTAS_ERROR_LOG_MAX);
+	}
+
+	return buf;
+}
+
+#define get_errorlog_buffer()	kmalloc(RTAS_ERROR_LOG_MAX, GFP_KERNEL)
+
+#else /* CONFIG_RTAS_ERROR_LOGGING */
+#define __fetch_rtas_last_error(x)	NULL
+#define get_errorlog_buffer()		NULL
+static void __init init_error_log_max(void) {}
+#endif
+
+
+static void
+va_rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret,
+		      va_list list)
+{
+	int i;
+
+	args->token = cpu_to_be32(token);
+	args->nargs = cpu_to_be32(nargs);
+	args->nret  = cpu_to_be32(nret);
+	args->rets  = &(args->args[nargs]);
+
+	for (i = 0; i < nargs; ++i)
+		args->args[i] = cpu_to_be32(va_arg(list, __u32));
+
+	for (i = 0; i < nret; ++i)
+		args->rets[i] = 0;
+
+	do_enter_rtas(args);
+}
+
+/**
+ * rtas_call_unlocked() - Invoke an RTAS firmware function without synchronization.
+ * @args: RTAS parameter block to be used for the call, must obey RTAS addressing
+ *        constraints.
+ * @token: Identifies the function being invoked.
+ * @nargs: Number of input parameters. Does not include token.
+ * @nret: Number of output parameters, including the call status.
+ * @....: List of @nargs input parameters.
+ *
+ * Invokes the RTAS function indicated by @token, which the caller
+ * should obtain via rtas_function_token().
+ *
+ * This function is similar to rtas_call(), but must be used with a
+ * limited set of RTAS calls specifically exempted from the general
+ * requirement that only one RTAS call may be in progress at any
+ * time. Examples include stop-self and ibm,nmi-interlock.
+ */
+void rtas_call_unlocked(struct rtas_args *args, int token, int nargs, int nret, ...)
+{
+	va_list list;
+
+	va_start(list, nret);
+	va_rtas_call_unlocked(args, token, nargs, nret, list);
+	va_end(list);
+}
+
+static bool token_is_restricted_errinjct(s32 token)
+{
+	return token == rtas_function_token(RTAS_FN_IBM_OPEN_ERRINJCT) ||
+	       token == rtas_function_token(RTAS_FN_IBM_ERRINJCT);
+}
+
+/**
+ * rtas_call() - Invoke an RTAS firmware function.
+ * @token: Identifies the function being invoked.
+ * @nargs: Number of input parameters. Does not include token.
+ * @nret: Number of output parameters, including the call status.
+ * @outputs: Array of @nret output words.
+ * @....: List of @nargs input parameters.
+ *
+ * Invokes the RTAS function indicated by @token, which the caller
+ * should obtain via rtas_function_token().
+ *
+ * The @nargs and @nret arguments must match the number of input and
+ * output parameters specified for the RTAS function.
+ *
+ * rtas_call() returns RTAS status codes, not conventional Linux errno
+ * values. Callers must translate any failure to an appropriate errno
+ * in syscall context. Most callers of RTAS functions that can return
+ * -2 or 990x should use rtas_busy_delay() to correctly handle those
+ * statuses before calling again.
+ *
+ * The return value descriptions are adapted from 7.2.8 [RTAS] Return
+ * Codes of the PAPR and CHRP specifications.
+ *
+ * Context: Process context preferably, interrupt context if
+ *          necessary.  Acquires an internal spinlock and may perform
+ *          GFP_ATOMIC slab allocation in error path. Unsafe for NMI
+ *          context.
+ * Return:
+ * *                          0 - RTAS function call succeeded.
+ * *                         -1 - RTAS function encountered a hardware or
+ *                                platform error, or the token is invalid,
+ *                                or the function is restricted by kernel policy.
+ * *                         -2 - Specs say "A necessary hardware device was busy,
+ *                                and the requested function could not be
+ *                                performed. The operation should be retried at
+ *                                a later time." This is misleading, at least with
+ *                                respect to current RTAS implementations. What it
+ *                                usually means in practice is that the function
+ *                                could not be completed while meeting RTAS's
+ *                                deadline for returning control to the OS (250us
+ *                                for PAPR/PowerVM, typically), but the call may be
+ *                                immediately reattempted to resume work on it.
+ * *                         -3 - Parameter error.
+ * *                         -7 - Unexpected state change.
+ * *                9000...9899 - Vendor-specific success codes.
+ * *                9900...9905 - Advisory extended delay. Caller should try
+ *                                again after ~10^x ms has elapsed, where x is
+ *                                the last digit of the status [0-5]. Again going
+ *                                beyond the PAPR text, 990x on PowerVM indicates
+ *                                contention for RTAS-internal resources. Other
+ *                                RTAS call sequences in progress should be
+ *                                allowed to complete before reattempting the
+ *                                call.
+ * *                      -9000 - Multi-level isolation error.
+ * *              -9999...-9004 - Vendor-specific error codes.
+ * * Additional negative values - Function-specific error.
+ * * Additional positive values - Function-specific success.
+ */
+int rtas_call(int token, int nargs, int nret, int *outputs, ...)
+{
+	struct pin_cookie cookie;
+	va_list list;
+	int i;
+	unsigned long flags;
+	struct rtas_args *args;
+	char *buff_copy = NULL;
+	int ret;
+
+	if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE)
+		return -1;
+
+	if (token_is_restricted_errinjct(token)) {
+		/*
+		 * It would be nicer to not discard the error value
+		 * from security_locked_down(), but callers expect an
+		 * RTAS status, not an errno.
+		 */
+		if (security_locked_down(LOCKDOWN_RTAS_ERROR_INJECTION))
+			return -1;
+	}
+
+	if ((mfmsr() & (MSR_IR|MSR_DR)) != (MSR_IR|MSR_DR)) {
+		WARN_ON_ONCE(1);
+		return -1;
+	}
+
+	raw_spin_lock_irqsave(&rtas_lock, flags);
+	cookie = lockdep_pin_lock(&rtas_lock);
+
+	/* We use the global rtas args buffer */
+	args = &rtas_args;
+
+	va_start(list, outputs);
+	va_rtas_call_unlocked(args, token, nargs, nret, list);
+	va_end(list);
+
+	/* A -1 return code indicates that the last command couldn't
+	   be completed due to a hardware error. */
+	if (be32_to_cpu(args->rets[0]) == -1)
+		buff_copy = __fetch_rtas_last_error(NULL);
+
+	if (nret > 1 && outputs != NULL)
+		for (i = 0; i < nret-1; ++i)
+			outputs[i] = be32_to_cpu(args->rets[i + 1]);
+	ret = (nret > 0) ? be32_to_cpu(args->rets[0]) : 0;
+
+	lockdep_unpin_lock(&rtas_lock, cookie);
+	raw_spin_unlock_irqrestore(&rtas_lock, flags);
+
+	if (buff_copy) {
+		log_error(buff_copy, ERR_TYPE_RTAS_LOG, 0);
+		if (slab_is_available())
+			kfree(buff_copy);
+	}
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rtas_call);
+
+/**
+ * rtas_busy_delay_time() - From an RTAS status value, calculate the
+ *                          suggested delay time in milliseconds.
+ *
+ * @status: a value returned from rtas_call() or similar APIs which return
+ *          the status of a RTAS function call.
+ *
+ * Context: Any context.
+ *
+ * Return:
+ * * 100000 - If @status is 9905.
+ * * 10000  - If @status is 9904.
+ * * 1000   - If @status is 9903.
+ * * 100    - If @status is 9902.
+ * * 10     - If @status is 9901.
+ * * 1      - If @status is either 9900 or -2. This is "wrong" for -2, but
+ *            some callers depend on this behavior, and the worst outcome
+ *            is that they will delay for longer than necessary.
+ * * 0      - If @status is not a busy or extended delay value.
+ */
+unsigned int rtas_busy_delay_time(int status)
+{
+	int order;
+	unsigned int ms = 0;
+
+	if (status == RTAS_BUSY) {
+		ms = 1;
+	} else if (status >= RTAS_EXTENDED_DELAY_MIN &&
+		   status <= RTAS_EXTENDED_DELAY_MAX) {
+		order = status - RTAS_EXTENDED_DELAY_MIN;
+		for (ms = 1; order > 0; order--)
+			ms *= 10;
+	}
+
+	return ms;
+}
+
+/*
+ * Early boot fallback for rtas_busy_delay().
+ */
+static bool __init rtas_busy_delay_early(int status)
+{
+	static size_t successive_ext_delays __initdata;
+	bool retry;
+
+	switch (status) {
+	case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
+		/*
+		 * In the unlikely case that we receive an extended
+		 * delay status in early boot, the OS is probably not
+		 * the cause, and there's nothing we can do to clear
+		 * the condition. Best we can do is delay for a bit
+		 * and hope it's transient. Lie to the caller if it
+		 * seems like we're stuck in a retry loop.
+		 */
+		mdelay(1);
+		retry = true;
+		successive_ext_delays += 1;
+		if (successive_ext_delays > 1000) {
+			pr_err("too many extended delays, giving up\n");
+			dump_stack();
+			retry = false;
+			successive_ext_delays = 0;
+		}
+		break;
+	case RTAS_BUSY:
+		retry = true;
+		successive_ext_delays = 0;
+		break;
+	default:
+		retry = false;
+		successive_ext_delays = 0;
+		break;
+	}
+
+	return retry;
+}
+
+/**
+ * rtas_busy_delay() - helper for RTAS busy and extended delay statuses
+ *
+ * @status: a value returned from rtas_call() or similar APIs which return
+ *          the status of a RTAS function call.
+ *
+ * Context: Process context. May sleep or schedule.
+ *
+ * Return:
+ * * true  - @status is RTAS_BUSY or an extended delay hint. The
+ *           caller may assume that the CPU has been yielded if necessary,
+ *           and that an appropriate delay for @status has elapsed.
+ *           Generally the caller should reattempt the RTAS call which
+ *           yielded @status.
+ *
+ * * false - @status is not @RTAS_BUSY nor an extended delay hint. The
+ *           caller is responsible for handling @status.
+ */
+bool __ref rtas_busy_delay(int status)
+{
+	unsigned int ms;
+	bool ret;
+
+	/*
+	 * Can't do timed sleeps before timekeeping is up.
+	 */
+	if (system_state < SYSTEM_SCHEDULING)
+		return rtas_busy_delay_early(status);
+
+	switch (status) {
+	case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
+		ret = true;
+		ms = rtas_busy_delay_time(status);
+		/*
+		 * The extended delay hint can be as high as 100 seconds.
+		 * Surely any function returning such a status is either
+		 * buggy or isn't going to be significantly slowed by us
+		 * polling at 1HZ. Clamp the sleep time to one second.
+		 */
+		ms = clamp(ms, 1U, 1000U);
+		/*
+		 * The delay hint is an order-of-magnitude suggestion, not
+		 * a minimum. It is fine, possibly even advantageous, for
+		 * us to pause for less time than hinted. For small values,
+		 * use usleep_range() to ensure we don't sleep much longer
+		 * than actually needed.
+		 *
+		 * See Documentation/timers/timers-howto.rst for
+		 * explanation of the threshold used here. In effect we use
+		 * usleep_range() for 9900 and 9901, msleep() for
+		 * 9902-9905.
+		 */
+		if (ms <= 20)
+			usleep_range(ms * 100, ms * 1000);
+		else
+			msleep(ms);
+		break;
+	case RTAS_BUSY:
+		ret = true;
+		/*
+		 * We should call again immediately if there's no other
+		 * work to do.
+		 */
+		cond_resched();
+		break;
+	default:
+		ret = false;
+		/*
+		 * Not a busy or extended delay status; the caller should
+		 * handle @status itself. Ensure we warn on misuses in
+		 * atomic context regardless.
+		 */
+		might_sleep();
+		break;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rtas_busy_delay);
+
+int rtas_error_rc(int rtas_rc)
+{
+	int rc;
+
+	switch (rtas_rc) {
+	case RTAS_HARDWARE_ERROR:	/* Hardware Error */
+		rc = -EIO;
+		break;
+	case RTAS_INVALID_PARAMETER:	/* Bad indicator/domain/etc */
+		rc = -EINVAL;
+		break;
+	case -9000:			/* Isolation error */
+		rc = -EFAULT;
+		break;
+	case -9001:			/* Outstanding TCE/PTE */
+		rc = -EEXIST;
+		break;
+	case -9002:			/* No usable slot */
+		rc = -ENODEV;
+		break;
+	default:
+		pr_err("%s: unexpected error %d\n", __func__, rtas_rc);
+		rc = -ERANGE;
+		break;
+	}
+	return rc;
+}
+EXPORT_SYMBOL_GPL(rtas_error_rc);
+
+int rtas_get_power_level(int powerdomain, int *level)
+{
+	int token = rtas_function_token(RTAS_FN_GET_POWER_LEVEL);
+	int rc;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	while ((rc = rtas_call(token, 1, 2, level, powerdomain)) == RTAS_BUSY)
+		udelay(1);
+
+	if (rc < 0)
+		return rtas_error_rc(rc);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(rtas_get_power_level);
+
+int rtas_set_power_level(int powerdomain, int level, int *setlevel)
+{
+	int token = rtas_function_token(RTAS_FN_SET_POWER_LEVEL);
+	int rc;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	do {
+		rc = rtas_call(token, 2, 2, setlevel, powerdomain, level);
+	} while (rtas_busy_delay(rc));
+
+	if (rc < 0)
+		return rtas_error_rc(rc);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(rtas_set_power_level);
+
+int rtas_get_sensor(int sensor, int index, int *state)
+{
+	int token = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);
+	int rc;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	do {
+		rc = rtas_call(token, 2, 2, state, sensor, index);
+	} while (rtas_busy_delay(rc));
+
+	if (rc < 0)
+		return rtas_error_rc(rc);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(rtas_get_sensor);
+
+int rtas_get_sensor_fast(int sensor, int index, int *state)
+{
+	int token = rtas_function_token(RTAS_FN_GET_SENSOR_STATE);
+	int rc;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	rc = rtas_call(token, 2, 2, state, sensor, index);
+	WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
+				    rc <= RTAS_EXTENDED_DELAY_MAX));
+
+	if (rc < 0)
+		return rtas_error_rc(rc);
+	return rc;
+}
+
+bool rtas_indicator_present(int token, int *maxindex)
+{
+	int proplen, count, i;
+	const struct indicator_elem {
+		__be32 token;
+		__be32 maxindex;
+	} *indicators;
+
+	indicators = of_get_property(rtas.dev, "rtas-indicators", &proplen);
+	if (!indicators)
+		return false;
+
+	count = proplen / sizeof(struct indicator_elem);
+
+	for (i = 0; i < count; i++) {
+		if (__be32_to_cpu(indicators[i].token) != token)
+			continue;
+		if (maxindex)
+			*maxindex = __be32_to_cpu(indicators[i].maxindex);
+		return true;
+	}
+
+	return false;
+}
+
+int rtas_set_indicator(int indicator, int index, int new_value)
+{
+	int token = rtas_function_token(RTAS_FN_SET_INDICATOR);
+	int rc;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	do {
+		rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
+	} while (rtas_busy_delay(rc));
+
+	if (rc < 0)
+		return rtas_error_rc(rc);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(rtas_set_indicator);
+
+/*
+ * Ignoring RTAS extended delay
+ */
+int rtas_set_indicator_fast(int indicator, int index, int new_value)
+{
+	int token = rtas_function_token(RTAS_FN_SET_INDICATOR);
+	int rc;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -ENOENT;
+
+	rc = rtas_call(token, 3, 1, NULL, indicator, index, new_value);
+
+	WARN_ON(rc == RTAS_BUSY || (rc >= RTAS_EXTENDED_DELAY_MIN &&
+				    rc <= RTAS_EXTENDED_DELAY_MAX));
+
+	if (rc < 0)
+		return rtas_error_rc(rc);
+
+	return rc;
+}
+
+/**
+ * rtas_ibm_suspend_me() - Call ibm,suspend-me to suspend the LPAR.
+ *
+ * @fw_status: RTAS call status will be placed here if not NULL.
+ *
+ * rtas_ibm_suspend_me() should be called only on a CPU which has
+ * received H_CONTINUE from the H_JOIN hcall. All other active CPUs
+ * should be waiting to return from H_JOIN.
+ *
+ * rtas_ibm_suspend_me() may suspend execution of the OS
+ * indefinitely. Callers should take appropriate measures upon return, such as
+ * resetting watchdog facilities.
+ *
+ * Callers may choose to retry this call if @fw_status is
+ * %RTAS_THREADS_ACTIVE.
+ *
+ * Return:
+ * 0          - The partition has resumed from suspend, possibly after
+ *              migration to a different host.
+ * -ECANCELED - The operation was aborted.
+ * -EAGAIN    - There were other CPUs not in H_JOIN at the time of the call.
+ * -EBUSY     - Some other condition prevented the suspend from succeeding.
+ * -EIO       - Hardware/platform error.
+ */
+int rtas_ibm_suspend_me(int *fw_status)
+{
+	int token = rtas_function_token(RTAS_FN_IBM_SUSPEND_ME);
+	int fwrc;
+	int ret;
+
+	fwrc = rtas_call(token, 0, 1, NULL);
+
+	switch (fwrc) {
+	case 0:
+		ret = 0;
+		break;
+	case RTAS_SUSPEND_ABORTED:
+		ret = -ECANCELED;
+		break;
+	case RTAS_THREADS_ACTIVE:
+		ret = -EAGAIN;
+		break;
+	case RTAS_NOT_SUSPENDABLE:
+	case RTAS_OUTSTANDING_COPROC:
+		ret = -EBUSY;
+		break;
+	case -1:
+	default:
+		ret = -EIO;
+		break;
+	}
+
+	if (fw_status)
+		*fw_status = fwrc;
+
+	return ret;
+}
+
+void __noreturn rtas_restart(char *cmd)
+{
+	if (rtas_flash_term_hook)
+		rtas_flash_term_hook(SYS_RESTART);
+	pr_emerg("system-reboot returned %d\n",
+		 rtas_call(rtas_function_token(RTAS_FN_SYSTEM_REBOOT), 0, 1, NULL));
+	for (;;);
+}
+
+void rtas_power_off(void)
+{
+	if (rtas_flash_term_hook)
+		rtas_flash_term_hook(SYS_POWER_OFF);
+	/* allow power on only with power button press */
+	pr_emerg("power-off returned %d\n",
+		 rtas_call(rtas_function_token(RTAS_FN_POWER_OFF), 2, 1, NULL, -1, -1));
+	for (;;);
+}
+
+void __noreturn rtas_halt(void)
+{
+	if (rtas_flash_term_hook)
+		rtas_flash_term_hook(SYS_HALT);
+	/* allow power on only with power button press */
+	pr_emerg("power-off returned %d\n",
+		 rtas_call(rtas_function_token(RTAS_FN_POWER_OFF), 2, 1, NULL, -1, -1));
+	for (;;);
+}
+
+/* Must be in the RMO region, so we place it here */
+static char rtas_os_term_buf[2048];
+static bool ibm_extended_os_term;
+
+void rtas_os_term(char *str)
+{
+	s32 token = rtas_function_token(RTAS_FN_IBM_OS_TERM);
+	static struct rtas_args args;
+	int status;
+
+	/*
+	 * Firmware with the ibm,extended-os-term property is guaranteed
+	 * to always return from an ibm,os-term call. Earlier versions without
+	 * this property may terminate the partition which we want to avoid
+	 * since it interferes with panic_timeout.
+	 */
+
+	if (token == RTAS_UNKNOWN_SERVICE || !ibm_extended_os_term)
+		return;
+
+	snprintf(rtas_os_term_buf, 2048, "OS panic: %s", str);
+
+	/*
+	 * Keep calling as long as RTAS returns a "try again" status,
+	 * but don't use rtas_busy_delay(), which potentially
+	 * schedules.
+	 */
+	do {
+		rtas_call_unlocked(&args, token, 1, 1, NULL, __pa(rtas_os_term_buf));
+		status = be32_to_cpu(args.rets[0]);
+	} while (rtas_busy_delay_time(status));
+
+	if (status != 0)
+		pr_emerg("ibm,os-term call failed %d\n", status);
+}
+
+/**
+ * rtas_activate_firmware() - Activate a new version of firmware.
+ *
+ * Context: This function may sleep.
+ *
+ * Activate a new version of partition firmware. The OS must call this
+ * after resuming from a partition hibernation or migration in order
+ * to maintain the ability to perform live firmware updates. It's not
+ * catastrophic for this method to be absent or to fail; just log the
+ * condition in that case.
+ */
+void rtas_activate_firmware(void)
+{
+	int token = rtas_function_token(RTAS_FN_IBM_ACTIVATE_FIRMWARE);
+	int fwrc;
+
+	if (token == RTAS_UNKNOWN_SERVICE) {
+		pr_notice("ibm,activate-firmware method unavailable\n");
+		return;
+	}
+
+	do {
+		fwrc = rtas_call(token, 0, 1, NULL);
+	} while (rtas_busy_delay(fwrc));
+
+	if (fwrc)
+		pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
+}
+
+/**
+ * get_pseries_errorlog() - Find a specific pseries error log in an RTAS
+ *                          extended event log.
+ * @log: RTAS error/event log
+ * @section_id: two character section identifier
+ *
+ * Return: A pointer to the specified errorlog or NULL if not found.
+ */
+noinstr struct pseries_errorlog *get_pseries_errorlog(struct rtas_error_log *log,
+						      uint16_t section_id)
+{
+	struct rtas_ext_event_log_v6 *ext_log =
+		(struct rtas_ext_event_log_v6 *)log->buffer;
+	struct pseries_errorlog *sect;
+	unsigned char *p, *log_end;
+	uint32_t ext_log_length = rtas_error_extended_log_length(log);
+	uint8_t log_format = rtas_ext_event_log_format(ext_log);
+	uint32_t company_id = rtas_ext_event_company_id(ext_log);
+
+	/* Check that we understand the format */
+	if (ext_log_length < sizeof(struct rtas_ext_event_log_v6) ||
+	    log_format != RTAS_V6EXT_LOG_FORMAT_EVENT_LOG ||
+	    company_id != RTAS_V6EXT_COMPANY_ID_IBM)
+		return NULL;
+
+	log_end = log->buffer + ext_log_length;
+	p = ext_log->vendor_log;
+
+	while (p < log_end) {
+		sect = (struct pseries_errorlog *)p;
+		if (pseries_errorlog_id(sect) == section_id)
+			return sect;
+		p += pseries_errorlog_length(sect);
+	}
+
+	return NULL;
+}
+
+/*
+ * The sys_rtas syscall, as originally designed, allows root to pass
+ * arbitrary physical addresses to RTAS calls. A number of RTAS calls
+ * can be abused to write to arbitrary memory and do other things that
+ * are potentially harmful to system integrity, and thus should only
+ * be used inside the kernel and not exposed to userspace.
+ *
+ * All known legitimate users of the sys_rtas syscall will only ever
+ * pass addresses that fall within the RMO buffer, and use a known
+ * subset of RTAS calls.
+ *
+ * Accordingly, we filter RTAS requests to check that the call is
+ * permitted, and that provided pointers fall within the RMO buffer.
+ * If a function is allowed to be invoked via the syscall, then its
+ * entry in the rtas_functions table points to a rtas_filter that
+ * describes its constraints, with the indexes of the parameters which
+ * are expected to contain addresses and sizes of buffers allocated
+ * inside the RMO buffer.
+ */
+
+static bool in_rmo_buf(u32 base, u32 end)
+{
+	return base >= rtas_rmo_buf &&
+		base < (rtas_rmo_buf + RTAS_USER_REGION_SIZE) &&
+		base <= end &&
+		end >= rtas_rmo_buf &&
+		end < (rtas_rmo_buf + RTAS_USER_REGION_SIZE);
+}
+
+static bool block_rtas_call(int token, int nargs,
+			    struct rtas_args *args)
+{
+	const struct rtas_function *func;
+	const struct rtas_filter *f;
+	const bool is_platform_dump = token == rtas_function_token(RTAS_FN_IBM_PLATFORM_DUMP);
+	const bool is_config_conn = token == rtas_function_token(RTAS_FN_IBM_CONFIGURE_CONNECTOR);
+	u32 base, size, end;
+
+	/*
+	 * If this token doesn't correspond to a function the kernel
+	 * understands, you're not allowed to call it.
+	 */
+	func = rtas_token_to_function_untrusted(token);
+	if (!func)
+		goto err;
+	/*
+	 * And only functions with filters attached are allowed.
+	 */
+	f = func->filter;
+	if (!f)
+		goto err;
+	/*
+	 * And some functions aren't allowed on LE.
+	 */
+	if (IS_ENABLED(CONFIG_CPU_LITTLE_ENDIAN) && func->banned_for_syscall_on_le)
+		goto err;
+
+	if (f->buf_idx1 != -1) {
+		base = be32_to_cpu(args->args[f->buf_idx1]);
+		if (f->size_idx1 != -1)
+			size = be32_to_cpu(args->args[f->size_idx1]);
+		else if (f->fixed_size)
+			size = f->fixed_size;
+		else
+			size = 1;
+
+		end = base + size - 1;
+
+		/*
+		 * Special case for ibm,platform-dump - NULL buffer
+		 * address is used to indicate end of dump processing
+		 */
+		if (is_platform_dump && base == 0)
+			return false;
+
+		if (!in_rmo_buf(base, end))
+			goto err;
+	}
+
+	if (f->buf_idx2 != -1) {
+		base = be32_to_cpu(args->args[f->buf_idx2]);
+		if (f->size_idx2 != -1)
+			size = be32_to_cpu(args->args[f->size_idx2]);
+		else if (f->fixed_size)
+			size = f->fixed_size;
+		else
+			size = 1;
+		end = base + size - 1;
+
+		/*
+		 * Special case for ibm,configure-connector where the
+		 * address can be 0
+		 */
+		if (is_config_conn && base == 0)
+			return false;
+
+		if (!in_rmo_buf(base, end))
+			goto err;
+	}
+
+	return false;
+err:
+	pr_err_ratelimited("sys_rtas: RTAS call blocked - exploit attempt?\n");
+	pr_err_ratelimited("sys_rtas: token=0x%x, nargs=%d (called by %s)\n",
+			   token, nargs, current->comm);
+	return true;
+}
+
+/* We assume to be passed big endian arguments */
+SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
+{
+	struct pin_cookie cookie;
+	struct rtas_args args;
+	unsigned long flags;
+	char *buff_copy, *errbuf = NULL;
+	int nargs, nret, token;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	if (!rtas.entry)
+		return -EINVAL;
+
+	if (copy_from_user(&args, uargs, 3 * sizeof(u32)) != 0)
+		return -EFAULT;
+
+	nargs = be32_to_cpu(args.nargs);
+	nret  = be32_to_cpu(args.nret);
+	token = be32_to_cpu(args.token);
+
+	if (nargs >= ARRAY_SIZE(args.args)
+	    || nret > ARRAY_SIZE(args.args)
+	    || nargs + nret > ARRAY_SIZE(args.args))
+		return -EINVAL;
+
+	/* Copy in args. */
+	if (copy_from_user(args.args, uargs->args,
+			   nargs * sizeof(rtas_arg_t)) != 0)
+		return -EFAULT;
+
+	if (token == RTAS_UNKNOWN_SERVICE)
+		return -EINVAL;
+
+	args.rets = &args.args[nargs];
+	memset(args.rets, 0, nret * sizeof(rtas_arg_t));
+
+	if (block_rtas_call(token, nargs, &args))
+		return -EINVAL;
+
+	if (token_is_restricted_errinjct(token)) {
+		int err;
+
+		err = security_locked_down(LOCKDOWN_RTAS_ERROR_INJECTION);
+		if (err)
+			return err;
+	}
+
+	/* Need to handle ibm,suspend_me call specially */
+	if (token == rtas_function_token(RTAS_FN_IBM_SUSPEND_ME)) {
+
+		/*
+		 * rtas_ibm_suspend_me assumes the streamid handle is in cpu
+		 * endian, or at least the hcall within it requires it.
+		 */
+		int rc = 0;
+		u64 handle = ((u64)be32_to_cpu(args.args[0]) << 32)
+		              | be32_to_cpu(args.args[1]);
+		rc = rtas_syscall_dispatch_ibm_suspend_me(handle);
+		if (rc == -EAGAIN)
+			args.rets[0] = cpu_to_be32(RTAS_NOT_SUSPENDABLE);
+		else if (rc == -EIO)
+			args.rets[0] = cpu_to_be32(-1);
+		else if (rc)
+			return rc;
+		goto copy_return;
+	}
+
+	buff_copy = get_errorlog_buffer();
+
+	raw_spin_lock_irqsave(&rtas_lock, flags);
+	cookie = lockdep_pin_lock(&rtas_lock);
+
+	rtas_args = args;
+	do_enter_rtas(&rtas_args);
+	args = rtas_args;
+
+	/* A -1 return code indicates that the last command couldn't
+	   be completed due to a hardware error. */
+	if (be32_to_cpu(args.rets[0]) == -1)
+		errbuf = __fetch_rtas_last_error(buff_copy);
+
+	lockdep_unpin_lock(&rtas_lock, cookie);
+	raw_spin_unlock_irqrestore(&rtas_lock, flags);
+
+	if (buff_copy) {
+		if (errbuf)
+			log_error(errbuf, ERR_TYPE_RTAS_LOG, 0);
+		kfree(buff_copy);
+	}
+
+ copy_return:
+	/* Copy out args. */
+	if (copy_to_user(uargs->args + nargs,
+			 args.args + nargs,
+			 nret * sizeof(rtas_arg_t)) != 0)
+		return -EFAULT;
+
+	return 0;
+}
+
+static void __init rtas_function_table_init(void)
+{
+	struct property *prop;
+
+	for (size_t i = 0; i < ARRAY_SIZE(rtas_function_table); ++i) {
+		struct rtas_function *curr = &rtas_function_table[i];
+		struct rtas_function *prior;
+		int cmp;
+
+		curr->token = RTAS_UNKNOWN_SERVICE;
+
+		if (i == 0)
+			continue;
+		/*
+		 * Ensure table is sorted correctly for binary search
+		 * on function names.
+		 */
+		prior = &rtas_function_table[i - 1];
+
+		cmp = strcmp(prior->name, curr->name);
+		if (cmp < 0)
+			continue;
+
+		if (cmp == 0) {
+			pr_err("'%s' has duplicate function table entries\n",
+			       curr->name);
+		} else {
+			pr_err("function table unsorted: '%s' wrongly precedes '%s'\n",
+			       prior->name, curr->name);
+		}
+	}
+
+	for_each_property_of_node(rtas.dev, prop) {
+		struct rtas_function *func;
+
+		if (prop->length != sizeof(u32))
+			continue;
+
+		func = __rtas_name_to_function(prop->name);
+		if (!func)
+			continue;
+
+		func->token = be32_to_cpup((__be32 *)prop->value);
+
+		pr_debug("function %s has token %u\n", func->name, func->token);
+	}
+}
+
+/*
+ * Call early during boot, before mem init, to retrieve the RTAS
+ * information from the device-tree and allocate the RMO buffer for userland
+ * accesses.
+ */
+void __init rtas_initialize(void)
+{
+	unsigned long rtas_region = RTAS_INSTANTIATE_MAX;
+	u32 base, size, entry;
+	int no_base, no_size, no_entry;
+
+	/* Get RTAS dev node and fill up our "rtas" structure with infos
+	 * about it.
+	 */
+	rtas.dev = of_find_node_by_name(NULL, "rtas");
+	if (!rtas.dev)
+		return;
+
+	no_base = of_property_read_u32(rtas.dev, "linux,rtas-base", &base);
+	no_size = of_property_read_u32(rtas.dev, "rtas-size", &size);
+	if (no_base || no_size) {
+		of_node_put(rtas.dev);
+		rtas.dev = NULL;
+		return;
+	}
+
+	rtas.base = base;
+	rtas.size = size;
+	no_entry = of_property_read_u32(rtas.dev, "linux,rtas-entry", &entry);
+	rtas.entry = no_entry ? rtas.base : entry;
+
+	init_error_log_max();
+
+	/* Must be called before any function token lookups */
+	rtas_function_table_init();
+
+	/*
+	 * Discover this now to avoid a device tree lookup in the
+	 * panic path.
+	 */
+	ibm_extended_os_term = of_property_read_bool(rtas.dev, "ibm,extended-os-term");
+
+	/* If RTAS was found, allocate the RMO buffer for it and look for
+	 * the stop-self token if any
+	 */
+#ifdef CONFIG_PPC64
+	if (firmware_has_feature(FW_FEATURE_LPAR))
+		rtas_region = min(ppc64_rma_size, RTAS_INSTANTIATE_MAX);
+#endif
+	rtas_rmo_buf = memblock_phys_alloc_range(RTAS_USER_REGION_SIZE, PAGE_SIZE,
+						 0, rtas_region);
+	if (!rtas_rmo_buf)
+		panic("ERROR: RTAS: Failed to allocate %lx bytes below %pa\n",
+		      PAGE_SIZE, &rtas_region);
+
+	rtas_work_area_reserve_arena(rtas_region);
+}
+
+int __init early_init_dt_scan_rtas(unsigned long node,
+		const char *uname, int depth, void *data)
+{
+	const u32 *basep, *entryp, *sizep;
+
+	if (depth != 1 || strcmp(uname, "rtas") != 0)
+		return 0;
+
+	basep  = of_get_flat_dt_prop(node, "linux,rtas-base", NULL);
+	entryp = of_get_flat_dt_prop(node, "linux,rtas-entry", NULL);
+	sizep  = of_get_flat_dt_prop(node, "rtas-size", NULL);
+
+#ifdef CONFIG_PPC64
+	/* need this feature to decide the crashkernel offset */
+	if (of_get_flat_dt_prop(node, "ibm,hypertas-functions", NULL))
+		powerpc_firmware_features |= FW_FEATURE_LPAR;
+#endif
+
+	if (basep && entryp && sizep) {
+		rtas.base = *basep;
+		rtas.entry = *entryp;
+		rtas.size = *sizep;
+	}
+
+#ifdef CONFIG_UDBG_RTAS_CONSOLE
+	basep = of_get_flat_dt_prop(node, "put-term-char", NULL);
+	if (basep)
+		rtas_putchar_token = *basep;
+
+	basep = of_get_flat_dt_prop(node, "get-term-char", NULL);
+	if (basep)
+		rtas_getchar_token = *basep;
+
+	if (rtas_putchar_token != RTAS_UNKNOWN_SERVICE &&
+	    rtas_getchar_token != RTAS_UNKNOWN_SERVICE)
+		udbg_init_rtas_console();
+
+#endif
+
+	/* break now */
+	return 1;
+}
+
+static DEFINE_RAW_SPINLOCK(timebase_lock);
+static u64 timebase = 0;
+
+void rtas_give_timebase(void)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&timebase_lock, flags);
+	hard_irq_disable();
+	rtas_call(rtas_function_token(RTAS_FN_FREEZE_TIME_BASE), 0, 1, NULL);
+	timebase = get_tb();
+	raw_spin_unlock(&timebase_lock);
+
+	while (timebase)
+		barrier();
+	rtas_call(rtas_function_token(RTAS_FN_THAW_TIME_BASE), 0, 1, NULL);
+	local_irq_restore(flags);
+}
+
+void rtas_take_timebase(void)
+{
+	while (!timebase)
+		barrier();
+	raw_spin_lock(&timebase_lock);
+	set_tb(timebase >> 32, timebase & 0xffffffff);
+	timebase = 0;
+	raw_spin_unlock(&timebase_lock);
+}