// 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);
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 = xa_load(&rtas_token_to_function_xarray, 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(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);
}