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WSL2-Linux-Kernel/arch/powerpc/kernel/rtas.c

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// 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.
*/
#include <linux/stdarg.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/export.h>
#include <linux/init.h>
#include <linux/capability.h>
#include <linux/delay.h>
#include <linux/cpu.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <linux/cpumask.h>
#include <linux/memblock.h>
#include <linux/slab.h>
#include <linux/reboot.h>
#include <linux/syscalls.h>
#include <asm/interrupt.h>
#include <asm/prom.h>
#include <asm/rtas.h>
#include <asm/hvcall.h>
#include <asm/machdep.h>
#include <asm/firmware.h>
#include <asm/page.h>
#include <asm/param.h>
#include <asm/delay.h>
#include <linux/uaccess.h>
#include <asm/udbg.h>
#include <asm/syscalls.h>
#include <asm/smp.h>
#include <linux/atomic.h>
#include <asm/time.h>
#include <asm/mmu.h>
#include <asm/topology.h>
/* This is here deliberately so it's only used in this file */
void enter_rtas(unsigned long);
static inline void do_enter_rtas(unsigned long args)
{
unsigned long msr;
/*
* Make sure MSR[RI] is currently enabled as it will be forced later
* in enter_rtas.
*/
msr = mfmsr();
BUG_ON(!(msr & MSR_RI));
enter_rtas(args);
srr_regs_clobbered(); /* rtas uses SRRs, invalidate */
}
struct rtas_t rtas = {
.lock = __ARCH_SPIN_LOCK_UNLOCKED
};
EXPORT_SYMBOL(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);
/* RTAS use home made raw locking instead of spin_lock_irqsave
* because those can be called from within really nasty contexts
* such as having the timebase stopped which would lockup with
* normal locks and spinlock debugging enabled
*/
static unsigned long lock_rtas(void)
{
unsigned long flags;
local_irq_save(flags);
preempt_disable();
arch_spin_lock(&rtas.lock);
return flags;
}
static void unlock_rtas(unsigned long flags)
{
arch_spin_unlock(&rtas.lock);
local_irq_restore(flags);
preempt_enable();
}
/*
* 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 s;
if (!rtas.base)
return;
s = lock_rtas();
rtas_call_unlocked(&rtas.args, 10, 1, 1, NULL, c);
unlock_rtas(s);
}
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_token("display-character");
set_indicator = rtas_token("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 __be32 *tokp;
if (rtas.dev == NULL)
return RTAS_UNKNOWN_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;
}
EXPORT_SYMBOL(rtas_service_present);
#ifdef CONFIG_RTAS_ERROR_LOGGING
/*
* 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)
{
static int rtas_error_log_max;
if (rtas_error_log_max)
return rtas_error_log_max;
rtas_error_log_max = rtas_token ("rtas-error-log-max");
if ((rtas_error_log_max == RTAS_UNKNOWN_SERVICE) ||
(rtas_error_log_max > RTAS_ERROR_LOG_MAX)) {
printk (KERN_WARNING "RTAS: bad log buffer size %d\n",
rtas_error_log_max);
rtas_error_log_max = RTAS_ERROR_LOG_MAX;
}
return rtas_error_log_max;
}
EXPORT_SYMBOL(rtas_get_error_log_max);
static char rtas_err_buf[RTAS_ERROR_LOG_MAX];
static int rtas_last_error_token;
/** 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)
{
struct rtas_args err_args, save_args;
u32 bufsz;
char *buf = NULL;
if (rtas_last_error_token == -1)
return NULL;
bufsz = rtas_get_error_log_max();
err_args.token = cpu_to_be32(rtas_last_error_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(__pa(&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
#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(__pa(args));
}
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);
}
int rtas_call(int token, int nargs, int nret, int *outputs, ...)
{
va_list list;
int i;
unsigned long s;
struct rtas_args *rtas_args;
char *buff_copy = NULL;
int ret;
if (!rtas.entry || token == RTAS_UNKNOWN_SERVICE)
return -1;
s = lock_rtas();
/* We use the global rtas args buffer */
rtas_args = &rtas.args;
va_start(list, outputs);
va_rtas_call_unlocked(rtas_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(rtas_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(rtas_args->rets[i+1]);
ret = (nret > 0)? be32_to_cpu(rtas_args->rets[0]): 0;
unlock_rtas(s);
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);
/* For RTAS_BUSY (-2), delay for 1 millisecond. For an extended busy status
* code of 990n, perform the hinted delay of 10^n (last digit) milliseconds.
*/
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;
}
EXPORT_SYMBOL(rtas_busy_delay_time);
/* For an RTAS busy status code, perform the hinted delay. */
unsigned int rtas_busy_delay(int status)
{
unsigned int ms;
might_sleep();
ms = rtas_busy_delay_time(status);
if (ms && need_resched())
msleep(ms);
return ms;
}
EXPORT_SYMBOL_GPL(rtas_busy_delay);
static int rtas_error_rc(int rtas_rc)
{
int rc;
switch (rtas_rc) {
case -1: /* Hardware Error */
rc = -EIO;
break;
case -3: /* 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:
printk(KERN_ERR "%s: unexpected RTAS error %d\n",
__func__, rtas_rc);
rc = -ERANGE;
break;
}
return rc;
}
int rtas_get_power_level(int powerdomain, int *level)
{
int token = rtas_token("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_token("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_token("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_token("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;
}
EXPORT_SYMBOL(rtas_indicator_present);
int rtas_set_indicator(int indicator, int index, int new_value)
{
int token = rtas_token("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 rc;
int token = rtas_token("set-indicator");
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 fwrc;
int ret;
fwrc = rtas_call(rtas_token("ibm,suspend-me"), 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);
printk("RTAS system-reboot returned %d\n",
rtas_call(rtas_token("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 */
printk("RTAS power-off returned %d\n",
rtas_call(rtas_token("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 */
printk("RTAS power-off returned %d\n",
rtas_call(rtas_token("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 s32 ibm_os_term_token = RTAS_UNKNOWN_SERVICE;
void rtas_os_term(char *str)
{
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 (ibm_os_term_token == RTAS_UNKNOWN_SERVICE)
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 {
status = rtas_call(ibm_os_term_token, 1, 1, NULL,
__pa(rtas_os_term_buf));
} while (rtas_busy_delay_time(status));
if (status != 0)
printk(KERN_EMERG "ibm,os-term call failed %d\n", status);
}
/**
* rtas_activate_firmware() - Activate a new version of firmware.
*
* 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.
*
* Context: This function may sleep.
*/
void rtas_activate_firmware(void)
{
int token;
int fwrc;
token = rtas_token("ibm,activate-firmware");
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);
}
/**
* Find a specific pseries error log in an RTAS extended event log.
* @log: RTAS error/event log
* @section_id: two character section identifier
*
* Returns a pointer to the specified errorlog or NULL if not found.
*/
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;
}
#ifdef CONFIG_PPC_RTAS_FILTER
/*
* 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.
* The rtas_filters list contains an entry for each permitted call,
* with the indexes of the parameters which are expected to contain
* addresses and sizes of buffers allocated inside the RMO buffer.
*/
struct rtas_filter {
const char *name;
int token;
/* Indexes into the args buffer, -1 if not used */
int buf_idx1;
int size_idx1;
int buf_idx2;
int size_idx2;
int fixed_size;
};
static struct rtas_filter rtas_filters[] __ro_after_init = {
{ "ibm,activate-firmware", -1, -1, -1, -1, -1 },
{ "ibm,configure-connector", -1, 0, -1, 1, -1, 4096 }, /* Special cased */
{ "display-character", -1, -1, -1, -1, -1 },
{ "ibm,display-message", -1, 0, -1, -1, -1 },
{ "ibm,errinjct", -1, 2, -1, -1, -1, 1024 },
{ "ibm,close-errinjct", -1, -1, -1, -1, -1 },
{ "ibm,open-errinjct", -1, -1, -1, -1, -1 },
{ "ibm,get-config-addr-info2", -1, -1, -1, -1, -1 },
{ "ibm,get-dynamic-sensor-state", -1, 1, -1, -1, -1 },
{ "ibm,get-indices", -1, 2, 3, -1, -1 },
{ "get-power-level", -1, -1, -1, -1, -1 },
{ "get-sensor-state", -1, -1, -1, -1, -1 },
{ "ibm,get-system-parameter", -1, 1, 2, -1, -1 },
{ "get-time-of-day", -1, -1, -1, -1, -1 },
{ "ibm,get-vpd", -1, 0, -1, 1, 2 },
{ "ibm,lpar-perftools", -1, 2, 3, -1, -1 },
{ "ibm,platform-dump", -1, 4, 5, -1, -1 }, /* Special cased */
{ "ibm,read-slot-reset-state", -1, -1, -1, -1, -1 },
{ "ibm,scan-log-dump", -1, 0, 1, -1, -1 },
{ "ibm,set-dynamic-indicator", -1, 2, -1, -1, -1 },
{ "ibm,set-eeh-option", -1, -1, -1, -1, -1 },
{ "set-indicator", -1, -1, -1, -1, -1 },
{ "set-power-level", -1, -1, -1, -1, -1 },
{ "set-time-for-power-on", -1, -1, -1, -1, -1 },
{ "ibm,set-system-parameter", -1, 1, -1, -1, -1 },
{ "set-time-of-day", -1, -1, -1, -1, -1 },
#ifdef CONFIG_CPU_BIG_ENDIAN
{ "ibm,suspend-me", -1, -1, -1, -1, -1 },
{ "ibm,update-nodes", -1, 0, -1, -1, -1, 4096 },
{ "ibm,update-properties", -1, 0, -1, -1, -1, 4096 },
#endif
{ "ibm,physical-attestation", -1, 0, 1, -1, -1 },
};
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)
{
int i;
for (i = 0; i < ARRAY_SIZE(rtas_filters); i++) {
struct rtas_filter *f = &rtas_filters[i];
u32 base, size, end;
if (token != f->token)
continue;
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 (!strcmp(f->name, "ibm,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 (!strcmp(f->name, "ibm,configure-connector") &&
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;
}
static void __init rtas_syscall_filter_init(void)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(rtas_filters); i++)
rtas_filters[i].token = rtas_token(rtas_filters[i].name);
}
#else
static bool block_rtas_call(int token, int nargs,
struct rtas_args *args)
{
return false;
}
static void __init rtas_syscall_filter_init(void)
{
}
#endif /* CONFIG_PPC_RTAS_FILTER */
/* We assume to be passed big endian arguments */
SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
{
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;
/* Need to handle ibm,suspend_me call specially */
if (token == rtas_token("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();
flags = lock_rtas();
rtas.args = args;
do_enter_rtas(__pa(&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);
unlock_rtas(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;
}
/*
* 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;
/*
* Discover these now to avoid device tree lookups in the
* panic path.
*/
if (of_property_read_bool(rtas.dev, "ibm,extended-os-term"))
ibm_os_term_token = rtas_token("ibm,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);
#ifdef CONFIG_RTAS_ERROR_LOGGING
rtas_last_error_token = rtas_token("rtas-last-error");
#endif
rtas_syscall_filter_init();
}
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 arch_spinlock_t timebase_lock;
static u64 timebase = 0;
void rtas_give_timebase(void)
{
unsigned long flags;
local_irq_save(flags);
hard_irq_disable();
arch_spin_lock(&timebase_lock);
rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
timebase = get_tb();
arch_spin_unlock(&timebase_lock);
while (timebase)
barrier();
rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
local_irq_restore(flags);
}
void rtas_take_timebase(void)
{
while (!timebase)
barrier();
arch_spin_lock(&timebase_lock);
set_tb(timebase >> 32, timebase & 0xffffffff);
timebase = 0;
arch_spin_unlock(&timebase_lock);
}
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