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Diffstat (limited to 'arch/powerpc/kernel/rtas.c')
-rw-r--r--arch/powerpc/kernel/rtas.c190
1 files changed, 142 insertions, 48 deletions
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 46b9476d75..8064d9c3de 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -18,6 +18,7 @@
#include <linux/kernel.h>
#include <linux/lockdep.h>
#include <linux/memblock.h>
+#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/reboot.h>
@@ -70,14 +71,33 @@ struct rtas_filter {
* ppc64le, and we want to keep it that way. It does
* not make sense for this to be set when @filter
* is NULL.
+ * @lock: Pointer to an optional dedicated per-function mutex. This
+ * should be set for functions that require multiple calls in
+ * sequence to complete a single operation, and such sequences
+ * will disrupt each other if allowed to interleave. Users of
+ * this function are required to hold the associated lock for
+ * the duration of the call sequence. Add an explanatory
+ * comment to the function table entry if setting this member.
*/
struct rtas_function {
s32 token;
const bool banned_for_syscall_on_le:1;
const char * const name;
const struct rtas_filter *filter;
+ struct mutex *lock;
};
+/*
+ * Per-function locks for sequence-based RTAS functions.
+ */
+static DEFINE_MUTEX(rtas_ibm_activate_firmware_lock);
+static DEFINE_MUTEX(rtas_ibm_get_dynamic_sensor_state_lock);
+static DEFINE_MUTEX(rtas_ibm_get_indices_lock);
+static DEFINE_MUTEX(rtas_ibm_lpar_perftools_lock);
+static DEFINE_MUTEX(rtas_ibm_physical_attestation_lock);
+static DEFINE_MUTEX(rtas_ibm_set_dynamic_indicator_lock);
+DEFINE_MUTEX(rtas_ibm_get_vpd_lock);
+
static struct rtas_function rtas_function_table[] __ro_after_init = {
[RTAS_FNIDX__CHECK_EXCEPTION] = {
.name = "check-exception",
@@ -125,6 +145,13 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
.buf_idx1 = -1, .size_idx1 = -1,
.buf_idx2 = -1, .size_idx2 = -1,
},
+ /*
+ * PAPR+ as of v2.13 doesn't explicitly impose any
+ * restriction, but this typically requires multiple
+ * calls before success, and there's no reason to
+ * allow sequences to interleave.
+ */
+ .lock = &rtas_ibm_activate_firmware_lock,
},
[RTAS_FNIDX__IBM_CBE_START_PTCAL] = {
.name = "ibm,cbe-start-ptcal",
@@ -196,6 +223,13 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
.buf_idx1 = 1, .size_idx1 = -1,
.buf_idx2 = -1, .size_idx2 = -1,
},
+ /*
+ * PAPR+ v2.13 R1–7.3.19–3 is explicit that the OS
+ * must not call ibm,get-dynamic-sensor-state with
+ * different inputs until a non-retry status has been
+ * returned.
+ */
+ .lock = &rtas_ibm_get_dynamic_sensor_state_lock,
},
[RTAS_FNIDX__IBM_GET_INDICES] = {
.name = "ibm,get-indices",
@@ -203,6 +237,12 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
.buf_idx1 = 2, .size_idx1 = 3,
.buf_idx2 = -1, .size_idx2 = -1,
},
+ /*
+ * PAPR+ v2.13 R1–7.3.17–2 says that the OS must not
+ * interleave ibm,get-indices call sequences with
+ * different inputs.
+ */
+ .lock = &rtas_ibm_get_indices_lock,
},
[RTAS_FNIDX__IBM_GET_RIO_TOPOLOGY] = {
.name = "ibm,get-rio-topology",
@@ -220,6 +260,11 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
.buf_idx1 = 0, .size_idx1 = -1,
.buf_idx2 = 1, .size_idx2 = 2,
},
+ /*
+ * PAPR+ v2.13 R1–7.3.20–4 indicates that sequences
+ * should not be allowed to interleave.
+ */
+ .lock = &rtas_ibm_get_vpd_lock,
},
[RTAS_FNIDX__IBM_GET_XIVE] = {
.name = "ibm,get-xive",
@@ -239,6 +284,11 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
.buf_idx1 = 2, .size_idx1 = 3,
.buf_idx2 = -1, .size_idx2 = -1,
},
+ /*
+ * PAPR+ v2.13 R1–7.3.26–6 says the OS should allow
+ * only one call sequence in progress at a time.
+ */
+ .lock = &rtas_ibm_lpar_perftools_lock,
},
[RTAS_FNIDX__IBM_MANAGE_FLASH_IMAGE] = {
.name = "ibm,manage-flash-image",
@@ -277,6 +327,14 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
.buf_idx1 = 0, .size_idx1 = 1,
.buf_idx2 = -1, .size_idx2 = -1,
},
+ /*
+ * This follows a sequence-based pattern similar to
+ * ibm,get-vpd et al. Since PAPR+ restricts
+ * interleaving call sequences for other functions of
+ * this style, assume the restriction applies here,
+ * even though it's not explicit in the spec.
+ */
+ .lock = &rtas_ibm_physical_attestation_lock,
},
[RTAS_FNIDX__IBM_PLATFORM_DUMP] = {
.name = "ibm,platform-dump",
@@ -284,6 +342,13 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
.buf_idx1 = 4, .size_idx1 = 5,
.buf_idx2 = -1, .size_idx2 = -1,
},
+ /*
+ * PAPR+ v2.13 7.3.3.4.1 indicates that concurrent
+ * sequences of ibm,platform-dump are allowed if they
+ * are operating on different dump tags. So leave the
+ * lock pointer unset for now. This may need
+ * reconsideration if kernel-internal users appear.
+ */
},
[RTAS_FNIDX__IBM_POWER_OFF_UPS] = {
.name = "ibm,power-off-ups",
@@ -331,6 +396,12 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
.buf_idx1 = 2, .size_idx1 = -1,
.buf_idx2 = -1, .size_idx2 = -1,
},
+ /*
+ * PAPR+ v2.13 R1–7.3.18–3 says the OS must not call
+ * this function with different inputs until a
+ * non-retry status has been returned.
+ */
+ .lock = &rtas_ibm_set_dynamic_indicator_lock,
},
[RTAS_FNIDX__IBM_SET_EEH_OPTION] = {
.name = "ibm,set-eeh-option",
@@ -459,6 +530,11 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
},
};
+#define for_each_rtas_function(funcp) \
+ for (funcp = &rtas_function_table[0]; \
+ funcp < &rtas_function_table[ARRAY_SIZE(rtas_function_table)]; \
+ ++funcp)
+
/*
* Nearly all RTAS calls need to be serialized. All uses of the
* default rtas_args block must hold rtas_lock.
@@ -530,10 +606,10 @@ static DEFINE_XARRAY(rtas_token_to_function_xarray);
static int __init rtas_token_to_function_xarray_init(void)
{
+ const struct rtas_function *func;
int err = 0;
- for (size_t i = 0; i < ARRAY_SIZE(rtas_function_table); ++i) {
- const struct rtas_function *func = &rtas_function_table[i];
+ for_each_rtas_function(func) {
const s32 token = func->token;
if (token == RTAS_UNKNOWN_SERVICE)
@@ -572,11 +648,21 @@ static const struct rtas_function *rtas_token_to_function(s32 token)
return NULL;
func = rtas_token_to_function_untrusted(token);
+ if (func)
+ return func;
+ /*
+ * Fall back to linear scan in case the reverse mapping hasn't
+ * been initialized yet.
+ */
+ if (xa_empty(&rtas_token_to_function_xarray)) {
+ for_each_rtas_function(func) {
+ if (func->token == token)
+ return func;
+ }
+ }
- if (WARN_ONCE(!func, "unexpected failed lookup for token %d", token))
- return NULL;
-
- return func;
+ WARN_ONCE(true, "unexpected failed lookup for token %d", token);
+ return NULL;
}
/* This is here deliberately so it's only used in this file */
@@ -590,28 +676,25 @@ static void __do_enter_rtas(struct rtas_args *args)
static void __do_enter_rtas_trace(struct rtas_args *args)
{
- const char *name = NULL;
+ const struct rtas_function *func = rtas_token_to_function(be32_to_cpu(args->token));
- if (args == &rtas_args)
- lockdep_assert_held(&rtas_lock);
/*
- * If the tracepoints that consume the function name aren't
- * active, avoid the lookup.
+ * If there is a per-function lock, it must be held by the
+ * caller.
*/
- 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);
+ if (func->lock)
+ lockdep_assert_held(func->lock);
- name = func->name;
- }
+ if (args == &rtas_args)
+ lockdep_assert_held(&rtas_lock);
- trace_rtas_input(args, name);
+ trace_rtas_input(args, func->name);
trace_rtas_ll_entry(args);
__do_enter_rtas(args);
trace_rtas_ll_exit(args);
- trace_rtas_output(args, name);
+ trace_rtas_output(args, func->name);
}
static void do_enter_rtas(struct rtas_args *args)
@@ -690,7 +773,7 @@ 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') {
+ if (c == '\n') {
while (width-- > 0)
call_rtas_display_status(' ');
width = 16;
@@ -700,7 +783,7 @@ static void call_rtas_display_status_delay(char c)
if (pending_newline) {
call_rtas_display_status('\r');
call_rtas_display_status('\n');
- }
+ }
pending_newline = 0;
if (width--) {
call_rtas_display_status(c);
@@ -840,7 +923,7 @@ void rtas_progress(char *s, unsigned short hex)
else
rtas_call(display_character, 1, 1, NULL, '\r');
}
-
+
if (row_width)
width = row_width[current_line];
else
@@ -860,9 +943,9 @@ void rtas_progress(char *s, unsigned short hex)
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');
@@ -872,7 +955,7 @@ void rtas_progress(char *s, unsigned short hex)
*/
rtas_call(display_character, 1, 1, NULL, *os);
}
-
+
if (row_width)
width = row_width[current_line];
else
@@ -881,15 +964,15 @@ void rtas_progress(char *s, unsigned short hex)
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 */
@@ -920,11 +1003,6 @@ int rtas_token(const char *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;
@@ -1658,10 +1736,14 @@ void rtas_activate_firmware(void)
return;
}
+ mutex_lock(&rtas_ibm_activate_firmware_lock);
+
do {
fwrc = rtas_call(token, 0, 1, NULL);
} while (rtas_busy_delay(fwrc));
+ mutex_unlock(&rtas_ibm_activate_firmware_lock);
+
if (fwrc)
pr_err("ibm,activate-firmware failed (%i)\n", fwrc);
}
@@ -1733,24 +1815,18 @@ static bool in_rmo_buf(u32 base, u32 end)
end < (rtas_rmo_buf + RTAS_USER_REGION_SIZE);
}
-static bool block_rtas_call(int token, int nargs,
+static bool block_rtas_call(const struct rtas_function *func, 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);
+ const bool is_platform_dump =
+ func == &rtas_function_table[RTAS_FNIDX__IBM_PLATFORM_DUMP];
+ const bool is_config_conn =
+ func == &rtas_function_table[RTAS_FNIDX__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.
+ * Only functions with filters attached are allowed.
*/
f = func->filter;
if (!f)
@@ -1807,14 +1883,15 @@ static bool block_rtas_call(int token, int nargs,
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);
+ pr_err_ratelimited("sys_rtas: %s nargs=%d (called by %s)\n",
+ func->name, nargs, current->comm);
return true;
}
/* We assume to be passed big endian arguments */
SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
{
+ const struct rtas_function *func;
struct pin_cookie cookie;
struct rtas_args args;
unsigned long flags;
@@ -1844,13 +1921,18 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
nargs * sizeof(rtas_arg_t)) != 0)
return -EFAULT;
- if (token == RTAS_UNKNOWN_SERVICE)
+ /*
+ * 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)
return -EINVAL;
args.rets = &args.args[nargs];
memset(args.rets, 0, nret * sizeof(rtas_arg_t));
- if (block_rtas_call(token, nargs, &args))
+ if (block_rtas_call(func, nargs, &args))
return -EINVAL;
if (token_is_restricted_errinjct(token)) {
@@ -1883,6 +1965,15 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
buff_copy = get_errorlog_buffer();
+ /*
+ * If this function has a mutex assigned to it, we must
+ * acquire it to avoid interleaving with any kernel-based uses
+ * of the same function. Kernel-based sequences acquire the
+ * appropriate mutex explicitly.
+ */
+ if (func->lock)
+ mutex_lock(func->lock);
+
raw_spin_lock_irqsave(&rtas_lock, flags);
cookie = lockdep_pin_lock(&rtas_lock);
@@ -1898,6 +1989,9 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
lockdep_unpin_lock(&rtas_lock, cookie);
raw_spin_unlock_irqrestore(&rtas_lock, flags);
+ if (func->lock)
+ mutex_unlock(func->lock);
+
if (buff_copy) {
if (errbuf)
log_error(errbuf, ERR_TYPE_RTAS_LOG, 0);