Adding upstream version 6.8.9.upstream/6.8.9

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

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);