From: Nathan Lynch <nathanl@linux.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linuxppc-dev@lists.ozlabs.org,
Tyrel Datwyler <tyreld@linux.ibm.com>,
Scott Cheloha <cheloha@linux.ibm.com>,
Andrew Donnellan <ajd@linux.ibm.com>,
Nick Child <nnac123@linux.ibm.com>,
Laurent Dufour <ldufour@linux.ibm.com>,
Nathan Lynch <nathanl@linux.ibm.com>
Subject: [PATCH 6/8] powerpc/rtas: lockdep annotations
Date: Mon, 06 Mar 2023 15:33:45 -0600 [thread overview]
Message-ID: <20230220-rtas-queue-for-6-4-v1-6-010e4416f13f@linux.ibm.com> (raw)
In-Reply-To: <20230220-rtas-queue-for-6-4-v1-0-010e4416f13f@linux.ibm.com>
Add lockdep annotations for the following properties that must hold:
* Any error log retrieval must be atomically coupled with the prior
RTAS call, without a window for another RTAS call to occur before the
error log can be retrieved.
* All users of the core rtas_args parameter block must hold rtas_lock.
Move the definitions of rtas_lock and rtas_args up in the file so that
__do_enter_rtas_trace() can refer to them.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
arch/powerpc/kernel/rtas.c | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 96a10a0abe3a..633c925164e7 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -16,6 +16,7 @@
#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>
@@ -453,6 +454,16 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
},
};
+/*
+ * 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.
@@ -560,6 +571,9 @@ static void __do_enter_rtas(struct rtas_args *args)
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.
@@ -619,16 +633,6 @@ static void do_enter_rtas(struct rtas_args *args)
struct rtas_t rtas;
-/*
- * 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;
-
DEFINE_SPINLOCK(rtas_data_buf_lock);
EXPORT_SYMBOL_GPL(rtas_data_buf_lock);
@@ -951,6 +955,8 @@ static char *__fetch_rtas_last_error(char *altbuf)
u32 bufsz;
char *buf = NULL;
+ lockdep_assert_held(&rtas_lock);
+
if (token == -1)
return NULL;
@@ -1107,6 +1113,7 @@ static bool token_is_restricted_errinjct(s32 token)
*/
int rtas_call(int token, int nargs, int nret, int *outputs, ...)
{
+ struct pin_cookie cookie;
va_list list;
int i;
unsigned long flags;
@@ -1133,6 +1140,8 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
}
raw_spin_lock_irqsave(&rtas_lock, flags);
+ cookie = lockdep_pin_lock(&rtas_lock);
+
/* We use the global rtas args buffer */
args = &rtas_args;
@@ -1150,6 +1159,7 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
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) {
@@ -1781,6 +1791,7 @@ static bool block_rtas_call(int token, int nargs,
/* 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;
@@ -1849,6 +1860,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
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);
@@ -1859,6 +1871,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
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) {
--
2.39.1
WARNING: multiple messages have this Message-ID (diff)
From: Nathan Lynch via B4 Relay <devnull+nathanl.linux.ibm.com@kernel.org>
To: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Nathan Lynch <nathanl@linux.ibm.com>,
Tyrel Datwyler <tyreld@linux.ibm.com>,
Nick Child <nnac123@linux.ibm.com>,
Andrew Donnellan <ajd@linux.ibm.com>,
Scott Cheloha <cheloha@linux.ibm.com>,
Laurent Dufour <ldufour@linux.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 6/8] powerpc/rtas: lockdep annotations
Date: Mon, 06 Mar 2023 15:33:45 -0600 [thread overview]
Message-ID: <20230220-rtas-queue-for-6-4-v1-6-010e4416f13f@linux.ibm.com> (raw)
In-Reply-To: <20230220-rtas-queue-for-6-4-v1-0-010e4416f13f@linux.ibm.com>
From: Nathan Lynch <nathanl@linux.ibm.com>
Add lockdep annotations for the following properties that must hold:
* Any error log retrieval must be atomically coupled with the prior
RTAS call, without a window for another RTAS call to occur before the
error log can be retrieved.
* All users of the core rtas_args parameter block must hold rtas_lock.
Move the definitions of rtas_lock and rtas_args up in the file so that
__do_enter_rtas_trace() can refer to them.
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
---
arch/powerpc/kernel/rtas.c | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 96a10a0abe3a..633c925164e7 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -16,6 +16,7 @@
#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>
@@ -453,6 +454,16 @@ static struct rtas_function rtas_function_table[] __ro_after_init = {
},
};
+/*
+ * 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.
@@ -560,6 +571,9 @@ static void __do_enter_rtas(struct rtas_args *args)
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.
@@ -619,16 +633,6 @@ static void do_enter_rtas(struct rtas_args *args)
struct rtas_t rtas;
-/*
- * 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;
-
DEFINE_SPINLOCK(rtas_data_buf_lock);
EXPORT_SYMBOL_GPL(rtas_data_buf_lock);
@@ -951,6 +955,8 @@ static char *__fetch_rtas_last_error(char *altbuf)
u32 bufsz;
char *buf = NULL;
+ lockdep_assert_held(&rtas_lock);
+
if (token == -1)
return NULL;
@@ -1107,6 +1113,7 @@ static bool token_is_restricted_errinjct(s32 token)
*/
int rtas_call(int token, int nargs, int nret, int *outputs, ...)
{
+ struct pin_cookie cookie;
va_list list;
int i;
unsigned long flags;
@@ -1133,6 +1140,8 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
}
raw_spin_lock_irqsave(&rtas_lock, flags);
+ cookie = lockdep_pin_lock(&rtas_lock);
+
/* We use the global rtas args buffer */
args = &rtas_args;
@@ -1150,6 +1159,7 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
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) {
@@ -1781,6 +1791,7 @@ static bool block_rtas_call(int token, int nargs,
/* 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;
@@ -1849,6 +1860,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
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);
@@ -1859,6 +1871,7 @@ SYSCALL_DEFINE1(rtas, struct rtas_args __user *, uargs)
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) {
--
2.39.1
next prev parent reply other threads:[~2023-03-06 21:33 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-06 21:33 [PATCH 0/8] RTAS changes for 6.4 Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-06 21:33 ` [PATCH 1/8] powerpc/rtas: ensure 8-byte alignment for struct rtas_args Nathan Lynch
2023-03-06 21:33 ` Nathan Lynch via B4 Relay
2023-03-23 4:00 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 2/8] powerpc/rtas: use memmove for potentially overlapping buffer copy Nathan Lynch
2023-03-06 21:33 ` Nathan Lynch via B4 Relay
2023-03-23 4:09 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 3/8] powerpc/rtas: rtas_call_unlocked() kerneldoc Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-23 4:15 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 4/8] powerpc/rtas: fix miswording in rtas_function kerneldoc Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-23 0:17 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 5/8] powerpc/rtas: rename va_rtas_call_unlocked() to va_rtas_call() Nathan Lynch
2023-03-06 21:33 ` Nathan Lynch via B4 Relay
2023-03-23 4:17 ` Andrew Donnellan
2023-03-23 16:11 ` Nathan Lynch
2023-03-29 12:24 ` Michael Ellerman
2023-03-06 21:33 ` Nathan Lynch [this message]
2023-03-06 21:33 ` [PATCH 6/8] powerpc/rtas: lockdep annotations Nathan Lynch via B4 Relay
2023-03-23 6:01 ` Andrew Donnellan
2023-03-06 21:33 ` [PATCH 7/8] powerpc/rtas: warn on unsafe argument to rtas_call_unlocked() Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-23 4:25 ` Andrew Donnellan
2023-03-23 12:17 ` Nathan Lynch
2023-03-24 0:56 ` Nathan Lynch
2023-03-29 12:20 ` Michael Ellerman
2023-03-29 16:23 ` Nathan Lynch
2023-03-06 21:33 ` [PATCH 8/8] powerpc/rtas: consume retry statuses in sys_rtas() Nathan Lynch via B4 Relay
2023-03-06 21:33 ` Nathan Lynch
2023-03-23 6:26 ` Andrew Donnellan
2023-03-23 19:39 ` Nathan Lynch
2023-03-23 9:44 ` Michael Ellerman
2023-03-23 13:40 ` Nathan Lynch
2024-01-25 15:55 ` Christophe Leroy
2024-01-25 16:33 ` Nathan Lynch
2024-01-25 16:46 ` Christophe Leroy
2024-01-25 17:23 ` Nathan Lynch
2023-04-06 1:09 ` (subset) [PATCH 0/8] RTAS changes for 6.4 Michael Ellerman
2023-04-26 12:12 ` Michael Ellerman
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