From: avik.sil@linaro.org (Avik Sil)
Subject: [ltt-dev] [PATCH] ARM: Set bit 0 for thumb mode in kallsyms_lookup_name returned address
Date: Fri, 16 Sep 2011 16:28:04 +0530 [thread overview]
Message-ID: <1316170684-1914-1-git-send-email-avik.sil@linaro.org> (raw)
This patch fixes the undefined instruction oops due to execution
of thumb-2 code in ARM mode. The zero bit in the symbol address
returned by kallsyms_lookup_name is not set, leading to switching
to ARM mode that generates oops while executing thumb-2 code. For
detailed discussion, see [1].
[1] http://lists.casi.polymtl.ca/pipermail/ltt-dev/2011-September/005176.html
Signed-off-by: Avik Sil <avik.sil at linaro.org>
---
lttng-context-prio.c | 11 ++++++++++-
wrapper/ftrace.h | 28 ++++++++++++++++++++++------
wrapper/splice.c | 14 ++++++++++++--
wrapper/vmalloc.h | 14 +++++++++++---
4 files changed, 55 insertions(+), 12 deletions(-)
diff --git a/lttng-context-prio.c b/lttng-context-prio.c
index ad1c42f..5e8c0d2 100644
--- a/lttng-context-prio.c
+++ b/lttng-context-prio.c
@@ -20,7 +20,16 @@ int (*wrapper_task_prio_sym)(struct task_struct *t);
int wrapper_task_prio_init(void)
{
- wrapper_task_prio_sym = (void *) kallsyms_lookup_name("task_prio");
+ unsigned long addr;
+
+ addr = kallsyms_lookup_name("task_prio");
+#ifdef CONFIG_ARM
+#ifdef CONFIG_THUMB2_KERNEL
+ if (addr)
+ addr |= 1; /* set bit 0 in address for thumb mode */
+#endif
+#endif
+ wrapper_task_prio_sym = (void *) addr;
if (!wrapper_task_prio_sym) {
printk(KERN_WARNING "LTTng: task_prio symbol lookup failed.\n");
return -EINVAL;
diff --git a/wrapper/ftrace.h b/wrapper/ftrace.h
index 9c18cc5..d79aa5e 100644
--- a/wrapper/ftrace.h
+++ b/wrapper/ftrace.h
@@ -21,10 +21,18 @@ static inline
int wrapper_register_ftrace_function_probe(char *glob,
struct ftrace_probe_ops *ops, void *data)
{
- int (*register_ftrace_function_probe_sym)(char *glob,
- struct ftrace_probe_ops *ops, void *data);
+ unsigned long addr;
+ int (*register_ftrace_function_probe_sym)(char *glob,
+ struct ftrace_probe_ops *ops, void *data);
- register_ftrace_function_probe_sym = (void *) kallsyms_lookup_name("register_ftrace_function_probe");
+ addr = kallsyms_lookup_name("register_ftrace_function_probe");
+#ifdef CONFIG_ARM
+#ifdef CONFIG_THUMB2_KERNEL
+ if (addr)
+ addr |= 1; /* set bit 0 in address for thumb mode */
+#endif
+#endif
+ register_ftrace_function_probe_sym = (void *) addr;
if (register_ftrace_function_probe_sym) {
return register_ftrace_function_probe_sym(glob, ops, data);
} else {
@@ -37,10 +45,18 @@ static inline
void wrapper_unregister_ftrace_function_probe(char *glob,
struct ftrace_probe_ops *ops, void *data)
{
- void (*unregister_ftrace_function_probe_sym)(char *glob,
- struct ftrace_probe_ops *ops, void *data);
+ unsigned long addr;
+ void (*unregister_ftrace_function_probe_sym)(char *glob,
+ struct ftrace_probe_ops *ops, void *data);
- unregister_ftrace_function_probe_sym = (void *) kallsyms_lookup_name("unregister_ftrace_function_probe");
+ addr = kallsyms_lookup_name("unregister_ftrace_function_probe");
+#ifdef CONFIG_ARM
+#ifdef CONFIG_THUMB2_KERNEL
+ if (addr)
+ addr |= 1; /* set bit 0 in address for thumb mode */
+#endif
+#endif
+ unregister_ftrace_function_probe_sym = (void *) addr;
if (unregister_ftrace_function_probe_sym) {
unregister_ftrace_function_probe_sym(glob, ops, data);
} else {
diff --git a/wrapper/splice.c b/wrapper/splice.c
index edc499c..c2c275b 100644
--- a/wrapper/splice.c
+++ b/wrapper/splice.c
@@ -21,8 +21,18 @@ ssize_t (*splice_to_pipe_sym)(struct pipe_inode_info *pipe,
ssize_t wrapper_splice_to_pipe(struct pipe_inode_info *pipe,
struct splice_pipe_desc *spd)
{
- if (!splice_to_pipe_sym)
- splice_to_pipe_sym = (void *) kallsyms_lookup_name("splice_to_pipe");
+ unsigned long addr;
+
+ if (!splice_to_pipe_sym) {
+ addr = kallsyms_lookup_name("splice_to_pipe");
+#ifdef CONFIG_ARM
+#ifdef CONFIG_THUMB2_KERNEL
+ if (addr)
+ addr |= 1; /* set bit 0 in address for thumb mode */
+#endif
+#endif
+ splice_to_pipe_sym = (void *) addr;
+ }
if (splice_to_pipe_sym) {
return splice_to_pipe_sym(pipe, spd);
} else {
diff --git a/wrapper/vmalloc.h b/wrapper/vmalloc.h
index 7d87855..d512c89 100644
--- a/wrapper/vmalloc.h
+++ b/wrapper/vmalloc.h
@@ -18,9 +18,17 @@
static inline
void wrapper_vmalloc_sync_all(void)
{
- void (*vmalloc_sync_all_sym)(void);
-
- vmalloc_sync_all_sym = (void *) kallsyms_lookup_name("vmalloc_sync_all");
+ unsigned long addr;
+ void (*vmalloc_sync_all_sym)(void);
+
+ addr = kallsyms_lookup_name("vmalloc_sync_all");
+#ifdef CONFIG_ARM
+#ifdef CONFIG_THUMB2_KERNEL
+ if (addr)
+ addr |= 1; /* set bit 0 in address for thumb mode */
+#endif
+#endif
+ vmalloc_sync_all_sym = (void *) addr;
if (vmalloc_sync_all_sym) {
vmalloc_sync_all_sym();
} else {
--
1.7.0.4
next reply other threads:[~2011-09-16 10:58 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-16 10:58 Avik Sil [this message]
2011-09-16 13:53 ` Mathieu Desnoyers
[not found] ` <BLU0-SMTP31816889BA02407E5EEBA296060@phx.gbl>
2011-09-16 15:32 ` Dave Martin
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