[PATCH] jump_label: Fix unaligned traps on sparc.

[PATCH] jump_label: Fix unaligned traps on sparc.

[David Miller]

The vmlinux.lds.h knobs to emit the __jump_table section in the main
kernel image takes care to align the section, but this doesn't help
for the __jump_table section that gets emitted into modules.

Fix the resulting lack of section alignment by explicitly specifying
it in the assembler.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/arch/sparc/include/asm/jump_label.h b/arch/sparc/include/asm/jump_label.h
index 62e66d7..d95cf44 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -14,6 +14,7 @@
 			 "nop\n\t"				\
 			 "nop\n\t"				\
 			 ".pushsection __jump_table,  \"a\"\n\t"\
+			 ".align 4\n\t"				\
 			 ".word 1b, %l[" #label "], %c0\n\t"	\
 			 ".popsection \n\t"			\
 			 : :  "i" (key) :  : label);\

Re: [PATCH] jump_label: Fix unaligned traps on sparc.

[Steven Rostedt]

On Sat, 2010-10-23 at 11:06 -0700, David Miller wrote:
> The vmlinux.lds.h knobs to emit the __jump_table section in the main
> kernel image takes care to align the section, but this doesn't help
> for the __jump_table section that gets emitted into modules.
> 
> Fix the resulting lack of section alignment by explicitly specifying
> it in the assembler.
> 
> Signed-off-by: David S. Miller <davem@davemloft.net>

Thanks! I'll pull this in tonight with the other jump label patches.

Unfortunately, it turns out that gcc has a bug that can cause crashes
when jump label is used. We need to set it to broken until gcc has a fix
and we can detect if the compiler has the bug or not.

-- Steve


> 
> diff --git a/arch/sparc/include/asm/jump_label.h b/arch/sparc/include/asm/jump_label.h
> index 62e66d7..d95cf44 100644
> --- a/arch/sparc/include/asm/jump_label.h
> +++ b/arch/sparc/include/asm/jump_label.h
> @@ -14,6 +14,7 @@
>  			 "nop\n\t"				\
>  			 "nop\n\t"				\
>  			 ".pushsection __jump_table,  \"a\"\n\t"\
> +			 ".align 4\n\t"				\
>  			 ".word 1b, %l[" #label "], %c0\n\t"	\
>  			 ".popsection \n\t"			\
>  			 : :  "i" (key) :  : label);\

[tip:perf/urgent] jump_label: Fix unaligned traps on sparc.

[tip-bot for David Miller]

Commit-ID:  f0daed0242d514033b9ecca9187108d3c4e281a5
Gitweb:     http://git.kernel.org/tip/f0daed0242d514033b9ecca9187108d3c4e281a5
Author:     David Miller <davem@davemloft.net>
AuthorDate: Sat, 23 Oct 2010 11:06:24 -0700
Committer:  Steven Rostedt <rostedt@goodmis.org>
CommitDate: Fri, 29 Oct 2010 12:57:06 -0400

jump_label: Fix unaligned traps on sparc.

The vmlinux.lds.h knobs to emit the __jump_table section in the main
kernel image takes care to align the section, but this doesn't help
for the __jump_table section that gets emitted into modules.

Fix the resulting lack of section alignment by explicitly specifying
it in the assembler.

Signed-off-by: David S. Miller <davem@davemloft.net>
LKML-Reference: <20101023.110624.226758370.davem@davemloft.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 arch/sparc/include/asm/jump_label.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/sparc/include/asm/jump_label.h b/arch/sparc/include/asm/jump_label.h
index 62e66d7..d95cf44 100644
--- a/arch/sparc/include/asm/jump_label.h
+++ b/arch/sparc/include/asm/jump_label.h
@@ -14,6 +14,7 @@
 			 "nop\n\t"				\
 			 "nop\n\t"				\
 			 ".pushsection __jump_table,  \"a\"\n\t"\
+			 ".align 4\n\t"				\
 			 ".word 1b, %l[" #label "], %c0\n\t"	\
 			 ".popsection \n\t"			\
 			 : :  "i" (key) :  : label);\