ARM: 9180/1: Thumb2: align ALT_UP() sections in modules sufficiently

commit 9f80ccda53b9417236945bc7ece4b519037df74d upstream.

When building for Thumb2, the .alt.smp.init sections that are emitted by
the ALT_UP() patching code may not be 32-bit aligned, even though the
fixup_smp_on_up() routine expects that. This results in alignment faults
at module load time, which need to be fixed up by the fault handler.

So let's align those sections explicitly, and prevent this from occurring.

Cc: <stable@vger.kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/arm/include/asm/assembler.h b/arch/arm/include/asm/assembler.h
index e2b1fd558bf3c4d1d6ccc55388e7f3e7b3b090dc..11bb9d12485fb65891f832dc6d9be555b0b9f8b0 100644 (file)
--- a/arch/arm/include/asm/assembler.h
+++ b/arch/arm/include/asm/assembler.h
@@ -259,6 +259,7 @@
  */
 #define ALT_UP(instr...)                                       \
        .pushsection ".alt.smp.init", "a"                       ;\
+       .align  2                                               ;\
        .long   9998b - .                                       ;\
 9997:  instr                                                   ;\
        .if . - 9997b == 2                                      ;\
@@ -270,6 +271,7 @@
        .popsection
 #define ALT_UP_B(label)                                        \
        .pushsection ".alt.smp.init", "a"                       ;\
+       .align  2                                               ;\
        .long   9998b - .                                       ;\
        W(b)    . + (label - 9998b)                                     ;\
        .popsection

diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 9e6b9728630773f445a094e7f9a837d2127a5ce1..8aeff55aebfaf5f1e35b9a0b2d001056dac3420e 100644 (file)
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -96,6 +96,7 @@ unsigned long get_wchan(struct task_struct *p);
 #define __ALT_SMP_ASM(smp, up)                                         \
        "9998:  " smp "\n"                                              \
        "       .pushsection \".alt.smp.init\", \"a\"\n"                \
+       "       .align  2\n"                                            \
        "       .long   9998b - .\n"                                    \
        "       " up "\n"                                               \
        "       .popsection\n"