ARM: 7895/1: signal: fix armv7-m build issue in sigreturn_codes.S

After "ARM: signal: sigreturn_codes should be endian neutral to
work in BE8" commit, thumb only platforms, like armv7m, fails to
compile sigreturn_codes.S. The reason is that for such arch
values '.arm' directive and arm opcodes are not allowed.

Fix conditionally enables arm opcodes only if no CONFIG_CPU_THUMBONLY
defined and it uses .org instructions to keep sigreturn_codes
layout.

Suggested-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Victor Kamensky <victor.kamensky@linaro.org>
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/kernel/sigreturn_codes.S b/arch/arm/kernel/sigreturn_codes.S
index 3c5d0f2170fd7ee309260c2d2c0a6108a24e54f8..b84d0cb13682ccd42e41a22894cb8d2c1821496d 100644 (file)
--- a/arch/arm/kernel/sigreturn_codes.S
+++ b/arch/arm/kernel/sigreturn_codes.S
@@ -30,6 +30,27 @@
  * snippets.
  */
 
+/*
+ * In CPU_THUMBONLY case kernel arm opcodes are not allowed.
+ * Note in this case codes skips those instructions but it uses .org
+ * directive to keep correct layout of sigreturn_codes array.
+ */
+#ifndef CONFIG_CPU_THUMBONLY
+#define ARM_OK(code...)        code
+#else
+#define ARM_OK(code...)
+#endif
+
+       .macro arm_slot n
+       .org    sigreturn_codes + 12 * (\n)
+ARM_OK(        .arm    )
+       .endm
+
+       .macro thumb_slot n
+       .org    sigreturn_codes + 12 * (\n) + 8
+       .thumb
+       .endm
+
 #if __LINUX_ARM_ARCH__ <= 4
        /*
         * Note we manually set minimally required arch that supports
@@ -45,26 +66,27 @@
        .global sigreturn_codes
        .type   sigreturn_codes, #object
 
-       .arm
+       .align
 
 sigreturn_codes:
 
        /* ARM sigreturn syscall code snippet */
-       mov     r7, #(__NR_sigreturn - __NR_SYSCALL_BASE)
-       swi     #(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE)
+       arm_slot 0
+ARM_OK(        mov     r7, #(__NR_sigreturn - __NR_SYSCALL_BASE)       )
+ARM_OK(        swi     #(__NR_sigreturn)|(__NR_OABI_SYSCALL_BASE)      )
 
        /* Thumb sigreturn syscall code snippet */
-       .thumb
+       thumb_slot 0
        movs    r7, #(__NR_sigreturn - __NR_SYSCALL_BASE)
        swi     #0
 
        /* ARM sigreturn_rt syscall code snippet */
-       .arm
-       mov     r7, #(__NR_rt_sigreturn - __NR_SYSCALL_BASE)
-       swi     #(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE)
+       arm_slot 1
+ARM_OK(        mov     r7, #(__NR_rt_sigreturn - __NR_SYSCALL_BASE)    )
+ARM_OK(        swi     #(__NR_rt_sigreturn)|(__NR_OABI_SYSCALL_BASE)   )
 
        /* Thumb sigreturn_rt syscall code snippet */
-       .thumb
+       thumb_slot 1
        movs    r7, #(__NR_rt_sigreturn - __NR_SYSCALL_BASE)
        swi     #0
 
@@ -74,7 +96,7 @@ sigreturn_codes:
         * it is thumb case or not, so we need additional
         * word after real last entry.
         */
-       .arm
+       arm_slot 2
        .space  4
 
        .size   sigreturn_codes, . - sigreturn_codes