MIPS: Fix BUILD_ROLLBACK_PROLOGUE for microMIPS

When the kernel is built for microMIPS, branches targets need to be
known to be microMIPS code in order to result in bit 0 of the PC being
set. The branch target in the BUILD_ROLLBACK_PROLOGUE macro was simply
the end of the macro, which may be pointing at padding rather than at
code. This results in recent enough GNU linkers complaining like so:

    mips-img-linux-gnu-ld: arch/mips/built-in.o: .text+0x3e3c: Unsupported branch between ISA modes.
    mips-img-linux-gnu-ld: final link failed: Bad value
    Makefile:936: recipe for target 'vmlinux' failed
    make: *** [vmlinux] Error 1

Fix this by changing the branch target to be the start of the
appropriate handler, skipping over any padding.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14019/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 17326a9..dc0b296 100644 (file)
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -142,9 +142,8 @@ LEAF(__r4k_wait)
        PTR_LA  k1, __r4k_wait
        ori     k0, 0x1f        /* 32 byte rollback region */
        xori    k0, 0x1f
-       bne     k0, k1, 9f
+       bne     k0, k1, \handler
        MTC0    k0, CP0_EPC
-9:
        .set pop
        .endm