MIPS: Fix sigreturn via VDSO on microMIPS kernel

commit 13eb192d10bcc9ac518d57356179071d603bcb4e upstream.

In microMIPS kernels, handle_signal() sets the isa16 mode bit in the
vdso address so that the sigreturn trampolines (which are offset from
the VDSO) get executed as microMIPS.

However commit ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
changed the offsets to come from the VDSO image, which already have the
isa16 mode bit set correctly since they're extracted from the VDSO
shared library symbol table.

Drop the isa16 mode bit handling from handle_signal() to fix sigreturn
for cores which support both microMIPS and normal MIPS. This doesn't fix
microMIPS only cores, since the VDSO is still built for normal MIPS, but
thats a separate problem.

Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO")
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/13348/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index fc7c1f0b3d8db9d75f6ce4160bea5d30bc0013c7..9e35b6b26aa8788e088d7764856ed07ca876a7c3 100644 (file)
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -770,15 +770,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
        sigset_t *oldset = sigmask_to_save();
        int ret;
        struct mips_abi *abi = current->thread.abi;
-#ifdef CONFIG_CPU_MICROMIPS
-       void *vdso;
-       unsigned long tmp = (unsigned long)current->mm->context.vdso;
-
-       set_isa16_mode(tmp);
-       vdso = (void *)tmp;
-#else
        void *vdso = current->mm->context.vdso;
-#endif
 
        if (regs->regs[0]) {
                switch(regs->regs[2]) {