MIPS: Move signal trampolines off of the stack.

This is a follow on to the vdso patch.

Since all processes now have signal trampolines permanently mapped, we
can use those instead of putting the trampoline on the stack and
invalidating the corresponding icache across all CPUs.  We also get rid
of a bunch of ICACHE_REFILLS_WORKAROUND_WAR code.

[Ralf: GDB 7.1 which has the necessary modifications to allow backtracing
over signal frames will supposedly be released tomorrow.  The old signal
frame format obsoleted by this patch exists in two variations, for sane
processors and for those requiring ICACHE_REFILLS_WORKAROUND_WAR.  So
there was never a GDB which did support backtracing over signal frames
on all MIPS systems.  This convinved me this series should be applied and
pushed upstream as soon as possible.]

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/974/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/mips/include/asm/abi.h b/arch/mips/include/asm/abi.h
index 1dd74fbdc09..9252d9b50e5 100644
--- a/arch/mips/include/asm/abi.h
+++ b/arch/mips/include/asm/abi.h
@@ -13,12 +13,14 @@
 #include <asm/siginfo.h>
 
 struct mips_abi {
-	int (* const setup_frame)(struct k_sigaction * ka,
+	int (* const setup_frame)(void *sig_return, struct k_sigaction *ka,
 	                          struct pt_regs *regs, int signr,
 	                          sigset_t *set);
-	int (* const setup_rt_frame)(struct k_sigaction * ka,
+	const unsigned long	signal_return_offset;
+	int (* const setup_rt_frame)(void *sig_return, struct k_sigaction *ka,
 	                       struct pt_regs *regs, int signr,
 	                       sigset_t *set, siginfo_t *info);
+	const unsigned long	rt_signal_return_offset;
 	const unsigned long	restart;
 };