MIPS: Add offsets to sigcontext FP fields to struct mips_abi

Add fields to struct mips_abi, which holds information regarding the
kernel-userland ABI regarding signals, to specify the offsets to the FP
related fields within the appropriate variant of struct sigcontext.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org
Cc: Richard Weinberger <richard@nod.at>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Maciej W. Rozycki <macro@codesourcery.com>
Patchwork: https://patchwork.linux-mips.org/patch/10788/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/abi.h

@@ -20,6 +20,10 @@ struct mips_abi {
 				     struct pt_regs *regs, sigset_t *set);
 	const unsigned long	rt_signal_return_offset;
 	const unsigned long	restart;
+
+	unsigned	off_sc_fpregs;
+	unsigned	off_sc_fpc_csr;
+	unsigned	off_sc_used_math;
 };
 
 #endif /* _ASM_ABI_H */

arch/mips/kernel/signal.c

@@ -521,7 +521,11 @@ struct mips_abi mips_abi = {
 	.setup_rt_frame = setup_rt_frame,
 	.rt_signal_return_offset =
 		offsetof(struct mips_vdso, rt_signal_trampoline),
-	.restart	= __NR_restart_syscall
+	.restart	= __NR_restart_syscall,
+
+	.off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
+	.off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
+	.off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
 };
 
 static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)

arch/mips/kernel/signal32.c

@@ -585,7 +585,11 @@ struct mips_abi mips_abi_32 = {
 	.setup_rt_frame = setup_rt_frame_32,
 	.rt_signal_return_offset =
 		offsetof(struct mips_vdso, o32_rt_signal_trampoline),
-	.restart	= __NR_O32_restart_syscall
+	.restart	= __NR_O32_restart_syscall,
+
+	.off_sc_fpregs = offsetof(struct sigcontext32, sc_fpregs),
+	.off_sc_fpc_csr = offsetof(struct sigcontext32, sc_fpc_csr),
+	.off_sc_used_math = offsetof(struct sigcontext32, sc_used_math),
 };
 
 static int signal32_init(void)

arch/mips/kernel/signal_n32.c

@@ -153,5 +153,9 @@ struct mips_abi mips_abi_n32 = {
 	.setup_rt_frame = setup_rt_frame_n32,
 	.rt_signal_return_offset =
 		offsetof(struct mips_vdso, n32_rt_signal_trampoline),
-	.restart	= __NR_N32_restart_syscall
+	.restart	= __NR_N32_restart_syscall,
+
+	.off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs),
+	.off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr),
+	.off_sc_used_math = offsetof(struct sigcontext, sc_used_math),
 };