MIPS64: signal: Fix o32 sigaction syscall

MIPS32 o32 ABI sigaction() processing on MIPS64 n64 kernel was incorrectly
set to processing aka rt_sigaction() variant only.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: paul.burton@imgtec.com
Cc: richard@nod.at
Cc: luto@amacapital.net
Cc: alex.smith@imgtec.com
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: mpe@ellerman.id.au
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11321/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/signal.h

@@ -11,11 +11,17 @@
 
 #include <uapi/asm/signal.h>
 
+#ifdef CONFIG_MIPS32_COMPAT
+extern struct mips_abi mips_abi_32;
 
-#ifdef CONFIG_TRAD_SIGNALS
-#define sig_uses_siginfo(ka)	((ka)->sa.sa_flags & SA_SIGINFO)
+#define sig_uses_siginfo(ka, abi)                               \
+	((abi != &mips_abi_32) ? 1 :                            \
+		((ka)->sa.sa_flags & SA_SIGINFO))
 #else
-#define sig_uses_siginfo(ka)	(1)
+#define sig_uses_siginfo(ka, abi)                               \
+	(config_enabled(CONFIG_64BIT) ? 1 :                     \
+		(config_enabled(CONFIG_TRAD_SIGNALS) ?          \
+			((ka)->sa.sa_flags & SA_SIGINFO) : 1) )
 #endif
 
 #include <asm/sigcontext.h>

arch/mips/kernel/signal.c

@@ -798,7 +798,7 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
 		regs->regs[0] = 0;		/* Don't deal with this again.	*/
 	}
 
-	if (sig_uses_siginfo(&ksig->ka))
+	if (sig_uses_siginfo(&ksig->ka, abi))
 		ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn,
 					  ksig, regs, oldset);
 	else