[MIPS] signal32: no need to save c0_status register in setup_sigconte…

…xt32()

All the information in the MIPS c0_status register is priviledged.
Nothing that would constitute part of the thread context.

The one flag one could possibly argument about might be c0_status.fr
but none of the ABIs or tools or application software can make use
of it.

So for consistency with restore_sigcontext32(), which does not
restore c0_status register, this patch remove the saving part.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/asm-offsets.c

@@ -249,7 +249,6 @@ void output_sc_defines(void)
 	offset("#define SC_MDHI       ", struct sigcontext, sc_mdhi);
 	offset("#define SC_MDLO       ", struct sigcontext, sc_mdlo);
 	offset("#define SC_PC         ", struct sigcontext, sc_pc);
-	offset("#define SC_STATUS     ", struct sigcontext, sc_status);
 	offset("#define SC_FPC_CSR    ", struct sigcontext, sc_fpc_csr);
 	offset("#define SC_FPC_EIR    ", struct sigcontext, sc_fpc_eir);
 	offset("#define SC_HI1        ", struct sigcontext, sc_hi1);

arch/mips/kernel/signal32.c

@@ -170,7 +170,6 @@ static int setup_sigcontext32(struct pt_regs *regs,
 	int i;
 
 	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
-	err |= __put_user(regs->cp0_status, &sc->sc_status);
 
 	err |= __put_user(0, &sc->sc_regs[0]);
 	for (i = 1; i < 32; i++)

include/asm-mips/sigcontext.h

@@ -19,7 +19,7 @@
  */
 struct sigcontext {
 	unsigned int		sc_regmask;	/* Unused */
-	unsigned int		sc_status;
+	unsigned int		sc_status;	/* Unused */
 	unsigned long long	sc_pc;
 	unsigned long long	sc_regs[32];
 	unsigned long long	sc_fpregs[32];
@@ -76,7 +76,7 @@ struct sigcontext {
 
 struct sigcontext32 {
 	__u32		sc_regmask;	/* Unused */
-	__u32		sc_status;
+	__u32		sc_status;	/* Unused */
 	__u64		sc_pc;
 	__u64		sc_regs[32];
 	__u64		sc_fpregs[32];