sh: don't pass saved userspace state to exception handlers

The compiler is permitted to generate code which overwrites the
parameters to a function. If those parameters include the only saved
copy we have of userspace's registers, we're in trouble.

Signed-off-by: Bobby Bingham <[e-mail]>
Cc: Paul Mundt <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/sh/include/asm/traps_32.h

···
 asmlinkage void do_address_error(struct pt_regs *regs,
 				 unsigned long writeaccess,
 				 unsigned long address);
-asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
-				unsigned long r6, unsigned long r7,
-				struct pt_regs __regs);
-asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
-				unsigned long r6, unsigned long r7,
-				struct pt_regs __regs);
-asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
-				unsigned long r6, unsigned long r7,
-				struct pt_regs __regs);
-asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
-				   unsigned long r6, unsigned long r7,
-				   struct pt_regs __regs);
+asmlinkage void do_divide_error(unsigned long r4);
+asmlinkage void do_reserved_inst(void);
+asmlinkage void do_illegal_slot_inst(void);
+asmlinkage void do_exception_error(void);
 
 #define BUILD_TRAP_HANDLER(name)					\
 asmlinkage void name##_trap_handler(unsigned long r4, unsigned long r5,	\

arch/sh/kernel/traps_32.c

···
 #endif /* CONFIG_SH_DSP */
 
 #ifdef CONFIG_CPU_SH2A
-asmlinkage void do_divide_error(unsigned long r4, unsigned long r5,
-				unsigned long r6, unsigned long r7,
-				struct pt_regs __regs)
+asmlinkage void do_divide_error(unsigned long r4)
 {
 	siginfo_t info;
 
···
 }
 #endif
 
-asmlinkage void do_reserved_inst(unsigned long r4, unsigned long r5,
-				unsigned long r6, unsigned long r7,
-				struct pt_regs __regs)
+asmlinkage void do_reserved_inst(void)
 {
-	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+	struct pt_regs *regs = current_pt_regs();
 	unsigned long error_code;
 	struct task_struct *tsk = current;
 
···
 }
 #endif
 
-asmlinkage void do_illegal_slot_inst(unsigned long r4, unsigned long r5,
-				unsigned long r6, unsigned long r7,
-				struct pt_regs __regs)
+asmlinkage void do_illegal_slot_inst(void)
 {
-	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
+	struct pt_regs *regs = current_pt_regs();
 	unsigned long inst;
 	struct task_struct *tsk = current;
 
···
 	die_if_no_fixup("illegal slot instruction", regs, inst);
 }
 
-asmlinkage void do_exception_error(unsigned long r4, unsigned long r5,
-				   unsigned long r6, unsigned long r7,
-				   struct pt_regs __regs)
+asmlinkage void do_exception_error(void)
 {
-	struct pt_regs *regs = RELOC_HIDE(&__regs, 0);
 	long ex;
 
 	ex = lookup_exception_vector();
-	die_if_kernel("exception", regs, ex);
+	die_if_kernel("exception", current_pt_regs(), ex);
 }
 
 void per_cpu_trap_init(void)