Commit 63dc68a8 authored by Ralf Baechle's avatar Ralf Baechle
Browse files

[MIPS] Use conditional traps for BUG_ON on MIPS II and better. 



This shaves of around 4kB and a few cycles for the average kernel that
has CONFIG_BUG enabled.

Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 00598560

arch/mips/kernel/traps.c

+10 −4
Original line number Diff line number Diff line
@@ -669,8 +669,6 @@ asmlinkage void do_bp(struct pt_regs *regs) 
	unsigned int opcode, bcode;

	siginfo_t info;



	die_if_kernel("Break instruction in kernel code", regs);



	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))

		goto out_sigsegv;
@@ -693,6 +691,7 @@ asmlinkage void do_bp(struct pt_regs *regs) 
	switch (bcode) {

	case BRK_OVERFLOW << 10:

	case BRK_DIVZERO << 10:

		die_if_kernel("Break instruction in kernel code", regs);

		if (bcode == (BRK_DIVZERO << 10))

			info.si_code = FPE_INTDIV;

		else
@@ -702,7 +701,11 @@ asmlinkage void do_bp(struct pt_regs *regs) 
		info.si_addr = (void __user *) regs->cp0_epc;

		force_sig_info(SIGFPE, &info, current);

		break;

	case BRK_BUG:

		die("Kernel bug detected", regs);

		break;

	default:

		die_if_kernel("Break instruction in kernel code", regs);

		force_sig(SIGTRAP, current);

	}
@@ -715,8 +718,6 @@ asmlinkage void do_tr(struct pt_regs *regs) 
	unsigned int opcode, tcode = 0;

	siginfo_t info;



	die_if_kernel("Trap instruction in kernel code", regs);



	if (get_user(opcode, (unsigned int __user *) exception_epc(regs)))

		goto out_sigsegv;
@@ -733,6 +734,7 @@ asmlinkage void do_tr(struct pt_regs *regs) 
	switch (tcode) {

	case BRK_OVERFLOW:

	case BRK_DIVZERO:

		die_if_kernel("Trap instruction in kernel code", regs);

		if (tcode == BRK_DIVZERO)

			info.si_code = FPE_INTDIV;

		else
@@ -742,7 +744,11 @@ asmlinkage void do_tr(struct pt_regs *regs) 
		info.si_addr = (void __user *) regs->cp0_epc;

		force_sig_info(SIGFPE, &info, current);

		break;

	case BRK_BUG:

		die("Kernel bug detected", regs);

		break;

	default:

		die_if_kernel("Trap instruction in kernel code", regs);

		force_sig(SIGTRAP, current);

	}

include/asm-mips/bug.h

+12 −0
Original line number Diff line number Diff line 
#ifndef __ASM_BUG_H

#define __ASM_BUG_H



#include <asm/sgidefs.h>



#ifdef CONFIG_BUG
@@ -13,6 +14,17 @@ do { \ 


#define HAVE_ARCH_BUG



#if (_MIPS_ISA > _MIPS_ISA_MIPS1)



#define BUG_ON(condition)						\

do {									\

	__asm__ __volatile__("tne $0, %0" : : "r" (condition));		\

} while (0)



#define HAVE_ARCH_BUG_ON



#endif /* _MIPS_ISA > _MIPS_ISA_MIPS1 */



#endif



#include <asm-generic/bug.h>

include/asm-mips/ptrace.h

+0 −2
Original line number Diff line number Diff line
@@ -80,8 +80,6 @@ struct pt_regs { 
#define instruction_pointer(regs) ((regs)->cp0_epc)

#define profile_pc(regs) instruction_pointer(regs)



extern void show_regs(struct pt_regs *);



extern asmlinkage void do_syscall_trace(struct pt_regs *regs, int entryexit);



#endif