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Commit 164881b6 authored by Eric W. Biederman's avatar Eric W. Biederman
Browse files

signal/x86/traps: Simplify trap generation 



Update the DO_ERROR macro to take si_code and si_addr values for a siginfo,
removing the need for the fill_trap_info function.

Update do_trap to also take the sicode and si_addr values for a sigininfo
and modify the code to call force_sig when a sicode is not passed in
and to call force_sig_fault when all of the information is present.

Making this a more obvious, simpler and less error prone construction.

Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
parent afe8448c

arch/x86/kernel/traps.c

+24 −61
Original line number Diff line number Diff line
@@ -240,40 +240,9 @@ static void show_signal(struct task_struct *tsk, int signr, 
	}

}



static siginfo_t *fill_trap_info(struct pt_regs *regs, int signr, int trapnr,

				siginfo_t *info)

{

	unsigned long siaddr;

	int sicode;



	switch (trapnr) {

	default:

		return SEND_SIG_PRIV;



	case X86_TRAP_DE:

		sicode = FPE_INTDIV;

		siaddr = uprobe_get_trap_addr(regs);

		break;

	case X86_TRAP_UD:

		sicode = ILL_ILLOPN;

		siaddr = uprobe_get_trap_addr(regs);

		break;

	case X86_TRAP_AC:

		sicode = BUS_ADRALN;

		siaddr = 0;

		break;

	}



	info->si_signo = signr;

	info->si_errno = 0;

	info->si_code = sicode;

	info->si_addr = (void __user *)siaddr;

	return info;

}



static void

do_trap(int trapnr, int signr, char *str, struct pt_regs *regs,

	long error_code, siginfo_t *info)

	long error_code, int sicode, void __user *addr)

{

	struct task_struct *tsk = current;
@@ -283,15 +252,16 @@ do_trap(int trapnr, int signr, char *str, struct pt_regs *regs, 


	show_signal(tsk, signr, "trap ", str, regs, error_code);



	force_sig_info(signr, info ?: SEND_SIG_PRIV, tsk);

	if (!sicode)

		force_sig(signr, tsk);

	else

		force_sig_fault(signr, sicode, addr, tsk);

}

NOKPROBE_SYMBOL(do_trap);



static void do_error_trap(struct pt_regs *regs, long error_code, char *str,

			  unsigned long trapnr, int signr)

	unsigned long trapnr, int signr, int sicode, void __user *addr)

{

	siginfo_t info;



	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");



	/*
@@ -304,26 +274,26 @@ static void do_error_trap(struct pt_regs *regs, long error_code, char *str, 
	if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) !=

			NOTIFY_STOP) {

		cond_local_irq_enable(regs);

		clear_siginfo(&info);

		do_trap(trapnr, signr, str, regs, error_code,

			fill_trap_info(regs, signr, trapnr, &info));

		do_trap(trapnr, signr, str, regs, error_code, sicode, addr);

	}

}



#define DO_ERROR(trapnr, signr, str, name)				\

#define IP ((void __user *)uprobe_get_trap_addr(regs))

#define DO_ERROR(trapnr, signr, sicode, addr, str, name)		   \

dotraplinkage void do_##name(struct pt_regs *regs, long error_code)	   \

{									   \

	do_error_trap(regs, error_code, str, trapnr, signr);		\

	do_error_trap(regs, error_code, str, trapnr, signr, sicode, addr); \

}



DO_ERROR(X86_TRAP_DE,     SIGFPE,  "divide error",		divide_error)

DO_ERROR(X86_TRAP_OF,     SIGSEGV, "overflow",			overflow)

DO_ERROR(X86_TRAP_UD,     SIGILL,  "invalid opcode",		invalid_op)

DO_ERROR(X86_TRAP_OLD_MF, SIGFPE,  "coprocessor segment overrun",coprocessor_segment_overrun)

DO_ERROR(X86_TRAP_TS,     SIGSEGV, "invalid TSS",		invalid_TSS)

DO_ERROR(X86_TRAP_NP,     SIGBUS,  "segment not present",	segment_not_present)

DO_ERROR(X86_TRAP_SS,     SIGBUS,  "stack segment",		stack_segment)

DO_ERROR(X86_TRAP_AC,     SIGBUS,  "alignment check",		alignment_check)

DO_ERROR(X86_TRAP_DE,     SIGFPE,  FPE_INTDIV,   IP, "divide error",        divide_error)

DO_ERROR(X86_TRAP_OF,     SIGSEGV,          0, NULL, "overflow",            overflow)

DO_ERROR(X86_TRAP_UD,     SIGILL,  ILL_ILLOPN,   IP, "invalid opcode",      invalid_op)

DO_ERROR(X86_TRAP_OLD_MF, SIGFPE,           0, NULL, "coprocessor segment overrun", coprocessor_segment_overrun)

DO_ERROR(X86_TRAP_TS,     SIGSEGV,          0, NULL, "invalid TSS",         invalid_TSS)

DO_ERROR(X86_TRAP_NP,     SIGBUS,           0, NULL, "segment not present", segment_not_present)

DO_ERROR(X86_TRAP_SS,     SIGBUS,           0, NULL, "stack segment",       stack_segment)

DO_ERROR(X86_TRAP_AC,     SIGBUS,  BUS_ADRALN, NULL, "alignment check",     alignment_check)

#undef IP



#ifdef CONFIG_VMAP_STACK

__visible void __noreturn handle_stack_overflow(const char *message,
@@ -540,7 +510,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code) 
	 * up here if the kernel has MPX turned off at compile

	 * time..

	 */

	do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, NULL);

	do_trap(X86_TRAP_BR, SIGSEGV, "bounds", regs, error_code, 0, NULL);

}



dotraplinkage void
@@ -624,7 +594,7 @@ dotraplinkage void notrace do_int3(struct pt_regs *regs, long error_code) 
		goto exit;



	cond_local_irq_enable(regs);

	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, NULL);

	do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, error_code, 0, NULL);

	cond_local_irq_disable(regs);



exit:
@@ -935,20 +905,13 @@ NOKPROBE_SYMBOL(do_device_not_available); 
#ifdef CONFIG_X86_32

dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)

{

	siginfo_t info;



	RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");

	local_irq_enable();



	clear_siginfo(&info);

	info.si_signo = SIGILL;

	info.si_errno = 0;

	info.si_code = ILL_BADSTK;

	info.si_addr = NULL;

	if (notify_die(DIE_TRAP, "iret exception", regs, error_code,

			X86_TRAP_IRET, SIGILL) != NOTIFY_STOP) {

		do_trap(X86_TRAP_IRET, SIGILL, "iret exception", regs, error_code,

			&info);

			ILL_BADSTK, (void __user *)NULL);

	}

}

#endif