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Commit 15770a13 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman
Browse files

powerpc/64s: Blacklist functions invoked on a trap 



Blacklist all functions involved while handling a trap. We:
- convert some of the symbols into private symbols, and
- blacklist most functions involved while handling a trap.

Reviewed-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 3639d661

arch/powerpc/kernel/entry_64.S

+22 −13
Original line number Diff line number Diff line
@@ -186,7 +186,7 @@ system_call: /* label this so stack traces look sane */ 
#ifdef CONFIG_PPC_BOOK3S

	/* No MSR:RI on BookE */

	andi.	r10,r8,MSR_RI

	beq-	unrecov_restore

	beq-	.Lunrecov_restore

#endif



/*
@@ -437,6 +437,7 @@ _GLOBAL(save_nvgprs) 
	clrrdi	r0,r11,1

	std	r0,_TRAP(r1)

	blr

_ASM_NOKPROBE_SYMBOL(save_nvgprs);



	

/*
@@ -807,11 +808,11 @@ restore: 
	ld	r5,SOFTE(r1)

	lbz	r6,PACASOFTIRQEN(r13)

	cmpwi	cr0,r5,0

	beq	restore_irq_off

	beq	.Lrestore_irq_off



	/* We are enabling, were we already enabled ? Yes, just return */

	cmpwi	cr0,r6,1

	beq	cr0,do_restore

	beq	cr0,.Ldo_restore



	/*

	 * We are about to soft-enable interrupts (we are hard disabled
@@ -820,14 +821,14 @@ restore: 
	 */

	lbz	r0,PACAIRQHAPPENED(r13)

	cmpwi	cr0,r0,0

	bne-	restore_check_irq_replay

	bne-	.Lrestore_check_irq_replay



	/*

	 * Get here when nothing happened while soft-disabled, just

	 * soft-enable and move-on. We will hard-enable as a side

	 * effect of rfi

	 */

restore_no_replay:

.Lrestore_no_replay:

	TRACE_ENABLE_INTS

	li	r0,1

	stb	r0,PACASOFTIRQEN(r13);
@@ -835,7 +836,7 @@ restore_no_replay: 
	/*

	 * Final return path. BookE is handled in a different file

	 */

do_restore:

.Ldo_restore:

#ifdef CONFIG_PPC_BOOK3E

	b	exception_return_book3e

#else
@@ -869,7 +870,7 @@ fast_exception_return: 
	REST_8GPRS(5, r1)



	andi.	r0,r3,MSR_RI

	beq-	unrecov_restore

	beq-	.Lunrecov_restore



	/* Load PPR from thread struct before we clear MSR:RI */

BEGIN_FTR_SECTION
@@ -927,7 +928,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR) 
	 * make sure that in this case, we also clear PACA_IRQ_HARD_DIS

	 * or that bit can get out of sync and bad things will happen

	 */

restore_irq_off:

.Lrestore_irq_off:

	ld	r3,_MSR(r1)

	lbz	r7,PACAIRQHAPPENED(r13)

	andi.	r0,r3,MSR_EE
@@ -937,13 +938,13 @@ restore_irq_off: 
1:	li	r0,0

	stb	r0,PACASOFTIRQEN(r13);

	TRACE_DISABLE_INTS

	b	do_restore

	b	.Ldo_restore



	/*

	 * Something did happen, check if a re-emit is needed

	 * (this also clears paca->irq_happened)

	 */

restore_check_irq_replay:

.Lrestore_check_irq_replay:

	/* XXX: We could implement a fast path here where we check

	 * for irq_happened being just 0x01, in which case we can

	 * clear it and return. That means that we would potentially
@@ -953,7 +954,7 @@ restore_check_irq_replay: 
	 */

	bl	__check_irq_replay

	cmpwi	cr0,r3,0

 	beq	restore_no_replay

	beq	.Lrestore_no_replay

 

	/*

	 * We need to re-emit an interrupt. We do so by re-using our
@@ -1002,10 +1003,18 @@ restore_check_irq_replay: 
#endif /* CONFIG_PPC_DOORBELL */

1:	b	ret_from_except /* What else to do here ? */

 

unrecov_restore:

.Lunrecov_restore:

	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	unrecoverable_exception

	b	unrecov_restore

	b	.Lunrecov_restore



_ASM_NOKPROBE_SYMBOL(ret_from_except);

_ASM_NOKPROBE_SYMBOL(ret_from_except_lite);

_ASM_NOKPROBE_SYMBOL(resume_kernel);

_ASM_NOKPROBE_SYMBOL(fast_exc_return_irq);

_ASM_NOKPROBE_SYMBOL(restore);

_ASM_NOKPROBE_SYMBOL(fast_exception_return);





#ifdef CONFIG_PPC_RTAS

/*

arch/powerpc/kernel/exceptions-64s.S

+2 −0
Original line number Diff line number Diff line
@@ -1594,6 +1594,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_CFAR) 
1:	addi	r3,r1,STACK_FRAME_OVERHEAD

	bl	kernel_bad_stack

	b	1b

_ASM_NOKPROBE_SYMBOL(bad_stack);



/*

 * When doorbell is triggered from system reset wakeup, the message is
@@ -1655,3 +1656,4 @@ ALT_FTR_SECTION_END_IFSET(CPU_FTR_HVMODE) 
1:

	blr



_ASM_NOKPROBE_SYMBOL(__replay_interrupt)

arch/powerpc/kernel/traps.c

+3 −0
Original line number Diff line number Diff line
@@ -237,6 +237,7 @@ void die(const char *str, struct pt_regs *regs, long err) 
		err = 0;

	oops_end(flags, regs, err);

}

NOKPROBE_SYMBOL(die);



void user_single_step_siginfo(struct task_struct *tsk,

				struct pt_regs *regs, siginfo_t *info)
@@ -1968,6 +1969,7 @@ void unrecoverable_exception(struct pt_regs *regs) 
	       regs->trap, regs->nip);

	die("Unrecoverable exception", regs, SIGABRT);

}

NOKPROBE_SYMBOL(unrecoverable_exception);



#if defined(CONFIG_BOOKE_WDT) || defined(CONFIG_40x)

/*
@@ -1998,6 +2000,7 @@ void kernel_bad_stack(struct pt_regs *regs) 
	       regs->gpr[1], regs->nip);

	die("Bad kernel stack pointer", regs, SIGABRT);

}

NOKPROBE_SYMBOL(kernel_bad_stack);



void __init trap_init(void)

{