Commit e51c3e13 authored by Christophe Leroy's avatar Christophe Leroy Committed by Michael Ellerman
Browse files

powerpc/entry32: Blacklist exception exit points for kprobe. 



kprobe does not handle events happening in real mode.

The very last part of exception exits cannot support a trap.
Blacklist them from kprobe.

While we are at it, remove exc_exit_start symbol which is not
used to avoid having to blacklist it.

Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Acked-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/098b0fd3f6299aa1bd692bd576bd7012c84608de.1585670437.git.christophe.leroy@c-s.fr
parent 7cdf4401

arch/powerpc/kernel/entry_32.S

+8 −1
Original line number Diff line number Diff line
@@ -806,6 +806,7 @@ fast_exception_return: 
	lwz	r11,GPR11(r11)

	SYNC

	RFI

_ASM_NOKPROBE_SYMBOL(fast_exception_return)



#if !(defined(CONFIG_4xx) || defined(CONFIG_BOOKE))

/* check if the exception happened in a restartable section */
@@ -1041,6 +1042,8 @@ exc_exit_restart: 
exc_exit_restart_end:

	SYNC

	RFI

_ASM_NOKPROBE_SYMBOL(exc_exit_restart)

_ASM_NOKPROBE_SYMBOL(exc_exit_restart_end)



#else /* !(CONFIG_4xx || CONFIG_BOOKE) */

	/*
@@ -1062,7 +1065,6 @@ exc_exit_restart_end: 
exc_exit_restart:

	lwz	r11,_NIP(r1)

	lwz	r12,_MSR(r1)

exc_exit_start:

	mtspr	SPRN_SRR0,r11

	mtspr	SPRN_SRR1,r12

	REST_2GPRS(11, r1)
@@ -1071,6 +1073,7 @@ exc_exit_start: 
exc_exit_restart_end:

	rfi

	b	.			/* prevent prefetch past rfi */

_ASM_NOKPROBE_SYMBOL(exc_exit_restart)



/*

 * Returning from a critical interrupt in user mode doesn't need
@@ -1182,6 +1185,7 @@ ret_from_crit_exc: 
	mtspr	SPRN_SRR0,r9;

	mtspr	SPRN_SRR1,r10;

	RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, PPC_RFCI)

_ASM_NOKPROBE_SYMBOL(ret_from_crit_exc)

#endif /* CONFIG_40x */



#ifdef CONFIG_BOOKE
@@ -1193,6 +1197,7 @@ ret_from_crit_exc: 
	RESTORE_xSRR(SRR0,SRR1);

	RESTORE_MMU_REGS;

	RET_FROM_EXC_LEVEL(SPRN_CSRR0, SPRN_CSRR1, PPC_RFCI)

_ASM_NOKPROBE_SYMBOL(ret_from_crit_exc)



	.globl	ret_from_debug_exc

ret_from_debug_exc:
@@ -1203,6 +1208,7 @@ ret_from_debug_exc: 
	RESTORE_xSRR(CSRR0,CSRR1);

	RESTORE_MMU_REGS;

	RET_FROM_EXC_LEVEL(SPRN_DSRR0, SPRN_DSRR1, PPC_RFDI)

_ASM_NOKPROBE_SYMBOL(ret_from_debug_exc)



	.globl	ret_from_mcheck_exc

ret_from_mcheck_exc:
@@ -1214,6 +1220,7 @@ ret_from_mcheck_exc: 
	RESTORE_xSRR(DSRR0,DSRR1);

	RESTORE_MMU_REGS;

	RET_FROM_EXC_LEVEL(SPRN_MCSRR0, SPRN_MCSRR1, PPC_RFMCI)

_ASM_NOKPROBE_SYMBOL(ret_from_mcheck_exc)

#endif /* CONFIG_BOOKE */



/*