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powerpc/entry32: Blacklist exception exit points for kprobe.

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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: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/098b0fd3f6299aa1bd692bd576bd7012c84608de.1585670437.git.christophe.leroy@c-s.fr
This commit is contained in:
Christophe Leroy 2020-03-31 16:03:47 +00:00 committed by Michael Ellerman
parent 7cdf440138
commit e51c3e1370
1 changed files with 8 additions and 1 deletions
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9
arch/powerpc/kernel/entry_32.S
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@ -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 */
/*