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Subject[PATCH 12/12] powerpc/entry32: Blacklist exception exit points for kprobe.
Date
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>
---
arch/powerpc/kernel/entry_32.S | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index 7035e838d422..e161fb7a0568 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -810,6 +810,7 @@ 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 */
@@ -1049,6 +1050,8 @@ 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) */
/*
@@ -1070,7 +1073,6 @@ 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)
@@ -1080,6 +1082,7 @@ exc_exit_restart_end:
PPC405_ERR77_SYNC
rfi
b . /* prevent prefetch past rfi */
+_ASM_NOKPROBE_SYMBOL(exc_exit_restart)

/*
* Returning from a critical interrupt in user mode doesn't need
@@ -1193,6 +1196,7 @@ 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
@@ -1204,6 +1208,7 @@ 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:
@@ -1214,6 +1219,7 @@ 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:
@@ -1225,6 +1231,7 @@ 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 */

/*
--
2.25.0
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