From e51c3e13709fe55d4d0eb50ba435bc53a64152bf Mon Sep 17 00:00:00 2001 From: Christophe Leroy Date: Tue, 31 Mar 2020 16:03:47 +0000 Subject: [PATCH] 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: Christophe Leroy Acked-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/098b0fd3f6299aa1bd692bd576bd7012c84608de.1585670437.git.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 5fa192b33509..217ebdf5b00b 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -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 */ /*