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From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	naveen.n.rao@linux.vnet.ibm.com
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 12/12] powerpc/entry32: Blacklist exception exit points for kprobe.
Date: Tue, 31 Mar 2020 16:03:47 +0000 (UTC)	[thread overview]
Message-ID: <098b0fd3f6299aa1bd692bd576bd7012c84608de.1585670437.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <1ae02b6637b87fc5aaa1d5012c3e2cb30e62b4a3.1585670437.git.christophe.leroy@c-s.fr>

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>
---
 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 577d17fe0d94..02c81192ba52 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


WARNING: multiple messages have this Message-ID (diff)
From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	 naveen.n.rao@linux.vnet.ibm.com
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: [PATCH v2 12/12] powerpc/entry32: Blacklist exception exit points for kprobe.
Date: Tue, 31 Mar 2020 16:03:47 +0000 (UTC)	[thread overview]
Message-ID: <098b0fd3f6299aa1bd692bd576bd7012c84608de.1585670437.git.christophe.leroy@c-s.fr> (raw)
In-Reply-To: <1ae02b6637b87fc5aaa1d5012c3e2cb30e62b4a3.1585670437.git.christophe.leroy@c-s.fr>

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>
---
 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 577d17fe0d94..02c81192ba52 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


  parent reply	other threads:[~2020-03-31 16:04 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-31 16:03 [PATCH v2 01/12] powerpc/52xx: Blacklist functions running with MMU disabled for kprobe Christophe Leroy
2020-03-31 16:03 ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 02/12] powerpc/82xx: Blacklist pq2_restart() " Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 03/12] powerpc/83xx: Blacklist mpc83xx_deep_resume() " Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 04/12] powerpc/powermac: Blacklist functions running with MMU disabled " Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 05/12] powerpc/mem: Blacklist flush_dcache_icache_phys() " Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 06/12] powerpc/32s: Make local symbols non visible in hash_low Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 07/12] powerpc/32s: Blacklist functions running with MMU disabled for kprobe Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 08/12] powerpc/rtas: Remove machine_check_in_rtas() Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 09/12] powerpc/32: Blacklist functions running with MMU disabled for kprobe Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` [PATCH v2 10/12] powerpc/entry32: Blacklist exception entry points " Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 17:05   ` Naveen N. Rao
2020-03-31 17:05     ` Naveen N. Rao
2020-03-31 16:03 ` [PATCH v2 11/12] powerpc/entry32: Blacklist syscall exit " Christophe Leroy
2020-03-31 16:03   ` Christophe Leroy
2020-03-31 16:03 ` Christophe Leroy [this message]
2020-03-31 16:03   ` [PATCH v2 12/12] powerpc/entry32: Blacklist exception " Christophe Leroy
2020-06-09  5:28 ` [PATCH v2 01/12] powerpc/52xx: Blacklist functions running with MMU disabled " Michael Ellerman

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