From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Anton Blanchard <anton@samba.org>,
Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 2/4] powerpc/kprobes: un-blacklist system_call() from kprobes
Date: Tue, 25 Apr 2017 22:04:07 +0530 [thread overview]
Message-ID: <81a735c1f1cf138d02b0c15b72d43f600baae0ca.1493137432.git.naveen.n.rao@linux.vnet.ibm.com> (raw)
In-Reply-To: <cover.1493137432.git.naveen.n.rao@linux.vnet.ibm.com>
In-Reply-To: <cover.1493137432.git.naveen.n.rao@linux.vnet.ibm.com>
It is actually safe to probe system_call() in entry_64.S, but only till
.Lsyscall_exit. To allow this, convert .Lsyscall_exit to a non-local
symbol __system_call() and blacklist that symbol, rather than
system_call().
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
---
arch/powerpc/kernel/entry_64.S | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 380361c0bb6a..e030ce34dd66 100644
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -176,7 +176,7 @@ system_call: /* label this so stack traces look sane */
mtctr r12
bctrl /* Call handler */
-.Lsyscall_exit:
+__system_call:
std r3,RESULT(r1)
CURRENT_THREAD_INFO(r12, r1)
@@ -294,12 +294,12 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
blt+ system_call
/* Return code is already in r3 thanks to do_syscall_trace_enter() */
- b .Lsyscall_exit
+ b __system_call
.Lsyscall_enosys:
li r3,-ENOSYS
- b .Lsyscall_exit
+ b __system_call
.Lsyscall_exit_work:
#ifdef CONFIG_PPC_BOOK3S
@@ -388,7 +388,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
b . /* prevent speculative execution */
#endif
_ASM_NOKPROBE_SYMBOL(system_call_common);
-_ASM_NOKPROBE_SYMBOL(system_call);
+_ASM_NOKPROBE_SYMBOL(__system_call);
/* Save non-volatile GPRs, if not already saved. */
_GLOBAL(save_nvgprs)
@@ -413,38 +413,38 @@ _GLOBAL(save_nvgprs)
_GLOBAL(ppc_fork)
bl save_nvgprs
bl sys_fork
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc_vfork)
bl save_nvgprs
bl sys_vfork
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc_clone)
bl save_nvgprs
bl sys_clone
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc32_swapcontext)
bl save_nvgprs
bl compat_sys_swapcontext
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc64_swapcontext)
bl save_nvgprs
bl sys_swapcontext
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ppc_switch_endian)
bl save_nvgprs
bl sys_switch_endian
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ret_from_fork)
bl schedule_tail
REST_NVGPRS(r1)
li r3,0
- b .Lsyscall_exit
+ b __system_call
_GLOBAL(ret_from_kernel_thread)
bl schedule_tail
@@ -456,7 +456,7 @@ _GLOBAL(ret_from_kernel_thread)
#endif
blrl
li r3,0
- b .Lsyscall_exit
+ b __system_call
/*
* This routine switches between two different tasks. The process
--
2.12.1
next prev parent reply other threads:[~2017-04-25 16:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-25 16:34 [PATCH 0/4] powerpc: build out kprobes blacklist Naveen N. Rao
2017-04-25 16:34 ` [PATCH 1/4] powerpc/kprobes: cleanup system_call_common and blacklist it from kprobes Naveen N. Rao
2017-04-25 16:34 ` Naveen N. Rao [this message]
2017-04-25 16:34 ` [PATCH 3/4] powerpc/kprobes: blacklist functions invoked on a trap Naveen N. Rao
2017-04-25 16:34 ` [PATCH 4/4] powerpc/kprobes: blacklist functions involved when returning from exception Naveen N. Rao
2017-04-27 2:24 ` [PATCH 0/4] powerpc: build out kprobes blacklist Masami Hiramatsu
2017-04-27 6:16 ` Naveen N. Rao
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