diff mbox

[v15,06/10] arm64: Treat all entry code as non-kprobe-able

Message ID 1467995754-32508-7-git-send-email-dave.long@linaro.org (mailing list archive)
State New, archived
Headers show

Commit Message

David Long July 8, 2016, 4:35 p.m. UTC 
From: Pratyush Anand <panand@redhat.com>

Entry symbols are not kprobe safe. So blacklist them for kprobing.

Signed-off-by: Pratyush Anand <panand@redhat.com>
Signed-off-by: David A. Long <dave.long@linaro.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
---
 arch/arm64/kernel/entry.S          |  3 +++
 arch/arm64/kernel/probes/kprobes.c | 26 ++++++++++++++++++++++++++
 arch/arm64/kernel/vmlinux.lds.S    |  1 +
 3 files changed, 30 insertions(+)

Comments

Catalin Marinas July 15, 2016, 4:47 p.m. UTC | #1 
On Fri, Jul 08, 2016 at 12:35:50PM -0400, David Long wrote:
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -243,6 +243,7 @@ tsk	.req	x28		// current thread_info
>   * Exception vectors.
>   */
>  
> +	.pushsection ".entry.text", "ax"
>  	.align	11
>  ENTRY(vectors)
>  	ventry	el1_sync_invalid		// Synchronous EL1t
> @@ -781,3 +782,5 @@ ENTRY(sys_rt_sigreturn_wrapper)
>  	mov	x0, sp
>  	b	sys_rt_sigreturn
>  ENDPROC(sys_rt_sigreturn_wrapper)
> +
> +	.popsection

Does the above sigreturn wrapper need to be included in the .entry.text
section?
David Long July 19, 2016, 12:53 a.m. UTC | #2 
On 07/15/2016 12:47 PM, Catalin Marinas wrote:
> On Fri, Jul 08, 2016 at 12:35:50PM -0400, David Long wrote:
>> --- a/arch/arm64/kernel/entry.S
>> +++ b/arch/arm64/kernel/entry.S
>> @@ -243,6 +243,7 @@ tsk	.req	x28		// current thread_info
>>    * Exception vectors.
>>    */
>>
>> +	.pushsection ".entry.text", "ax"
>>   	.align	11
>>   ENTRY(vectors)
>>   	ventry	el1_sync_invalid		// Synchronous EL1t
>> @@ -781,3 +782,5 @@ ENTRY(sys_rt_sigreturn_wrapper)
>>   	mov	x0, sp
>>   	b	sys_rt_sigreturn
>>   ENDPROC(sys_rt_sigreturn_wrapper)
>> +
>> +	.popsection
>
> Does the above sigreturn wrapper need to be included in the .entry.text
> section?
>

Apparently not. It wouldn't make sense for that to be in entry.text when 
sys_rt_sigreturn() isn't. I'll put that in the list of changes.

Thanks,
-dl
diff mbox

Patch

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 12e8d2b..7d99bed 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -243,6 +243,7 @@  tsk	.req	x28		// current thread_info
  * Exception vectors.
  */
 
+	.pushsection ".entry.text", "ax"
 	.align	11
 ENTRY(vectors)
 	ventry	el1_sync_invalid		// Synchronous EL1t
@@ -781,3 +782,5 @@  ENTRY(sys_rt_sigreturn_wrapper)
 	mov	x0, sp
 	b	sys_rt_sigreturn
 ENDPROC(sys_rt_sigreturn_wrapper)
+
+	.popsection
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index 4496801..0fe2b65 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -30,6 +30,7 @@ 
 #include <asm/insn.h>
 #include <asm/uaccess.h>
 #include <asm/irq.h>
+#include <asm-generic/sections.h>
 
 #include "decode-insn.h"
 
@@ -519,6 +520,31 @@  int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
 	return 1;
 }
 
+bool arch_within_kprobe_blacklist(unsigned long addr)
+{
+	extern char __idmap_text_start[], __idmap_text_end[];
+	extern char __hyp_idmap_text_start[], __hyp_idmap_text_end[];
+
+	if ((addr >= (unsigned long)__kprobes_text_start &&
+	    addr < (unsigned long)__kprobes_text_end) ||
+	    (addr >= (unsigned long)__entry_text_start &&
+	    addr < (unsigned long)__entry_text_end) ||
+	    (addr >= (unsigned long)__idmap_text_start &&
+	    addr < (unsigned long)__idmap_text_end) ||
+	    !!search_exception_tables(addr))
+		return true;
+
+	if (!is_kernel_in_hyp_mode()) {
+		if ((addr >= (unsigned long)__hyp_text_start &&
+		    addr < (unsigned long)__hyp_text_end) ||
+		    (addr >= (unsigned long)__hyp_idmap_text_start &&
+		    addr < (unsigned long)__hyp_idmap_text_end))
+			return true;
+	}
+
+	return false;
+}
+
 int __init arch_init_kprobes(void)
 {
 	return 0;
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 075ce32..9f59394 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -118,6 +118,7 @@  SECTIONS
 			__exception_text_end = .;
 			IRQENTRY_TEXT
 			SOFTIRQENTRY_TEXT
+			ENTRY_TEXT
 			TEXT_TEXT
 			SCHED_TEXT
 			LOCK_TEXT