diff mbox

[2/2] arm64: Make all entry code as non-kprobe-able

Message ID 683f80cef9b2b778be868e77b01a245585448a86.1436158027.git.panand@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Pratyush Anand July 6, 2015, 5:03 a.m. UTC 
Entry symbols are not kprobe safe. So blacklist them for kprobing.

Signed-off-by: Pratyush Anand <panand@redhat.com>
---
 arch/arm64/kernel/entry.S       | 3 +++
 arch/arm64/kernel/kprobes.c     | 9 +++++++++
 arch/arm64/kernel/vmlinux.lds.S | 1 +
 3 files changed, 13 insertions(+)

Comments

Masami Hiramatsu July 6, 2015, 11:03 a.m. UTC | #1 
On 2015/07/06 14:03, Pratyush Anand wrote:
> Entry symbols are not kprobe safe. So blacklist them for kprobing.

As I've said, you can also use _ASM_NOKPROBE().
This patch itself looks good to me, but I'd like to ask arm64
maintainers' opinion, whether they accept introducing entry-text
section only for this purpose or not.

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thank you,

> 
> Signed-off-by: Pratyush Anand <panand@redhat.com>
> ---
>  arch/arm64/kernel/entry.S       | 3 +++
>  arch/arm64/kernel/kprobes.c     | 9 +++++++++
>  arch/arm64/kernel/vmlinux.lds.S | 1 +
>  3 files changed, 13 insertions(+)
> 
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index a7691a378668..2ea24f6bc06b 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -202,6 +202,7 @@ tsk	.req	x28		// current thread_info
>   * Exception vectors.
>   */
>  
> +	.section ".entry.text", "ax"
>  	.align	11
>  ENTRY(vectors)
>  	ventry	el1_sync_invalid		// Synchronous EL1t
> @@ -737,3 +738,5 @@ ENTRY(sys_rt_sigreturn_wrapper)
>  	mov	x0, sp
>  	b	sys_rt_sigreturn
>  ENDPROC(sys_rt_sigreturn_wrapper)
> +
> +	.section ".text", "ax"
> diff --git a/arch/arm64/kernel/kprobes.c b/arch/arm64/kernel/kprobes.c
> index 6c9f8b5f04ce..9bc02c151f7f 100644
> --- a/arch/arm64/kernel/kprobes.c
> +++ b/arch/arm64/kernel/kprobes.c
> @@ -28,6 +28,7 @@
>  #include <asm/debug-monitors.h>
>  #include <asm/system_misc.h>
>  #include <asm/insn.h>
> +#include <asm-generic/sections.h>
>  
>  #include "kprobes.h"
>  #include "kprobes-arm64.h"
> @@ -661,6 +662,14 @@ int __kprobes arch_trampoline_kprobe(struct kprobe *p)
>  	return 0;
>  }
>  
> +bool arch_within_kprobe_blacklist(unsigned long addr)
> +{
> +	return  (addr >= (unsigned long)__kprobes_text_start &&
> +		 addr < (unsigned long)__kprobes_text_end) ||
> +		(addr >= (unsigned long)__entry_text_start &&
> +		 addr < (unsigned long)__entry_text_end);
> +}
> +
>  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 1fa6adc7aa83..11fb2b0117d0 100644
> --- a/arch/arm64/kernel/vmlinux.lds.S
> +++ b/arch/arm64/kernel/vmlinux.lds.S
> @@ -97,6 +97,7 @@ SECTIONS
>  			*(.exception.text)
>  			__exception_text_end = .;
>  			IRQENTRY_TEXT
> +			ENTRY_TEXT
>  			TEXT_TEXT
>  			SCHED_TEXT
>  			LOCK_TEXT
>
Pratyush Anand July 6, 2015, 11:54 a.m. UTC | #2 
On 06/07/2015:08:03:17 PM, Masami Hiramatsu wrote:
> On 2015/07/06 14:03, Pratyush Anand wrote:
> > Entry symbols are not kprobe safe. So blacklist them for kprobing.
> 
> As I've said, you can also use _ASM_NOKPROBE().

Thanks for this info.. May be we can use it if we find some single
discrete asm routines. Since here all the entry routines need to be
blacklisted, so may be this approach should be fine. This approach
have been emulated from x86 entry code blacklist.

> This patch itself looks good to me, but I'd like to ask arm64
> maintainers' opinion, whether they accept introducing entry-text
> section only for this purpose or not.
> 
> Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

Thanks.

~Pratyush
diff mbox

Patch

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index a7691a378668..2ea24f6bc06b 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -202,6 +202,7 @@  tsk	.req	x28		// current thread_info
  * Exception vectors.
  */
 
+	.section ".entry.text", "ax"
 	.align	11
 ENTRY(vectors)
 	ventry	el1_sync_invalid		// Synchronous EL1t
@@ -737,3 +738,5 @@  ENTRY(sys_rt_sigreturn_wrapper)
 	mov	x0, sp
 	b	sys_rt_sigreturn
 ENDPROC(sys_rt_sigreturn_wrapper)
+
+	.section ".text", "ax"
diff --git a/arch/arm64/kernel/kprobes.c b/arch/arm64/kernel/kprobes.c
index 6c9f8b5f04ce..9bc02c151f7f 100644
--- a/arch/arm64/kernel/kprobes.c
+++ b/arch/arm64/kernel/kprobes.c
@@ -28,6 +28,7 @@ 
 #include <asm/debug-monitors.h>
 #include <asm/system_misc.h>
 #include <asm/insn.h>
+#include <asm-generic/sections.h>
 
 #include "kprobes.h"
 #include "kprobes-arm64.h"
@@ -661,6 +662,14 @@  int __kprobes arch_trampoline_kprobe(struct kprobe *p)
 	return 0;
 }
 
+bool arch_within_kprobe_blacklist(unsigned long addr)
+{
+	return  (addr >= (unsigned long)__kprobes_text_start &&
+		 addr < (unsigned long)__kprobes_text_end) ||
+		(addr >= (unsigned long)__entry_text_start &&
+		 addr < (unsigned long)__entry_text_end);
+}
+
 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 1fa6adc7aa83..11fb2b0117d0 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -97,6 +97,7 @@  SECTIONS
 			*(.exception.text)
 			__exception_text_end = .;
 			IRQENTRY_TEXT
+			ENTRY_TEXT
 			TEXT_TEXT
 			SCHED_TEXT
 			LOCK_TEXT