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

[David Long]

From: Pratyush Anand <panand@xxxxxxxxxx>

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

Signed-off-by: Pratyush Anand <panand@xxxxxxxxxx>
Signed-off-by: David A. Long <dave.long@xxxxxxxxxx>
Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
---
 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(+)

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
-- 
2.5.0