summaryrefslogtreecommitdiffstats
path: root/arch/arm64/kernel/probes/decode-insn.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm64/kernel/probes/decode-insn.c')
-rw-r--r--arch/arm64/kernel/probes/decode-insn.c48
1 files changed, 23 insertions, 25 deletions
diff --git a/arch/arm64/kernel/probes/decode-insn.c b/arch/arm64/kernel/probes/decode-insn.c
index 37e47a9d617e..d1731bf977ef 100644
--- a/arch/arm64/kernel/probes/decode-insn.c
+++ b/arch/arm64/kernel/probes/decode-insn.c
@@ -16,6 +16,7 @@
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/module.h>
+#include <linux/kallsyms.h>
#include <asm/kprobes.h>
#include <asm/insn.h>
#include <asm/sections.h>
@@ -122,7 +123,7 @@ arm_probe_decode_insn(kprobe_opcode_t insn, struct arch_specific_insn *asi)
static bool __kprobes
is_probed_address_atomic(kprobe_opcode_t *scan_start, kprobe_opcode_t *scan_end)
{
- while (scan_start > scan_end) {
+ while (scan_start >= scan_end) {
/*
* atomic region starts from exclusive load and ends with
* exclusive store.
@@ -142,33 +143,30 @@ arm_kprobe_decode_insn(kprobe_opcode_t *addr, struct arch_specific_insn *asi)
{
enum kprobe_insn decoded;
kprobe_opcode_t insn = le32_to_cpu(*addr);
- kprobe_opcode_t *scan_start = addr - 1;
- kprobe_opcode_t *scan_end = addr - MAX_ATOMIC_CONTEXT_SIZE;
-#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
- struct module *mod;
-#endif
-
- if (addr >= (kprobe_opcode_t *)_text &&
- scan_end < (kprobe_opcode_t *)_text)
- scan_end = (kprobe_opcode_t *)_text;
-#if defined(CONFIG_MODULES) && defined(MODULES_VADDR)
- else {
- preempt_disable();
- mod = __module_address((unsigned long)addr);
- if (mod && within_module_init((unsigned long)addr, mod) &&
- !within_module_init((unsigned long)scan_end, mod))
- scan_end = (kprobe_opcode_t *)mod->init_layout.base;
- else if (mod && within_module_core((unsigned long)addr, mod) &&
- !within_module_core((unsigned long)scan_end, mod))
- scan_end = (kprobe_opcode_t *)mod->core_layout.base;
- preempt_enable();
+ kprobe_opcode_t *scan_end = NULL;
+ unsigned long size = 0, offset = 0;
+
+ /*
+ * If there's a symbol defined in front of and near enough to
+ * the probe address assume it is the entry point to this
+ * code and use it to further limit how far back we search
+ * when determining if we're in an atomic sequence. If we could
+ * not find any symbol skip the atomic test altogether as we
+ * could otherwise end up searching irrelevant text/literals.
+ * KPROBES depends on KALLSYMS so this last case should never
+ * happen.
+ */
+ if (kallsyms_lookup_size_offset((unsigned long) addr, &size, &offset)) {
+ if (offset < (MAX_ATOMIC_CONTEXT_SIZE*sizeof(kprobe_opcode_t)))
+ scan_end = addr - (offset / sizeof(kprobe_opcode_t));
+ else
+ scan_end = addr - MAX_ATOMIC_CONTEXT_SIZE;
}
-#endif
decoded = arm_probe_decode_insn(insn, asi);
- if (decoded == INSN_REJECTED ||
- is_probed_address_atomic(scan_start, scan_end))
- return INSN_REJECTED;
+ if (decoded != INSN_REJECTED && scan_end)
+ if (is_probed_address_atomic(addr - 1, scan_end))
+ return INSN_REJECTED;
return decoded;
}