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authorDoug Anderson <dianders@chromium.org>2014-04-22 15:14:51 -0700
committerKees Cook <keescook@chromium.org>2014-10-16 14:38:53 -0700
commit23a4e4050ba9c98ab67db0980a9fb20e5096d9ea (patch)
treea5571f323a6f923d5b8d4674112eec798f0bb13b /arch/arm/kernel/kgdb.c
parent42d720d1731a9d7035c2812437c35e271ec4dd78 (diff)
downloadlinux-sh-23a4e4050ba9c98ab67db0980a9fb20e5096d9ea.tar.gz
arm: kgdb: Handle read-only text / modules
Handle the case where someone has set the text segment of the kernel as read-only by using the newly introduced "patch" mechanism. Signed-off-by: Doug Anderson <dianders@chromium.org> [kees: switched structure size check to BUILD_BUG_ON (sboyd)] Signed-off-by: Kees Cook <keescook@chromium.org> Acked-by: Nicolas Pitre <nico@linaro.org>
Diffstat (limited to 'arch/arm/kernel/kgdb.c')
-rw-r--r--arch/arm/kernel/kgdb.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
index a74b53c1b7df..07db2f8a1b45 100644
--- a/arch/arm/kernel/kgdb.c
+++ b/arch/arm/kernel/kgdb.c
@@ -12,8 +12,12 @@
#include <linux/irq.h>
#include <linux/kdebug.h>
#include <linux/kgdb.h>
+#include <linux/uaccess.h>
+
#include <asm/traps.h>
+#include "patch.h"
+
struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
{
{ "r0", 4, offsetof(struct pt_regs, ARM_r0)},
@@ -244,6 +248,31 @@ void kgdb_arch_exit(void)
unregister_die_notifier(&kgdb_notifier);
}
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+ int err;
+
+ /* patch_text() only supports int-sized breakpoints */
+ BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE);
+
+ err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+ BREAK_INSTR_SIZE);
+ if (err)
+ return err;
+
+ patch_text((void *)bpt->bpt_addr,
+ *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr);
+
+ return err;
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+ patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr);
+
+ return 0;
+}
+
/*
* Register our undef instruction hooks with ARM undef core.
* We regsiter a hook specifically looking for the KGB break inst