ARM: kgdb: ignore breakpoint instructions from user mode

Avoid conflicts with user mode usage of the same instructions, as with
Clang -ftrapv.

Change-Id: I12d1c6d8f94376bfd2503cb0be843d7e478fb6ea
Signed-off-by: Todd Poynor <toddpoynor@google.com>

diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
index 9232caee70604c686e07b7aef4c21598c7196fa4..f3c662299531351d62c7e4081c6d3158778d5e05 100644 (file)
--- a/arch/arm/kernel/kgdb.c
+++ b/arch/arm/kernel/kgdb.c
@@ -140,6 +140,8 @@ int kgdb_arch_handle_exception(int exception_vector, int signo,
 
 static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
 {
+       if (user_mode(regs))
+               return -1;
        kgdb_handle_exception(1, SIGTRAP, 0, regs);
 
        return 0;
@@ -147,6 +149,8 @@ static int kgdb_brk_fn(struct pt_regs *regs, unsigned int instr)
 
 static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
 {
+       if (user_mode(regs))
+               return -1;
        compiled_break = 1;
        kgdb_handle_exception(1, SIGTRAP, 0, regs);