arm64: debug: fix mdscr.ss check when enabling debug exceptions

When we take an exception at EL1, we only want to enable debug
exceptions if we're not currently stepping, otherwise we can easily get
stuck in a loop stepping into interrupt handlers.

Unfortunately, the current code tests the wrong bit in the mdscr, so fix
that.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h
index c8eedc6049844dbb0d2142fa9aca90478e163025..5aceb83b3f5c3c5dd9dc1168a157bb0e41f1c8e9 100644 (file)
--- a/arch/arm64/include/asm/assembler.h
+++ b/arch/arm64/include/asm/assembler.h
@@ -82,7 +82,7 @@
 
        .macro  enable_dbg_if_not_stepping, tmp
        mrs     \tmp, mdscr_el1
-       tbnz    \tmp, #1, 9990f
+       tbnz    \tmp, #0, 9990f
        enable_dbg
 9990:
        .endm