From d5f7bd296f72c1a75a910aff6dd9c43f4365a188 Mon Sep 17 00:00:00 2001 From: Palmer Dabbelt Date: Fri, 17 Mar 2017 15:39:02 -0700 Subject: [PATCH] Prohibit relaxing the initial gp generation I've added an additional linker relaxation that relaxes two instruction pc-relative sequences to one instruction gp relative sequences when possible. This sequence now optimizes the initial gp generation to mv gp, gp which is obviously bogus. The fix is to disable relaxations when setting up gp, preventing the linker from relaxing away this setup code. --- benchmarks/common/crt.S | 3 +++ debug/programs/entry.S | 3 +++ 2 files changed, 6 insertions(+) diff --git a/benchmarks/common/crt.S b/benchmarks/common/crt.S index 3e6cee4..d75e81e 100644 --- a/benchmarks/common/crt.S +++ b/benchmarks/common/crt.S @@ -111,7 +111,10 @@ _start: csrw mtvec, t0 # initialize global pointer +.option push +.option norelax la gp, __global_pointer$ +.option pop la tp, _end + 63 and tp, tp, -64 diff --git a/debug/programs/entry.S b/debug/programs/entry.S index b507a93..e021860 100755 --- a/debug/programs/entry.S +++ b/debug/programs/entry.S @@ -35,7 +35,10 @@ handle_reset: csrwi mie, 0 # initialize global pointer +.option push +.option norelax la gp, __global_pointer$ +.option pop # initialize stack pointer la sp, stack_top -- 2.30.2