Comment 2 for bug 947111

Revision history for this message
In , Arnaud Patard (arnaud-patard) wrote :

As noticed by debian bug 623964, when building an arm kernel with a snasphot made on 04/19, compiling head.S is failing with :

Error: selected processor does not support requested special purpose register -- `mrs r2,cpsr'

It's valid for current head.

To reproduce, create a head.S containing:

                mrs r2, cpsr
                msr cpsr_c, r2

And then build with ./gas/as-new -march=all -c head.S -o head.o

I believe it's due to this commit :
http://sourceware.org/git/?p=binutils.git;a=commitdiff;h=335cd49156302284cea0438fd068f0a7cc11355a

I've written this workaround:

--- binutils.orig/gas/config/tc-arm.c
+++ binutils/gas/config/tc-arm.c
@@ -5356,6 +5356,11 @@ parse_psr (char **str, bfd_boolean lhs)
   bfd_boolean is_apsr = FALSE;
   bfd_boolean m_profile = ARM_CPU_HAS_FEATURE (selected_cpu, arm_ext_m);

+ /* march=all, will match the m_profile case too, so things like 'mrs r2,cpsr'
+ * will now fail. Workaround by saying it's not a m profile */
+ if (selected_cpu.core == arm_arch_any.core)
+ m_profile = FALSE;
+
   /* CPSR's and SPSR's can now be lowercase. This is just a convenience
      feature for ease of use and backwards compatibility. */
   p = *str;

It doesn't seem to create any regression but I'm not sure how good is this patch. At least, I hope it'll help fixing the bug.