[PATCH 3/5] powerpc/fsl: Fix mfpmr build errors with newer binutils

Michael Ellerman mpe at ellerman.id.au
Thu Feb 29 23:25:19 AEDT 2024


Binutils 2.38 complains about the use of mfpmr when building
ppc6xx_defconfig:

    CC      arch/powerpc/kernel/pmc.o
  {standard input}: Assembler messages:
  {standard input}:45: Error: unrecognized opcode: `mfpmr'
  {standard input}:56: Error: unrecognized opcode: `mtpmr'

This is because by default the kernel is built with -mcpu=powerpc, and
the mt/mfpmr instructions are not defined.

It can be avoided by enabling CONFIG_E300C3_CPU, but just adding that to
the defconfig will leave open the possibility of randconfig failures.

So add machine directives around the mt/mfpmr instructions to tell
binutils how to assemble them.

Cc: stable at vger.kernel.org
Reported-by: Jan-Benedict Glaw <jbglaw at lug-owl.de>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
---
 arch/powerpc/include/asm/reg_fsl_emb.h | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/reg_fsl_emb.h b/arch/powerpc/include/asm/reg_fsl_emb.h
index a21f529c43d9..8359c06d92d9 100644
--- a/arch/powerpc/include/asm/reg_fsl_emb.h
+++ b/arch/powerpc/include/asm/reg_fsl_emb.h
@@ -12,9 +12,16 @@
 #ifndef __ASSEMBLY__
 /* Performance Monitor Registers */
 #define mfpmr(rn)	({unsigned int rval; \
-			asm volatile("mfpmr %0," __stringify(rn) \
+			asm volatile(".machine push; " \
+				     ".machine e300; " \
+				     "mfpmr %0," __stringify(rn) ";" \
+				     ".machine pop; " \
 				     : "=r" (rval)); rval;})
-#define mtpmr(rn, v)	asm volatile("mtpmr " __stringify(rn) ",%0" : : "r" (v))
+#define mtpmr(rn, v)	asm volatile(".machine push; " \
+				     ".machine e300; " \
+				     "mtpmr " __stringify(rn) ",%0; " \
+				     ".machine pop; " \
+				     : : "r" (v))
 #endif /* __ASSEMBLY__ */
 
 /* Freescale Book E Performance Monitor APU Registers */
-- 
2.43.2



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