powerpc/4xx: Fix build errors from mfdcr()
lkp reported a build error in fsp2.o: CC arch/powerpc/platforms/44x/fsp2.o {standard input}:577: Error: unsupported relocation against base Which comes from: pr_err("GESR0: 0x%08x\n", mfdcr(base + PLB4OPB_GESR0)); Where our mfdcr() macro is stringifying "base + PLB4OPB_GESR0", and passing that to the assembler, which obviously doesn't work. The mfdcr() macro already checks that the argument is constant using __builtin_constant_p(), and if not calls the out-of-line version of mfdcr(). But in this case GCC is smart enough to notice that "base + PLB4OPB_GESR0" will be constant, even though it's not something we can immediately stringify into a register number. Segher pointed out that passing the register number to the inline asm as a constant would be better, and in fact it fixes the build error, presumably because it gives GCC a chance to resolve the value. While we're at it, change mtdcr() similarly. Reported-by:kernel test robot <lkp@intel.com> Suggested-by:
Segher Boessenkool <segher@kernel.crashing.org> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au> Acked-by:
Feng Tang <feng.tang@intel.com> Link: https://lore.kernel.org/r/20210218123058.748882-1-mpe@ellerman.id.au
parent
fe07bfda