From: Anders Roxell anders.roxell@linaro.org
commit fe663df7825811358531dc2e8a52d9eaa5e3515e upstream.
Building tinyconfig with gcc (Debian 11.2.0-16) and assembler (Debian 2.37.90.20220207) the following build error shows up:
{standard input}: Assembler messages: {standard input}:2088: Error: unrecognized opcode: `ptesync' make[3]: *** [/builds/linux/scripts/Makefile.build:287: arch/powerpc/lib/sstep.o] Error 1
Add the 'ifdef CONFIG_PPC64' around the 'ptesync' in function 'emulate_update_regs()' to like it is in 'analyse_instr()'. Since it looks like it got dropped inadvertently by commit 3cdfcbfd32b9 ("powerpc: Change analyse_instr so it doesn't modify *regs").
A key detail is that analyse_instr() will never recognise lwsync or ptesync on 32-bit (because of the existing ifdef), and as a result emulate_update_regs() should never be called with an op specifying either of those on 32-bit. So removing them from emulate_update_regs() should be a nop in terms of runtime behaviour.
Fixes: 3cdfcbfd32b9 ("powerpc: Change analyse_instr so it doesn't modify *regs") Cc: stable@vger.kernel.org # v4.14+ Suggested-by: Arnd Bergmann arnd@arndb.de Signed-off-by: Anders Roxell anders.roxell@linaro.org [mpe: Add last paragraph of change log mentioning analyse_instr() details] Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20220211005113.1361436-1-anders.roxell@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/lib/sstep.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -2787,12 +2787,14 @@ void emulate_update_regs(struct pt_regs case BARRIER_EIEIO: eieio(); break; +#ifdef CONFIG_PPC64 case BARRIER_LWSYNC: asm volatile("lwsync" : : : "memory"); break; case BARRIER_PTESYNC: asm volatile("ptesync" : : : "memory"); break; +#endif } break;