From: Anders Roxell <anders.roxell@linaro.org> stable inclusion from stable-v5.10.110 commit 68fa67e939d81e9886cba00606ea64825abf64dc bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 8219d31effa7be5dbc7ff915d7970672e028c701 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}:10576: Error: unrecognized opcode: `stbcx.' {standard input}:10680: Error: unrecognized opcode: `lharx' {standard input}:10694: Error: unrecognized opcode: `lbarx' Rework to add assembler directives [1] around the instruction. The problem with this might be that we can trick a power6 into single-stepping through an stbcx. for instance, and it will execute that in kernel mode. [1] https://sourceware.org/binutils/docs/as/PowerPC_002dPseudo.html#PowerPC_002d... Fixes: 350779a29f11 ("powerpc: Handle most loads and stores in instruction emulation code") Cc: stable@vger.kernel.org # v4.14+ Co-developed-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Anders Roxell <anders.roxell@linaro.org> Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20220224162215.3406642-3-anders.roxell@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yu Liao <liaoyu15@huawei.com> Reviewed-by: Wei Li <liwei391@huawei.com> Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com> --- arch/powerpc/lib/sstep.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c index ac5ea8d5a183..2d19655328f1 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -949,7 +949,10 @@ NOKPROBE_SYMBOL(emulate_dcbz); #define __put_user_asmx(x, addr, err, op, cr) \ __asm__ __volatile__( \ + ".machine push\n" \ + ".machine power8\n" \ "1: " op " %2,0,%3\n" \ + ".machine pop\n" \ " mfcr %1\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ @@ -962,7 +965,10 @@ NOKPROBE_SYMBOL(emulate_dcbz); #define __get_user_asmx(x, addr, err, op) \ __asm__ __volatile__( \ + ".machine push\n" \ + ".machine power8\n" \ "1: "op" %1,0,%2\n" \ + ".machine pop\n" \ "2:\n" \ ".section .fixup,\"ax\"\n" \ "3: li %0,%3\n" \ -- 2.20.1