From 71ca99a50960efe95e048d5ef786df593aa79d86 Mon Sep 17 00:00:00 2001 From: Anders Roxell Date: Thu, 24 Feb 2022 17:22:15 +0100 Subject: [PATCH] powerpc/lib/sstep: Fix build errors with newer binutils 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_002dPseudo Fixes: 350779a29f11 ("powerpc: Handle most loads and stores in instruction emulation code") Cc: stable@vger.kernel.org # v4.14+ Co-developed-by: Arnd Bergmann Signed-off-by: Arnd Bergmann Signed-off-by: Anders Roxell Reviewed-by: Segher Boessenkool Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20220224162215.3406642-3-anders.roxell@linaro.org Signed-off-by: Greg Kroah-Hartman --- 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 0c5f7c589b03..27650cd5857f 100644 --- a/arch/powerpc/lib/sstep.c +++ b/arch/powerpc/lib/sstep.c @@ -906,7 +906,10 @@ 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" \ @@ -919,7 +922,10 @@ 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" \