This series overrides barrier_before_unreachable() for MIPS to add a .insn assembler directive. Due to the subsequent __builtin_unreachable(), the assembler can't tell that a label on the empty inline asm is code rather than data, so any microMIPS branches targeting it (which sadly can't be removed) raise errors due to the mismatching ISA mode, Adding the .insn in patch 4 tells the assembler that it should be treated as code. To do this we add a new standard asm/compiler.h for architecture overrides in patch 3. There are a few existing asm/compiler.h files already existing, most of which are fairly simple and don't include anything else (arm, arm64, mips). Unfortunately the alpha one includes linux/compiler.h though, so it can undefine some inline macros. On Arnd's suggestion this is converted to use OPTIMIZE_INLINING instead in patch 1. A build of alpha's defconfig on GCC 7.3 before and after this series results in the following size differences, which appear harmless to me: $ ./scripts/bloat-o-meter vmlinux.1 vmlinux.2 add/remove: 1/1 grow/shrink: 3/0 up/down: 264/-348 (-84) Function old new delta cap_bprm_set_creds 1496 1664 +168 cap_issubset - 68 +68 flex_array_put 328 344 +16 cap_capset 488 500 +12 nonroot_raised_pE.constprop 348 - -348 Total: Before=5823709, After=5823625, chg -0.00% Also um needs the generated/ include directory adding to the include paths in patch 2 so that an asm-generic wrapper asm/compiler.h can be included from automatically included headers. Applies cleanly atop v4.18-rc8. Changes in v6 (Paul): - Fix patch 2 to find the generated headers in $(objtree). - Remove CC's for defunct MIPS email addresses (Matthew & Robert). - CC linux-um@xxxxxxxxxxxxxxxxxxx. Changes in v5 (Paul): - Rebase atop v4.18-rc8. - Comment & commit message tweaks. - Add SPDX-License-Identifier to asm-generic/compiler.h. Changes in v4 (James): - Fix asm-generic/compiler.h include from check, compiler_types.h is included on the command line so linux/compiler.h may not be included (kbuild test robot). - New patch 2 to fix um (kbuild test robot). Changes in v3 (James): - New patch 1. - Rebase after 4.17 arch removal and update commit messages. - Use asm/compiler.h instead of compiler-gcc.h (Arnd). - Drop stable tag for now. Changes in v2 (Paul): - Add generic-y entries to arch Kbuild files. Oops! James Hogan (2): alpha: Use OPTIMIZE_INLINING instead of asm/compiler.h um: Add generated/ to MODE_INCLUDE Paul Burton (2): compiler.h: Allow arch-specific overrides MIPS: Workaround GCC __builtin_unreachable reordering bug arch/alpha/Kconfig | 6 ++++++ arch/alpha/include/asm/compiler.h | 11 ----------- arch/arc/include/asm/Kbuild | 1 + arch/c6x/include/asm/Kbuild | 1 + arch/h8300/include/asm/Kbuild | 1 + arch/hexagon/include/asm/Kbuild | 1 + arch/ia64/include/asm/Kbuild | 1 + arch/m68k/include/asm/Kbuild | 1 + arch/microblaze/include/asm/Kbuild | 1 + arch/mips/include/asm/compiler.h | 30 ++++++++++++++++++++++++++++++ arch/nds32/include/asm/Kbuild | 1 + arch/nios2/include/asm/Kbuild | 1 + arch/openrisc/include/asm/Kbuild | 1 + arch/parisc/include/asm/Kbuild | 1 + arch/powerpc/include/asm/Kbuild | 1 + arch/riscv/include/asm/Kbuild | 1 + arch/s390/include/asm/Kbuild | 1 + arch/sh/include/asm/Kbuild | 1 + arch/sparc/include/asm/Kbuild | 1 + arch/um/Makefile | 1 + arch/um/include/asm/Kbuild | 1 + arch/unicore32/include/asm/Kbuild | 1 + arch/x86/include/asm/Kbuild | 1 + arch/xtensa/include/asm/Kbuild | 1 + include/asm-generic/compiler.h | 10 ++++++++++ include/linux/compiler-gcc.h | 2 ++ include/linux/compiler_types.h | 3 +++ 27 files changed, 72 insertions(+), 11 deletions(-) create mode 100644 include/asm-generic/compiler.h -- 2.18.0
