From: Nathan Chancellor nathan@kernel.org
commit 61114e734ccb804bc12561ab4020745e02c468c2 upstream.
After commit 49b290e430d3 ("riscv: prevent compressed instructions in alternatives"), builds with LLVM's integrated assembler fail:
In file included from arch/riscv/mm/init.c:10: In file included from ./include/linux/mm.h:29: In file included from ./include/linux/pgtable.h:6: In file included from ./arch/riscv/include/asm/pgtable.h:108: ./arch/riscv/include/asm/tlbflush.h:23:2: error: expected assembly-time absolute expression ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory")); ^ ./arch/riscv/include/asm/errata_list.h:33:5: note: expanded from macro 'ALT_FLUSH_TLB_PAGE' asm(ALTERNATIVE("sfence.vma %0", "sfence.vma", SIFIVE_VENDOR_ID, \ ^ ./arch/riscv/include/asm/alternative-macros.h:187:2: note: expanded from macro 'ALTERNATIVE' _ALTERNATIVE_CFG(old_content, new_content, vendor_id, errata_id, CONFIG_k) ^ ./arch/riscv/include/asm/alternative-macros.h:113:2: note: expanded from macro '_ALTERNATIVE_CFG' __ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, IS_ENABLED(CONFIG_k)) ^ ./arch/riscv/include/asm/alternative-macros.h:110:2: note: expanded from macro '__ALTERNATIVE_CFG' ALT_NEW_CONTENT(vendor_id, errata_id, enable, new_c) ^ ./arch/riscv/include/asm/alternative-macros.h:99:3: note: expanded from macro 'ALT_NEW_CONTENT' ".org . - (889b - 888b) + (887b - 886b)\n" \ ^ <inline asm>:26:6: note: instantiated into assembly here .org . - (889b - 888b) + (887b - 886b) ^
This error happens because LLVM's integrated assembler has a one-pass design, which means it cannot figure out the instruction lengths when the .org directive is outside of the subsection that contains the instructions, which was changed by the .option directives added by the above change.
Move the .org directives before the .previous directive so that these directives are always within the same subsection, which resolves the failures and does not introduce any new issues with GNU as. This was done for arm64 in commit 966a0acce2fc ("arm64/alternatives: move length validation inside the subsection") and commit 22315a2296f4 ("arm64: alternatives: Move length validation in alternative_{insn, endif}").
While there is no error from the assembly versions of the macro, they appear to have the same problem so just make the same change there as well so that there are no problems in the future.
Link: https://github.com/ClangBuiltLinux/linux/issues/1640 Reported-by: kernel test robot lkp@intel.com Signed-off-by: Nathan Chancellor nathan@kernel.org Reviewed-by: Heiko Stuebner heiko@sntech.de Tested-by: Heiko Stuebner heiko@sntech.de Link: https://lore.kernel.org/r/20220516214520.3252074-1-nathan@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/riscv/include/asm/alternative-macros.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/riscv/include/asm/alternative-macros.h +++ b/arch/riscv/include/asm/alternative-macros.h @@ -23,9 +23,9 @@ 888 : \new_c 889 : - .previous .org . - (889b - 888b) + (887b - 886b) .org . - (887b - 886b) + (889b - 888b) + .previous .endif .endm
@@ -60,9 +60,9 @@ "888 :\n" \ new_c "\n" \ "889 :\n" \ - ".previous\n" \ ".org . - (887b - 886b) + (889b - 888b)\n" \ ".org . - (889b - 888b) + (887b - 886b)\n" \ + ".previous\n" \ ".endif\n"
#define __ALTERNATIVE_CFG(old_c, new_c, vendor_id, errata_id, enable) \