this seems to break build of 5.10.y (and maybe earlier) for me: CALL scripts/checksyscalls.sh - due to target missing CALL scripts/atomic/check-atomics.sh - due to target missing CHK include/generated/compile.h AS arch/arm64/kvm/hyp/nvhe/hyp-init.nvhe.o - due to target missing arch/arm64/kvm/hyp/nvhe/hyp-init.S: Assembler messages: arch/arm64/kvm/hyp/nvhe/hyp-init.S:87: Error: missing ')' arch/arm64/kvm/hyp/nvhe/hyp-init.S:87: Error: missing ')' arch/arm64/kvm/hyp/nvhe/hyp-init.S:87: Error: missing ')' arch/arm64/kvm/hyp/nvhe/hyp-init.S:87: Error: missing ')' arch/arm64/kvm/hyp/nvhe/hyp-init.S:87: Error: missing ')' arch/arm64/kvm/hyp/nvhe/hyp-init.S:87: Error: missing ')' arch/arm64/kvm/hyp/nvhe/hyp-init.S:87: Error: unexpected characters following instruction at operand 2 -- `mov x1,#((1U<<31)|(1<<23))' arch/arm64/kvm/hyp/nvhe/Makefile:28: recipe for target 'arch/arm64/kvm/hyp/nvhe/hyp-init.nvhe.o' failed make[5]: *** [arch/arm64/kvm/hyp/nvhe/hyp-init.nvhe.o] Error 1 scripts/Makefile.build:497: recipe for target 'arch/arm64/kvm/hyp/nvhe' failed make[4]: *** [arch/arm64/kvm/hyp/nvhe] Error 2 scripts/Makefile.build:497: recipe for target 'arch/arm64/kvm/hyp' failed make[3]: *** [arch/arm64/kvm/hyp] Error 2 scripts/Makefile.build:497: recipe for target 'arch/arm64/kvm' failed make[2]: *** [arch/arm64/kvm] Error 2 Makefile:1822: recipe for target 'arch/arm64' failed make[1]: *** [arch/arm64] Error 2 Makefile:336: recipe for target '__build_one_by_one' failed make: *** [__build_one_by_one] Error 2 Looking at the problematic line 87 of hyp-init.S shows that there is a macro expansion: mov x1, #TCR_EL2_RES1 This macro was modified by the $subject patch (commit c71b5f37b5ff1a673b2e4a91d1b34ea027546e23 in v5.10.y) and reverting the patch makes the compile succeed. Now: why does it build for me for v5.15.y and v5.16-rc5? I think it is because my build system switches to gcc 6.3 instead of gcc 4.9 depending on scripts/min-tool-version.sh. So I assume that the fix is not compatible with the minimum requirement for 5.10.y of gcc 4.9 (or even less - I don't know exactly). Earlier kernels may also be affected if $subject patch was also backported there, but I have not tested. This should somehow be fixed so that arch/arm64/include/asm/kvm_arm.h can be included by older assemblers. BR and thanks, Nikolaus Schaller