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2023-01-26MIPS: Always use -Wa,-msoft-float and eliminate GAS_HAS_SET_HARDFLOATNathan Chancellor1-3/+3
-Wa,-msoft-float is tested with as-option, which will be a problem for clang with an upcoming change to move as-option to use KBUILD_AFLAGS instead of KBUILD_CFLAGS due to a lack of '-mno-abicalls' in KBUILD_AFLAGS at the point that this check occurs; $(cflags-y) is added to KBUILD_AFLAGS towards the end of this file. clang: error: ignoring '-fno-PIE' option as it cannot be used with implicit usage of -mabicalls and the N64 ABI [-Werror,-Woption-ignored] This could be resolved by switching to a cc-option check but '$(cflags-y)' would need to be added so that '-mno-abicalls' is present for the test. However, this check is no longer necessary, as -msoft-float is supported by all supported assembler versions (GNU as 2.25+ and LLVM 11+). Eliminate GAS_HAS_SET_HARDFLOAT and all of its uses, inlining SET_HARDFLOAT where necessary. Link: https://lore.kernel.org/202209101939.bvk64Fok-lkp@intel.com/ Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Tested-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2016-07-05MIPS: KVM: Fix fpu.S misassembly with r6James Hogan1-2/+5
__kvm_save_fpu and __kvm_restore_fpu use .set mips64r2 so that they can access the odd FPU registers as well as the even, however this causes misassembly of the return instruction on MIPSr6. Fix by replacing .set mips64r2 with .set fp=64, which doesn't change the architecture revision. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim KrÄmář <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-03-28MIPS: KVM: Add base guest FPU supportJames Hogan1-0/+122
Add base code for supporting FPU in MIPS KVM guests. The FPU cannot yet be enabled in the guest, we're just laying the groundwork. Whether the guest's FPU context is loaded is stored in a bit in the fpu_inuse vcpu member. This allows the FPU to be disabled when the guest disables it, but keeping the FPU context loaded so it doesn't have to be reloaded if the guest re-enables it. An fpu_enabled vcpu member stores whether userland has enabled the FPU capability (which will be wired up in a later patch). New assembly code is added for saving and restoring the FPU context, and for saving/clearing and restoring FCSR (which can itself cause an FP exception depending on the value). The FCSR is restored before returning to the guest if the FPU is already enabled, and a die notifier is registered to catch the possible FP exception and step over the ctc1 instruction. The helper function kvm_lose_fpu() is added to save FPU context and disable the FPU, which is used when saving hardware state before a context switch or KVM exit (the vcpu_get_regs() callback). The helper function kvm_own_fpu() is added to enable the FPU and restore the FPU context if it isn't already loaded, which will be used in a later patch when the guest attempts to use the FPU for the first time and triggers a co-processor unusable exception. The helper function kvm_drop_fpu() is added to discard the FPU context and disable the FPU, which will be used in a later patch when the FPU state will become architecturally UNPREDICTABLE (change of FR mode) to force a reload of [stale] context in the new FR mode. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Gleb Natapov <gleb@kernel.org> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org