| /* SPDX-License-Identifier: GPL-2.0-only */ |
| |
| __fpu_start: |
| /* Preserve BIST. */ |
| movl %eax, %ebp |
| |
| /* |
| * Clear the CR0[2] bit (the "Emulation" flag, EM). |
| * |
| * This indicates that the processor has an (internal or external) |
| * x87 FPU, i.e. floating point operations will be executed by the |
| * hardware (and not emulated in software). |
| * |
| * Additionally, if this bit is not cleared, MMX/SSE instructions won't |
| * work, i.e., they will trigger an invalid opcode exception (#UD). |
| */ |
| movl %cr0, %eax |
| andl $~(1 << 2), %eax |
| movl %eax, %cr0 |
| |
| /* Restore BIST. */ |
| movl %ebp, %eax |
