x86_64/cpu: fix asm input constraint

The "X" constraint tells GCC that any operand whatsoever is valid to be
placed in the assembler template. This makes no sense in this case,
since that would allow for the exact expression to be inserted. If that
happens, which it does when `-Og` is active, GCC is unable to assemble
that template.

The correct constraint is forcing the value into a register.

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/x86_64/arch/cpu/global_descriptor_table.hpp b/arch/x86_64/arch/cpu/global_descriptor_table.hpp
index 986dd566..0bd7677d 100644
--- a/arch/x86_64/arch/cpu/global_descriptor_table.hpp
+++ b/arch/x86_64/arch/cpu/global_descriptor_table.hpp
@@ -73,8 +73,8 @@ namespace arch::cpu
                    "mov %%rax, %%fs\n"
                    "mov %%rax, %%gs\n"
                    :
-                   : "X"(code_segment_index * sizeof(segment_descriptor)),
-                     "X"(data_segment_index * sizeof(segment_descriptor))
+                   : "r"(code_segment_index * sizeof(segment_descriptor)),
+                     "r"(data_segment_index * sizeof(segment_descriptor))
                    : "rax");
     }