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#include "arch/kernel/cpu/segment_register.hpp"
#include "arch/context_switching/interrupt_descriptor_table/segment_selector.hpp"
#include "arch/exception_handling/assert.hpp"
namespace teachos::arch::kernel::cpu
{
[[gnu::naked]]
auto reload_segment_registers() -> void
{
asm volatile("xor %rax, %rax\n"
"mov %rax, %ss\n"
"mov %rax, %ds\n"
"mov %rax, %es\n"
"mov %rax, %fs\n"
"mov %rax, %gs\n"
"ret");
}
[[gnu::naked]]
auto set_segment_registers(context_switching::interrupt_descriptor_table::segment_selector segment_selector) -> void
{
asm volatile("xor %%rax, %%rax\n"
"mov %[input], %%ax\n"
"mov %%rax, %%ds\n"
"mov %%rax, %%es\n"
"mov %%rax, %%fs\n"
"mov %%rax, %%gs\n"
"ret"
: /* No output from call */
: [input] "m"(segment_selector));
}
auto read_code_segment_register() -> context_switching::interrupt_descriptor_table::segment_selector
{
context_switching::interrupt_descriptor_table::segment_selector current_value;
asm volatile("mov %%cs, %[output]" : [output] "=r"(current_value));
return current_value;
}
auto validate_data_segment_registers() -> context_switching::interrupt_descriptor_table::segment_selector
{
context_switching::interrupt_descriptor_table::segment_selector ss;
context_switching::interrupt_descriptor_table::segment_selector ds;
context_switching::interrupt_descriptor_table::segment_selector es;
context_switching::interrupt_descriptor_table::segment_selector fs;
context_switching::interrupt_descriptor_table::segment_selector gs;
asm volatile(
"mov %%ss, %[ss_output]\n"
"mov %%ds, %[ds_output]\n"
"mov %%es, %[es_output]\n"
"mov %%fs, %[fs_output]\n"
"mov %%gs, %[gs_output]\n"
: [ss_output] "=r"(ss), [ds_output] "=r"(ds), [es_output] "=r"(es), [fs_output] "=r"(fs), [gs_output] "=r"(gs));
auto result = ss == ds && ss == es && ss == fs && ss == gs;
exception_handling::assert(result, "[Segment Register] Values in data register are not the same.");
return ss;
}
} // namespace teachos::arch::kernel::cpu
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