From 2d3399ab6072acd85811a54fce8eff50628888b6 Mon Sep 17 00:00:00 2001 From: Felix Morgner Date: Thu, 24 Jul 2025 16:35:34 +0000 Subject: x86_64: move files out of the way --- arch/x86_64/pre/src/kernel/cpu/msr.cpp | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) create mode 100644 arch/x86_64/pre/src/kernel/cpu/msr.cpp (limited to 'arch/x86_64/pre/src/kernel/cpu/msr.cpp') diff --git a/arch/x86_64/pre/src/kernel/cpu/msr.cpp b/arch/x86_64/pre/src/kernel/cpu/msr.cpp new file mode 100644 index 0000000..9c474a1 --- /dev/null +++ b/arch/x86_64/pre/src/kernel/cpu/msr.cpp @@ -0,0 +1,31 @@ +#include "arch/kernel/cpu/msr.hpp" + +namespace teachos::arch::kernel::cpu +{ + namespace + { + auto constexpr IA32_EFER_ADDRESS = 0xC0000080; + } + + auto read_msr(uint32_t msr) -> uint64_t + { + uint32_t low, high; + asm volatile("rdmsr" : "=a"(low), "=d"(high) : "c"(msr)); + return (static_cast(high) << 32) | low; + } + + auto write_msr(uint32_t msr, uint64_t value) -> void + { + uint32_t low = value; + uint32_t high = value >> 32; + asm volatile("wrmsr" + : /* no output from call */ + : "c"(msr), "a"(low), "d"(high)); + } + + auto set_efer_bit(efer_flags flag) -> void + { + auto const efer = read_msr(IA32_EFER_ADDRESS); + write_msr(IA32_EFER_ADDRESS, static_cast::type>(flag) | efer); + } +} // namespace teachos::arch::kernel::cpu -- cgit v1.2.3