From 57e6722453c27d35a3b02309ce21263d225a23e3 Mon Sep 17 00:00:00 2001 From: Aleksa Vuckovic Date: Wed, 22 Feb 2023 17:31:52 +0100 Subject: curr_cpu_apic_id() now works on old amd cpus --- kernel/src/cpu/msr.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) create mode 100644 kernel/src/cpu/msr.c (limited to 'kernel/src/cpu/msr.c') diff --git a/kernel/src/cpu/msr.c b/kernel/src/cpu/msr.c new file mode 100644 index 0000000..75fc602 --- /dev/null +++ b/kernel/src/cpu/msr.c @@ -0,0 +1,21 @@ +#include + +uint64_t read_msr(uint32_t addr) +{ + uint64_t eax; + uint64_t edx; + uint64_t ecx = addr; + + __asm__ volatile ("rdmsr;" : "=a"(eax), "=d"(edx) : "c"(ecx) :); + + return (edx << 32) | eax; +} + +void write_msr(uint32_t addr, uint64_t value) +{ + uint64_t eax = value & 0xFFFFFFFF; + uint64_t edx = value >> 32; + uint64_t ecx = addr; + + __asm__ volatile ("wrmsr;" : : "a"(eax), "d"(edx), "c"(ecx) :); +} -- cgit v1.2.3