RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 14:38:11 +00:00
Code Issues Activity Actions

Kernel: Disable x86 RDTSC instruction in userspace

Browse source 
It's still possible to read the TSC via the read_tsc() syscall, but we
will now clear some of the bottom bits for unprivileged users.
This commit is contained in:
Andreas Kling 2020-01-01 18:18:02 +01:00
parent dfd759f75a
commit 38f93ef13b
6 changed files with 25 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

8
Kernel/init.cpp
View file

@ -266,6 +266,14 @@ extern "C" [[noreturn]] void init(u32 physical_address_for_kernel_page_tables)
kprintf("x86: UMIP support enabled\n");
}
if (g_cpu_supports_tsc) {
asm volatile(
"mov %cr4, %eax\n"
"orl $0x4, %eax\n"
"mov %eax, %cr4\n");
kprintf("x86: RDTSC support restricted\n");
}
RTC::initialize();
PIC::initialize();
gdt_init();