• Linus Torvalds's avatar
    Merge tag 'x86-fred-2024-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip · b1360211
    Linus Torvalds authored
    Pull x86 FRED updates from Thomas Gleixner:
    
     - Enable FRED right after init_mem_mapping() because at that point the
       early IDT fault handler is replaced by the real fault handler. The
       real fault handler retrieves the faulting address from the stack
       frame and not from CR2 when the FRED feature is set. But that
       obviously only works when FRED is enabled in the CPU as well.
    
     - Set SS to __KERNEL_DS when enabling FRED to prevent a corner case
       where ERETS can observe a SS mismatch and raises a #GP.
    
    * tag 'x86-fred-2024-09-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
      x86/entry: Set FRED RSP0 on return to userspace instead of context switch
      x86/msr: Switch between WRMSRNS and WRMSR with the alternatives mechanism
      x86/entry: Test ti_work for zero before processing individual bits
      x86/fred: Set SS to __KERNEL_DS when enabling FRED
      x86/fred: Enable FRED right after init_mem_mapping()
      x86/fred: Move FRED RSP initialization into a separate function
      x86/fred: Parse cmdline param "fred=" in cpu_parse_early_param()
    b1360211
traps.c 40.1 KB