Hi Andy, thanks a lot for your valuable reviews! On Tue, Feb 11, 2020 at 02:18:52PM -0800, Andy Lutomirski wrote: > On Tue, Feb 11, 2020 at 5:53 AM Joerg Roedel <joro@xxxxxxxxxx> wrote: > > + entry.offset_low = (u16)(address & 0xffff); > > + entry.segment = __KERNEL_CS; > > + entry.bits.type = GATE_TRAP; > > ^^^ > > I realize we're not running a real kernel here, but GATE_TRAP is > madness. Please use GATE_INTERRUPT. Changed that. > > + /* Build pt_regs */ > > + .if \error_code == 0 > > + pushq $0 > > + .endif > > cld Added. > > + popq %rdi > > if error_code? The code above pushes a $0 for exceptions without an error code, so it needs to be removed unconditionally. > > + > > + /* Remove error code and return */ > > + addq $8, %rsp > > + > > + /* > > + * Make sure we return to __KERNEL_CS - the CS selector on > > + * the IRET frame might still be from an old BIOS GDT > > + */ > > + movq $__KERNEL_CS, 8(%rsp) > > + > > If this actually happens, you have a major bug. Please sanitize all > the segment registers after installing the GDT rather than hacking > around it here. Okay, will change that. I thought I could safe some instructions in the head_64.S code, but you are right that its better to setup a defined environment first. Thanks, Joerg
