I doubt this will ever matter, but I think this is correct. I hope this isn't an annoying patch. Just trying to get my feet wet in the kernel. It compiled and ran on my machine for what it's worth.
Chris Waddey Index: gidt.S =================================================================== RCS file: /cvs/src/sys/arch/amd64/stand/libsa/gidt.S,v retrieving revision 1.12 diff -u -p -r1.12 gidt.S --- gidt.S 9 Nov 2019 17:58:46 -0000 1.12 +++ gidt.S 4 Sep 2020 23:11:23 -0000 @@ -260,14 +260,14 @@ gdt: .byte (LINKADDR >> 16) & 0xff # midbase .byte SDT_MEMERAC | 0 | 0x80 # RXAC, dpl = 0, present .byte 0x0 | 0 | 0 | 0 # hilimit, xx, 16bit, byte granularity - .byte (LINKADDR >> 20) & 0xff # hibase + .byte (LINKADDR >> 24) & 0xff # hibase /* 0x20 : 16 bit data */ .word 0xFFFF # lolimit .word (LINKADDR & 0xffff) # lobase .byte (LINKADDR >> 16) & 0xff # midbase .byte SDT_MEMRWA | 0 | 0x80 # RWA, dpl = 0, present .byte 0x0 | 0 | 0 | 0 # hilimit, xx, 16bit, byte granularity - .byte (LINKADDR >> 20) & 0xff # hibase + .byte (LINKADDR >> 24) & 0xff # hibase .globl Gdtr Gdtr: .word . - gdt - 1