Hello,
Damien Zammit via Bug reports for the GNU Hurd, le sam. 21 déc. 2024 23:55:17
+0000, a ecrit:
> + movl %eax, %ebx
> +
> + /* Make eax hold offset to my cpus gdt */
> + movl $((GDT_DESCR_M32 + GDT_TABLE_M32) * 4), %eax
> + mul %ebp
> +
> + /* Patch only our own copy of gdt */
> + movl $apboot_percpu_low, %ecx
> + addl %eax, %ecx
> + movw %bx, (%ecx)
> + shr $16, %ebx
> + addl $2, %ecx
> + movb %bl, (%ecx)
> + shr $8, %bx
> + addl $3, %ecx
> + movb %bl, (%ecx)
> +
> + /* Patch only our own copy of gdt descriptor */
> + movl $apboot_gdt_descr, %ecx
> + addl %eax, %ecx
> + movl %ecx, %edx
> + addl $2, %edx
> + movl (%edx), %ebx
> + addl %eax, %ebx
> + movl %ebx, (%edx)
> +
> + /* Reload our copy of gdt */
> + lgdtl (%ecx)
> + ljmpl $KERNEL_CS, $2f
This is quite verbose. Could you check that the attached patch on top of
it still works?
Samuel
diff --git a/i386/i386/cpuboot.S b/i386/i386/cpuboot.S
index b9b6d632..6ba7aa42 100644
--- a/i386/i386/cpuboot.S
+++ b/i386/i386/cpuboot.S
@@ -44,6 +44,7 @@ apboot_gdt_top:
.word 0
apboot_gdt_descr:
.word (GDT_TABLE_M32 * 4) - 1
+apboot_gdt_descr_addr:
.long apboot_gdt - KERNELBASE
.align 16
apboot_gdt:
@@ -200,27 +201,17 @@ apboot_jmp_offset:
mul %ebp
/* Patch only our own copy of gdt */
- movl $apboot_percpu_low, %ecx
- addl %eax, %ecx
- movw %bx, (%ecx)
+ movw %bx, apboot_percpu_low(%eax)
shr $16, %ebx
- addl $2, %ecx
- movb %bl, (%ecx)
+ movb %bl, apboot_percpu_med(%eax)
shr $8, %bx
- addl $3, %ecx
- movb %bl, (%ecx)
+ movb %bl, apboot_percpu_high(%eax)
/* Patch only our own copy of gdt descriptor */
- movl $apboot_gdt_descr, %ecx
- addl %eax, %ecx
- movl %ecx, %edx
- addl $2, %edx
- movl (%edx), %ebx
- addl %eax, %ebx
- movl %ebx, (%edx)
+ addl %eax, apboot_gdt_descr_addr(%eax)
/* Reload our copy of gdt */
- lgdtl (%ecx)
+ lgdtl apboot_gdt_descr(%eax)
ljmpl $KERNEL_CS, $2f
2:
