arch/x86: Clean up bootblock assembly
We have identical gdtptr16 and gdtptr. The reference in
gdtptr_offset calculation is not accounted for when
considering --gc-sections, so to support linking
gdt_init.S separately add dummy use of gdtptr symbol.
Realmode execution already accessed gdt that was located
outside [_start16bit,_estart16bit] region. Remove latter
symbol as the former was not really a start of region,
but entry point symbol.
With the romcc bootblock solution, entry32.inc may have
been linked into romstage before, but the !ENV_BOOTBLOCK
case seems obsolete now.
Change-Id: I0a3f6aeb217ca4e38b936b8c9ec8b0b69732cbb9
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47964
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/src/cpu/x86/16bit/entry16.inc b/src/cpu/x86/16bit/entry16.inc
index 13d12be..2665cc6 100644
--- a/src/cpu/x86/16bit/entry16.inc
+++ b/src/cpu/x86/16bit/entry16.inc
@@ -108,7 +108,7 @@
movw $nullidt_offset, %bx
subw %ax, %bx
lidt %cs:(%bx)
- movw $gdtptr16_offset, %bx
+ movw $gdtptr_offset, %bx
subw %ax, %bx
lgdtl %cs:(%bx)
@@ -127,11 +127,8 @@
* The gdt is defined in entry32.inc, it has a 4 Gb code segment
* at 0x08, and a 4 GB data segment at 0x10;
*/
-.align 4
-.globl gdtptr16
-gdtptr16:
- .word gdt_end - gdt -1 /* compute the table limit */
- .long gdt /* we know the offset */
+__gdtptr:
+ .long gdtptr
.align 4
.globl nullidt
@@ -139,7 +136,3 @@
.word 0 /* limit */
.long 0
.word 0
-
-.globl _estart16bit
-_estart16bit:
- .code32