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[metal] Allow programs larger than 440 KiB to run in bare metal mode (#685)

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* [metal] Copy program pages to extended memory at startup
* [metal] Reclaim base memory pages for later app use
* [metal] Load program pages beyond 1st 440 KiB to extended memory

o//examples/hellolua.com now runs correctly under QEMU (in
legacy BIOS mode).

* [metal] Place GDT in read/write segment

The CPU absolutely needs to alter the GDT when loading the
task register (via ltr).  To account for this, I move the
GDT into a read/write data section.  There is still a "rump"
read-only GDT in the text section that is used by the real
mode bootloader.

We also delay the loading of the task register (ltr) until
after the IDT and TSS are finally set up.

* [metal] Get examples/vga2.c serial output working for UEFI boot
* [metal] Get examples/vga2.c VGA output working for UEFI boot
* [metal] Allow munmap() to reclaim dynamically allocated pages
* Place TLS sections right after .text, not after embedded zip file

Co-authored-by: tkchia <tkchia-cosmo@gmx.com>
This commit is contained in:
tkchia 2022-12-18 09:51:20 +08:00 • committed by GitHub
parent 120079b0a6
commit 0da47c51de
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16 changed files with 725 additions and 191 deletions
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5
libc/intrin/interrupts.S
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@ -109,8 +109,7 @@ __excep0_isr:
isr_init:
testb IsMetal()
jz 9f
ezlea _tss+0x24,di # fill up TSS, we already loaded
# task register in ape/ape.S
ezlea _tss+0x24,di # fill up TSS
ezlea _isr_stk_1+ISR_STK_SZ,ax
and $-ISR_STK_ALIGN,%al # be paranoid & enforce correct
stosq # alignment of stack pointers
@ -142,6 +141,8 @@ isr_init:
stosq
add $__excep1_isr-__excep0_isr,%rdx
loop 1b
mov $GDT_LONG_TSS,%cl # load task register (cx = 0 here)
ltr %cx
9: ret
// String constants.