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x86: ia32: load GDT in virtual memory after loading page table

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This reverts commit d40e8ede8e.

This fixes triple faults after wiping the identity mapping of
physical memory when running entering userspace.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>
This commit is contained in:
Daniel Leung 2021-03-07 21:48:48 -08:00 • committed by Anas Nashif
commit 9109fbb1a2
2 changed files with 10 additions and 27 deletions
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14
arch/x86/core/ia32/crt0.S
View file

@ -213,9 +213,15 @@ __csSet:
call z_data_copy
#endif
/* Note that installing page tables must be done after
* z_data_copy() as the page tables are being copied into
* RAM there.
*/
install_page_tables
#ifdef CONFIG_GDT_DYNAMIC
/* activate RAM-based Global Descriptor Table (GDT) */
lgdt %ds:Z_MEM_PHYS_ADDR(_gdt)
lgdt %ds:_gdt
#endif
#if defined(CONFIG_X86_ENABLE_TSS)
@ -223,12 +229,6 @@ __csSet:
ltr %ax
#endif
/* Note that installing page tables must be done after
* z_data_copy() as the page tables are being copied into
* RAM there.
*/
install_page_tables
/* Clear BSS */
call z_bss_zero

23
arch/x86/gen_gdt.py
View file

@ -197,24 +197,7 @@ def main():
# x86_64 does not use descriptor for thread local storage
num_entries += 1
if "CONFIG_X86_MMU" in syms:
vm_base = syms["CONFIG_KERNEL_VM_BASE"]
vm_offset = syms["CONFIG_KERNEL_VM_OFFSET"]
sram_base = syms["CONFIG_SRAM_BASE_ADDRESS"]
if "CONFIG_SRAM_OFFSET" in syms:
sram_offset = syms["CONFIG_SRAM_OFFSET"]
else:
sram_offset = 0
# Figure out if there is any need to do virtual-to-physical
# address translation
virt_to_phys_offset = (sram_base + sram_offset) - (vm_base + vm_offset)
else:
virt_to_phys_offset = 0
gdt_base = syms["_gdt"] + virt_to_phys_offset
gdt_base = syms["_gdt"]
with open(args.output_gdt, "wb") as output_fp:
# The pseudo descriptor is stuffed into the NULL descriptor
@ -230,8 +213,8 @@ def main():
FLAGS_GRAN, ACCESS_RW))
if num_entries >= 5:
main_tss = syms["_main_tss"] + virt_to_phys_offset
df_tss = syms["_df_tss"] + virt_to_phys_offset
main_tss = syms["_main_tss"]
df_tss = syms["_df_tss"]
# Selector 0x18: main TSS
output_fp.write(create_tss_entry(main_tss, 0x67, 0))