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- Don't update CR3 in KTSS, it's not used.

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- Don't read a useless stack pointer anymore.
- Update KTSS_ESP0 near the end of context switching, not at the beginning anymore.
- Same for IOPM and I/O Redirection Map Base Address.

svn path=/trunk/; revision=24182
This commit is contained in:
Alex Ionescu 2006-09-18 00:10:58 +00:00
parent eaf28f0509
commit 8de07ee7b4
1 changed files with 24 additions and 32 deletions
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56
reactos/ntoskrnl/ke/i386/ctxswitch.S
View file

@ -318,26 +318,6 @@ AfterTrace:
/* Update kernel stack */
mov [edi+KTHREAD_KERNEL_STACK], esp
/* Get stack pointers */
mov eax, [esi+KTHREAD_INITIAL_STACK]
mov ecx, [esi+KTHREAD_STACK_LIMIT]
/* Make space for the NPX Frame */
sub eax, NPX_FRAME_LENGTH
/* Check if this isn't V86 Mode, so we can bias the Esp0 */
test dword ptr [eax - KTRAP_FRAME_SIZE + KTRAP_FRAME_EFLAGS], X86_EFLAGS_VM
jnz NoAdjust
/* Bias esp */
sub eax, KTRAP_FRAME_V86_GS - KTRAP_FRAME_SS
NoAdjust:
/* Set new ESP0 */
mov ecx, [ebx+KPCR_TSS]
mov [ecx+KTSS_ESP0], eax
/* Switch to new stack */
mov esp, [esi+KTHREAD_KERNEL_STACK]
@ -357,21 +337,10 @@ NoAdjust:
jnz LdtReload
UpdateCr3:
/* Get the address space */
mov edi, ebp
mov eax, [edi+KPROCESS_DIRECTORY_TABLE_BASE]
/* Get the IOPM and TSS */
mov ebp, [ebx+KPCR_TSS]
mov ecx, [edi+KPROCESS_IOPM_OFFSET]
/* Switch address space */
mov [ebp+KTSS_CR3], eax
mov eax, [ebp+KPROCESS_DIRECTORY_TABLE_BASE]
mov cr3, eax
/* Set current IOPM offset in the TSS */
mov [ebp+KTSS_IOMAPBASE], cx
SameProcess:
/* Clear gs */
xor eax, eax
@ -385,6 +354,29 @@ SameProcess:
mov [ecx+0x3C], al
mov [ecx+0x3F], ah
/* Get stack pointer */
mov eax, [esi+KTHREAD_INITIAL_STACK]
/* Make space for the NPX Frame */
sub eax, NPX_FRAME_LENGTH
/* Check if this isn't V86 Mode, so we can bias the Esp0 */
test dword ptr [eax - KTRAP_FRAME_SIZE + KTRAP_FRAME_EFLAGS], X86_EFLAGS_VM
jnz NoAdjust
/* Bias esp */
sub eax, KTRAP_FRAME_V86_GS - KTRAP_FRAME_SS
NoAdjust:
/* Set new ESP0 */
mov ecx, [ebx+KPCR_TSS]
mov [ecx+KTSS_ESP0], eax
/* Set current IOPM offset in the TSS */
mov ax, [ebp+KPROCESS_IOPM_OFFSET]
mov [ecx+KTSS_IOMAPBASE], ax
/* Increase context switches */
inc dword ptr [esi+KTHREAD_CONTEXT_SWITCHES]