X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/3903760236c30e3b5ace7a4eefac3a269d68957c..527f99514973766e9c0382a4d8550dfb00f54939:/osfmk/i386/pcb_native.c

diff --git a/osfmk/i386/pcb_native.c b/osfmk/i386/pcb_native.c
index d77d20134..34df7c119 100644
--- a/osfmk/i386/pcb_native.c
+++ b/osfmk/i386/pcb_native.c
@@ -54,7 +54,6 @@
  * the rights to redistribute these changes.
  */
 
-#include <mach_rt.h>
 #include <mach_debug.h>
 #include <mach_ldebug.h>
 
@@ -138,6 +137,7 @@ act_machine_switch_pcb(__unused thread_t old, thread_t new)
 	set_ds(NULL_SEG);
 	set_es(NULL_SEG);
 	set_fs(NULL_SEG);
+
 	if (get_gs() != NULL_SEG) {
 		swapgs();		/* switch to user's GS context */
 		set_gs(NULL_SEG);
@@ -159,9 +159,7 @@ act_machine_switch_pcb(__unused thread_t old, thread_t new)
 	/* require 16-byte alignment */
 	assert((pcb_stack_top & 0xF) == 0);
 
-	/* Interrupt stack is pcb */
-	current_ktss64()->rsp0 = pcb_stack_top;
-
+	current_ktss64()->rsp0 = cdp->cpu_desc_index.cdi_sstku;
 	/*
 	 * Top of temporary sysenter stack points to pcb stack.
 	 * Although this is not normally used by 64-bit users,
@@ -169,6 +167,8 @@ act_machine_switch_pcb(__unused thread_t old, thread_t new)
 	 */
 	*current_sstk64() = pcb_stack_top;
 
+	cdp->cd_estack = cpu_shadowp(cdp->cpu_number)->cd_estack = cdp->cpu_desc_index.cdi_sstku;
+
 	if (is_saved_state64(pcb->iss)) {
 
 		cdp->cpu_task_map = new->map->pmap->pm_task_map; 
@@ -177,8 +177,8 @@ act_machine_switch_pcb(__unused thread_t old, thread_t new)
 		 * Enable the 64-bit user code segment, USER64_CS.
 		 * Disable the 32-bit user code segment, USER_CS.
 		 */
-		ldt_desc_p(USER64_CS)->access |= ACC_PL_U;
-		ldt_desc_p(USER_CS)->access &= ~ACC_PL_U;
+		gdt_desc_p(USER64_CS)->access |= ACC_PL_U;
+		gdt_desc_p(USER_CS)->access &= ~ACC_PL_U;
 
 		/*
 		 * Switch user's GS base if necessary
@@ -190,12 +190,12 @@ act_machine_switch_pcb(__unused thread_t old, thread_t new)
 		 * in the event it was altered in user space.
 		 */
 		if ((pcb->cthread_self != 0) || (new->task != kernel_task)) {
-			if ((cdp->cpu_uber.cu_user_gs_base != pcb->cthread_self) || (pcb->cthread_self != rdmsr64(MSR_IA32_KERNEL_GS_BASE))) {
+			if ((cdp->cpu_uber.cu_user_gs_base != pcb->cthread_self) ||
+			    (pcb->cthread_self != rdmsr64(MSR_IA32_KERNEL_GS_BASE))) {
 				cdp->cpu_uber.cu_user_gs_base = pcb->cthread_self;
 				wrmsr64(MSR_IA32_KERNEL_GS_BASE, pcb->cthread_self);
 			}
 		}
-
 	} else {
 
 		cdp->cpu_task_map = TASK_MAP_32BIT;
@@ -204,8 +204,14 @@ act_machine_switch_pcb(__unused thread_t old, thread_t new)
 		 * Disable USER64_CS
 		 * Enable USER_CS
 		 */
-		ldt_desc_p(USER64_CS)->access &= ~ACC_PL_U;
-		ldt_desc_p(USER_CS)->access |= ACC_PL_U;
+
+		/* It's possible that writing to the GDT areas
+		 * is expensive, if the processor intercepts those
+		 * writes to invalidate its internal segment caches
+		 * TODO: perhaps only do this if switching bitness
+		 */
+		gdt_desc_p(USER64_CS)->access &= ~ACC_PL_U;
+		gdt_desc_p(USER_CS)->access |= ACC_PL_U;
 
 		/*
 		 * Set the thread`s cthread (a.k.a pthread)
@@ -359,7 +365,7 @@ machine_thread_create(
 	}
 
 	/*
-	 * Assure that the synthesized 32-bit state including
+	 * Ensure that the synthesized 32-bit state including
 	 * the 64-bit interrupt state can be acommodated in the 
 	 * 64-bit state we allocate for both 32-bit and 64-bit threads.
 	 */
@@ -397,9 +403,7 @@ machine_thread_create(
 	 * segment.
 	 */
 	if ((pcb->cthread_desc.access & ACC_P) == 0) {
-		struct real_descriptor  *ldtp;
-		ldtp = (struct real_descriptor *)current_ldt();
-		pcb->cthread_desc = ldtp[sel_idx(USER_DS)];
+		pcb->cthread_desc = *gdt_desc_p(USER_DS);
 	}
 
 	return(KERN_SUCCESS);
@@ -422,7 +426,7 @@ machine_thread_destroy(
 #endif
 
 	if (pcb->ifps != 0)
-		fpu_free(pcb->ifps);
+		fpu_free(thread, pcb->ifps);
 	if (pcb->iss != 0) {
 		zfree(iss_zone, pcb->iss);
 		pcb->iss = 0;