* Moved the syscall stuff from arch_commpage.cpp to x86_syscalls.{cpp,h}.

* On context switches we do now set the IA32_MSR_SYSENTER_ESP. This saves us
  setting esp at the beginning of x86_sysenter(). More importantly when
  entering it in single-step mode, this no longer causes a double fault
  (cf. #3487). We still don't handle the resulting debug exception correctly,
  so that we still get a (continuable) panic().


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@35609 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/kernel/arch/x86/Jamfile

@@ -36,6 +36,7 @@ KernelMergeObject kernel_arch_x86.o :
 	vm86.cpp
 	x86_physical_page_mapper.cpp
 	x86_physical_page_mapper_large_memory.cpp
+	x86_syscalls.cpp
 
 	x86_apic.cpp
 	x86_hpet.cpp

src/system/kernel/arch/x86/arch_commpage.cpp

@@ -7,99 +7,7 @@
 
 #include <commpage.h>
 
-#include <string.h>
+#include "x86_syscalls.h"
-
-#include <KernelExport.h>
-
-#include <cpu.h>
-#include <elf.h>
-#include <smp.h>
-
-
-// user syscall assembly stubs
-extern "C" void _user_syscall_int(void);
-extern unsigned int _user_syscall_int_end;
-extern "C" void _user_syscall_sysenter(void);
-extern unsigned int _user_syscall_sysenter_end;
-
-// sysenter handler
-extern "C" void x86_sysenter();
-
-
-static bool
-all_cpus_have_feature(enum x86_feature_type type, int feature)
-{
-	int i;
-	int cpuCount = smp_get_num_cpus();
-
-	for (i = 0; i < cpuCount; i++) {
-		if (!(gCPU[i].arch.feature[type] & feature))
-			return false;
-	}
-
-	return true;
-}
-
-
-static void
-init_intel_syscall_registers(void* dummy, int cpuNum)
-{
-	x86_write_msr(IA32_MSR_SYSENTER_CS, KERNEL_CODE_SEG);
-	x86_write_msr(IA32_MSR_SYSENTER_ESP, 0);
-	x86_write_msr(IA32_MSR_SYSENTER_EIP, (addr_t)x86_sysenter);
-}
-
-
-#if 0
-static void
-init_amd_syscall_registers(void* dummy, int cpuNum)
-{
-	// TODO: ...
-}
-#endif
-
-
-static status_t
-initialize_commpage_syscall(void)
-{
-	void* syscallCode = (void *)&_user_syscall_int;
-	void* syscallCodeEnd = &_user_syscall_int_end;
-
-	// check syscall
-	if (all_cpus_have_feature(FEATURE_COMMON, IA32_FEATURE_SEP)
-		&& !(gCPU[0].arch.family == 6 && gCPU[0].arch.model < 3
-			&& gCPU[0].arch.stepping < 3)) {
-		// Intel sysenter/sysexit
-		dprintf("initialize_commpage_syscall(): sysenter/sysexit supported\n");
-
-		// the code to be used in userland
-		syscallCode = (void *)&_user_syscall_sysenter;
-		syscallCodeEnd = &_user_syscall_sysenter_end;
-
-		// tell all CPUs to init their sysenter/sysexit related registers
-		call_all_cpus_sync(&init_intel_syscall_registers, NULL);
-	} else if (all_cpus_have_feature(FEATURE_EXT_AMD,
-			IA32_FEATURE_AMD_EXT_SYSCALL)) {
-		// AMD syscall/sysret
-		dprintf("initialize_commpage_syscall(): syscall/sysret supported "
-			"-- not yet by Haiku, though");
-	} else {
-		// no special syscall support
-		dprintf("initialize_commpage_syscall(): no special syscall support\n");
-	}
-
-	// fill in the table entry
-	size_t len = (size_t)((addr_t)syscallCodeEnd - (addr_t)syscallCode);
-	fill_commpage_entry(COMMPAGE_ENTRY_X86_SYSCALL, syscallCode, len);
-
-	// add syscall to the commpage image
-	image_id image = get_commpage_image();
-	elf_add_memory_image_symbol(image, "commpage_syscall",
-		((addr_t*)USER_COMMPAGE_ADDR)[COMMPAGE_ENTRY_X86_SYSCALL], len,
-		B_SYMBOL_TYPE_TEXT);
-
-	return B_OK;
-}
 
 
 status_t
@@ -113,7 +21,7 @@ status_t
 arch_commpage_init_post_cpus(void)
 {
 	// select the optimum syscall mechanism and patch the commpage
-	initialize_commpage_syscall();
+	x86_initialize_commpage_syscall();
 
 	return B_OK;
 }

src/system/kernel/arch/x86/arch_interrupts.S

@@ -555,9 +555,8 @@ FUNCTION_END(handle_syscall)
 	ecx - user esp
 */
 FUNCTION(x86_sysenter):
-	// switch the stack
+	// get the thread
 	movl	%dr3, %edx
-	movl	THREAD_kernel_stack_top(%edx), %esp
 
 	// push the iframe
 	pushl	$USER_DATA_SEG			// user_ss

src/system/kernel/arch/x86/arch_thread.cpp

@@ -26,6 +26,7 @@
 #include <vm/VMAddressSpace.h>
 
 #include "x86_paging.h"
+#include "x86_syscalls.h"
 #include "X86VMTranslationMap.h"
 
 
@@ -357,6 +358,7 @@ void
 arch_thread_context_switch(struct thread *from, struct thread *to)
 {
 	i386_set_tss_and_kstack(to->kernel_stack_top);
+	x86_set_syscall_stack(to->kernel_stack_top);
 
 	// set TLS GDT entry to the current thread - since this action is
 	// dependent on the current CPU, we have to do it here
@@ -451,6 +453,7 @@ arch_thread_enter_userspace(struct thread *t, addr_t entry, void *args1,
 	// set the CPU dependent GDT entry for TLS
 	set_tls_context(t);
 
+	x86_set_syscall_stack(t->kernel_stack_top);
 	x86_enter_userspace(entry, stackTop);
 
 	return B_OK;

src/system/kernel/arch/x86/x86_syscalls.cpp

@@ -0,0 +1,118 @@
+/*
+ * Copyright 2008-2010, Ingo Weinhold, [email protected].
+ * Copyright 2007, Travis Geiselbrecht. All rights reserved.
+ * Distributed under the terms of the MIT License.
+ */
+
+
+#include "x86_syscalls.h"
+
+#include <string.h>
+
+#include <KernelExport.h>
+
+#include <commpage.h>
+#include <cpu.h>
+#include <elf.h>
+#include <smp.h>
+
+
+// user syscall assembly stubs
+extern "C" void _user_syscall_int(void);
+extern unsigned int _user_syscall_int_end;
+extern "C" void _user_syscall_sysenter(void);
+extern unsigned int _user_syscall_sysenter_end;
+
+// sysenter handler
+extern "C" void x86_sysenter();
+
+
+void (*gX86SetSyscallStack)(addr_t stackTop) = NULL;
+
+
+static bool
+all_cpus_have_feature(enum x86_feature_type type, int feature)
+{
+	int i;
+	int cpuCount = smp_get_num_cpus();
+
+	for (i = 0; i < cpuCount; i++) {
+		if (!(gCPU[i].arch.feature[type] & feature))
+			return false;
+	}
+
+	return true;
+}
+
+
+static void
+set_intel_syscall_stack(addr_t stackTop)
+{
+	x86_write_msr(IA32_MSR_SYSENTER_ESP, stackTop);
+}
+
+
+static void
+init_intel_syscall_registers(void* dummy, int cpuNum)
+{
+	x86_write_msr(IA32_MSR_SYSENTER_CS, KERNEL_CODE_SEG);
+	x86_write_msr(IA32_MSR_SYSENTER_ESP, 0);
+	x86_write_msr(IA32_MSR_SYSENTER_EIP, (addr_t)x86_sysenter);
+
+	gX86SetSyscallStack = &set_intel_syscall_stack;
+}
+
+
+#if 0
+static void
+init_amd_syscall_registers(void* dummy, int cpuNum)
+{
+	// TODO: ...
+}
+#endif
+
+
+// #pragma mark -
+
+
+status_t
+x86_initialize_commpage_syscall(void)
+{
+	void* syscallCode = (void *)&_user_syscall_int;
+	void* syscallCodeEnd = &_user_syscall_int_end;
+
+	// check syscall
+	if (all_cpus_have_feature(FEATURE_COMMON, IA32_FEATURE_SEP)
+		&& !(gCPU[0].arch.family == 6 && gCPU[0].arch.model < 3
+			&& gCPU[0].arch.stepping < 3)) {
+		// Intel sysenter/sysexit
+		dprintf("initialize_commpage_syscall(): sysenter/sysexit supported\n");
+
+		// the code to be used in userland
+		syscallCode = (void *)&_user_syscall_sysenter;
+		syscallCodeEnd = &_user_syscall_sysenter_end;
+
+		// tell all CPUs to init their sysenter/sysexit related registers
+		call_all_cpus_sync(&init_intel_syscall_registers, NULL);
+	} else if (all_cpus_have_feature(FEATURE_EXT_AMD,
+			IA32_FEATURE_AMD_EXT_SYSCALL)) {
+		// AMD syscall/sysret
+		dprintf("initialize_commpage_syscall(): syscall/sysret supported "
+			"-- not yet by Haiku, though");
+	} else {
+		// no special syscall support
+		dprintf("initialize_commpage_syscall(): no special syscall support\n");
+	}
+
+	// fill in the table entry
+	size_t len = (size_t)((addr_t)syscallCodeEnd - (addr_t)syscallCode);
+	fill_commpage_entry(COMMPAGE_ENTRY_X86_SYSCALL, syscallCode, len);
+
+	// add syscall to the commpage image
+	image_id image = get_commpage_image();
+	elf_add_memory_image_symbol(image, "commpage_syscall",
+		((addr_t*)USER_COMMPAGE_ADDR)[COMMPAGE_ENTRY_X86_SYSCALL], len,
+		B_SYMBOL_TYPE_TEXT);
+
+	return B_OK;
+}

src/system/kernel/arch/x86/x86_syscalls.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2010, Ingo Weinhold, [email protected].
+ * Distributed under the terms of the MIT License.
+ */
+#ifndef _KERNEL_ARCH_X86_SYSCALLS_H
+#define _KERNEL_ARCH_X86_SYSCALLS_H
+
+
+#include <SupportDefs.h>
+
+
+extern void (*gX86SetSyscallStack)(addr_t stackTop);
+
+
+status_t	x86_initialize_commpage_syscall();
+
+
+static inline void
+x86_set_syscall_stack(addr_t stackTop)
+{
+	if (gX86SetSyscallStack != NULL)
+		gX86SetSyscallStack(stackTop);
+}
+
+
+#endif	// _KERNEL_ARCH_X86_SYSCALLS_H