From 1df4e3c87dcfd0593c3313955594b7b7316e9af6 Mon Sep 17 00:00:00 2001
From: acevest <zhaoyanbai@126.com>
Date: Mon, 15 May 2023 23:41:33 +0800
Subject: [PATCH] =?utf8?q?=E6=94=AF=E6=8C=81=E4=B8=A4=E7=A7=8D=E6=8C=87?=
 =?utf8?q?=E5=AE=9Asysenter=E7=9A=84esp=E7=9A=84=E6=96=B9=E5=BC=8F?=
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Content-Type: text/plain; charset=utf8
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---
 Makefile         |  2 +-
 kernel/sched.c   | 11 +++++++++--
 kernel/setup.c   |  8 ++++++++
 kernel/syscall.S |  3 +++
 kernel/syscall.c |  5 +++--
 5 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/Makefile b/Makefile
index a12c79e..c4903f0 100644
--- a/Makefile
+++ b/Makefile
@@ -23,7 +23,7 @@ else ifeq ($(OS), Linux)
 endif
 
 
-CFLAGS		= -g -c -fno-builtin -m32 -DBUILDER='"$(shell whoami)"'
+CFLAGS		= -g -c -fno-builtin -m32 -DBUILDER='"$(shell whoami)"' -DFIX_SYSENTER_ESP_MODE=1
 SYSTEMMAP	= System.map
 KERNELBIN	= KERNEL.BIN
 LINKSCRIPT	= scripts/link.ld
diff --git a/kernel/sched.c b/kernel/sched.c
index 819fa3c..1309aa4 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -71,8 +71,11 @@ void init_root_task() {
     root_task.cr3 = va2pa((unsigned long)(init_pgd));
 
     tss.esp0 = root_task.esp0;
-
+#if FIX_SYSENTER_ESP_MODE
+    // do nothing
+#else
     wrmsr(MSR_SYSENTER_ESP, root_task.esp0, 0);
+#endif
 
     printk("init_root_task tss.esp0 %08x\n", tss.esp0);
 }
@@ -100,7 +103,11 @@ task_union *alloc_task_union() {
 void switch_to() {
     LoadCR3(current->cr3);
     tss.esp0 = current->esp0;
+#if FIX_SYSENTER_ESP_MODE
+    // do nothing
+#else
     wrmsr(MSR_SYSENTER_ESP, current->esp0, 0);
+#endif
 }
 
 void context_switch(task_union *prev, task_union *next) {
@@ -208,7 +215,7 @@ unsigned long schedule() {
         // printk("switch to: %s:%d\n", next->name, next->pid);
         list_for_each_safe(pos, t, &all_tasks) {
             p = list_entry(pos, task_union, list);
-            printl(MPL_TASK_0 + p->pid * 2, " ");  //清掉上一次显示的 '>'
+            printl(MPL_TASK_0 + p->pid * 2, " ");  // 清掉上一次显示的 '>'
             printl(MPL_TASK_0 + p->pid * 2, "%s%4s:%d [%08x] state %s weight %03d sched %u", next == p ? ">" : " ",
                    p->name, p->pid, p, task_state(p->state), p->weight, p->sched_cnt);
         }
diff --git a/kernel/setup.c b/kernel/setup.c
index 2c29d1b..aff660d 100644
--- a/kernel/setup.c
+++ b/kernel/setup.c
@@ -58,6 +58,14 @@ const char *version = "Kernel version " VERSION " @ " BUILDER
 void setup_kernel() {
     init_ttys();
 
+    printk("sysenter esp mode: %s\n",
+#if FIX_SYSENTER_ESP_MODE
+           "fixed to &tss.esp0"
+#else
+           "use task union stack"
+#endif
+    );
+
     init_mm();
 
     // printk("kernel: %08x - %08x\n", system.kernel_begin, system.kernel_end);
diff --git a/kernel/syscall.S b/kernel/syscall.S
index f813627..b11cdee 100644
--- a/kernel/syscall.S
+++ b/kernel/syscall.S
@@ -30,6 +30,9 @@
 //.global syscall_exit
 
 syscall_entry:
+#if FIX_SYSENTER_ESP_MODE
+    movl    (%esp),%esp 
+#endif
     // 这段代码纯是为了pt_regs_t准备的
     // 后续看看直接优化掉
     pushl   $(SELECTOR_USER_SS)
diff --git a/kernel/syscall.c b/kernel/syscall.c
index 2a25a9f..c837488 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -27,8 +27,9 @@ unsigned long sysc_handler_table[SYSC_NUM];
 void setup_sysc() {
     wrmsr(MSR_SYSENTER_CS, SELECTOR_KRNL_CS, 0);
     wrmsr(MSR_SYSENTER_EIP, syscall_entry, 0);
-    // wrmsr(MSR_SYSENTER_ESP, &(tss.esp0), 0);
-
+#if FIX_SYSENTER_ESP_MODE
+    wrmsr(MSR_SYSENTER_ESP, &(tss.esp0), 0);
+#endif
     init_sysc_handler_table();
 }
 
-- 
2.44.0