fix: corner case for x87 context restore on execve

chore: clean up unused fields

diff --git a/lunaix-os/includes/lunaix/process.h b/lunaix-os/includes/lunaix/process.h
index 7d385a472d899283bb2773cc581513245df4df1e..1453e71634a72b5ee562f97131899693928ebb12 100644 (file)
--- a/lunaix-os/includes/lunaix/process.h
+++ b/lunaix-os/includes/lunaix/process.h
@@ -45,8 +45,6 @@
 #define proc_hanged(proc) (((proc)->state) & PS_BLOCKED)
 #define proc_runnable(proc) (((proc)->state) & PS_PAUSED)
 
 #define proc_hanged(proc) (((proc)->state) & PS_BLOCKED)
 #define proc_runnable(proc) (((proc)->state) & PS_PAUSED)
 

-#define PROC_FINPAUSE 1
-

 struct sigact
 {
     struct sigact* prev;
 struct sigact
 {
     struct sigact* prev;


@@ -76,17 +74,17 @@ struct proc_info
 {
     /*
         Any change to *critical section*, including layout, size
 {
     /*
         Any change to *critical section*, including layout, size

-        must be reflected in kernel/asm/x86/interrupt.S to avoid
+        must be reflected in arch/x86/interrupt.S.inc to avoid

         disaster!
      */
 
     /* ---- critical section start ---- */
 
         disaster!
      */
 
     /* ---- critical section start ---- */
 

-    pid_t pid;                // offset = 0
-    struct proc_info* parent; // offset = 4
-    isr_param* intr_ctx;      // offset = 8
-    ptr_t ustack_top;         // offset = 84 -> 56 -> 60 -> 12
-    ptr_t page_table;         // offset = 88 -> 60 -> 64 -> 16
+    pid_t pid;
+    struct proc_info* parent;
+    isr_param* intr_ctx;
+    ptr_t ustack_top;
+    ptr_t page_table;

 
     /* ---- critical section end ---- */
 
 
     /* ---- critical section end ---- */
 


@@ -108,7 +106,6 @@ struct proc_info
     u8_t state;
     int32_t exit_code;
     int32_t k_status;
     u8_t state;
     int32_t exit_code;
     int32_t k_status;

-    int flags;

     struct sighail sigctx;
     struct v_fdtable* fdtable;
     struct v_dnode* cwd;
     struct sighail sigctx;
     struct v_fdtable* fdtable;
     struct v_dnode* cwd;


@@ -195,4 +192,7 @@ get_process(pid_t pid);
 void
 proc_setsignal(struct proc_info* proc, int signum);
 
 void
 proc_setsignal(struct proc_info* proc, int signum);
 

+void
+proc_clear_signal(struct proc_info* proc);
+

 #endif /* __LUNAIX_PROCESS_H */
 #endif /* __LUNAIX_PROCESS_H */

diff --git a/lunaix-os/kernel/asm/x86/interrupt.S b/lunaix-os/kernel/asm/x86/interrupt.S
index 80dee1aff37a88af8ba536fc08a82471dbfd3dbe..f308503c7aac3722a39f721afcae32f1462259e4 100644 (file)
--- a/lunaix-os/kernel/asm/x86/interrupt.S
+++ b/lunaix-os/kernel/asm/x86/interrupt.S
@@ -35,34 +35,6 @@
 .section .text
     .global interrupt_wrapper
     interrupt_wrapper:
 .section .text
     .global interrupt_wrapper
     interrupt_wrapper:

-        /*
-         Stack layout (layout of struct isr_param)
-    msa:   [ss]             > 76 -> 28
-           [esp]            > 72 -> 24
-           eflags           > 68 -> 20
-           cs               > 64 -> 16
-           eip              > 60 -> 12
-           err_code         > 56 -> 8
-           vector           > offset = 52 -> 4
-           [saved_prev_ctx] > offset = 0
-           ---
-           esp       > 12 * 4 = 48
-           gs
-           fs
-           es
-           ds         > offset = 8 * 4 = 32
-           esi
-           ebp
-           edi
-           edx
-           ecx
-           ebx
-           eax
-    lsa:   depth       > offset = 0
-
-            las: Least Significant Address
-            msa: Most Significant Address
-        */

         cld
 
         subl $4, %esp
         cld
 
         subl $4, %esp


@@ -98,19 +70,19 @@
         movw %ax, %ds
         movw %ax, %es
 
         movw %ax, %ds
         movw %ax, %es
 

-        movl __current, %eax
-
-        # 保存用户栈顶指针。因为我们允许同级中断的产生，所以需要该手段跟踪用户栈的地址。
-        movl iuesp(%esp), %ebx     # 取出esp
-        movl %ebx, proc_ustack_top(%eax)     # 存入__current->ustack_top
+        movl __current, %ebx

 
         # Save x87 context to user stack, rather than kernel's memory.
 
         # Save x87 context to user stack, rather than kernel's memory.

-        # XXX: what will happen if we triggered a page fault during fxsave?
+        # XXX what will happen if we triggered a page fault during fxsave?
+        # FIXME can we remove this overhead?

         movl iuesp(%esp), %eax
         andl $stack_alignment, %eax 
         subl $512, %eax
         fxsave (%eax)
 
         movl iuesp(%esp), %eax
         andl $stack_alignment, %eax 
         subl $512, %eax
         fxsave (%eax)
 

+        # 保存用户栈顶指针。因为我们允许同级中断的产生，所以需要该手段跟踪用户栈的地址。
+        movl %eax, proc_ustack_top(%ebx)     # 存入__current->ustack_top
+

     /* kernel space same-level switch */
     1:
         movl %esp, %eax
     /* kernel space same-level switch */
     1:
         movl %esp, %eax


@@ -132,18 +104,15 @@
         movl exeip(%eax), %eax
         movl %eax, (debug_resv + 4) # eip
 #endif
         movl exeip(%eax), %eax
         movl %eax, (debug_resv + 4) # eip
 #endif

-        // movl __current, %eax
-        // movl proc_fxstate(%eax), %eax
-        
-        // test %eax, %eax     # do we have stored x87 context?

 
         movl ics(%esp), %eax
         andl $3, %eax
         jz 1f 
 
 
         movl ics(%esp), %eax
         andl $3, %eax
         jz 1f 
 

-        movl iuesp(%esp), %eax
-        andl $stack_alignment, %eax 
-        subl $512, %eax
+        movl __current, %eax
+        movl proc_ustack_top(%eax), %eax
+        test %eax, %eax
+        jz 1f

         fxrstor (%eax)
 
 1:
         fxrstor (%eax)
 
 1:


@@ -165,7 +134,6 @@
 
         movl %eax, tmp_store
         movl __current, %eax
 
         movl %eax, tmp_store
         movl __current, %eax

-        

 
         # nested intr: restore saved context
         popl proc_intr_ctx(%eax)
 
         # nested intr: restore saved context
         popl proc_intr_ctx(%eax)


@@ -221,6 +189,7 @@
         movl %ecx, (tss_esp0_off + _tss)
 
         jmp handle_signal
         movl %ecx, (tss_esp0_off + _tss)
 
         jmp handle_signal

+

     1:
         movl proc_intr_ctx(%ebx), %eax
         jmp soft_iret
     1:
         movl proc_intr_ctx(%ebx), %eax
         jmp soft_iret

diff --git a/lunaix-os/kernel/exe/exec.c b/lunaix-os/kernel/exe/exec.c
index a8461269ec3d15d24431c8fb4bbe8e99764c12ab..21814d16c042ffb50e96fbe8d7ebb89cee846a80 100644 (file)
--- a/lunaix-os/kernel/exe/exec.c
+++ b/lunaix-os/kernel/exe/exec.c
@@ -224,6 +224,10 @@ __DEFINE_LXSYSCALL3(int,
     execp->esp = container.stack_top;
     execp->eip = container.exe.entry;
 
     execp->esp = container.stack_top;
     execp->eip = container.exe.entry;
 

+    // these become meaningless once execved!
+    __current->ustack_top = 0;
+    proc_clear_signal(__current);
+

 done:
     // set return value
     store_retval(DO_STATUS(errno));
 done:
     // set return value
     store_retval(DO_STATUS(errno));

diff --git a/lunaix-os/kernel/process/signal.c b/lunaix-os/kernel/process/signal.c
index d00e75755cf16136481e6e1213ebe7865d70abd4..8c4322f442a9fd33680b4ebbb6ba327fb91170c5 100644 (file)
--- a/lunaix-os/kernel/process/signal.c
+++ b/lunaix-os/kernel/process/signal.c
@@ -77,6 +77,12 @@ signal_dispatch()
     return sigframe;
 }
 
     return sigframe;
 }
 

+void
+proc_clear_signal(struct proc_info* proc)
+{
+    memset(&proc->sigctx, 0, sizeof(proc->sigctx));
+}
+

 void
 proc_setsignal(struct proc_info* proc, int signum)
 {
 void
 proc_setsignal(struct proc_info* proc, int signum)
 {