[Mini-OS] Fix x86 arch_switch_thread

Fix x86 arch_switch_thread by making it pure assembly.
There were missing general register clobbers for x86_64, and BP should
theorically be clobbered too, but gcc does not believe that, so the
only simple safe solution is to use pure assembly.

Signed-off-by: Samuel Thibault <samuel.thibault@citrix.com>

diff --git a/extras/mini-os/arch/x86/x86_32.S b/extras/mini-os/arch/x86/x86_32.S
index 2d359ab44a46316c083a12563bebdc09966aa21c..09ffeda9bab25c721491639275744e1304a2f4c4 100644 (file)
--- a/extras/mini-os/arch/x86/x86_32.S
+++ b/extras/mini-os/arch/x86/x86_32.S
@@ -288,3 +288,21 @@ ENTRY(thread_starter)
     call *%ebx
     call exit_thread 
     
+ENTRY(__arch_switch_threads)
+    movl 4(%esp), %ecx         /* prev */
+    movl 8(%esp), %edx         /* next */
+    pushl %ebp
+    pushl %ebx
+    pushl %esi
+    pushl %edi
+    movl %esp, (%ecx)          /* save ESP */
+    movl (%edx), %esp          /* restore ESP */
+    movl $1f, 4(%ecx)          /* save EIP */
+    pushl 4(%edx)              /* restore EIP */
+    ret
+1:
+    popl %edi
+    popl %esi
+    popl %ebx
+    popl %ebp
+    ret

diff --git a/extras/mini-os/arch/x86/x86_64.S b/extras/mini-os/arch/x86/x86_64.S
index 0f855777169adcb5b29b8214d42c872c1a9bd0ec..55b17da5f717aaaab41ac22b8c1645963be41d03 100644 (file)
--- a/extras/mini-os/arch/x86/x86_64.S
+++ b/extras/mini-os/arch/x86/x86_64.S
@@ -386,3 +386,23 @@ ENTRY(thread_starter)
         call exit_thread 
         
 
+ENTRY(__arch_switch_threads)
+       pushq %rbp
+       pushq %rbx
+       pushq %r12
+       pushq %r13
+       pushq %r14
+       pushq %r15
+       movq %rsp, (%rdi)               /* save ESP */
+       movq (%rsi), %rsp               /* restore ESP */
+       movq $1f, 8(%rdi)               /* save EIP */
+       pushq 8(%rsi)                   /* restore EIP */
+       ret
+1:
+       popq %r15
+       popq %r14
+       popq %r13
+       popq %r12
+       popq %rbx
+       popq %rbp
+       ret

diff --git a/extras/mini-os/include/sched.h b/extras/mini-os/include/sched.h
index 1425d0943c25d0f8277c5abe7d2459639d4567c0..9f209f195da051a4fc5150aba4d6aa31a01dec7b 100644 (file)
--- a/extras/mini-os/include/sched.h
+++ b/extras/mini-os/include/sched.h
@@ -10,6 +10,7 @@ struct thread
     char *name;
     char *stack;
 #if !defined(__ia64__)
+    /* keep in that order */
     unsigned long sp;  /* Stack pointer */
     unsigned long ip;  /* Instruction pointer */
 #else /* !defined(__ia64__) */

diff --git a/extras/mini-os/include/x86/arch_sched.h b/extras/mini-os/include/x86/arch_sched.h
index 7bf0036fac54ee5fab55597830dc25222730fd70..35a4344efdf54cb2e6ededc078b08bb8a389cc87 100644 (file)
--- a/extras/mini-os/include/x86/arch_sched.h
+++ b/extras/mini-os/include/x86/arch_sched.h
@@ -15,44 +15,9 @@ static inline struct thread* get_current(void)
     return *current;
 }
 
-#ifdef __i386__
-#define arch_switch_threads(prev, next) do {                            \
-    unsigned long esi,edi;                                              \
-    __asm__ __volatile__("pushfl\n\t"                                   \
-                         "pushl %%ebp\n\t"                              \
-                         "movl %%esp,%0\n\t"         /* save ESP */     \
-                         "movl %4,%%esp\n\t"        /* restore ESP */   \
-                         "movl $1f,%1\n\t"          /* save EIP */      \
-                         "pushl %5\n\t"             /* restore EIP */   \
-                         "ret\n\t"                                      \
-                         "1:\t"                                         \
-                         "popl %%ebp\n\t"                               \
-                         "popfl"                                        \
-                         :"=m" (prev->sp),"=m" (prev->ip),            \
-                          "=S" (esi),"=D" (edi)             \
-                         :"m" (next->sp),"m" (next->ip),              \
-                          "2" (prev), "d" (next));                      \
-} while (0)
-#elif __x86_64__
-#define arch_switch_threads(prev, next) do {                                 \
-    unsigned long rsi,rdi;                                              \
-    __asm__ __volatile__("pushfq\n\t"                                   \
-                         "pushq %%rbp\n\t"                              \
-                         "movq %%rsp,%0\n\t"         /* save RSP */     \
-                         "movq %4,%%rsp\n\t"        /* restore RSP */   \
-                         "movq $1f,%1\n\t"          /* save RIP */      \
-                         "pushq %5\n\t"             /* restore RIP */   \
-                         "ret\n\t"                                      \
-                         "1:\t"                                         \
-                         "popq %%rbp\n\t"                               \
-                         "popfq"                                        \
-                         :"=m" (prev->sp),"=m" (prev->ip),            \
-                          "=S" (rsi),"=D" (rdi)             \
-                         :"m" (next->sp),"m" (next->ip),              \
-                          "2" (prev), "d" (next));                      \
-} while (0)
-#endif
+extern void __arch_switch_threads(unsigned long *prevctx, unsigned long *nextctx);
 
+#define arch_switch_threads(prev,next) __arch_switch_threads(&(prev)->sp, &(next)->sp)