diff options
Diffstat (limited to 'kc/core/cpu/cpu_task.S')
| -rw-r--r-- | kc/core/cpu/cpu_task.S | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/kc/core/cpu/cpu_task.S b/kc/core/cpu/cpu_task.S index f2fb473..4f9fd7b 100644 --- a/kc/core/cpu/cpu_task.S +++ b/kc/core/cpu/cpu_task.S @@ -17,6 +17,10 @@ cpu_set_thread: * rsi: pointer to control block of the current thread * rdx: pointer to this cpu's task state segment esp0 field */ + // test for a NULL origin thread + test %rsi,%rsi + // skip saving the state for a NULL origin thread + jz .Lnull_thread push %rbx push %r12 push %r13 @@ -24,7 +28,8 @@ cpu_set_thread: push %r15 push %rbp /* the current task will be in rsi */ - mov %esp, 0(%rsi) // save the stack pointer for the current task + mov %rsp, 0(%rsi) // save the stack pointer for the current task +.Lnull_thread: mov 0(%rdi),%rsp // new stack is the next's task's stack mov 8(%rdi),%rbx // top of the next task's kernel stack mov %rbx,0(%rdx) // save the esp0 to the tss |