*
* XXX if we had a free scratch register we could save the RSP into the stack frame
* and report it properly in ps. Unfortunately we haven't.
+ *
+ * When user can change the frames always force IRET. That is because
+ * it deals with uncanonical addresses better. SYSRET has trouble
+ * with them due to bugs in both AMD and Intel CPUs.
*/
ENTRY(system_call)
xorl %esi,%esi # oldset -> arg2
call ptregscall_common
1: movl $_TIF_NEED_RESCHED,%edi
- jmp sysret_check
+ /* Use IRET because user could have changed frame. This
+ works because ptregscall_common has called FIXUP_TOP_OF_STACK. */
+ cli
+ jmp int_with_check
badsys:
movq $-ENOSYS,RAX-ARGOFFSET(%rsp)
ja 1f
movq %r10,%rcx /* fixup for C */
call *sys_call_table(,%rax,8)
- movq %rax,RAX-ARGOFFSET(%rsp)
-1: SAVE_REST
- movq %rsp,%rdi
- call syscall_trace_leave
- RESTORE_TOP_OF_STACK %rbx
- RESTORE_REST
- jmp ret_from_sys_call
+1: movq %rax,RAX-ARGOFFSET(%rsp)
+ /* Use IRET because user could have changed frame */
+ jmp int_ret_from_sys_call
CFI_ENDPROC
/*
CFI_ADJUST_CFA_OFFSET -8
CFI_REGISTER rip, r11
SAVE_REST
- movq %r11, %r15
- CFI_REGISTER rip, r15
FIXUP_TOP_OF_STACK %r11
call sys_execve
- GET_THREAD_INFO(%rcx)
- bt $TIF_IA32,threadinfo_flags(%rcx)
- CFI_REMEMBER_STATE
- jc exec_32bit
RESTORE_TOP_OF_STACK %r11
- movq %r15, %r11
- CFI_REGISTER rip, r11
- RESTORE_REST
- pushq %r11
- CFI_ADJUST_CFA_OFFSET 8
- CFI_REL_OFFSET rip, 0
- ret
-
-exec_32bit:
- CFI_RESTORE_STATE
movq %rax,RAX(%rsp)
RESTORE_REST
jmp int_ret_from_sys_call
/* force a signal here? this matches i386 behaviour */
/* running with kernel gs */
bad_iret:
- movq $-9999,%rdi /* better code? */
+ movq $11,%rdi /* SIGSEGV */
+ sti
jmp do_exit
.previous