[Xen-changelog] Fixup SYSCALL path correctly in xenlinux when calling into C code.

[BitKeeper Bot <riel@xxxxxxxxxxx>]

ChangeSet 1.1714, 2005/06/10 10:10:18+01:00, kaf24@xxxxxxxxxxxxxxxxxxxx

        Fixup SYSCALL path correctly in xenlinux when calling into C code.
        Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>



 entry.S |   19 +++++++++++++++++--
 1 files changed, 17 insertions(+), 2 deletions(-)


diff -Nru a/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/entry.S 
b/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/entry.S
--- a/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/entry.S    2005-06-10 
06:02:16 -04:00
+++ b/linux-2.6.11-xen-sparse/arch/xen/x86_64/kernel/entry.S    2005-06-10 
06:02:16 -04:00
@@ -109,7 +109,6 @@
 #define preempt_stop
 #define retint_kernel retint_restore_args
 #endif 
-       
 
 /*
  * C code is not supposed to know about undefined top of stack. Every time 
@@ -118,7 +117,15 @@
  * RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs
  * manipulation.
  */            
-               
+
+       /* %rsp:at FRAMEEND */ 
+       .macro FIXUP_TOP_OF_STACK tmp
+       movq    $__USER_CS,CS(%rsp)
+       movq    $-1,RCX(%rsp)
+       .endm
+
+       .macro RESTORE_TOP_OF_STACK tmp,offset=0
+       .endm
 
        .macro FAKE_STACK_FRAME child_rip
        /* push in order ss, rsp, eflags, cs, rip */
@@ -209,6 +216,7 @@
        je   int_ret_from_sys_call
        testl $_TIF_IA32,threadinfo_flags(%rcx)
        jnz  int_ret_from_sys_call
+       RESTORE_TOP_OF_STACK %rdi,ARGOFFSET
        jmp ret_from_sys_call
 rff_trace:
        movq %rsp,%rdi
@@ -311,6 +319,7 @@
 tracesys:                       
        SAVE_REST
        movq $-ENOSYS,RAX(%rsp)
+       FIXUP_TOP_OF_STACK %rdi
        movq %rsp,%rdi
        call syscall_trace_enter
        LOAD_ARGS ARGOFFSET  /* reload args from stack in case ptrace changed 
it */
@@ -323,6 +332,7 @@
 1:     SAVE_REST
        movq %rsp,%rdi
        call syscall_trace_leave
+       RESTORE_TOP_OF_STACK %rbx
        RESTORE_REST
        jmp ret_from_sys_call
                
@@ -421,7 +431,9 @@
        CFI_ADJUST_CFA_OFFSET   -8
        SAVE_REST
        movq %r11, %r15
+       FIXUP_TOP_OF_STACK %r11
        call *%rax
+       RESTORE_TOP_OF_STACK %r11
        movq %r15, %r11
        RESTORE_REST
        pushq %r11
@@ -435,10 +447,12 @@
        CFI_ADJUST_CFA_OFFSET   -8
        SAVE_REST
        movq %r11, %r15
+       FIXUP_TOP_OF_STACK %r11
        call sys_execve
        GET_THREAD_INFO(%rcx)
        bt $TIF_IA32,threadinfo_flags(%rcx)
        jc exec_32bit
+       RESTORE_TOP_OF_STACK %r11
        movq %r15, %r11
        RESTORE_REST
        push %r11
@@ -460,6 +474,7 @@
        addq $8, %rsp           
        SAVE_REST
        movq %rsp,%rdi
+       FIXUP_TOP_OF_STACK %r11
        call sys_rt_sigreturn
        movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer
        RESTORE_REST

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