diff options
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/xen-asm.S | 22 |
1 files changed, 9 insertions, 13 deletions
diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S index 1ac08082a4b..53cae923e14 100644 --- a/arch/x86/xen/xen-asm.S +++ b/arch/x86/xen/xen-asm.S @@ -223,9 +223,7 @@ hyper_iret: ds } SAVE_ALL state eax } : : - ebx } - ---------------- - return addr <- esp + ebx }<- esp ---------------- In order to deliver the nested exception properly, we need to shift @@ -240,10 +238,8 @@ hyper_iret: it's usermode state which we eventually need to restore. */ ENTRY(xen_iret_crit_fixup) - /* offsets +4 for return address */ - /* - Paranoia: Make sure we're really coming from userspace. + Paranoia: Make sure we're really coming from kernel space. One could imagine a case where userspace jumps into the critical range address, but just before the CPU delivers a GP, it decides to deliver an interrupt instead. Unlikely? @@ -252,32 +248,32 @@ ENTRY(xen_iret_crit_fixup) jump instruction itself, not the destination, but some virtual environments get this wrong. */ - movl PT_CS+4(%esp), %ecx + movl PT_CS(%esp), %ecx andl $SEGMENT_RPL_MASK, %ecx cmpl $USER_RPL, %ecx je 2f - lea PT_ORIG_EAX+4(%esp), %esi - lea PT_EFLAGS+4(%esp), %edi + lea PT_ORIG_EAX(%esp), %esi + lea PT_EFLAGS(%esp), %edi /* If eip is before iret_restore_end then stack hasn't been restored yet. */ cmp $iret_restore_end, %eax jae 1f - movl 0+4(%edi),%eax /* copy EAX */ - movl %eax, PT_EAX+4(%esp) + movl 0+4(%edi),%eax /* copy EAX (just above top of frame) */ + movl %eax, PT_EAX(%esp) lea ESP_OFFSET(%edi),%edi /* move dest up over saved regs */ /* set up the copy */ 1: std - mov $(PT_EIP+4) / 4, %ecx /* copy ret+saved regs up to orig_eax */ + mov $PT_EIP / 4, %ecx /* saved regs up to orig_eax */ rep movsl cld lea 4(%edi),%esp /* point esp to new frame */ -2: ret +2: jmp xen_do_upcall ENTRY(xen_sysexit) |