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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2008-03-17 16:37:22 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-24 23:57:32 +0200 |
| commit | 0f2c87695219b1129ccf93e0f58acdcdd49724b9 (patch) | |
| tree | 8c0d50e19a880f10d0fc5c92666b043d0257eb2d | |
| parent | dbe9e994c99ac9ac12d2b66ea42f44558f54fa52 (diff) | |
| download | lwn-0f2c87695219b1129ccf93e0f58acdcdd49724b9.tar.gz lwn-0f2c87695219b1129ccf93e0f58acdcdd49724b9.zip | |
xen: jump to iret fixup
Use jmp rather than call for the iret fixup, so its consistent with
the sysexit fixup, and it simplifies the stack (which is already
complex).
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | arch/x86/kernel/entry_32.S | 3 | ||||
| -rw-r--r-- | arch/x86/xen/xen-asm.S | 22 |
2 files changed, 10 insertions, 15 deletions
diff --git a/arch/x86/kernel/entry_32.S b/arch/x86/kernel/entry_32.S index 5d80d53eaff8..209c334bb920 100644 --- a/arch/x86/kernel/entry_32.S +++ b/arch/x86/kernel/entry_32.S @@ -1042,8 +1042,7 @@ ENTRY(xen_hypervisor_callback) cmpl $xen_iret_end_crit,%eax jae 1f - call xen_iret_crit_fixup - jmp 2f + jmp xen_iret_crit_fixup 1: cmpl $xen_sysexit_start_crit,%eax jb 2f diff --git a/arch/x86/xen/xen-asm.S b/arch/x86/xen/xen-asm.S index 1ac08082a4b4..53cae923e148 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) |