FW: UefiCpuPkg/CpuDxe: Fix boot error

FW: UefiCpuPkg/CpuDxe: Fix boot error

[Guo Dong]

[-- Attachment #1: Type: text/plain, Size: 4583 bytes --]


Hi Mike,

I just did a test with retfq, it looks the compiler will take 'retfq' as a label with a warnig:
"CpuAsm.iii:26: warning: label alone on a line without a colon might be in error"

CpuAsm.nasm is the source file.
Both CpuAsm.iii and CpuAsm.obj are from the build folder.
CpuAsm_dasm.txt is the dasm file using objdump.

I am using "NASM version 2.12.01rc2 compiled on Mar  7 2016".
BTW, if using "O64 retf" instead of "retfq", the generated obj matches with DB one.
Do you prefer using " O64 retf" comparing with "DB 0x48, 0xcb"?

Thanks,
Guo

> -----Original Message-----
> From: Kinney, Michael D <michael.d.kinney@intel.com>
> Sent: Tuesday, January 5, 2021 7:01 PM
> To: Dong, Guo <guo.dong@intel.com>; devel@edk2.groups.io; Kinney, Michael
> D <michael.d.kinney@intel.com>
> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> lersek@redhat.com; Kumar, Rahul1 <rahul1.kumar@intel.com>
> Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
> 
> Hi Guo,
> 
> Could be the port from MASM to NASM did not check to see if NASM supported
> the instruction.
> 
> You can verify the NASM disassembly to make sure it matches the DB bytes.
> 
> Mike
> 
> > -----Original Message-----
> > From: Dong, Guo <guo.dong@intel.com>
> > Sent: Tuesday, January 5, 2021 4:51 PM
> > To: Kinney, Michael D <michael.d.kinney@intel.com>; devel@edk2.groups.io
> > Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> lersek@redhat.com; Kumar, Rahul1
> > <rahul1.kumar@intel.com>
> > Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
> >
> >
> > Hi Mike,
> >
> > Thanks for the comments. I will remove DB and submit a new patch.
> > I used DB because retfq is used in EDK2 only in
> OvmfPkg\Library\LoadLinuxLib\X64\JumpToKernel.nasm and it used DB.
> > Not sure if there is any BKM why they use it.
> >
> > Thanks,
> > Guo
> >
> > > -----Original Message-----
> > > From: Kinney, Michael D <michael.d.kinney@intel.com>
> > > Sent: Monday, January 4, 2021 9:31 PM
> > > To: devel@edk2.groups.io; Dong, Guo <guo.dong@intel.com>; Kinney,
> Michael
> > > D <michael.d.kinney@intel.com>
> > > Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> > > lersek@redhat.com; Kumar, Rahul1 <rahul1.kumar@intel.com>
> > > Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
> > >
> > > Hi Guo,
> > >
> > > NASM has good support for instructions.  Can the DB be removed and
> replaced
> > > with the equivalent instruction?
> > >
> > > Thanks,
> > >
> > > Mike
> > >
> > > > -----Original Message-----
> > > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Guo
> Dong
> > > > Sent: Thursday, December 24, 2020 12:04 PM
> > > > To: devel@edk2.groups.io
> > > > Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> > > lersek@redhat.com; Kumar, Rahul1
> > > > <rahul1.kumar@intel.com>
> > > > Subject: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
> > > >
> > > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3084
> > > >
> > > > When DXE drivers are dispatched above 4GB memory in 64bit
> > > > mode, the address setCodeSelectorLongJump in stack will
> > > > be override by parameter. Jump to Qword is not supported
> > > > by some processors. So use retfq instead.
> > > >
> > > > Signed-off-by: Guo Dong <guo.dong@intel.com>
> > > > ---
> > > >  UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm | 8 +++-----
> > > >  1 file changed, 3 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
> > > b/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
> > > > index c3489bcc3e..e33ddb2784 100644
> > > > --- a/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
> > > > +++ b/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
> > > > @@ -20,13 +20,11 @@
> > > >  ;------------------------------------------------------------------------------
> > > >  global ASM_PFX(SetCodeSelector)
> > > >  ASM_PFX(SetCodeSelector):
> > > > -    sub     rsp, 0x10
> > > > +    push    rcx,
> > > >      lea     rax, [setCodeSelectorLongJump]
> > > > -    mov     [rsp], rax
> > > > -    mov     [rsp+4], cx
> > > > -    jmp     dword far [rsp]
> > > > +    push    rax
> > > > +    DB 0x48, 0xcb                      ; retfq
> > > >  setCodeSelectorLongJump:
> > > > -    add     rsp, 0x10
> > > >      ret
> > > >
> > > >  ;------------------------------------------------------------------------------
> > > > --
> > > > 2.16.2.windows.1
> > > >
> > > >
> > > >
> > > > 
> > > >


[-- Attachment #2: CpuAsm.iii --]
[-- Type: application/x-iphone, Size: 1139 bytes --]

[-- Attachment #3: CpuAsm.obj --]
[-- Type: application/octet-stream, Size: 1329 bytes --]

[-- Attachment #4: CpuAsm_dasm.txt --]
[-- Type: text/plain, Size: 734 bytes --]


/mnt/c/projects/sources/Gitlab/uefi/Edk2Open/Build/UefiPayloadPkgX64/DEBUG_VS2015x86/X64/UefiCpuPkg/CpuDxe/CpuDxe/OUTPUT/X64/CpuAsm.obj:     file format pe-x86-64


Disassembly of section .text:

0000000000000000 <SetCodeSelector>:
   0:	51                   	push   %rcx
   1:	48 8d 05 01 00 00 00 	lea    0x1(%rip),%rax        # 9 <retfq>
   8:	50                   	push   %rax

0000000000000009 <retfq>:
   9:	c3                   	retq   

000000000000000a <SetDataSelectors>:
   a:	66 8e d1             	mov    %cx,%ss
   d:	66 8e d9             	mov    %cx,%ds
  10:	66 8e c1             	mov    %cx,%es
  13:	66 8e e1             	mov    %cx,%fs
  16:	66 8e e9             	mov    %cx,%gs
  19:	c3                   	retq   

[-- Attachment #5: CpuAsm.nasm --]
[-- Type: application/octet-stream, Size: 1175 bytes --]

;------------------------------------------------------------------------------
;*
;*   Copyright (c) 2016, Intel Corporation. All rights reserved.<BR>
;*   SPDX-License-Identifier: BSD-2-Clause-Patent
;*
;*    CpuAsm.nasm
;*
;*   Abstract:
;*
;------------------------------------------------------------------------------

    DEFAULT REL
    SECTION .text

;------------------------------------------------------------------------------
; VOID
; SetCodeSelector (
;   UINT16 Selector
;   );
;------------------------------------------------------------------------------
global ASM_PFX(SetCodeSelector)
ASM_PFX(SetCodeSelector):
    push    rcx,
    lea     rax, [setCodeSelectorLongJump]
    push    rax
    retfq
setCodeSelectorLongJump:
    ret

;------------------------------------------------------------------------------
; VOID
; SetDataSelectors (
;   UINT16 Selector
;   );
;------------------------------------------------------------------------------
global ASM_PFX(SetDataSelectors)
ASM_PFX(SetDataSelectors):
o16 mov     ss, cx
o16 mov     ds, cx
o16 mov     es, cx
o16 mov     fs, cx
o16 mov     gs, cx
    ret

Re: UefiCpuPkg/CpuDxe: Fix boot error

[Michael D Kinney]

Guo,

Yes.  Using the following looks like the correct solution:

	o64 retf

Thanks,

Mike

> -----Original Message-----
> From: Dong, Guo <guo.dong@intel.com>
> Sent: Wednesday, January 6, 2021 2:07 PM
> To: devel@edk2.groups.io; Kinney, Michael D <michael.d.kinney@intel.com>
> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; lersek@redhat.com; Kumar, Rahul1
> <rahul1.kumar@intel.com>
> Subject: FW: UefiCpuPkg/CpuDxe: Fix boot error
> 
> 
> Hi Mike,
> 
> I just did a test with retfq, it looks the compiler will take 'retfq' as a label with a warnig:
> "CpuAsm.iii:26: warning: label alone on a line without a colon might be in error"
> 
> CpuAsm.nasm is the source file.
> Both CpuAsm.iii and CpuAsm.obj are from the build folder.
> CpuAsm_dasm.txt is the dasm file using objdump.
> 
> I am using "NASM version 2.12.01rc2 compiled on Mar  7 2016".
> BTW, if using "O64 retf" instead of "retfq", the generated obj matches with DB one.
> Do you prefer using " O64 retf" comparing with "DB 0x48, 0xcb"?
> 
> Thanks,
> Guo
> 
> > -----Original Message-----
> > From: Kinney, Michael D <michael.d.kinney@intel.com>
> > Sent: Tuesday, January 5, 2021 7:01 PM
> > To: Dong, Guo <guo.dong@intel.com>; devel@edk2.groups.io; Kinney, Michael
> > D <michael.d.kinney@intel.com>
> > Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> > lersek@redhat.com; Kumar, Rahul1 <rahul1.kumar@intel.com>
> > Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
> >
> > Hi Guo,
> >
> > Could be the port from MASM to NASM did not check to see if NASM supported
> > the instruction.
> >
> > You can verify the NASM disassembly to make sure it matches the DB bytes.
> >
> > Mike
> >
> > > -----Original Message-----
> > > From: Dong, Guo <guo.dong@intel.com>
> > > Sent: Tuesday, January 5, 2021 4:51 PM
> > > To: Kinney, Michael D <michael.d.kinney@intel.com>; devel@edk2.groups.io
> > > Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> > lersek@redhat.com; Kumar, Rahul1
> > > <rahul1.kumar@intel.com>
> > > Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
> > >
> > >
> > > Hi Mike,
> > >
> > > Thanks for the comments. I will remove DB and submit a new patch.
> > > I used DB because retfq is used in EDK2 only in
> > OvmfPkg\Library\LoadLinuxLib\X64\JumpToKernel.nasm and it used DB.
> > > Not sure if there is any BKM why they use it.
> > >
> > > Thanks,
> > > Guo
> > >
> > > > -----Original Message-----
> > > > From: Kinney, Michael D <michael.d.kinney@intel.com>
> > > > Sent: Monday, January 4, 2021 9:31 PM
> > > > To: devel@edk2.groups.io; Dong, Guo <guo.dong@intel.com>; Kinney,
> > Michael
> > > > D <michael.d.kinney@intel.com>
> > > > Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> > > > lersek@redhat.com; Kumar, Rahul1 <rahul1.kumar@intel.com>
> > > > Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
> > > >
> > > > Hi Guo,
> > > >
> > > > NASM has good support for instructions.  Can the DB be removed and
> > replaced
> > > > with the equivalent instruction?
> > > >
> > > > Thanks,
> > > >
> > > > Mike
> > > >
> > > > > -----Original Message-----
> > > > > From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Guo
> > Dong
> > > > > Sent: Thursday, December 24, 2020 12:04 PM
> > > > > To: devel@edk2.groups.io
> > > > > Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
> > > > lersek@redhat.com; Kumar, Rahul1
> > > > > <rahul1.kumar@intel.com>
> > > > > Subject: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
> > > > >
> > > > > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3084
> > > > >
> > > > > When DXE drivers are dispatched above 4GB memory in 64bit
> > > > > mode, the address setCodeSelectorLongJump in stack will
> > > > > be override by parameter. Jump to Qword is not supported
> > > > > by some processors. So use retfq instead.
> > > > >
> > > > > Signed-off-by: Guo Dong <guo.dong@intel.com>
> > > > > ---
> > > > >  UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm | 8 +++-----
> > > > >  1 file changed, 3 insertions(+), 5 deletions(-)
> > > > >
> > > > > diff --git a/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
> > > > b/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
> > > > > index c3489bcc3e..e33ddb2784 100644
> > > > > --- a/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
> > > > > +++ b/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
> > > > > @@ -20,13 +20,11 @@
> > > > >  ;------------------------------------------------------------------------------
> > > > >  global ASM_PFX(SetCodeSelector)
> > > > >  ASM_PFX(SetCodeSelector):
> > > > > -    sub     rsp, 0x10
> > > > > +    push    rcx,
> > > > >      lea     rax, [setCodeSelectorLongJump]
> > > > > -    mov     [rsp], rax
> > > > > -    mov     [rsp+4], cx
> > > > > -    jmp     dword far [rsp]
> > > > > +    push    rax
> > > > > +    DB 0x48, 0xcb                      ; retfq
> > > > >  setCodeSelectorLongJump:
> > > > > -    add     rsp, 0x10
> > > > >      ret
> > > > >
> > > > >  ;------------------------------------------------------------------------------
> > > > > --
> > > > > 2.16.2.windows.1
> > > > >
> > > > >
> > > > >
> > > > > 
> > > > >

Re: UefiCpuPkg/CpuDxe: Fix boot error

[Laszlo Ersek]

On 01/07/21 02:00, Kinney, Michael D wrote:
> Guo,
> 
> Yes.  Using the following looks like the correct solution:
> 
> 	o64 retf

I agree; these operand size prefixes are one of the strengths of NASM.

Thanks!
Laszlo

> 
> Thanks,
> 
> Mike
> 
>> -----Original Message-----
>> From: Dong, Guo <guo.dong@intel.com>
>> Sent: Wednesday, January 6, 2021 2:07 PM
>> To: devel@edk2.groups.io; Kinney, Michael D <michael.d.kinney@intel.com>
>> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>; lersek@redhat.com; Kumar, Rahul1
>> <rahul1.kumar@intel.com>
>> Subject: FW: UefiCpuPkg/CpuDxe: Fix boot error
>>
>>
>> Hi Mike,
>>
>> I just did a test with retfq, it looks the compiler will take 'retfq' as a label with a warnig:
>> "CpuAsm.iii:26: warning: label alone on a line without a colon might be in error"
>>
>> CpuAsm.nasm is the source file.
>> Both CpuAsm.iii and CpuAsm.obj are from the build folder.
>> CpuAsm_dasm.txt is the dasm file using objdump.
>>
>> I am using "NASM version 2.12.01rc2 compiled on Mar  7 2016".
>> BTW, if using "O64 retf" instead of "retfq", the generated obj matches with DB one.
>> Do you prefer using " O64 retf" comparing with "DB 0x48, 0xcb"?
>>
>> Thanks,
>> Guo
>>
>>> -----Original Message-----
>>> From: Kinney, Michael D <michael.d.kinney@intel.com>
>>> Sent: Tuesday, January 5, 2021 7:01 PM
>>> To: Dong, Guo <guo.dong@intel.com>; devel@edk2.groups.io; Kinney, Michael
>>> D <michael.d.kinney@intel.com>
>>> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
>>> lersek@redhat.com; Kumar, Rahul1 <rahul1.kumar@intel.com>
>>> Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
>>>
>>> Hi Guo,
>>>
>>> Could be the port from MASM to NASM did not check to see if NASM supported
>>> the instruction.
>>>
>>> You can verify the NASM disassembly to make sure it matches the DB bytes.
>>>
>>> Mike
>>>
>>>> -----Original Message-----
>>>> From: Dong, Guo <guo.dong@intel.com>
>>>> Sent: Tuesday, January 5, 2021 4:51 PM
>>>> To: Kinney, Michael D <michael.d.kinney@intel.com>; devel@edk2.groups.io
>>>> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
>>> lersek@redhat.com; Kumar, Rahul1
>>>> <rahul1.kumar@intel.com>
>>>> Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
>>>>
>>>>
>>>> Hi Mike,
>>>>
>>>> Thanks for the comments. I will remove DB and submit a new patch.
>>>> I used DB because retfq is used in EDK2 only in
>>> OvmfPkg\Library\LoadLinuxLib\X64\JumpToKernel.nasm and it used DB.
>>>> Not sure if there is any BKM why they use it.
>>>>
>>>> Thanks,
>>>> Guo
>>>>
>>>>> -----Original Message-----
>>>>> From: Kinney, Michael D <michael.d.kinney@intel.com>
>>>>> Sent: Monday, January 4, 2021 9:31 PM
>>>>> To: devel@edk2.groups.io; Dong, Guo <guo.dong@intel.com>; Kinney,
>>> Michael
>>>>> D <michael.d.kinney@intel.com>
>>>>> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
>>>>> lersek@redhat.com; Kumar, Rahul1 <rahul1.kumar@intel.com>
>>>>> Subject: RE: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
>>>>>
>>>>> Hi Guo,
>>>>>
>>>>> NASM has good support for instructions.  Can the DB be removed and
>>> replaced
>>>>> with the equivalent instruction?
>>>>>
>>>>> Thanks,
>>>>>
>>>>> Mike
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Guo
>>> Dong
>>>>>> Sent: Thursday, December 24, 2020 12:04 PM
>>>>>> To: devel@edk2.groups.io
>>>>>> Cc: Dong, Eric <eric.dong@intel.com>; Ni, Ray <ray.ni@intel.com>;
>>>>> lersek@redhat.com; Kumar, Rahul1
>>>>>> <rahul1.kumar@intel.com>
>>>>>> Subject: [edk2-devel] [PATCH] UefiCpuPkg/CpuDxe: Fix boot error
>>>>>>
>>>>>> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3084
>>>>>>
>>>>>> When DXE drivers are dispatched above 4GB memory in 64bit
>>>>>> mode, the address setCodeSelectorLongJump in stack will
>>>>>> be override by parameter. Jump to Qword is not supported
>>>>>> by some processors. So use retfq instead.
>>>>>>
>>>>>> Signed-off-by: Guo Dong <guo.dong@intel.com>
>>>>>> ---
>>>>>>  UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm | 8 +++-----
>>>>>>  1 file changed, 3 insertions(+), 5 deletions(-)
>>>>>>
>>>>>> diff --git a/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
>>>>> b/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
>>>>>> index c3489bcc3e..e33ddb2784 100644
>>>>>> --- a/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
>>>>>> +++ b/UefiCpuPkg/CpuDxe/X64/CpuAsm.nasm
>>>>>> @@ -20,13 +20,11 @@
>>>>>>  ;------------------------------------------------------------------------------
>>>>>>  global ASM_PFX(SetCodeSelector)
>>>>>>  ASM_PFX(SetCodeSelector):
>>>>>> -    sub     rsp, 0x10
>>>>>> +    push    rcx,
>>>>>>      lea     rax, [setCodeSelectorLongJump]
>>>>>> -    mov     [rsp], rax
>>>>>> -    mov     [rsp+4], cx
>>>>>> -    jmp     dword far [rsp]
>>>>>> +    push    rax
>>>>>> +    DB 0x48, 0xcb                      ; retfq
>>>>>>  setCodeSelectorLongJump:
>>>>>> -    add     rsp, 0x10
>>>>>>      ret
>>>>>>
>>>>>>  ;------------------------------------------------------------------------------
>>>>>> --
>>>>>> 2.16.2.windows.1
>>>>>>
>>>>>>
>>>>>>
>>>>>> 
>>>>>>
>