On 05/13/14 15:50, Ludovic Rousseau wrote:
> Hello,
>
> I hope this is the correct mailing list for my request. If not sorry.
>
> I use OVMF-X64-r15214 with qemu version 1.1.2 (Debian
> 1.1.2+dfsg-6a+deb7u2). It works great for my first tests.
>
> I now want to use the DEBUG() call to have some debug traces.
> My program is very simple. I use gnu-efi to build it.
>
> #include <efi.h>
> #include <efilib.h>
>
> EFI_STATUS
> EFIAPI
> efi_main (EFI_HANDLE ImageHandle, EFI_SYSTEM_TABLE *SystemTable)
> {
> InitializeLib(ImageHandle, SystemTable);
>
> Print(L"a\n");
> DEBUG(( D_INFO, (CHAR8 *)"D_INFO\r\n"));
> Print(L"b\n");
> DEBUG(( D_ERROR, (CHAR8 *)"D_ERROR\r\n"));
> Print(L"c\n");
>
> return EFI_SUCCESS;
> }
>
> I start qemu using:
> qemu-system-x86_64 -bios OVMF-X64-r15214/OVMF.fd \
> -boot c -m 128 -hda 'disk.img' \
> -serial file:serial.log
>
> In the qemu graphical window I see 2 lines:
> a
> b
>
> In the serial.log file I have:
> [...]
> Shell> fs0:
> FS0:\> usb1
> a
> b
> D_ERROR
>
> The first call to DEBUG() with D_INFO is not displayed. I guess it is
> because of the lines in /usr/include/efi/efidebug.h
> //
> // Current Debug level of the system, value of EFIDebug
> //
> //#define EFI_DBUG_MASK (D_ERROR | D_WARN | D_LOAD | D_BLKIO | D_INIT)
> #define EFI_DBUG_MASK (D_ERROR)
>
>
> The problem is that right after the "D_ERROR" is logged I get a crash
> of the virtual machine with:
> qemu: fatal: Trying to execute code outside RAM or ROM at 0x00000000000b0000
>
> RAX=0000000000000000 RBX=0000000080000000 RCX=0000000000000000
> RDX=0000000000000018
> RSI=0000000000000005 RDI=0000000007dd0c30 RBP=0000000007f94560
> RSP=0000000007f94518
> R8 =0000000000000000 R9 =0000000007f93f5c R10=00000000000003f8
> R11=0000000000000040
> R12=0000000000000005 R13=0000000000000000 R14=0000000000000000
> R15=0000000000000000
> RIP=00000000000affae RFL=00000202 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
> ES =0008 0000000000000000 ffffffff 00cf9300 DPL=0 DS [-WA]
> CS =0028 0000000000000000 ffffffff 00af9b00 DPL=0 CS64 [-RA]
> SS =0008 0000000000000000 ffffffff 00cf9300 DPL=0 DS [-WA]
> DS =0008 0000000000000000 ffffffff 00cf9300 DPL=0 DS [-WA]
> FS =0008 0000000000000000 ffffffff 00cf9300 DPL=0 DS [-WA]
> GS =0008 0000000000000000 ffffffff 00cf9300 DPL=0 DS [-WA]
> LDT=0000 0000000000000000 0000ffff 00008200 DPL=0 LDT
> TR =0000 0000000000000000 0000ffff 00008b00 DPL=0 TSS64-busy
> GDT= 0000000007f1ed98 0000003f
> IDT= 000000000747f018 00000fff
> CR0=80000033 CR2=0000000000000000 CR3=0000000007f33000 CR4=00000668
> DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
> DR3=0000000000000000
> DR6=00000000ffff0ff0 DR7=0000000000000400
> CCS=0000000000000000 CCD=0000000000000000 CCO=ADDB
> EFER=0000000000000500
> FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80
> FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
> FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
> FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
> FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
> XMM00=00000000000000000000000000000000 XMM01=00000000000000000000000000000000
> XMM02=00000000000000000000000000000000 XMM03=00000000000000000000000000000000
> XMM04=00000000000000000000000000000000 XMM05=00000000000000000000000000000000
> XMM06=00000000000000000000000000000000 XMM07=00000000000000000000000000000000
> XMM08=00000000000000000000000000000000 XMM09=00000000000000000000000000000000
> XMM10=00000000000000000000000000000000 XMM11=00000000000000000000000000000000
> XMM12=00000000000000000000000000000000 XMM13=00000000000000000000000000000000
> XMM14=00000000000000000000000000000000 XMM15=00000000000000000000000000000000
>
> I also tried to start qemu using "-debugcon file:debug.log -global
> isa-debugcon.iobase=0x402" as indicated in [1] but I get the same
> crash and not log or debug at all.
>
>
> Is it a bug in OVMF-X64-r15214 or in qemu version 1.1.2?
> Do I need to initialize something before I can call DEBUG()?
>
> Thanks
>
> [1] https://github.com/tianocore/edk2-OvmfPkg
>
This looks to me like a gnu-efi bug.
(See
- http://thread.gmane.org/gmane.comp.bios.tianocore.devel/3669
- http://thread.gmane.org/gmane.comp.bios.tianocore.devel/6639/focus=6665
for background.)
Namely, gnu-efi's va_start() implementation, from "inc/efistdarg.h":
#define va_start(ap,v) ( ap = (va_list)&v + _INTSIZEOF(v) )
only works if the function using va_start() has been called with the
EFIAPI calling convention. What you have here is:
DEBUG() [inc/efidebug.h]
DbgPrint() [lib/print.c]
va_start() [inc/efistdarg.h]
The prototype of DbgPrint() is incorrect, at the end of
"inc/efidebug.h". Consequently, when your program calls DbgPrint() via
the DEBUG() macro, it fails to set up the stack correctly (it does not
pass the arguments through the ellipsis (...) according to the EFIAPI
calling convention). However, va_start() inside DbgPrint() *assumes*
that stack.
Please rebuild your gnu-efi installation with the attached patch, and
retest your app.
Laszlo
diff -Nurp gnu-efi-3.0.orig/inc/efidebug.h gnu-efi-3.0/inc/efidebug.h
--- gnu-efi-3.0.orig/inc/efidebug.h 2014-04-01 16:18:19.000000000 +0200
+++ gnu-efi-3.0/inc/efidebug.h 2014-05-13 16:21:52.875935248 +0200
@@ -99,7 +99,7 @@ DbgAssert (
CHAR8 *string
);
-INTN
+INTN EFIAPI
DbgPrint (
INTN mask,
CHAR8 *format,
diff -Nurp gnu-efi-3.0.orig/lib/print.c gnu-efi-3.0/lib/print.c
--- gnu-efi-3.0.orig/lib/print.c 2014-04-01 16:18:19.000000000 +0200
+++ gnu-efi-3.0/lib/print.c 2014-05-13 16:21:42.075882632 +0200
@@ -179,7 +179,7 @@ _PoolPrint (
IN CHAR16 *Buffer
);
-INTN
+INTN EFIAPI
DbgPrint (
IN INTN mask,
IN CHAR8 *fmt,
------------------------------------------------------------------------------
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