Re: [PATCH edk2-platforms v2 06/18] ARM/VExpressPkg: Add and update debug ASSERTS

[Evan Lloyd <Evan.Lloyd@arm.com>]

> -----Original Message-----
> From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
> Sent: 04 January 2018 19:24
> To: Girish Pathak <Girish.Pathak@arm.com>
> Cc: Evan Lloyd <Evan.Lloyd@arm.com>; Matteo Carlini
> <Matteo.Carlini@arm.com>; nd <nd@arm.com>; edk2-devel@lists.01.org;
> Thomas Abraham <thomas.abraham@arm.com>; Arvind Chauhan
> <Arvind.Chauhan@arm.com>; leif.lindholm@linaro.org
> Subject: Re: [edk2] [PATCH edk2-platforms v2 06/18] ARM/VExpressPkg:
> Add and update debug ASSERTS
> 
> On 4 January 2018 at 18:55, Girish Pathak <Girish.Pathak@arm.com>
> wrote:
> > Hi Ard,
> >
> >> -----Original Message-----
> >> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf
> >> Of Ard Biesheuvel
> >> Sent: 23 December 2017 14:12
> >> To: Evan Lloyd <Evan.Lloyd@arm.com>
> >> Cc: "Matteo.Carlini@arm.com"@arm.com;
> >> "leif.lindholm@linaro.org"@arm.com; "nd@arm.com"@arm.com; edk2-
> >> devel@lists.01.org; Thomas Abraham <thomas.abraham@arm.com>;
> Arvind
> >> Chauhan <Arvind.Chauhan@arm.com>;
> "ard.biesheuvel@linaro.org"@arm.com
> >> Subject: Re: [edk2] [PATCH edk2-platforms v2 06/18] ARM/VExpressPkg:
> >> Add and update debug ASSERTS
> >>
> >> On 22 December 2017 at 19:08,  <evan.lloyd@arm.com> wrote:
> >> > From: Girish Pathak <girish.pathak at arm.com>
> >> >
> >> > This change adds some debug assertions e.g to catch NULL pointer
> >> > errors missing in PL11Lcd and HdLcd platform libraries.
> >> >
> >> > Contributed-under: TianoCore Contribution Agreement 1.1
> >> > Signed-off-by: Girish Pathak <girish.pathak@arm.com>
> >> > Signed-off-by: Evan Lloyd <evan.lloyd@arm.com>
> >> > ---
> >> >
> >>
> Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVExp
> r
> >> ess.c       | 22 +++++++++++++++++-
> >> >
> >> >
> >>
> Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111LcdAr
> m
> >> VEx
> >> > press.c | 24 +++++++++++++++++++-
> >> >  2 files changed, 44 insertions(+), 2 deletions(-)
> >> >
> >> > diff --git
> >> >
> >>
> a/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVE
> x
> >> pres
> >> > s.c
> >> >
> >>
> b/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVE
> x
> >> pres
> >> > s.c index
> >> >
> >>
> 6afd764897f49c64490ce891682f99bb0f5d993b..a8fe8696da0653017ce9fa
> 6e4a
> >> 86
> >> > caf283bc04c9 100644
> >> > ---
> >> >
> >>
> a/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVE
> x
> >> pres
> >> > s.c
> >> > +++
> >>
> b/Platform/ARM/VExpressPkg/Library/HdLcdArmVExpressLib/HdLcdArmVE
> x
> >> > +++ press.c
> >> > @@ -153,6 +153,9 @@ LcdPlatformGetVram (
> >> >    EFI_STATUS              Status;
> >> >    EFI_ALLOCATE_TYPE       AllocationType;
> >> >
> >> > +  ASSERT (VramBaseAddress != NULL);  ASSERT (VramSize != NULL);
> >> > +
> >> >    // Set the vram size
> >> >    *VramSize = LCD_VRAM_SIZE;
> >> >
> >> > @@ -171,6 +174,7 @@ LcdPlatformGetVram (
> >> >                    VramBaseAddress
> >> >                    );
> >> >    if (EFI_ERROR (Status)) {
> >> > +    ASSERT (FALSE);
> >> >      return Status;
> >> >    }
> >> >
> >> > @@ -181,8 +185,8 @@ LcdPlatformGetVram (
> >> >                    *VramSize,
> >> >                    EFI_MEMORY_WC
> >> >                    );
> >> > -  ASSERT_EFI_ERROR (Status);
> >> >    if (EFI_ERROR (Status)) {
> >> > +    ASSERT (FALSE);
> >>
> >> As in the sibling patch against EDK2, this patch makes it more
> >> difficult to figure out what went wrong when you hit the ASSERT.
> >> ASSERT_EFI_ERROR prints the value of Status, ASSERT(FALSE) only
> >> prints
> >> '0 != 1'
> >>
> >
> > This change(and other similar changes) is in response to review
> > comments on patch v1
> > https://lists.01.org/pipermail/edk2-devel/2017-October/015995.html
> >
> > with above reference, Can you please confirm if we should revert to the
> patch v1 version ?
> >
> 
> I guess Leif and I are in disagreement here. In particular, I think his comment
> 
> """
> ASSERT (FALSE)?  (You already know Status is an EFI_ERROR, and a console
> message saying ASSERT (Status) is not getting you out of looking at the
> source code to find out what happened.) """
> 
> is misguided, given that ASSERT_EFI_ERROR (Status) will actually print the
> value of Status to the debug console.
> 
> However, the objections against putting function calls in ASSERT()s are
> justified: ASSERT() should not have side effects if its condition is met, and
> function calls may have side effects.
> 
> I suppose we should wait for Leif to return on the 22nd before proceeding
> with the review.
> Apologies for the confusion, and for the delay.

 [[Evan Lloyd]] An alternative might be for Girish to take the other route Leif suggested, and cache the condition in a variable.
That might be a slight overhead, and the (presumably BOOLEAN) variable may need careful naming, but...

> 
> 
> 
> >> >      gBS->FreePages (*VramBaseAddress, EFI_SIZE_TO_PAGES
> (*VramSize));
> >> >      return Status;
> >> >    }
> >> > @@ -221,6 +225,7 @@ LcdPlatformSetMode (
> >> >    EFI_STATUS            Status;
> >> >
> >> >    if (ModeNumber >= LcdPlatformGetMaxMode ()) {
> >> > +    ASSERT (FALSE);
> >>
> >> These are fine: the code itself explains adequately which condition
> >> triggered the ASSERT to fire.
> >>
> >> >      return EFI_INVALID_PARAMETER;
> >> >    }
> >> >
> >> > @@ -279,7 +284,10 @@ LcdPlatformQueryMode (
> >> >    OUT EFI_GRAPHICS_OUTPUT_MODE_INFORMATION * CONST  Info
> >> >    )
> >> >  {
> >> > +  ASSERT (Info != NULL);
> >> > +
> >> >    if (ModeNumber >= LcdPlatformGetMaxMode ()) {
> >> > +    ASSERT (FALSE);
> >> >      return EFI_INVALID_PARAMETER;
> >> >    }
> >> >
> >> > @@ -343,7 +351,18 @@ LcdPlatformGetTimings (
> >> >    OUT UINT32 * CONST                            VFrontPorch
> >> >    )
> >> >  {
> >> > +  // One of the pointers is NULL
> >> > +  ASSERT (HRes != NULL);
> >> > +  ASSERT (HSync != NULL);
> >> > +  ASSERT (HBackPorch != NULL);
> >> > +  ASSERT (HFrontPorch != NULL);
> >> > +  ASSERT (VRes != NULL);
> >> > +  ASSERT (VSync != NULL);
> >> > +  ASSERT (VBackPorch != NULL);
> >> > +  ASSERT (VFrontPorch != NULL);
> >> > +
> >> >    if (ModeNumber >= LcdPlatformGetMaxMode ()) {
> >> > +    ASSERT (FALSE);
> >> >      return EFI_INVALID_PARAMETER;
> >> >    }
> >> >
> >> > @@ -376,6 +395,7 @@ LcdPlatformGetBpp (
> >> >    )
> >> >  {
> >> >    if (ModeNumber >= LcdPlatformGetMaxMode ()) {
> >> > +    ASSERT (FALSE);
> >> >      return EFI_INVALID_PARAMETER;
> >> >    }
> >> >
> >> > diff --git
> >> >
> >>
> a/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111Lcd
> Ar
> >> mV
> >> > Express.c
> >> >
> >>
> b/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111Lcd
> Ar
> >> mV
> >> > Express.c index
> >> >
> >>
> 799fb3fc781ce04bb64cb1fa0b87f262a670ed78..fd4eea8f8e2397bc7d4ddf
> 4cfe
> >> 3d
> >> > cc97a5109edb 100644
> >> > ---
> >> >
> >>
> a/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111Lcd
> Ar
> >> mV
> >> > Express.c
> >> > +++
> >>
> b/Platform/ARM/VExpressPkg/Library/PL111LcdArmVExpressLib/PL111Lcd
> >> > +++ ArmVExpress.c
> >> > @@ -205,6 +205,9 @@ LcdPlatformGetVram (
> >> >
> >> >    Status = EFI_SUCCESS;
> >> >
> >> > +  ASSERT (VramBaseAddress != NULL);  ASSERT (VramSize != NULL);
> >> > +
> >> >    // Is it on the motherboard or on the daughterboard?
> >> >    switch (PL111_CLCD_SITE) {
> >> >
> >> > @@ -225,6 +228,7 @@ LcdPlatformGetVram (
> >> >                      VramBaseAddress
> >> >                      );
> >> >      if (EFI_ERROR (Status)) {
> >> > +      ASSERT (FALSE);
> >> >        return Status;
> >> >      }
> >> >
> >> > @@ -235,8 +239,8 @@ LcdPlatformGetVram (
> >> >                      *VramSize,
> >> >                      EFI_MEMORY_WC
> >> >                      );
> >> > -    ASSERT_EFI_ERROR (Status);
> >> >      if (EFI_ERROR (Status)) {
> >> > +      ASSERT (FALSE);
> >> >        gBS->FreePages (*VramBaseAddress, EFI_SIZE_TO_PAGES
> >> (*VramSize));
> >> >        return Status;
> >> >      }
> >> > @@ -294,6 +298,7 @@ LcdPlatformSetMode (
> >> >    UINT32                SysId;
> >> >
> >> >    if (ModeNumber >= LcdPlatformGetMaxMode ()) {
> >> > +    ASSERT (FALSE);
> >> >      return EFI_INVALID_PARAMETER;
> >> >    }
> >> >
> >> > @@ -369,7 +374,10 @@ LcdPlatformQueryMode (
> >> >    OUT EFI_GRAPHICS_OUTPUT_MODE_INFORMATION * CONST Info
> >> >    )
> >> >  {
> >> > +  ASSERT (Info != NULL);
> >> > +
> >> >    if (ModeNumber >= LcdPlatformGetMaxMode ()) {
> >> > +    ASSERT (FALSE);
> >> >      return EFI_INVALID_PARAMETER;
> >> >    }
> >> >
> >> > @@ -433,7 +441,18 @@ LcdPlatformGetTimings (
> >> >    OUT UINT32 * CONST                      VFrontPorch
> >> >    )
> >> >  {
> >> > +  // One of the pointers is NULL
> >> > +  ASSERT (HRes != NULL);
> >> > +  ASSERT (HSync != NULL);
> >> > +  ASSERT (HBackPorch != NULL);
> >> > +  ASSERT (HFrontPorch != NULL);
> >> > +  ASSERT (VRes != NULL);
> >> > +  ASSERT (VSync != NULL);
> >> > +  ASSERT (VBackPorch != NULL);
> >> > +  ASSERT (VFrontPorch != NULL);
> >> > +
> >> >    if (ModeNumber >= LcdPlatformGetMaxMode ()) {
> >> > +    ASSERT (FALSE);
> >> >      return EFI_INVALID_PARAMETER;
> >> >    }
> >> >
> >> > @@ -465,7 +484,10 @@ LcdPlatformGetBpp (
> >> >    OUT LCD_BPP * CONST                     Bpp
> >> >    )
> >> >  {
> >> > +  ASSERT (Bpp != NULL);
> >> > +
> >> >    if (ModeNumber >= LcdPlatformGetMaxMode ()) {
> >> > +    ASSERT (FALSE);
> >> >      return EFI_INVALID_PARAMETER;
> >> >    }
> >> >
> >> > --
> >> > Guid("CE165669-3EF3-493F-B85D-6190EE5B9759")
> >> >
> >> > _______________________________________________
> >> > edk2-devel mailing list
> >> > edk2-devel@lists.01.org
> >> > https://lists.01.org/mailman/listinfo/edk2-devel
> >> _______________________________________________
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