You have to fix this

You have to fix this

[David Miller]

You cannot put such monster sized local data objects on the stack:

drivers/net/ethernet/chelsio/cxgb4/t4_hw.c: In function ‘t4_memory_rw.constprop.6’:
drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:484:1: warning: the frame size of 2056 bytes is larger than 2048 bytes [-Wframe-larger-than=]

That's because of this thing:

		__be32 data[MEMWIN0_APERTURE/sizeof(__be32)];

I'm really surprised this didn't show up in any of your test builds.
Or are you ignoring warnings that your changes add?

Re: You have to fix this

[Vipul Pandya]

On 28-09-2012 04:04, David Miller wrote:
> 
> You cannot put such monster sized local data objects on the stack:
> 
> drivers/net/ethernet/chelsio/cxgb4/t4_hw.c: In function ‘t4_memory_rw.constprop.6’:
> drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:484:1: warning: the frame size of 2056 bytes is larger than 2048 bytes [-Wframe-larger-than=]
> 
> That's because of this thing:
> 
> 		__be32 data[MEMWIN0_APERTURE/sizeof(__be32)];
> 
> I'm really surprised this didn't show up in any of your test builds.
> Or are you ignoring warnings that your changes add?
> 

Thanks for pointing this out. We will send a patch for this soon.
I am not ignoring any warnings. I did build my tree different way as
shown below but did not get above warning message.
#> make
#> make allmodconfig
#> make allnoconfig

Please let me know how else would I get above warning message?

I missed doing make checkstack which doesn't display warning message but
lists the function names.

Thanks,
Vipul Pandya

Re: You have to fix this

[David Miller]

From: Vipul Pandya <vipul@chelsio.com>
Date: Fri, 28 Sep 2012 17:29:22 +0530

> Please let me know how else would I get above warning message?

Maybe your compiler is too old.  Does -Wframe-larger-than= show up in your
build logs with "make V=1"?

Re: You have to fix this

[Vipul Pandya]

On 28-09-2012 23:13, David Miller wrote:
> From: Vipul Pandya <vipul@chelsio.com>
> Date: Fri, 28 Sep 2012 17:29:22 +0530
> 
>> Please let me know how else would I get above warning message?
> 
> Maybe your compiler is too old.  Does -Wframe-larger-than= show up in your
> build logs with "make V=1"?
> 

I am using gcc version 4.4.4 20100726. Yes -Wframe-larger-than=2048 does
show up in my build logs as shown below:
===
gcc -Wp,-MD,arch/x86/kernel/.hw_breakpoint.o.d  -nostdinc -isystem
/usr/lib/gcc/x86_64-redhat-linux/4.4.4/include
-I/root/git_kernel_tree/net-next/arch/x86/include
-Iarch/x86/include/generated -Iinclude  -include
/root/git_kernel_tree/net-next/include/linux/kconfig.h -D__KERNEL__
-Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing
-fno-common -Werror-implicit-function-declaration -Wno-format-security
-fno-delete-null-pointer-checks -O2 -m64 -mtune=generic -mno-red-zone
-mcmodel=kernel -funit-at-a-time -maccumulate-outgoing-args
-DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1
-DCONFIG_AS_CFI_SECTIONS=1 -DCONFIG_AS_FXSAVEQ=1 -DCONFIG_AS_AVX=1 -pipe
-Wno-sign-compare -fno-asynchronous-unwind-tables -mno-sse -mno-mmx
-mno-sse2 -mno-3dnow -mno-avx -Wframe-larger-than=2048
-fno-stack-protector -Wno-unused-but-set-variable -fomit-frame-pointer
-Wdeclaration-after-statement -Wno-pointer-sign -fno-strict-overflow
-fconserve-stack -DCC_HAVE_ASM_GOTO    -D"KBUILD_STR(s)=#s"
-D"KBUILD_BASENAME=KBUILD_STR(hw_breakpoint)"
-D"KBUILD_MODNAME=KBUILD_STR(hw_breakpoint)" -c -o
arch/x86/kernel/hw_breakpoint.o arch/x86/kernel/hw_breakpoint.c
===

Re: You have to fix this

[Randy Dunlap]

On 10/03/2012 03:12 AM, Vipul Pandya wrote:

> 
> 
> On 28-09-2012 23:13, David Miller wrote:
>> From: Vipul Pandya <vipul@chelsio.com>
>> Date: Fri, 28 Sep 2012 17:29:22 +0530
>>
>>> Please let me know how else would I get above warning message?
>>
>> Maybe your compiler is too old.  Does -Wframe-larger-than= show up in your
>> build logs with "make V=1"?
>>
> 
> I am using gcc version 4.4.4 20100726. Yes -Wframe-larger-than=2048 does
> show up in my build logs as shown below:
> ===
> gcc -Wp,-MD,arch/x86/kernel/.hw_breakpoint.o.d  -nostdinc -isystem
> /usr/lib/gcc/x86_64-redhat-linux/4.4.4/include
> -I/root/git_kernel_tree/net-next/arch/x86/include
> -Iarch/x86/include/generated -Iinclude  -include
> /root/git_kernel_tree/net-next/include/linux/kconfig.h -D__KERNEL__
> -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs -fno-strict-aliasing
> -fno-common -Werror-implicit-function-declaration -Wno-format-security
> -fno-delete-null-pointer-checks -O2 -m64 -mtune=generic -mno-red-zone
> -mcmodel=kernel -funit-at-a-time -maccumulate-outgoing-args
> -DCONFIG_AS_CFI=1 -DCONFIG_AS_CFI_SIGNAL_FRAME=1
> -DCONFIG_AS_CFI_SECTIONS=1 -DCONFIG_AS_FXSAVEQ=1 -DCONFIG_AS_AVX=1 -pipe
> -Wno-sign-compare -fno-asynchronous-unwind-tables -mno-sse -mno-mmx
> -mno-sse2 -mno-3dnow -mno-avx -Wframe-larger-than=2048
> -fno-stack-protector -Wno-unused-but-set-variable -fomit-frame-pointer
> -Wdeclaration-after-statement -Wno-pointer-sign -fno-strict-overflow
> -fconserve-stack -DCC_HAVE_ASM_GOTO    -D"KBUILD_STR(s)=#s"
> -D"KBUILD_BASENAME=KBUILD_STR(hw_breakpoint)"
> -D"KBUILD_MODNAME=KBUILD_STR(hw_breakpoint)" -c -o
> arch/x86/kernel/hw_breakpoint.o arch/x86/kernel/hw_breakpoint.c
> ===


Regardless, you could just go ahead and fix it and use
scripts/checkstack.pl (or make checkstack) to check it for stack
usage as well as test the binary code to make sure that it works OK.

-- 
~Randy