Re: linus: arm64: error: call to '__compiletime_assert_536' declared with attribute error: FIELD_PREP: value too large for the field

Adam Ford
2025-01-30T20:20:34Z

On Thu, Jan 30, 2025 at 2:01 PM David Laight
<david.laight.linux@gmail.com> wrote:
>
> On Thu, 30 Jan 2025 15:22:06 +0530
> Naresh Kamboju <naresh.kamboju@linaro.org> wrote:
>
> > The arm64 build failed with defconfig with gcc-8 toolchain failed due to
> > following build warnings / errors on the mainline linux master branch.
> > But the gcc-13 builds pass.
> >
> > First seen on v6.13-9485-g72deda0abee6 on Jan. 30, 2025
> > Good: v6.13-9338-g05dbaf8dd8bf on Jan. 29, 2025
> > Bad: v6.13-9485-g72deda0abee6 on Jan. 30, 2025
> >
> > arm64:
> > build:
> > * gcc-8-i386_defconfig
> >
> > Reported-by: Linux Kernel Functional Testing
> >
> > Build log:
> > ---
> > ake --silent --keep-going --jobs=8
> > O=/home/tuxbuild/.cache/tuxmake/builds/1/build ARCH=arm64
> > CROSS_COMPILE=aarch64-linux-gnu-
> > CROSS_COMPILE_COMPAT=arm-linux-gnueabihf- 'CC=sccache
> > aarch64-linux-gnu-gcc' 'HOSTCC=sccache gcc'
> > In file included from <command-line>:
> > In function 'fsl_samsung_hdmi_phy_configure_pll_lock_det.isra.10',
> > inlined from 'fsl_samsung_hdmi_phy_configure' at
> > drivers/phy/freescale/phy-fsl-samsung-hdmi.c:469:2:
> > include/linux/compiler_types.h:542:38: error: call to
> > '__compiletime_assert_536' declared with attribute error: FIELD_PREP:
> > value too large for the field
> ...
> > drivers/phy/freescale/phy-fsl-samsung-hdmi.c:344:9: note: in expansion
> > of macro 'FIELD_PREP'
> > writeb(FIELD_PREP(REG12_CK_DIV_MASK, div), phy->regs + PHY_REG(12));
> > ^~~~~~~~~~
>
> Yep...
> Broken by d567679f2b6a8
>
> Preceded by:
> /* Find int_pllclk speed */
> for (div = 0; div < 4; div++) {
> int_pllclk = pclk / (1 << div);
> if (int_pllclk < (50 * MHZ))
> break;
> }
> with:
> #define REG12_CK_DIV_MASK GENMASK(5, 4)
>
> The compiler has optimised (pessimised?) the code somewhat.
> If pclk is very large the loop doesn't 'break' so div == 4.

I believe a fix was submitted:
https://patchwork.kernel.org/project/linux-phy/patch/5b9a5f765f075263498f9a7b62b0b1030d87b6ba.1736476210.git.xiaopei01@kylinos.cn/

It appears to be waiting for approval and/or merge. If someone wants
to test it. I added Pei,the author of the fix, to the CC in this
thread.

adam

adam

> It then does FIELD_PREP(GENMASK(5, 4), 4) - which is an error.
>
> David
>
>
>