[PATCH 2/2] drm/amdgpu: Fix type of second parameter in odn_edit_dpm_table() callback

[Alex Deucher]

Applied the series.  Thanks!

Alex

On Wed, Nov 2, 2022 at 11:43 AM Kees Cook <keescook at chromium.org> wrote:
>
> On Wed, Nov 02, 2022 at 08:25:40AM -0700, Nathan Chancellor wrote:
> > With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
> > indirect call targets are validated against the expected function
> > pointer prototype to make sure the call target is valid to help mitigate
> > ROP attacks. If they are not identical, there is a failure at run time,
> > which manifests as either a kernel panic or thread getting killed. A
> > proposed warning in clang aims to catch these at compile time, which
> > reveals:
> >
> >   drivers/gpu/drm/amd/amdgpu/../pm/swsmu/amdgpu_smu.c:3008:29: error: incompatible function pointer types initializing 'int (*)(void *, uint32_t, long *, uint32_t)' (aka 'int (*)(void *, unsigned int, long *, unsigned int)') with an expression of type 'int (void *, enum PP_OD_DPM_TABLE_COMMAND, long *, uint32_t)' (aka 'int (void *, enum PP_OD_DPM_TABLE_COMMAND, long *, unsigned int)') [-Werror,-Wincompatible-function-pointer-types-strict]
> >           .odn_edit_dpm_table      = smu_od_edit_dpm_table,
> >                                      ^~~~~~~~~~~~~~~~~~~~~
> >   1 error generated.
> >
> > There are only two implementations of ->odn_edit_dpm_table() in 'struct
> > amd_pm_funcs': smu_od_edit_dpm_table() and pp_odn_edit_dpm_table(). One
> > has a second parameter type of 'enum PP_OD_DPM_TABLE_COMMAND' and the
> > other uses 'u32'. Ultimately, smu_od_edit_dpm_table() calls
> > ->od_edit_dpm_table() from 'struct pptable_funcs' and
> > pp_odn_edit_dpm_table() calls ->odn_edit_dpm_table() from 'struct
> > pp_hwmgr_func', which both have a second parameter type of 'enum
> > PP_OD_DPM_TABLE_COMMAND'.
> >
> > Update the type parameter in both the prototype in 'struct amd_pm_funcs'
> > and pp_odn_edit_dpm_table() to 'enum PP_OD_DPM_TABLE_COMMAND', which
> > cleans up the warning.
> >
> > Link: https://github.com/ClangBuiltLinux/linux/issues/1750
> > Reported-by: Sami Tolvanen <samitolvanen at google.com>
> > Signed-off-by: Nathan Chancellor <nathan at kernel.org>
>
> Reviewed-by: Kees Cook <keescook at chromium.org>
>
> --
> Kees Cook