After enabling CONFIG_GCOV_KERNEL and CONFIG_GCOV_PROFILE_ALL, following
build failure is observed under GCC 14.2.1:
In function 'amdv1pt_install_leaf_entry',
inlined from '__do_map_single_page' at drivers/iommu/generic_pt/fmt/../iommu_pt.h:650:3,
inlined from '__map_single_page0' at drivers/iommu/generic_pt/fmt/../iommu_pt.h:661:1,
inlined from 'pt_descend' at drivers/iommu/generic_pt/fmt/../pt_iter.h:391:9,
inlined from '__do_map_single_page' at drivers/iommu/generic_pt/fmt/../iommu_pt.h:657:10,
inlined from '__map_single_page1.constprop' at drivers/iommu/generic_pt/fmt/../iommu_pt.h:661:1:
././include/linux/compiler_types.h:706:45: error: call to '__compiletime_assert_71' declared with attribute error: FIELD_PREP: value too large for the field
706 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
|
......
drivers/iommu/generic_pt/fmt/amdv1.h:220:26: note: in expansion of macro 'FIELD_PREP'
220 | FIELD_PREP(AMDV1PT_FMT_OA,
| ^~~~~~~~~~
In the path '__do_map_single_page()', level 0 always invokes
'pt_install_leaf_entry(&pts, map->oa, PAGE_SHIFT, …)'. At runtime that
lands in the 'if (oasz_lg2 == isz_lg2)' arm of 'amdv1pt_install_leaf_entry()';
the contiguous-only 'else' block is unreachable for 4 KiB pages.
With CONFIG_GCOV_KERNEL + CONFIG_GCOV_PROFILE_ALL, the extra
instrumentation changes GCC's inlining so that the "dead" 'else' branch
still gets instantiated. The compiler constant-folds the contiguous OA
expression, runs the 'FIELD_PREP()' compile-time check, and produces:
FIELD_PREP: value too large for the field
gcov-enabled builds therefore fail even though the code path never executes.
Fix this by marking amdv1pt_install_leaf_entry as __always_inline.
Fixes: dcd6a011a8 ("iommupt: Add map_pages op")
Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sherry Yang <sherry.yang@oracle.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
8b72aa5704