Re: [PATCH 1/1] x86/elf: Add a new .note section containing Xfeatures information to x86 core files

[kernel test robot <lkp@intel.com>]

Hi Vignesh,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.8 next-20240315]
[cannot apply to kees/for-next/execve tip/x86/core powerpc/next powerpc/fixes]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Vignesh-Balasubramanian/x86-elf-Add-a-new-note-section-containing-Xfeatures-information-to-x86-core-files/20240314-192650
base:   linus/master
patch link:    https://lore.kernel.org/r/20240314112359.50713-2-vigbalas%40amd.com
patch subject: [PATCH 1/1] x86/elf: Add a new .note section containing Xfeatures information to x86 core files
config: i386-buildonly-randconfig-001-20240315 (https://download.01.org/0day-ci/archive/20240315/202403151742.VEz04MqR-lkp@intel.com/config)
compiler: clang version 17.0.6 (https://github.com/llvm/llvm-project 6009708b4367171ccdbf4b5905cb6a803753fe18)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240315/202403151742.VEz04MqR-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202403151742.VEz04MqR-lkp@intel.com/

All errors (new ones prefixed by >>):

>> arch/x86/kernel/fpu/xstate.c:1858:8: error: call to undeclared function 'dump_emit'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1858 |                 if (!dump_emit(cprm, &xc, sizeof(struct xfeat_component)))
         |                      ^
   arch/x86/kernel/fpu/xstate.c:1869:8: error: call to undeclared function 'dump_emit'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1869 |                 if (!dump_emit(cprm, &xc, sizeof(struct xfeat_component)))
         |                      ^
   arch/x86/kernel/fpu/xstate.c:1899:7: error: call to undeclared function 'dump_emit'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1899 |         if (!dump_emit(cprm, &en, sizeof(en)))
         |              ^
>> arch/x86/kernel/fpu/xstate.c:1903:7: error: call to undeclared function 'dump_align'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1903 |         if (!dump_align(cprm, 4))
         |              ^
   4 errors generated.


vim +/dump_emit +1858 arch/x86/kernel/fpu/xstate.c

  1846	
  1847		struct xfeat_component xc;
  1848		int num_records = 0;
  1849		int i;
  1850	
  1851		/* XFEATURE_FPU and XFEATURE_SSE, both are fixed legacy states. */
  1852		for (i = 0; i < FIRST_EXTENDED_XFEATURE; i++) {
  1853			xc.xfeat_type = i;
  1854			xc.xfeat_sz = xstate_sizes[i];
  1855			xc.xfeat_off = xstate_offsets[i];
  1856			xc.xfeat_flags = xstate_flags[i];
  1857	
> 1858			if (!dump_emit(cprm, &xc, sizeof(struct xfeat_component)))
  1859				return 0;
  1860			num_records++;
  1861		}
  1862	
  1863		for_each_extended_xfeature(i, fpu_user_cfg.max_features) {
  1864			xc.xfeat_type = i;
  1865			xc.xfeat_sz = xstate_sizes[i];
  1866			xc.xfeat_off = xstate_offsets[i];
  1867			xc.xfeat_flags = xstate_flags[i];
  1868	
  1869			if (!dump_emit(cprm, &xc, sizeof(struct xfeat_component)))
  1870				return 0;
  1871			num_records++;
  1872		}
  1873	
  1874		return num_records;
  1875	}
  1876	
  1877	static int get_xsave_desc_size(void)
  1878	{
  1879		/* XFEATURE_FP and XFEATURE_SSE, both are fixed legacy states */
  1880		int xfeatures_count = 2;
  1881		int i;
  1882	
  1883		for_each_extended_xfeature(i, fpu_user_cfg.max_features)
  1884			xfeatures_count++;
  1885	
  1886		return xfeatures_count * (sizeof(struct xfeat_component));
  1887	}
  1888	
  1889	int elf_coredump_extra_notes_write(struct coredump_params *cprm)
  1890	{
  1891		const char *owner_name = "LINUX";
  1892		int num_records = 0;
  1893		struct elf_note en;
  1894	
  1895		en.n_namesz = strlen(owner_name) + 1;
  1896		en.n_descsz = get_xsave_desc_size();
  1897		en.n_type = NT_X86_XSAVE_LAYOUT;
  1898	
  1899		if (!dump_emit(cprm, &en, sizeof(en)))
  1900			return 1;
  1901		if (!dump_emit(cprm, owner_name, en.n_namesz))
  1902			return 1;
> 1903		if (!dump_align(cprm, 4))
  1904			return 1;
  1905	
  1906		num_records = dump_xsave_layout_desc(cprm);
  1907		if (!num_records) {
  1908			pr_warn("Error adding XSTATE layout ELF note. XSTATE buffer in the core file will be unparseable.");
  1909			return 1;
  1910		}
  1911	
  1912		/* Total size should be equal to the number of records */
  1913		if ((sizeof(struct xfeat_component) * num_records) != en.n_descsz) {
  1914			pr_warn("Error adding XSTATE layout ELF note. The size of the .note section does not match with the total size of the records.");
  1915			return 1;
  1916		}
  1917	
  1918		if (!dump_align(cprm, 4))
  1919			return 1;
  1920	
  1921		return 0;
  1922	}
  1923	

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