Re: [powerpc:next-test 8/8] arch/powerpc/lib/feature-fixups.c:304:30: error: cast to smaller integer type 'enum l1d_flush_type' from 'void *'

Le 04/05/2021 à 20:31, kernel test robot a écrit :

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next-test
head:   a5014a5c936a2a9a223e699e1f3abd54d5f68d2c
commit: a5014a5c936a2a9a223e699e1f3abd54d5f68d2c [8/8] powerpc/64s: Fix crashes when toggling entry flush barrier
config: powerpc-randconfig-r022-20210503 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 8f5a2a5836cc8e4c1def2bdeb022e7b496623439)
reproduce (this is a W=1 build):
         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
         chmod +x ~/bin/make.cross
         # install powerpc cross compiling tool for clang build
         # apt-get install binutils-powerpc-linux-gnu
         # https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git/commit/?id=a5014a5c936a2a9a223e699e1f3abd54d5f68d2c
         git remote add powerpc https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git
         git fetch --no-tags powerpc next-test
         git checkout a5014a5c936a2a9a223e699e1f3abd54d5f68d2c
         # save the attached .config to linux build tree
         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=powerpc

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All errors (new ones prefixed by >>):

    arch/powerpc/lib/feature-fixups.c:233:32: error: cast to smaller integer type 'enum stf_barrier_type' from 'void *' [-Werror,-Wvoid-pointer-to-enum-cast]
            enum stf_barrier_type types = (enum stf_barrier_type)data;
                                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~

quoted

quoted

arch/powerpc/lib/feature-fixups.c:304:30: error: cast to smaller integer type 'enum l1d_flush_type' from 'void *' [-Werror,-Wvoid-pointer-to-enum-cast]

            enum l1d_flush_type types = (enum l1d_flush_type)data;
                                        ^~~~~~~~~~~~~~~~~~~~~~~~~
    2 errors generated.


vim +304 arch/powerpc/lib/feature-fixups.c

    301	
    302	static int __do_entry_flush_fixups(void *data)
    303	{
  > 304		enum l1d_flush_type types = (enum l1d_flush_type)data;

That looks strange to use an enumeration for 'types', as we perform logical ops with it below (eg: 
types & L1D_FLUSH_ORI).

I think it should be an int.

    305		unsigned int instrs[3], *dest;
    306		long *start, *end;
    307		int i;
    308	
    309		instrs[0] = 0x60000000; /* nop */
    310		instrs[1] = 0x60000000; /* nop */
    311		instrs[2] = 0x60000000; /* nop */
    312	
    313		i = 0;
    314		if (types == L1D_FLUSH_FALLBACK) {
    315			instrs[i++] = 0x7d4802a6; /* mflr r10		*/
    316			instrs[i++] = 0x60000000; /* branch patched below */
    317			instrs[i++] = 0x7d4803a6; /* mtlr r10		*/
    318		}
    319	
    320		if (types & L1D_FLUSH_ORI) {
    321			instrs[i++] = 0x63ff0000; /* ori 31,31,0 speculation barrier */
    322			instrs[i++] = 0x63de0000; /* ori 30,30,0 L1d flush*/
    323		}
    324	
    325		if (types & L1D_FLUSH_MTTRIG)
    326			instrs[i++] = 0x7c12dba6; /* mtspr TRIG2,r0 (SPR #882) */
    327	
    328		start = PTRRELOC(&__start___entry_flush_fixup);
    329		end = PTRRELOC(&__stop___entry_flush_fixup);
    330		for (i = 0; start < end; start++, i++) {
    331			dest = (void *)start + *start;
    332	
    333			pr_devel("patching dest %lx\n", (unsigned long)dest);
    334	
    335			patch_instruction((struct ppc_inst *)dest, ppc_inst(instrs[0]));
    336	
    337			if (types == L1D_FLUSH_FALLBACK)
    338				patch_branch((struct ppc_inst *)(dest + 1), (unsigned long)&entry_flush_fallback,
    339					     BRANCH_SET_LINK);
    340			else
    341				patch_instruction((struct ppc_inst *)(dest + 1), ppc_inst(instrs[1]));
    342	
    343			patch_instruction((struct ppc_inst *)(dest + 2), ppc_inst(instrs[2]));
    344		}
    345	
    346		start = PTRRELOC(&__start___scv_entry_flush_fixup);
    347		end = PTRRELOC(&__stop___scv_entry_flush_fixup);
    348		for (; start < end; start++, i++) {
    349			dest = (void *)start + *start;
    350	
    351			pr_devel("patching dest %lx\n", (unsigned long)dest);
    352	
    353			patch_instruction((struct ppc_inst *)dest, ppc_inst(instrs[0]));
    354	
    355			if (types == L1D_FLUSH_FALLBACK)
    356				patch_branch((struct ppc_inst *)(dest + 1), (unsigned long)&scv_entry_flush_fallback,
    357					     BRANCH_SET_LINK);
    358			else
    359				patch_instruction((struct ppc_inst *)(dest + 1), ppc_inst(instrs[1]));
    360	
    361			patch_instruction((struct ppc_inst *)(dest + 2), ppc_inst(instrs[2]));
    362		}
    363	
    364	
    365		printk(KERN_DEBUG "entry-flush: patched %d locations (%s flush)\n", i,
    366			(types == L1D_FLUSH_NONE)       ? "no" :
    367			(types == L1D_FLUSH_FALLBACK)   ? "fallback displacement" :
    368			(types &  L1D_FLUSH_ORI)        ? (types & L1D_FLUSH_MTTRIG)
    369								? "ori+mttrig type"
    370								: "ori type" :
    371			(types &  L1D_FLUSH_MTTRIG)     ? "mttrig type"
    372							: "unknown");
    373	
    374		return 0;
    375	}
    376	

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