Re: [PATCH v2 21/25] powerpc/ftrace: Don't use copy_from_kernel_nofault() in module_trampoline_target()

[kernel test robot]

Hi Christophe,

I love your patch! Perhaps something to improve:

[auto build test WARNING on powerpc/next]
[also build test WARNING on powerpc/topic/ppc-kvm v5.18-rc5 next-20220506]
[cannot apply to rostedt-trace/for-next]
[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]

url:    https://github.com/intel-lab-lkp/linux/commits/Christophe-Leroy/powerpc-ftrace-optimisation-and-cleanup-and-more-v2/20220507-145034
base:   https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-randconfig-s031-20220506 (https://download.01.org/0day-ci/archive/20220507/202205071900.opHsWE8v-lkp@xxxxxxxxx/config)
compiler: powerpc-linux-gcc (GCC) 11.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-dirty
        # https://github.com/intel-lab-lkp/linux/commit/1c6a385ed330a6ed959cad02f89306fb84e4334c
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Christophe-Leroy/powerpc-ftrace-optimisation-and-cleanup-and-more-v2/20220507-145034
        git checkout 1c6a385ed330a6ed959cad02f89306fb84e4334c
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=powerpc SHELL=/bin/bash arch/powerpc/kernel/

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


sparse warnings: (new ones prefixed by >>)
>> arch/powerpc/kernel/module_32.c:298:43: sparse: sparse: incorrect type in argument 1 (different base types) @@     expected struct ppc_inst_t [usertype] *inst @@     got unsigned int * @@
   arch/powerpc/kernel/module_32.c:298:43: sparse:     expected struct ppc_inst_t [usertype] *inst
   arch/powerpc/kernel/module_32.c:298:43: sparse:     got unsigned int *
   arch/powerpc/kernel/module_32.c:300:49: sparse: sparse: incorrect type in argument 1 (different base types) @@     expected struct ppc_inst_t [usertype] *inst @@     got unsigned int * @@
   arch/powerpc/kernel/module_32.c:300:49: sparse:     expected struct ppc_inst_t [usertype] *inst
   arch/powerpc/kernel/module_32.c:300:49: sparse:     got unsigned int *
   arch/powerpc/kernel/module_32.c:302:49: sparse: sparse: incorrect type in argument 1 (different base types) @@     expected struct ppc_inst_t [usertype] *inst @@     got unsigned int * @@
   arch/powerpc/kernel/module_32.c:302:49: sparse:     expected struct ppc_inst_t [usertype] *inst
   arch/powerpc/kernel/module_32.c:302:49: sparse:     got unsigned int *
   arch/powerpc/kernel/module_32.c:304:49: sparse: sparse: incorrect type in argument 1 (different base types) @@     expected struct ppc_inst_t [usertype] *inst @@     got unsigned int * @@
   arch/powerpc/kernel/module_32.c:304:49: sparse:     expected struct ppc_inst_t [usertype] *inst
   arch/powerpc/kernel/module_32.c:304:49: sparse:     got unsigned int *

vim +298 arch/powerpc/kernel/module_32.c

   290	
   291	#ifdef CONFIG_DYNAMIC_FTRACE
   292	notrace int module_trampoline_target(struct module *mod, unsigned long addr,
   293					     unsigned long *target)
   294	{
   295		unsigned int jmp[4];
   296	
   297		/* Find where the trampoline jumps to */
 > 298		if (copy_inst_from_kernel_nofault(jmp, (void *)addr))
   299			return -EFAULT;
   300		if (__copy_inst_from_kernel_nofault(jmp + 1, (void *)addr + 4))
   301			return -EFAULT;
   302		if (__copy_inst_from_kernel_nofault(jmp + 2, (void *)addr + 8))
   303			return -EFAULT;
   304		if (__copy_inst_from_kernel_nofault(jmp + 3, (void *)addr + 12))
   305			return -EFAULT;
   306	
   307		/* verify that this is what we expect it to be */
   308		if ((jmp[0] & 0xffff0000) != PPC_RAW_LIS(_R12, 0) ||
   309		    (jmp[1] & 0xffff0000) != PPC_RAW_ADDI(_R12, _R12, 0) ||
   310		    jmp[2] != PPC_RAW_MTCTR(_R12) ||
   311		    jmp[3] != PPC_RAW_BCTR())
   312			return -EINVAL;
   313	
   314		addr = (jmp[1] & 0xffff) | ((jmp[0] & 0xffff) << 16);
   315		if (addr & 0x8000)
   316			addr -= 0x10000;
   317	
   318		*target = addr;
   319	
   320		return 0;
   321	}
   322	

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