Re: [PATCH] arm: fix page faults in do_alignment
From: kbuild test robot
Date: Sat Aug 31 2019 - 08:49:20 EST
Hi Jing,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on arm/for-next]
[cannot apply to v5.3-rc6 next-20190830]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Jing-Xiangfeng/arm-fix-page-faults-in-do_alignment/20190831-173417
base: git://git.armlinux.org.uk/~rmk/linux-arm.git for-next
config: arm-allmodconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (GCC) 7.4.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=7.4.0 make.cross ARCH=arm
If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@xxxxxxxxx>
All warnings (new ones prefixed by >>):
arch/arm/mm/alignment.c: In function 'do_alignment':
>> arch/arm/mm/alignment.c:792:28: warning: passing argument 1 of '__copy_from_user' makes pointer from integer without a cast [-Wint-conversion]
fault = __copy_from_user(tinstr,
^~~~~~
In file included from include/linux/sched/task.h:11:0,
from include/linux/sched/signal.h:9,
from arch/arm/mm/alignment.c:20:
include/linux/uaccess.h:67:1: note: expected 'void *' but argument is of type 'u16 {aka short unsigned int}'
__copy_from_user(void *to, const void __user *from, unsigned long n)
^~~~~~~~~~~~~~~~
arch/arm/mm/alignment.c:801:30: warning: passing argument 1 of '__copy_from_user' makes pointer from integer without a cast [-Wint-conversion]
fault = __copy_from_user(tinst2,
^~~~~~
In file included from include/linux/sched/task.h:11:0,
from include/linux/sched/signal.h:9,
from arch/arm/mm/alignment.c:20:
include/linux/uaccess.h:67:1: note: expected 'void *' but argument is of type 'u16 {aka short unsigned int}'
__copy_from_user(void *to, const void __user *from, unsigned long n)
^~~~~~~~~~~~~~~~
arch/arm/mm/alignment.c:813:28: warning: passing argument 1 of '__copy_from_user' makes pointer from integer without a cast [-Wint-conversion]
fault = __copy_from_user(instr,
^~~~~
In file included from include/linux/sched/task.h:11:0,
from include/linux/sched/signal.h:9,
from arch/arm/mm/alignment.c:20:
include/linux/uaccess.h:67:1: note: expected 'void *' but argument is of type 'long unsigned int'
__copy_from_user(void *to, const void __user *from, unsigned long n)
^~~~~~~~~~~~~~~~
vim +/__copy_from_user +792 arch/arm/mm/alignment.c
769
770 static int
771 do_alignment(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
772 {
773 union offset_union uninitialized_var(offset);
774 unsigned long instr = 0, instrptr;
775 int (*handler)(unsigned long addr, unsigned long instr, struct pt_regs *regs);
776 unsigned int type;
777 mm_segment_t fs;
778 unsigned int fault;
779 u16 tinstr = 0;
780 int isize = 4;
781 int thumb2_32b = 0;
782
783 if (interrupts_enabled(regs))
784 local_irq_enable();
785
786 instrptr = instruction_pointer(regs);
787
788 fs = get_fs();
789 set_fs(KERNEL_DS);
790 if (thumb_mode(regs)) {
791 u16 *ptr = (u16 *)(instrptr & ~1);
> 792 fault = __copy_from_user(tinstr,
793 (__force const void __user *)ptr,
794 sizeof(tinstr));
795 tinstr = __mem_to_opcode_thumb16(tinstr);
796 if (!fault) {
797 if (cpu_architecture() >= CPU_ARCH_ARMv7 &&
798 IS_T32(tinstr)) {
799 /* Thumb-2 32-bit */
800 u16 tinst2 = 0;
801 fault = __copy_from_user(tinst2,
802 (__force const void __user *)(ptr+1),
803 sizeof(tinst2));
804 tinst2 = __mem_to_opcode_thumb16(tinst2);
805 instr = __opcode_thumb32_compose(tinstr, tinst2);
806 thumb2_32b = 1;
807 } else {
808 isize = 2;
809 instr = thumb2arm(tinstr);
810 }
811 }
812 } else {
813 fault = __copy_from_user(instr,
814 (__force const void __user *)instrptr,
815 sizeof(instr));
816 instr = __mem_to_opcode_arm(instr);
817 }
818
819 set_fs(fs);
820 if (fault) {
821 type = TYPE_FAULT;
822 goto bad_or_fault;
823 }
824
825 if (user_mode(regs))
826 goto user;
827
828 ai_sys += 1;
829 ai_sys_last_pc = (void *)instruction_pointer(regs);
830
831 fixup:
832
833 regs->ARM_pc += isize;
834
835 switch (CODING_BITS(instr)) {
836 case 0x00000000: /* 3.13.4 load/store instruction extensions */
837 if (LDSTHD_I_BIT(instr))
838 offset.un = (instr & 0xf00) >> 4 | (instr & 15);
839 else
840 offset.un = regs->uregs[RM_BITS(instr)];
841
842 if ((instr & 0x000000f0) == 0x000000b0 || /* LDRH, STRH */
843 (instr & 0x001000f0) == 0x001000f0) /* LDRSH */
844 handler = do_alignment_ldrhstrh;
845 else if ((instr & 0x001000f0) == 0x000000d0 || /* LDRD */
846 (instr & 0x001000f0) == 0x000000f0) /* STRD */
847 handler = do_alignment_ldrdstrd;
848 else if ((instr & 0x01f00ff0) == 0x01000090) /* SWP */
849 goto swp;
850 else
851 goto bad;
852 break;
853
854 case 0x04000000: /* ldr or str immediate */
855 if (COND_BITS(instr) == 0xf0000000) /* NEON VLDn, VSTn */
856 goto bad;
857 offset.un = OFFSET_BITS(instr);
858 handler = do_alignment_ldrstr;
859 break;
860
861 case 0x06000000: /* ldr or str register */
862 offset.un = regs->uregs[RM_BITS(instr)];
863
864 if (IS_SHIFT(instr)) {
865 unsigned int shiftval = SHIFT_BITS(instr);
866
867 switch(SHIFT_TYPE(instr)) {
868 case SHIFT_LSL:
869 offset.un <<= shiftval;
870 break;
871
872 case SHIFT_LSR:
873 offset.un >>= shiftval;
874 break;
875
876 case SHIFT_ASR:
877 offset.sn >>= shiftval;
878 break;
879
880 case SHIFT_RORRRX:
881 if (shiftval == 0) {
882 offset.un >>= 1;
883 if (regs->ARM_cpsr & PSR_C_BIT)
884 offset.un |= 1 << 31;
885 } else
886 offset.un = offset.un >> shiftval |
887 offset.un << (32 - shiftval);
888 break;
889 }
890 }
891 handler = do_alignment_ldrstr;
892 break;
893
894 case 0x08000000: /* ldm or stm, or thumb-2 32bit instruction */
895 if (thumb2_32b) {
896 offset.un = 0;
897 handler = do_alignment_t32_to_handler(&instr, regs, &offset);
898 } else {
899 offset.un = 0;
900 handler = do_alignment_ldmstm;
901 }
902 break;
903
904 default:
905 goto bad;
906 }
907
908 if (!handler)
909 goto bad;
910 type = handler(addr, instr, regs);
911
912 if (type == TYPE_ERROR || type == TYPE_FAULT) {
913 regs->ARM_pc -= isize;
914 goto bad_or_fault;
915 }
916
917 if (type == TYPE_LDST)
918 do_alignment_finish_ldst(addr, instr, regs, offset);
919
920 return 0;
921
922 bad_or_fault:
923 if (type == TYPE_ERROR)
924 goto bad;
925 /*
926 * We got a fault - fix it up, or die.
927 */
928 do_bad_area(addr, fsr, regs);
929 return 0;
930
931 swp:
932 pr_err("Alignment trap: not handling swp instruction\n");
933
934 bad:
935 /*
936 * Oops, we didn't handle the instruction.
937 */
938 pr_err("Alignment trap: not handling instruction "
939 "%0*lx at [<%08lx>]\n",
940 isize << 1,
941 isize == 2 ? tinstr : instr, instrptr);
942 ai_skipped += 1;
943 return 1;
944
945 user:
946 ai_user += 1;
947
948 if (ai_usermode & UM_WARN)
949 printk("Alignment trap: %s (%d) PC=0x%08lx Instr=0x%0*lx "
950 "Address=0x%08lx FSR 0x%03x\n", current->comm,
951 task_pid_nr(current), instrptr,
952 isize << 1,
953 isize == 2 ? tinstr : instr,
954 addr, fsr);
955
956 if (ai_usermode & UM_FIXUP)
957 goto fixup;
958
959 if (ai_usermode & UM_SIGNAL) {
960 force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)addr);
961 } else {
962 /*
963 * We're about to disable the alignment trap and return to
964 * user space. But if an interrupt occurs before actually
965 * reaching user space, then the IRQ vector entry code will
966 * notice that we were still in kernel space and therefore
967 * the alignment trap won't be re-enabled in that case as it
968 * is presumed to be always on from kernel space.
969 * Let's prevent that race by disabling interrupts here (they
970 * are disabled on the way back to user space anyway in
971 * entry-common.S) and disable the alignment trap only if
972 * there is no work pending for this thread.
973 */
974 raw_local_irq_disable();
975 if (!(current_thread_info()->flags & _TIF_WORK_MASK))
976 set_cr(cr_no_alignment);
977 }
978
979 return 0;
980 }
981
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