$B%a%b%j4IM}!"%"%I%l%96u4V!"%Z!<%8%F!<%V%k(B

$B%V%m%C%/!&%G%P%$%9$N%a%8%c! $ ls -l /dev/sda2 brw-r----- 1 root disk 8, 2 Jan 24 12:00 /dev/sda2 $ $B%U%!%$%k$N(B inode $BHV9f$O!"(Bls -i $B$G$o$+$k!#(B

$ ls -li /bin/bash 
481554 -rwxr-xr-x 1 root root 735004 Jan 22  2009 /bin/bash
$ ls -li /lib/libnss_dns-2.5.so 
490576 -rwxr-xr-x 1 root root 21948 Oct 26 08:16 /lib/libnss_dns-2.5.so
$ 

$B"#%Z!<%8%F!<%V%k(B

$B"!2>A[%"%I%l%9$HJ*M}%"%I%l%9(B

• $B%a%b%j$K$O!"J*M}%"%I%l%9$,$U$i$l$F$$$k!#(B
• $B%f!<%6!&%W%m%;%9$,A[%"%I%l%9(B(virtual address) $B$r(B $B=PNO$9$k!#(B
• $B2>A[%"%I%l%9$N$&$A!">e0L$O!"(BMMU (MMU) $B$K$h$jJQ49$9$k!#(B
• $B2>A[%"%I%l%9$N$&$A!"2<0L(B($B%Z!<%8%5%$%:J,(B)$B$O!"$=$N$^$^%a%b%j$KAw$i$l$k!#(B

$B"!(B1$BCJ$N%Z!<%8!&%F!<%V%k(B

• p: 31..12$B%S%C%H!#%Z!<%8%F!<%V%k$N%$%s%G%C%/%9(B (20$B%S%C%H(B)
• offset: 11..0$B!#%Z!<%8Fb%*%U%;%C%H(B (12$B%S%C%H(B)

MMU($B%O!<%I%&%'%"(B) $B$O!"$3$N%Z!<%8%F!<%V%k$r;H$C$F!"A[%"(B $B%I%l%9$+$iJ*M}%"%I%l%9$r5a$a$k!#0J2<$O!"(BMMU $B$NF0$-$r(B C $B8@8l$G@bL@$7$?$b(B $B$N!#(B

unsigned long int physical_address( unsigned long int virtual v ) {
    unsigned long int p, page, offset;
    p = v >> 12;         // 32$BCf!">e0L(B20$B%S%C%H(B(32-12==20)$B$N




$B?^(B? 1$BCJ$N%Z!<%8%F!<%V%k(B




$BCm0U(B: $BGr$$ItJ,$O!"(B0 $B$,F~$C$F$$$k!#(B0 $B$NItJ,$O!"%Z!<%8!&%U%l!<%`$,3d$jEv(B
$B$F$i$l$F$$$J$$$3$H$r0UL#$9$k!#(B0 $B$rJ];}$9$k$?$a$K$b!"%a%b%j$,I,MW$G$"$k!#(B



page_table[] $B$O!"(B0x100000 $B8D(B ==  1024 * 1024 $B8D(B == 1M $B8D$NMWAG$+$i$J$k!#(B
1$BMWAG$,(B 4 $B%P%$%H(B(32$B%S%C%H(B) $B$J$i!"(B4MB $B$N%a%b%j$,I,MW$K$J$k!#(B




$B"!B?CJ$N%Z!<%8!&%F!<%V%k(B

$B


$B2>A[%"%I%l%9$N9=@.$N(B $BNc(B$B!#(B
1$B%Z!<%8$,(B4KB$B!"2>A[%"%I%l%9$,(B32$B%S%C%H$N;~$NJ,3d$NNc(B($BB>$NJ,3dJ}K!$b9M$($i(B
$B$l$k(B)


 p: 31..27$B%S%C%H!#(BPGD$B$N%$%s%G%C%/%9(B(5$B%S%C%H(B)
 q: 26..22$B%S%C%H!#(BPUD$B$N%$%s%G%C%/%9(B(5$B%S%C%H(B)
 r: 21..17$B%S%C%H!#(BPMD$B$N%$%s%G%C%/%9(B(5$B%S%C%H(B)
 s: 16..12$B%S%C%H!#(Bpt$B$N%$%s%G%C%/%9(B(5$B%S%C%H(B)
 offset: 11..0$B%S%C%H!#%Z!<%8Fb%*%U%;%C%H(B(12$B%S%C%H(B)





$B?^(B? $B2>A[%"%I%l%9$N(B4$B$D$NItJ,$X$NJ,3dNc(B








$B?^(B? 4$BCJ$N%Z!<%8%F!<%V%k(B





 PGD: Page Global Directory
 PUD: Page Upper Directory
 PMD: Page Middle Directory
 Page Table Entry$B$NG[Ns(B (pte $B$NG[Ns(B)


unsigned int pgd[0x20];

unsigned long int physical_address( unsigned long int virtual v ) {
    unsigned int *pud, *pmd, *pte, p, q, r, s, page, offset;
    p = v >> (32-5) ;
    q = (v >> (32-10)) & 0x1f;
    r = (v >> (32-15)) & 0x1f;
    s = (v >> (32-20)) & 0x1f;
    offset = v & 0xfff;
    pud = pgd[p];
    pmd = pud[q];
    pte = pmd[r];
    page = pte[s]
    return( page + offset );
}



$B"!(Bx86$B$N%Z!<%8!&%F!<%V%k(B

x86 $B$G$O!"=>Mh!"(B2$BCJ$N%Z!<%8%F!<%V%k$rMQ$$$F$$$k!#
 p $B$,(B 10 $B%S%C%H(B (31..22$B%S%C%H(B)
 q $B$,(B 0 $B%S%C%H(B
 r $B$,(B 0 $B%S%C%H(B
 s $B$,(B 10 $B%S%C%H(B (21..12$B%S%C%H(B)
 offset $B$,(B 12 $B%S%C%H(B (11..0$B%S%C%H(B)





$B?^(B? $B2>A[%"%I%l%9$N(B3$B$D$NItJ,$X$NJ,3dNc(B







$B?^(B? x86$B$N(B2$BCJ$N%Z!<%8%F!<%V%k(B





$B"!(Bx86$B$N%Z!<%8!&%F!<%V%k(B(PAE$BM-8z(B)


x86 $B$G(B PAE$B!J(BPhysical Address Extension)$B$,M-8z$N;~$K$O!"A[%"%I%l%9$O!"(B32$B%S%C%H$G$"$k$,!"J*M}%"%I%l%9$O!"(B36$B%S%C%H$^$G;H$($k$h$&$K$J$k!#(B


 p $B$,(B 2 $B%S%C%H(B
 q $B$,(B 0 $B%S%C%H(B
 r $B$,(B 9 $B%S%C%H(B
 s $B$,(B 9 $B%S%C%H(B
 offset $B$,(B 12 $B%S%C%H(B




$B"#%Z!<%8!&%U%)!<%k%H(B

$B%a%b%j$,3d$jEv$F$i$l$F$$$J$$>l=j$r%W%m%;%9$,%"%/%;%9$7$?;~$K$O!"%Z!<%8!&(B
$B%U%)!<%k%H$,H/@8$9$k!#(B


 $B@5$7$$%"%I%l%9$r:G=i$K%"%/%;%9$7$?>l9g(B

 $B%Z!<%8%F!<%V%k$,$J$1$l$P:n$k!#(B
 $B%Z!<%8!&%U%l!<%`$,3d$jEv$F$i$l$F$$$J$1$l$P!"3d$jEv$F$k!#(B
 $B%U%!%$%k$HBP1~$7$F$$$l$P!"%U%!%$%k$+$iFbMF$rFI$_9~$`!#(B
$BBP1~$7$F$$$J$1$l$P!"(B0 $B$GKd$a$k!#(B

 $B@5$7$$%"%I%l%9$r#22sL\0J9_$K%"%/%;%9$7$?>l9g(B

 $B%Z!<%8%$%s$N=hM}$r9T$&(B

 $BIT@5$J%"%I%l%9$r%"%/%;%9(B

 $B%(%i!<(B(EFAULT$BEy(B) $B$G%W%m%;%9$r=*N;$5$;$k(B



$B4X?t(Bdo_page_fault() $B$,$3$N$h$&$J=hM}$r9T$&!#$3$N4X?t$O!"8"8B30$N%"%/%;(B
$B%9!"$?$H$($P!"=q$-9~$_6X;_$N%a%b%j$K=q$-9~$_$r;n$_$?>l9g$N%(%i!<$b=hM}(B
$B$9$k!#(B


$B"!(Bx86 do_page_fault()



linux-3.1.3/arch/x86/mm/fault.c

 987:	dotraplinkage void __kprobes
 988:	do_page_fault(struct pt_regs *regs, unsigned long error_code)
 989:	{
 990:	        struct vm_area_struct *vma;
 991:	        struct task_struct *tsk;
 992:	        unsigned long address;
 993:	        struct mm_struct *mm;
 994:	        int fault;
 995:	        int write = error_code & PF_WRITE;
 996:	        unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
 997:	                                        (write ? FAULT_FLAG_WRITE : 0);
 998:	
 999:	        tsk = current;
1000:	        mm = tsk->mm;
...
1003:	        address = read_cr2();
...
1119:	        vma = find_vma(mm, address);
...
1120:	        if (unlikely(!vma)) {
1121:	                bad_area(regs, error_code, address);
1122:	                return;
1123:	        }
1124:	        if (likely(vma->vm_start <= address))
1125:	                goto good_area;
1126:	        if (unlikely(!(vma->vm_flags & VM_GROWSDOWN))) {
1127:	                bad_area(regs, error_code, address);
1128:	                return;
1129:	        }
...
1142:	        if (unlikely(expand_stack(vma, address))) {
1143:	                bad_area(regs, error_code, address);
1144:	                return;
1145:	        }
...
1151:	good_area:
1152:	        if (unlikely(access_error(error_code, vma))) {
1153:	                bad_area_access_error(regs, error_code, address);
1154:	                return;
1155:	        }
...
1162:	        fault = handle_mm_fault(mm, vma, address, flags);
...
1195:	}




 $B%O!<%I%&%'%"0MB8$N%3!<%I!#(Barch/x86 $B$N2<$K$"$k!#(B

 tsk $B$K8=:_ mm $B$K8=:_ Linux $B%+!<%M%k$K=P$F$/$k(B likely() $B$d(B unlikely() $B$O!"9bB.2=$N$?$a$N(B
$B%R%s%H$J$N$G!"0UL#$rGD0.$9$k;~$K$OB8:_$7$J$$$b$N$H$7$F$h$$!#(B

 x86 $B$N(B cr2 (control register 2) $B$K!"%Z!<%8!&%U%)!<%k%H$,@8$8$?(B
$B%"%I%l%9$,4^$^$l$F$$$k!#(B

 find_vma() $B$G!"(Bvm_area_struct $B$rC5$9!#8+$D$+$i$J$1$l$P!"(B
bad_area()$B!#(Bfind_vma() $B$O!"%-%c%C%7%c$d(B red-black tree $B$r;H$C$F9bB.$K(B
vm_area_struct $B$rC5$9!#(B

 $BIaDL$O!"(Bvma->vm_start $B$h$j$b(B address $B$OBg$-$$!#(B

 $B%9%?%C%/$K$D$$$F$O!"(Bvm_flags $B$N(B VM_GROWSDOWN $B%S%C%H$,(B
$BN)$C$F$$$k!#(B

 $B$=$N>l9g$O!"%9%?%C%/$N(B vma $B$r<+F0E*$K3HD%$9$k!#(B

 handle_mm_fault() $B$r8F$S!"%Z!<%8%F!<%V%k$r:n$k!#(B



$B"!(Bhandle_mm_fault()

linux-3.1.3/mm/memory.c

3442:	int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
3443:	                unsigned long address, unsigned int flags)
3444:	{
3445:	        pgd_t *pgd;
3446:	        pud_t *pud;
3447:	        pmd_t *pmd;
3448:	        pte_t *pte;
...
3461:	        pgd = pgd_offset(mm, address);
3462:	        pud = pud_alloc(mm, pgd, address);
3463:	        if (!pud)
3464:	                return VM_FAULT_OOM;
3465:	        pmd = pmd_alloc(mm, pud, address);
3466:	        if (!pmd)
3467:	                return VM_FAULT_OOM;
...
3501:	        pte = pte_offset_map(pmd, address);
3502:	
3503:	        return handle_pte_fault(mm, vma, address, pte, pmd, flags);
3504:	}



 $B%Z!<%8%F!<%V%k$r(B pgd, pud, pmd, pte $B$N=g$K3d$jEv$F$F$$$/!#(B
 $B:G8e$K(B pte $B$N(B1$B%(%s%H%j$r(B handle_pte_fault() $B$G:n$k!#(B


$B"!(Bhandle_pte_fault()

linux-3.1.3/mm/memory.c
3386:	int handle_pte_fault(struct mm_struct *mm,
3387:	                     struct vm_area_struct *vma, unsigned long address,
3388:	                     pte_t *pte, pmd_t *pmd, unsigned int flags)
3389:	{
3390:	        pte_t entry;
...
3393:	        entry = *pte;
...
3395:	                if (pte_none(entry)) {
3396:	                        if (vma->vm_ops) {
3397:	                                if (likely(vma->vm_ops->fault))
3398:	                                        return do_linear_fault(mm, vma, address,
3399:	                                                pte, pmd, flags, entry);
3400:	                        }
3401:	                        return do_anonymous_page(mm, vma, address,
3402:	                                                 pte, pmd, flags);
3403:	                }
3404:	                if (pte_file(entry))
3405:	                        return do_nonlinear_fault(mm, vma, address,
3406:	                                        pte, pmd, flags, entry);
3407:	                return do_swap_page(mm, vma, address,
3408:	                                        pte, pmd, flags, entry);
...
3437:	}



 pte $B$,$^$C$5$i(B($B=i$a$F%"%/%;%9$5$l$?(B)

 vma->vm_ops->fault $B$H$$$&4X?t$,$"$l$P!"(B
do_linear_fault() $B$G=hM}$9$k!#(B

 $BL5$1$l$P!"(Bdo_anonymous_page() $B$G=hM}!#(B
0 $B$G=i4|2=$5$l$?%Z!<%8$r3d$jEv$F$k!#(B


 pte $B$,$^$C$5$i$G$O$J$$(B

 do_swap_page() $B$G%Z!<%8%$%s!#(B
$B%G%#%9%/$+$i#1%Z!<%8FI$_=P$9!#(B







$B"#%/%$%:(B5
 $B%a%b%j4IM}!"%"%I%l%96u4V!"%Z!<%8%F!<%V%k(B

$B!zLdBj(B(501) /proc/PID/maps

/proc/PID/maps$B$NFbMF$O!"$3$N%Z!<%8$NCf$G$I$N9=B$BN$N%j%9%H$rI=<($7$?$b$N$H(B
$B9M$($i$l$k$+!#
 $B%j%9%H$N5/E@$rJ];}$7$F$$$k9=B$BN$NL>A0(B
 $B%j%9%H$N5/E@$rJ];}$7$F$$$k9=B$BN$NCf$N%U%#!<%k%IL>(B
 $B%j%9%H$K$D$J$,$l$F$$$k9=B$BN$NL>A0(B



$B!zLdBj(B(502) 1$BCJ$N%Z!<%8%F!<%V%k(B



$B2>A[%"%I%l%9$N%5%$%:$,(B32$B%S%C%H!"(B1$B%Z!<%8$NBg$-$5$,(B4KB$B$H$9$k!#(B
$B
 0x00000000 $B$+$i(B 0x00000fff $B$^$G(B
 0x00001000 $B$+$i(B 0x00001fff $B$^$G(B
 0xfffff000 $B$+$i(B 0xffffffff $B$^$G(B


1$BCJ$N%Z!<%8%F!<%V%k$rMQ$$$F$$$?>l9g!"%Z!<%8%F!<%V%k$KI,MW$J%a%b%j$O2?%P(B
$B%$%H$K$J$k$+!#%Z!<%8%F!<%V%k$N(B1$B%(%s%H%j$N%P%$%H$O!"(B4$B%P%$%H$H$9$k!#(B

$B$J$*!"KvC<$N%Z!<%8!&%U%l!<%`$KI,MW$J%a%b%j(B($B$3$N>l9g$O!"(B3$B%Z!<%8!"(B12KB)$B$O!"(B
$B%Z!<%8%F!<%V%k$KI,MW$J%a%b%j$G$O$J$$$N$G!"7W;;$KF~$l$J$$!#(B


$B!zLdBj(B(503) 2$BCJ$N%Z!<%8%F!<%V%k(B

$BLdBj(B(502) $B$G!"$B!V(Bx86$B$N%Z!<%8!&%F!<%V%k!W(B$B$HF1$8(B)
$B$rMQ$$$F$$$?$H$9$k!#(B


 1$BCJL\(B: 31..22$B%S%C%H(B ($B>e0L(B10$B%S%C%H(B)
 2$BCJL\(B: 21..12$B%S%C%H(B
 $B%*%U%;%C%H(B: $B2<0L(B12$B%S%C%H(B (11..0$B%S%C%H(B)


$B$3$N;~!"%Z!<%8%F!<%V%k$KI,MW$J%a%b%j$O2?%P%$%H$K$J$k$+!#%Z!<%8%F!<%V%k(B
$B$N(B1$B%(%s%H%j$N%P%$%H$O!">e0L$N%Z!<%8%F!<%V%k$b2<0L$N%Z!<%8%F!<%V%k$b(B4$B%P(B
$B%$%H$H$9$k!#(B




Last updated: 2012/02/07 17:26:15
 

 Yasushi Shinjo / <yas@is.tsukuba.ac.jp>