[parisc-linux] [patch] handle pagefaults on unaligned access
Joel Soete
soete.joel@tiscali.be
Sun, 19 Oct 2003 13:43:43 +0000
Hi Randolph,
I don't yet fully tested (just compile 2.6) but imho need this change:
=====
--- unaligned.c.RC.orig 2003-10-19 15:02:22.000000000 +0200
+++ unaligned.c 2003-10-19 15:03:00.000000000 +0200
@@ -474,7 +474,7 @@
" .word 5b,(6b-5b)\n"
#endif
" .previous\n"
- : "r" (ret)
+ : "=r" (ret)
: "r" (valh), "r" (vall), "r" (regs->ior), "r" (regs->isr)
: "r19", "r20", "r21", "r1" );
}
=====
hth,
Joel
Randolph Chung wrote:
> while testing out gcj today, i was able to crash the machine
> consistently with both 2.4 and 2.6 kernel. turns out our unaligned
> handler doesn't handle page faults properly. in the case for gcj, there
> was a ldh on the edge of the page, the first byte is on a resident page,
> the 2nd byte is on a faulting page.
>
> this patch seems to fix it (at least the case i was seeing). any
> comments before i commit it?
>
> thanks
> randolph
>
> Index: arch/parisc/kernel/unaligned.c
> ===================================================================
> RCS file: /var/cvs/linux-2.4/arch/parisc/kernel/unaligned.c,v
> retrieving revision 1.21
> diff -u -p -r1.21 unaligned.c
> --- arch/parisc/kernel/unaligned.c 23 Sep 2003 20:15:33 -0000 1.21
> +++ arch/parisc/kernel/unaligned.c 19 Oct 2003 06:29:00 -0000
> @@ -128,6 +128,9 @@
> #define IM5_3(i) IM((i),5)
> #define IM14(i) IM((i),14)
>
> +#define ERR_NOTHANDLED -1
> +#define ERR_PAGEFAULT -2
> +
> int unaligned_enabled = 1;
>
> void die_if_kernel (char *str, struct pt_regs *regs, long err);
> @@ -136,16 +139,28 @@ static int emulate_ldh(struct pt_regs *r
> {
> unsigned long saddr = regs->ior;
> unsigned long val = 0;
> + int ret;
>
> DPRINTF("load " RFMT ":" RFMT " to r%d for 2 bytes\n",
> regs->isr, regs->ior, toreg);
>
> __asm__ __volatile__ (
> -" mtsp %3, %%sr1\n"
> -" ldbs 0(%%sr1,%2), %%r20\n"
> -" ldbs 1(%%sr1,%2), %0\n"
> - "depw %%r20, 23, 24, %0\n"
> - : "=r" (val)
> +" mtsp %4, %%sr1\n"
> +"1: ldbs 0(%%sr1,%3), %%r20\n"
> +"2: ldbs 1(%%sr1,%3), %0\n"
> +" depw %%r20, 23, 24, %0\n"
> +" cmpclr,= %%r0, %%r0, %1\n"
> +"3: ldo -2(%%r0), %1\n"
> +" .section __ex_table,\"a\"\n"
> +#ifdef __LP64__
> +" .dword 1b,(3b-1b)\n"
> +" .dword 2b,(3b-2b)\n"
> +#else
> +" .word 1b,(3b-1b)\n"
> +" .word 2b,(3b-2b)\n"
> +#endif
> +" .previous\n"
> + : "=r" (val), "=r" (ret)
> : "0" (val), "r" (saddr), "r" (regs->isr)
> : "r20" );
>
> @@ -154,26 +169,39 @@ static int emulate_ldh(struct pt_regs *r
> if (toreg)
> regs->gr[toreg] = val;
>
> - return 0;
> + return ret;
> }
> +
> static int emulate_ldw(struct pt_regs *regs, int toreg, int flop)
> {
> unsigned long saddr = regs->ior;
> unsigned long val = 0;
> + int ret;
>
> DPRINTF("load " RFMT ":" RFMT " to r%d for 4 bytes\n",
> regs->isr, regs->ior, toreg);
>
> __asm__ __volatile__ (
> -" zdep %2,28,2,%%r19\n" /* r19=(ofs&3)*8 */
> -" mtsp %3, %%sr1\n"
> -" depw %%r0,31,2,%2\n"
> -" ldw 0(%%sr1,%2),%0\n"
> -" ldw 4(%%sr1,%2),%%r20\n"
> +" zdep %3,28,2,%%r19\n" /* r19=(ofs&3)*8 */
> +" mtsp %4, %%sr1\n"
> +" depw %%r0,31,2,%3\n"
> +"1: ldw 0(%%sr1,%3),%0\n"
> +"2: ldw 4(%%sr1,%3),%%r20\n"
> " subi 32,%%r19,%%r19\n"
> " mtctl %%r19,11\n"
> " vshd %0,%%r20,%0\n"
> - : "=r" (val)
> +" cmpclr,= %%r0, %%r0, %1\n"
> +"3: ldo -2(%%r0), %1\n"
> +" .section __ex_table,\"a\"\n"
> +#ifdef __LP64__
> +" .dword 1b,(3b-1b)\n"
> +" .dword 2b,(3b-2b)\n"
> +#else
> +" .word 1b,(3b-1b)\n"
> +" .word 2b,(3b-2b)\n"
> +#endif
> +" .previous\n"
> + : "=r" (val), "=r" (ret)
> : "0" (val), "r" (saddr), "r" (regs->isr)
> : "r19", "r20" );
>
> @@ -184,12 +212,13 @@ static int emulate_ldw(struct pt_regs *r
> else if (toreg)
> regs->gr[toreg] = val;
>
> - return 0;
> + return ret;
> }
> static int emulate_ldd(struct pt_regs *regs, int toreg, int flop)
> {
> unsigned long saddr = regs->ior;
> __u64 val = 0;
> + int ret;
>
> DPRINTF("load " RFMT ":" RFMT " to r%d for 8 bytes\n",
> regs->isr, regs->ior, toreg);
> @@ -200,51 +229,77 @@ static int emulate_ldd(struct pt_regs *r
> return -1;
> #endif
> __asm__ __volatile__ (
> -" depd,z %2,60,3,%%r19\n" /* r19=(ofs&7)*8 */
> -" mtsp %3, %%sr1\n"
> -" depd %%r0,63,3,%2\n"
> -" ldd 0(%%sr1,%2),%0\n"
> -" ldd 8(%%sr1,%2),%%r20\n"
> +" depd,z %3,60,3,%%r19\n" /* r19=(ofs&7)*8 */
> +" mtsp %4, %%sr1\n"
> +" depd %%r0,63,3,%3\n"
> +"1: ldd 0(%%sr1,%3),%0\n"
> +"2: ldd 8(%%sr1,%3),%%r20\n"
> " subi 64,%%r19,%%r19\n"
> " mtsar %%r19\n"
> " shrpd %0,%%r20,%%sar,%0\n"
> - : "=r" (val)
> +" cmpclr,= %%r0, %%r0, %1\n"
> +"3: ldo -2(%%r0), %1\n"
> +" .section __ex_table,\"a\"\n"
> +#ifdef __LP64__
> +" .dword 1b,(3b-1b)\n"
> +" .dword 2b,(3b-2b)\n"
> +#else
> +" .word 1b,(3b-1b)\n"
> +" .word 2b,(3b-2b)\n"
> +#endif
> +" .previous\n"
> + : "=r" (val), "=r" (ret)
> : "0" (val), "r" (saddr), "r" (regs->isr)
> : "r19", "r20" );
> #else
> {
> unsigned long valh=0,vall=0;
> __asm__ __volatile__ (
> -" zdep %4,29,2,%%r19\n" /* r19=(ofs&3)*8 */
> -" mtsp %5, %%sr1\n"
> -" dep %%r0,31,2,%4\n"
> -" ldw 0(%%sr1,%5),%0\n"
> -" ldw 4(%%sr1,%5),%1\n"
> -" ldw 8(%%sr1,%5),%%r20\n"
> +" zdep %5,29,2,%%r19\n" /* r19=(ofs&3)*8 */
> +" mtsp %6, %%sr1\n"
> +" dep %%r0,31,2,%5\n"
> +"1: ldw 0(%%sr1,%6),%0\n"
> +"2: ldw 4(%%sr1,%6),%1\n"
> +"3: ldw 8(%%sr1,%6),%%r20\n"
> " subi 32,%%r19,%%r19\n"
> " mtsar %%r19\n"
> " vshd %0,%1,%0\n"
> " vshd %1,%%r20,%1\n"
> - : "=r" (valh), "=r" (vall)
> +" cmpclr,= %%r0, %%r0, %2\n"
> +"4: ldo -2(%%r0), %2\n"
> +" .section __ex_table,\"a\"\n"
> +#ifdef __LP64__
> +" .dword 1b,(4b-1b)\n"
> +" .dword 2b,(4b-2b)\n"
> +" .dword 3b,(4b-3b)\n"
> +#else
> +" .word 1b,(4b-1b)\n"
> +" .word 2b,(4b-2b)\n"
> +" .word 3b,(4b-3b)\n"
> +#endif
> +" .previous\n"
> + : "=r" (valh), "=r" (vall), "=r" (ret)
> : "0" (valh), "1" (vall), "r" (saddr), "r" (regs->isr)
> : "r19", "r20" );
> val=((__u64)valh<<32)|(__u64)vall;
> }
> #endif
>
> - DPRINTF("val = 0x" RFMT "\n", val);
> + DPRINTF("val = 0xllx\n", val);
>
> if (flop)
> regs->fr[toreg] = val;
> else if (toreg)
> regs->gr[toreg] = val;
>
> - return 0;
> + return ret;
> }
>
> static int emulate_sth(struct pt_regs *regs, int frreg)
> {
> unsigned long val = regs->gr[frreg];
> + int ret;
> +
> if (!frreg)
> val = 0;
>
> @@ -252,19 +307,32 @@ static int emulate_sth(struct pt_regs *r
> val, regs->isr, regs->ior);
>
> __asm__ __volatile__ (
> -" mtsp %2, %%sr1\n"
> -" extrw,u %0, 23, 8, %%r19\n"
> -" stb %0, 1(%%sr1, %1)\n"
> -" stb %%r19, 0(%%sr1, %1)\n"
> - :
> +" mtsp %3, %%sr1\n"
> +" extrw,u %1, 23, 8, %%r19\n"
> +"1: stb %1, 1(%%sr1, %2)\n"
> +"2: stb %%r19, 0(%%sr1, %2)\n"
> +" cmpclr,= %%r0, %%r0, %0\n"
> +"3: ldo -2(%%r0), %0\n"
> +" .section __ex_table,\"a\"\n"
> +#ifdef __LP64__
> +" .dword 1b,(3b-1b)\n"
> +" .dword 2b,(3b-2b)\n"
> +#else
> +" .word 1b,(3b-1b)\n"
> +" .word 2b,(3b-2b)\n"
> +#endif
> +" .previous\n"
> + : "=r" (ret)
> : "r" (val), "r" (regs->ior), "r" (regs->isr)
> : "r19" );
>
> - return 0;
> + return ret;
> }
> +
> static int emulate_stw(struct pt_regs *regs, int frreg, int flop)
> {
> unsigned long val;
> + int ret;
>
> if (flop)
> val = ((__u32*)(regs->fr))[frreg];
> @@ -278,22 +346,33 @@ static int emulate_stw(struct pt_regs *r
>
>
> __asm__ __volatile__ (
> -" mtsp %2, %%sr1\n"
> -" zdep %1, 28, 2, %%r19\n"
> -" dep %%r0, 31, 2, %1\n"
> +" mtsp %3, %%sr1\n"
> +" zdep %2, 28, 2, %%r19\n"
> +" dep %%r0, 31, 2, %2\n"
> " mtsar %%r19\n"
> " depwi,z -2, %%sar, 32, %%r19\n"
> -" ldw 0(%%sr1,%1),%%r20\n"
> -" ldw 4(%%sr1,%1),%%r21\n"
> -" vshd %%r0, %0, %%r22\n"
> -" vshd %0, %%r0, %%r1\n"
> +"1: ldw 0(%%sr1,%2),%%r20\n"
> +"2: ldw 4(%%sr1,%2),%%r21\n"
> +" vshd %%r0, %1, %%r22\n"
> +" vshd %1, %%r0, %%r1\n"
> " and %%r20, %%r19, %%r20\n"
> " andcm %%r21, %%r19, %%r21\n"
> " or %%r22, %%r20, %%r20\n"
> " or %%r1, %%r21, %%r21\n"
> -" stw %%r20,0(%%sr1,%1)\n"
> -" stw %%r21,4(%%sr1,%1)\n"
> - :
> +" stw %%r20,0(%%sr1,%2)\n"
> +" stw %%r21,4(%%sr1,%2)\n"
> +" cmpclr,= %%r0, %%r0, %0\n"
> +"3: ldo -2(%%r0), %0\n"
> +" .section __ex_table,\"a\"\n"
> +#ifdef __LP64__
> +" .dword 1b,(3b-1b)\n"
> +" .dword 2b,(3b-2b)\n"
> +#else
> +" .word 1b,(3b-1b)\n"
> +" .word 2b,(3b-2b)\n"
> +#endif
> +" .previous\n"
> + : "=r" (ret)
> : "r" (val), "r" (regs->ior), "r" (regs->isr)
> : "r19", "r20", "r21", "r22", "r1" );
>
> @@ -302,6 +381,7 @@ static int emulate_stw(struct pt_regs *r
> static int emulate_std(struct pt_regs *regs, int frreg, int flop)
> {
> __u64 val;
> + int ret;
>
> if (flop)
> val = regs->fr[frreg];
> @@ -310,7 +390,7 @@ static int emulate_std(struct pt_regs *r
> else
> val = 0;
>
> - DPRINTF("store r%d (0x" %016llx ") to " RFMT ":" RFMT " for 8 bytes\n", frreg,
> + DPRINTF("store r%d (0x%016llx) to " RFMT ":" RFMT " for 8 bytes\n", frreg,
> val, regs->isr, regs->ior);
>
> #ifdef CONFIG_PA20
> @@ -319,52 +399,84 @@ static int emulate_std(struct pt_regs *r
> return -1;
> #endif
> __asm__ __volatile__ (
> -" mtsp %2, %%sr1\n"
> -" depd,z %1, 60, 3, %%r19\n"
> -" depd %%r0, 63, 3, %1\n"
> +" mtsp %3, %%sr1\n"
> +" depd,z %2, 60, 3, %%r19\n"
> +" depd %%r0, 63, 3, %2\n"
> " mtsar %%r19\n"
> " depdi,z -2, %%sar, 64, %%r19\n"
> -" ldd 0(%%sr1,%1),%%r20\n"
> -" ldd 8(%%sr1,%1),%%r21\n"
> -" shrpd %%r0, %0, %%sar, %%r22\n"
> -" shrpd %0, %%r0, %%sar, %%r1\n"
> +"1: ldd 0(%%sr1,%2),%%r20\n"
> +"2: ldd 8(%%sr1,%2),%%r21\n"
> +" shrpd %%r0, %1, %%sar, %%r22\n"
> +" shrpd %1, %%r0, %%sar, %%r1\n"
> " and %%r20, %%r19, %%r20\n"
> " andcm %%r21, %%r19, %%r21\n"
> " or %%r22, %%r20, %%r20\n"
> " or %%r1, %%r21, %%r21\n"
> -" std %%r20,0(%%sr1,%1)\n"
> -" std %%r21,8(%%sr1,%1)\n"
> - :
> +"3: std %%r20,0(%%sr1,%2)\n"
> +"4: std %%r21,8(%%sr1,%2)\n"
> +" cmpclr,= %%r0, %%r0, %0\n"
> +"5: ldo -2(%%r0), %0\n"
> +" .section __ex_table,\"a\"\n"
> +#ifdef __LP64__
> +" .dword 1b,(5b-1b)\n"
> +" .dword 2b,(5b-2b)\n"
> +" .dword 3b,(5b-3b)\n"
> +" .dword 4b,(5b-4b)\n"
> +#else
> +" .word 1b,(5b-1b)\n"
> +" .word 2b,(5b-2b)\n"
> +" .word 3b,(5b-3b)\n"
> +" .word 4b,(5b-4b)\n"
> +#endif
> +" .previous\n"
> + : "=r" (ret)
> : "r" (val), "r" (regs->ior), "r" (regs->isr)
> : "r19", "r20", "r21", "r22", "r1" );
> #else
> {
> unsigned long valh=(val>>32),vall=(val&0xffffffffl);
> __asm__ __volatile__ (
> -" mtsp %3, %%sr1\n"
> -" zdep %1, 29, 2, %%r19\n"
> -" dep %%r0, 31, 2, %1\n"
> +" mtsp %4, %%sr1\n"
> +" zdep %2, 29, 2, %%r19\n"
> +" dep %%r0, 31, 2, %2\n"
> " mtsar %%r19\n"
> " zvdepi -2, 32, %%r19\n"
> -" ldw 0(%%sr1,%2),%%r20\n"
> -" ldw 8(%%sr1,%2),%%r21\n"
> -" vshd %0, %1, %%r1\n"
> -" vshd %%r0, %0, %0\n"
> -" vshd %1, %%r0, %1\n"
> +"1: ldw 0(%%sr1,%3),%%r20\n"
> +"2: ldw 8(%%sr1,%3),%%r21\n"
> +" vshd %1, %2, %%r1\n"
> +" vshd %%r0, %1, %1\n"
> +" vshd %2, %%r0, %2\n"
> " and %%r20, %%r19, %%r20\n"
> " andcm %%r21, %%r19, %%r21\n"
> -" or %0, %%r20, %0\n"
> -" or %1, %%r21, %1\n"
> -" stw %0,0(%%sr1,%2)\n"
> -" stw %%r1,4(%%sr1,%2)\n"
> -" stw %1,8(%%sr1,%2)\n"
> - :
> +" or %1, %%r20, %1\n"
> +" or %2, %%r21, %2\n"
> +"3: stw %1,0(%%sr1,%1)\n"
> +"4: stw %%r1,4(%%sr1,%3)\n"
> +"5: stw %2,8(%%sr1,%3)\n"
> +" cmpclr,= %%r0, %%r0, %0\n"
> +"6: ldo -2(%%r0), %0\n"
> +" .section __ex_table,\"a\"\n"
> +#ifdef __LP64__
> +" .dword 1b,(6b-1b)\n"
> +" .dword 2b,(6b-2b)\n"
> +" .dword 3b,(6b-3b)\n"
> +" .dword 4b,(6b-4b)\n"
> +" .dword 5b,(6b-5b)\n"
> +#else
> +" .word 1b,(6b-1b)\n"
> +" .word 2b,(6b-2b)\n"
> +" .word 3b,(6b-3b)\n"
> +" .word 4b,(6b-4b)\n"
> +" .word 5b,(6b-5b)\n"
> +#endif
> +" .previous\n"
> + : "r" (ret)
> : "r" (valh), "r" (vall), "r" (regs->ior), "r" (regs->isr)
> : "r19", "r20", "r21", "r1" );
> }
> #endif
>
> - return 0;
> + return ret;
> }
>
> void handle_unaligned(struct pt_regs *regs)
> @@ -373,7 +485,7 @@ void handle_unaligned(struct pt_regs *re
> static unsigned long last_time = 0;
> unsigned long newbase = R1(regs->iir)?regs->gr[R1(regs->iir)]:0;
> int modify = 0;
> - int ret = -1;
> + int ret = ERR_NOTHANDLED;
> struct siginfo si;
> register int flop=0; /* true if this is a flop */
>
> @@ -567,7 +679,7 @@ void handle_unaligned(struct pt_regs *re
> case OPCODE_LDCW_I:
> case OPCODE_LDCD_S:
> case OPCODE_LDCW_S:
> - ret = -1; /* "undefined", but lets kill them. */
> + ret = ERR_NOTHANDLED; /* "undefined", but lets kill them. */
> break;
> }
> #ifdef CONFIG_PA20
> @@ -632,7 +744,7 @@ void handle_unaligned(struct pt_regs *re
> regs->gr[R1(regs->iir)] = newbase;
>
>
> - if (ret < 0)
> + if (ret == ERR_NOTHANDLED)
> printk(KERN_CRIT "Not-handled unaligned insn 0x%08lx\n", regs->iir);
>
> DPRINTF("ret = %d\n", ret);
> @@ -641,13 +753,25 @@ void handle_unaligned(struct pt_regs *re
> {
> printk(KERN_CRIT "Unaligned handler failed, ret = %d\n", ret);
> die_if_kernel("Unaligned data reference", regs, 28);
> +
> + if (ret == ERR_PAGEFAULT)
> + {
> + si.si_signo = SIGSEGV;
> + si.si_errno = 0;
> + si.si_code = SEGV_MAPERR;
> + si.si_addr = (void *)regs->ior;
> + force_sig_info(SIGSEGV, &si, current);
> + }
> + else
> + {
> force_sigbus:
> - /* couldn't handle it ... */
> - si.si_signo = SIGBUS;
> - si.si_errno = 0;
> - si.si_code = BUS_ADRALN;
> - si.si_addr = (void *)regs->ior;
> - force_sig_info(SIGBUS, &si, current);
> + /* couldn't handle it ... */
> + si.si_signo = SIGBUS;
> + si.si_errno = 0;
> + si.si_code = BUS_ADRALN;
> + si.si_addr = (void *)regs->ior;
> + force_sig_info(SIGBUS, &si, current);
> + }
>
> return;
> }