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ARM: make it one-personality arch

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ARM in fact _is_ one personality.

We had two personalities for it because it has a handful of
syscalls with huge scnos (0x000f00xx).

Extending syscall table to have [0x000f0005] index is of course
not a good idea.

Someone decided to handle that by having a separate personality
just for these syscalls.

But multi-personality arch does a bit more work in other parts.

This patch is another alternative: "move" 0x000f00nn syscalls
down to the entries just above last ordinary syscall,
by manipulating scno if it falls into the 0x000f00xx range.

In order to not worsen genuine undefined scnos' printing,
the code remaps scno back to actual value before printing
"syscall_NNN" string.

* defs.h: Remove multi-reprsonality defines from ARM.
* syscall.c (shuffle_scno): New function.
(undefined_scno_name): New function.
(get_scno): [ARM] Replace personality setting with scno shuffling.
(trace_syscall_entering): Print unknown syscall name using
undefined_scno_name().
(trace_syscall_exiting): Likewise.
* linux/arm/syscallent.h: Add ARM specific syscalls at the end.
* linux/arm/errnoent1.h: Deleted.
* linux/arm/ioctlent1.h: Deleted.
* linux/arm/signalent1.h: Deleted.
* linux/arm/syscallent1.h: Deleted.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2013-02-21 15:46:34 +01:00
parent e7030e5a7e
commit 7270de551c
7 changed files with 79 additions and 35 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
defs.h
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@ -318,9 +318,7 @@ struct arm_pt_regs {
#endif
#ifdef ARM
# define SUPPORTED_PERSONALITIES 2
# define PERSONALITY0_WORDSIZE 4
# define PERSONALITY1_WORDSIZE 4
/* one personality */
#endif
#ifdef AARCH64

2
linux/arm/errnoent1.h
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@ -1,2 +0,0 @@
/* "ARM specific syscall" personality */
#include "../errnoent.h"

2
linux/arm/ioctlent1.h
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@ -1,2 +0,0 @@
/* "ARM specific syscall" personality */
#include "../ioctlent.h"

2
linux/arm/signalent1.h
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@ -1,2 +0,0 @@
/* "ARM specific syscall" personality */
#include "../signalent.h"

37
linux/arm/syscallent.h
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@ -406,8 +406,9 @@
{ 2, TD, sys_setns, "setns" }, /* 375 */
{ 6, 0, sys_process_vm_readv, "process_vm_readv" }, /* 376 */
{ 6, 0, sys_process_vm_writev, "process_vm_writev" }, /* 377 */
#ifndef __ARM_EABI__
#ifdef __ARM_EABI__
# define ARM_LAST_ORDINARY_SYSCALL 377
#else
{ 5, 0, NULL, NULL }, /* 378 */
{ 5, 0, NULL, NULL }, /* 379 */
{ 5, 0, NULL, NULL }, /* 380 */
@ -430,9 +431,9 @@
{ 5, 0, NULL, NULL }, /* 397 */
{ 5, 0, NULL, NULL }, /* 398 */
{ 5, 0, NULL, NULL }, /* 399 */
#if SYS_socket_subcall != 400
#error fix me
#endif
# if SYS_socket_subcall != 400
# error fix me
# endif
{ 6, 0, printargs, "socket_subcall"}, /* 400 */
{ 3, TN, sys_socket, "socket" }, /* 401 */
{ 3, TN, sys_bind, "bind" }, /* 402 */
@ -454,9 +455,9 @@
{ 4, TN, sys_accept4, "accept4" }, /* 418 */
{ 5, TN, sys_recvmmsg, "recvmmsg" }, /* 419 */
#if SYS_ipc_subcall != 420
#error fix me
#endif
# if SYS_ipc_subcall != 420
# error fix me
# endif
{ 4, 0, printargs, "ipc_subcall" }, /* 420 */
{ 4, TI, sys_semop, "semop" }, /* 421 */
{ 4, TI, sys_semget, "semget" }, /* 422 */
@ -482,4 +483,22 @@
{ 4, TI, sys_shmdt, "shmdt" }, /* 442 */
{ 4, TI, sys_shmget, "shmget" }, /* 443 */
{ 4, TI, sys_shmctl, "shmctl" }, /* 444 */
#endif
# define ARM_LAST_ORDINARY_SYSCALL 444
#endif /* !EABI */
/* __ARM_NR_cmpxchg (0x000ffff0).
* Remapped by shuffle_scno() to be directly after ordinary syscalls
* in this table.
*/
{ 5, 0, printargs, "cmpxchg" },
/* ARM specific syscalls. Encoded with scno 0x000f00xx.
* Remapped by shuffle_scno() to be directly after __ARM_NR_cmpxchg.
*/
{ 5, 0, NULL, NULL }, /* 0 */
{ 5, 0, printargs, "breakpoint" }, /* 1 */
{ 5, 0, printargs, "cacheflush" }, /* 2 */
{ 5, 0, printargs, "usr26" }, /* 3 */
{ 5, 0, printargs, "usr32" }, /* 4 */
{ 5, 0, printargs, "set_tls" }, /* 5 */
#define ARM_LAST_SPECIAL_SYSCALL 5

7
linux/arm/syscallent1.h
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@ -1,7 +0,0 @@
/* "ARM specific syscall" personality */
{ 5, 0, NULL, NULL }, /* 0 */
{ 5, 0, printargs, "breakpoint" }, /* 1 */
{ 5, 0, printargs, "cacheflush" }, /* 2 */
{ 5, 0, printargs, "usr26" }, /* 3 */
{ 5, 0, printargs, "usr32" }, /* 4 */
{ 5, 0, printargs, "set_tls" }, /* 5 */

60
syscall.c
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@ -899,6 +899,51 @@ printcall(struct tcb *tcp)
#endif /* architecture */
}
/* Shuffle syscall numbers so that we don't have huge gaps in syscall table.
* The shuffling should be reversible: shuffle_scno(shuffle_scno(n)) == n.
*/
#if defined(ARM) /* So far only ARM needs this */
static long
shuffle_scno(unsigned long scno)
{
if (scno <= ARM_LAST_ORDINARY_SYSCALL)
return scno;
/* __ARM_NR_cmpxchg? Swap with LAST_ORDINARY+1 */
if (scno == 0x000ffff0)
return ARM_LAST_ORDINARY_SYSCALL+1;
if (scno == ARM_LAST_ORDINARY_SYSCALL+1)
return 0x000ffff0;
/* Is it ARM specific syscall?
* Swap with [LAST_ORDINARY+2, LAST_ORDINARY+2 + LAST_SPECIAL] range.
*/
if (scno >= 0x000f0000
&& scno <= 0x000f0000 + ARM_LAST_SPECIAL_SYSCALL
) {
return scno - 0x000f0000 + (ARM_LAST_ORDINARY_SYSCALL+2);
}
if (/* scno >= ARM_LAST_ORDINARY_SYSCALL+2 - always true */ 1
&& scno <= (ARM_LAST_ORDINARY_SYSCALL+2) + ARM_LAST_SPECIAL_SYSCALL
) {
return scno + 0x000f0000 - (ARM_LAST_ORDINARY_SYSCALL+2);
}
return scno;
}
#else
# define shuffle_scno(scno) ((long)(scno))
#endif
static char*
undefined_scno_name(struct tcb *tcp)
{
static char buf[sizeof("syscall_%lu") + sizeof(long)*3];
sprintf(buf, "syscall_%lu", shuffle_scno(tcp->scno));
return buf;
}
#ifndef get_regs
long get_regs_error;
void
@ -1246,13 +1291,8 @@ get_scno(struct tcb *tcp)
scno &= 0x000fffff;
}
}
if (scno & 0x000f0000) {
/* ARM specific syscall. We handle it as a separate "personality" */
update_personality(tcp, 1);
scno &= 0x0000ffff;
} else {
update_personality(tcp, 0);
}
scno = shuffle_scno(scno);
#elif defined(M68K)
if (upeek(tcp, 4*PT_ORIG_D0, &scno) < 0)
return -1;
@ -1835,7 +1875,7 @@ trace_syscall_entering(struct tcb *tcp)
if (scno_good != 1)
tprints("????" /* anti-trigraph gap */ "(");
else if (!SCNO_IS_VALID(tcp->scno))
tprintf("syscall_%lu(", tcp->scno);
tprintf("%s(", undefined_scno_name(tcp));
else
tprintf("%s(", sysent[tcp->scno].sys_name);
/*
@ -1882,7 +1922,7 @@ trace_syscall_entering(struct tcb *tcp)
printleader(tcp);
if (!SCNO_IS_VALID(tcp->scno))
tprintf("syscall_%lu(", tcp->scno);
tprintf("%s(", undefined_scno_name(tcp));
else
tprintf("%s(", sysent[tcp->scno].sys_name);
if (!SCNO_IS_VALID(tcp->scno) ||
@ -2369,7 +2409,7 @@ trace_syscall_exiting(struct tcb *tcp)
tcp->flags &= ~TCB_REPRINT;
printleader(tcp);
if (!SCNO_IS_VALID(tcp->scno))
tprintf("<... syscall_%lu resumed> ", tcp->scno);
tprintf("<... %s resumed> ", undefined_scno_name(tcp));
else
tprintf("<... %s resumed> ", sysent[tcp->scno].sys_name);
}