On X86_64 and I386, use PTRACE_GETREGS to fetch all registers
Before this change, registers were read with PTRACE_PEEKUSER ptrace operation, one per register. This is slower than fetching them all in one ptrace operation. * defs.h: include asm/ptrace.h on X86_64 and I386. * syscall.c: New static variables i386_regs and x86_64_regs. Remove static eax/rax variables. (get_scno): Fetch all registers with single PTRACE_GETREGS operation. (get_syscall_result): Likewise. (syscall_fixup_on_sysenter): Use PTRACE_GETREGS results in i386/x86_64_regs. (syscall_enter): Set tcp->u_arg[i] from PTRACE_GETREGS results. (get_error): Set tcp->u_rval, tcp->u_error from PTRACE_GETREGS results. Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
This commit is contained in:
Denys Vlasenko
parent
a673f3fa62
commit
eb0e3e8f50
6
defs.h
6
defs.h
@ -193,6 +193,12 @@ extern int ptrace(int, int, char *, int, ...);
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#define PTRACE_PEEKUSER PTRACE_PEEKUSR
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#define PTRACE_POKEUSER PTRACE_POKEUSR
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#endif
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#if defined(X86_64) || defined(I386)
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/* For struct pt_regs. x86 strace uses PTRACE_GETREGS.
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* PTRACE_GETREGS returns registers in the layout of this struct.
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*/
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# include <asm/ptrace.h>
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#endif
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#ifdef ALPHA
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# define REG_R0 0
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# define REG_A0 16
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120
syscall.c
120
syscall.c
@ -716,7 +716,9 @@ struct tcb *tcp_last = NULL;
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#ifdef LINUX
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# if defined (I386)
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static long eax;
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static struct pt_regs i386_regs;
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# elif defined(X86_64)
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static struct pt_regs x86_64_regs;
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# elif defined (IA64)
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long r8, r10, psr; /* TODO: make static? */
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long ia32 = 0; /* not static */
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@ -752,8 +754,6 @@ static long r28;
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static long r0;
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# elif defined(SH64)
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static long r9;
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# elif defined(X86_64)
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static long rax;
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# elif defined(CRISV10) || defined(CRISV32)
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static long r10;
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# elif defined(MICROBLAZE)
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@ -895,34 +895,26 @@ get_scno(struct tcb *tcp)
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if (upeek(tcp, PT_ORIG_P0, &scno))
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return -1;
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# elif defined (I386)
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if (upeek(tcp, 4*ORIG_EAX, &scno) < 0)
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if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (long) &i386_regs) < 0)
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return -1;
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scno = i386_regs.orig_eax;
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# elif defined (X86_64)
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if (upeek(tcp, 8*ORIG_RAX, &scno) < 0)
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return -1;
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/* TODO: speed up strace by not doing this at every syscall.
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* We only need to do it after execve.
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*/
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int currpers;
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long val;
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int pid = tcp->pid;
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if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (long) &x86_64_regs) < 0)
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return -1;
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scno = x86_64_regs.orig_rax;
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/* Check CS register value. On x86-64 linux it is:
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* 0x33 for long mode (64 bit)
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* 0x23 for compatibility mode (32 bit)
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* It takes only one ptrace and thus doesn't need
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* to be cached.
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*/
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if (upeek(tcp, 8*CS, &val) < 0)
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return -1;
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switch (val) {
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switch (x86_64_regs.cs) {
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case 0x23: currpers = 1; break;
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case 0x33: currpers = 0; break;
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default:
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fprintf(stderr, "Unknown value CS=0x%02X while "
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fprintf(stderr, "Unknown value CS=0x%08X while "
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"detecting personality of process "
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"PID=%d\n", (int)val, pid);
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"PID=%d\n", (int)x86_64_regs.cs, tcp->pid);
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currpers = current_personality;
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break;
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}
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@ -933,14 +925,13 @@ get_scno(struct tcb *tcp)
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*/
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unsigned long val, rip, i;
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if (upeek(tcp, 8*RIP, &rip) < 0)
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perror("upeek(RIP)");
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rip = x86_64_regs.rip;
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/* sizeof(syscall) == sizeof(int 0x80) == 2 */
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rip -= 2;
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errno = 0;
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call = ptrace(PTRACE_PEEKTEXT, pid, (char *)rip, (char *)0);
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call = ptrace(PTRACE_PEEKTEXT, tcp->pid, (char *)rip, (char *)0);
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if (errno)
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fprintf(stderr, "ptrace_peektext failed: %s\n",
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strerror(errno));
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@ -954,7 +945,7 @@ get_scno(struct tcb *tcp)
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fprintf(stderr,
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"Unknown syscall opcode (0x%04X) while "
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"detecting personality of process "
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"PID=%d\n", (int)call, pid);
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"PID=%d\n", (int)call, tcp->pid);
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break;
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}
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# endif
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@ -962,14 +953,14 @@ get_scno(struct tcb *tcp)
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static const char *const names[] = {"64 bit", "32 bit"};
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set_personality(currpers);
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fprintf(stderr, "[ Process PID=%d runs in %s mode. ]\n",
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pid, names[current_personality]);
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tcp->pid, names[current_personality]);
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}
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# elif defined(IA64)
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# define IA64_PSR_IS ((long)1 << 34)
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if (upeek(tcp, PT_CR_IPSR, &psr) >= 0)
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ia32 = (psr & IA64_PSR_IS) != 0;
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if (ia32) {
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if (upeek(tcp, PT_R1, &scno) < 0) /* orig eax */
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if (upeek(tcp, PT_R1, &scno) < 0)
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return -1;
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} else {
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if (upeek(tcp, PT_R15, &scno) < 0)
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@ -1291,26 +1282,17 @@ syscall_fixup_on_sysenter(struct tcb *tcp)
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#ifdef LINUX
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/* A common case of "not a syscall entry" is post-execve SIGTRAP */
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#if defined (I386)
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/* With PTRACE_O_TRACEEXEC, post-execve SIGTRAP is disabled.
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* Every extra ptrace call is expensive, so check EAX
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* on syscall entry only if PTRACE_O_TRACEEXEC is not enabled:
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*/
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if (!(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
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if (upeek(tcp, 4*EAX, &eax) < 0)
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return -1;
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if (eax != -ENOSYS) {
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if (debug)
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fprintf(stderr, "not a syscall entry (eax = %ld)\n", eax);
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return 0;
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}
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if (i386_regs.eax != -ENOSYS) {
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if (debug)
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fprintf(stderr, "not a syscall entry (eax = %ld)\n", i386_regs.eax);
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return 0;
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}
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#elif defined (X86_64)
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if (!(ptrace_setoptions & PTRACE_O_TRACEEXEC)) {
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if (upeek(tcp, 8*RAX, &rax) < 0)
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return -1;
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{
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long rax = x86_64_regs.rax;
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if (current_personality == 1)
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rax = (long int)(int)rax; /* sign extend from 32 bits */
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if (rax != -ENOSYS && entering(tcp)) {
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rax = (int)rax; /* sign extend from 32 bits */
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if (rax != -ENOSYS) {
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if (debug)
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fprintf(stderr, "not a syscall entry (rax = %ld)\n", rax);
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return 0;
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@ -1521,6 +1503,7 @@ syscall_enter(struct tcb *tcp)
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for (i = 0; i < nargs; ++i)
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tcp->u_arg[i] = regs.uregs[i];
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# elif defined(AVR32)
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/* TODO: make it faster by unrolling into 6 direct assignments */
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static const unsigned long *argregp[MAX_ARGS] = { ®s.r12,
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®s.r11,
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®s.r10,
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@ -1553,14 +1536,24 @@ syscall_enter(struct tcb *tcp)
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if (upeek(tcp, REG_GENERAL(syscall_regs[i]), &tcp->u_arg[i]) < 0)
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return -1;
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# elif defined(X86_64)
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static const int argreg[SUPPORTED_PERSONALITIES][MAX_ARGS] = {
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{ 8 * RDI, 8 * RSI, 8 * RDX, 8 * R10, 8 * R8 , 8 * R9 }, /* x86-64 ABI */
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{ 8 * RBX, 8 * RCX, 8 * RDX, 8 * RSI, 8 * RDI, 8 * RBP } /* i386 ABI */
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};
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for (i = 0; i < nargs; ++i)
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if (upeek(tcp, argreg[current_personality][i], &tcp->u_arg[i]) < 0)
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return -1;
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(void)i;
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(void)nargs;
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if (current_personality == 0) { /* x86-64 ABI */
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tcp->u_arg[0] = x86_64_regs.rdi;
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tcp->u_arg[1] = x86_64_regs.rsi;
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tcp->u_arg[2] = x86_64_regs.rdx;
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tcp->u_arg[3] = x86_64_regs.r10;
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tcp->u_arg[4] = x86_64_regs.r8;
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tcp->u_arg[5] = x86_64_regs.r9;
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} else { /* i386 ABI */
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/* Sign-extend lower 32 bits */
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tcp->u_arg[0] = (long)(int)x86_64_regs.rbx;
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tcp->u_arg[1] = (long)(int)x86_64_regs.rcx;
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tcp->u_arg[2] = (long)(int)x86_64_regs.rdx;
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tcp->u_arg[3] = (long)(int)x86_64_regs.rsi;
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tcp->u_arg[4] = (long)(int)x86_64_regs.rdi;
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tcp->u_arg[5] = (long)(int)x86_64_regs.rbp;
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}
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# elif defined(MICROBLAZE)
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for (i = 0; i < nargs; ++i)
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if (upeek(tcp, (5 + i) * 4, &tcp->u_arg[i]) < 0)
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@ -1582,7 +1575,16 @@ syscall_enter(struct tcb *tcp)
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for (i = 0; i < nargs; ++i)
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if (upeek(tcp, (i < 5 ? i : i + 2)*4, &tcp->u_arg[i]) < 0)
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return -1;
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# else /* Other architecture (like i386) (32bits specific) */
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# elif defined(I386)
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(void)i;
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(void)nargs;
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tcp->u_arg[0] = i386_regs.ebx;
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tcp->u_arg[1] = i386_regs.ecx;
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tcp->u_arg[2] = i386_regs.edx;
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tcp->u_arg[3] = i386_regs.esi;
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tcp->u_arg[4] = i386_regs.edi;
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tcp->u_arg[5] = i386_regs.ebp;
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# else /* Other architecture (32bits specific) */
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for (i = 0; i < nargs; ++i)
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if (upeek(tcp, i*4, &tcp->u_arg[i]) < 0)
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return -1;
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@ -1882,10 +1884,10 @@ get_syscall_result(struct tcb *tcp)
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if (upeek(tcp, PT_R0, &r0) < 0)
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return -1;
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# elif defined (I386)
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if (upeek(tcp, 4*EAX, &eax) < 0)
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if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (long) &i386_regs) < 0)
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return -1;
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# elif defined (X86_64)
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if (upeek(tcp, 8*RAX, &rax) < 0)
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if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (long) &x86_64_regs) < 0)
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return -1;
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# elif defined(IA64)
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# define IA64_PSR_IS ((long)1 << 34)
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@ -2053,20 +2055,20 @@ get_error(struct tcb *tcp)
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tcp->u_rval = gpr2;
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}
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# elif defined(I386)
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if (check_errno && is_negated_errno(eax)) {
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if (check_errno && is_negated_errno(i386_regs.eax)) {
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tcp->u_rval = -1;
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u_error = -eax;
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u_error = -i386_regs.eax;
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}
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else {
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tcp->u_rval = eax;
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tcp->u_rval = i386_regs.eax;
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}
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# elif defined(X86_64)
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if (check_errno && is_negated_errno(rax)) {
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if (check_errno && is_negated_errno(x86_64_regs.rax)) {
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tcp->u_rval = -1;
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u_error = -rax;
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u_error = -x86_64_regs.rax;
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}
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else {
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tcp->u_rval = rax;
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tcp->u_rval = x86_64_regs.rax;
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}
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# elif defined(IA64)
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if (ia32) {
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