Optimize out PTRACE_PEEKUSER with -i
strace -i was fetching PC with a separate PEEKUSER
despite having GETREGS data:
ptrace(PTRACE_GETREGS, 22331, 0, 0x8087f00) = 0
ptrace(PTRACE_PEEKUSER, 22331, 4*EIP, [0x80dd7b7]) = 0
write(3, "[080dd7b7] ioctl(0, SNDCTL_TMR_T"..., 82) = 82
ptrace(PTRACE_SYSCALL, 22331, 0, SIG_0) = 0
Now it does this:
ptrace(PTRACE_GETREGS, 22549, 0, 0x8087ea0) = 0
write(3, "[080dd7b7] ioctl(0, SNDCTL_TMR_T"..., 82) = 82
ptrace(PTRACE_SYSCALL, 22549, 0, SIG_0) = 0
Analogous improvement in sys_sigreturn() is also implemented.
* defs.h: Declare extern struct pt_regs regs for SPARC[64] and ARM.
Declare clear_regs(), get_regs() and get_regs_error flag variable.
* strace.c (trace): Call get_regs(pid) as soon as we know the tcb
and that it is stopped.
* syscall.c (get_regs): New function. Used to fetch registers early,
just after tracee has stopped.
(printcall): Move it here from util.c. Use global regs.REG data,
if available on the arch, instead of re-fetching it.
(get_scno): Use global regs.REG data.
(get_syscall_result): Likewise.
* signal.c (sys_sigreturn): Likewise.
* util.c (printcall): Moved to syscall.c.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/syscall.c b/syscall.c
index 69eceed..87a66fc 100644
--- a/syscall.c
+++ b/syscall.c
@@ -618,9 +618,6 @@
long val = -1;
#if defined(SPARC) || defined(SPARC64)
- struct pt_regs regs;
- if (ptrace(PTRACE_GETREGS, tcp->pid, (char *)®s, 0) < 0)
- return -1;
val = regs.u_regs[U_REG_O1];
#elif defined(SH)
if (upeek(tcp, 4*(REG_REG0+1), &val) < 0)
@@ -668,17 +665,20 @@
#elif defined(BFIN)
static long r0;
#elif defined(ARM)
-static struct pt_regs regs;
+struct pt_regs regs; /* not static */
#elif defined(AARCH64)
static struct user_pt_regs aarch64_regs;
static struct arm_pt_regs regs;
+static struct iovec aarch64_io = {
+ .iov_base = &aarch64_regs
+};
#elif defined(ALPHA)
static long r0;
static long a3;
#elif defined(AVR32)
static struct pt_regs regs;
#elif defined(SPARC) || defined(SPARC64)
-static struct pt_regs regs;
+struct pt_regs regs; /* not static */
static unsigned long trap;
#elif defined(LINUX_MIPSN32)
static long long a3;
@@ -702,6 +702,172 @@
static long r3;
#endif
+void
+printcall(struct tcb *tcp)
+{
+#define PRINTBADPC tprintf(sizeof(long) == 4 ? "[????????] " : \
+ sizeof(long) == 8 ? "[????????????????] " : \
+ NULL /* crash */)
+ if (get_regs_error) {
+ PRINTBADPC;
+ return;
+ }
+#if defined(I386)
+ tprintf("[%08lx] ", i386_regs.eip);
+#elif defined(S390) || defined(S390X)
+ long psw;
+ if (upeek(tcp, PT_PSWADDR, &psw) < 0) {
+ PRINTBADPC;
+ return;
+ }
+# ifdef S390
+ tprintf("[%08lx] ", psw);
+# elif S390X
+ tprintf("[%16lx] ", psw);
+# endif
+#elif defined(X86_64) || defined(X32)
+ tprintf("[%16lx] ", x86_64_regs.ip);
+#elif defined(IA64)
+ long ip;
+
+ if (upeek(tcp, PT_B0, &ip) < 0) {
+ PRINTBADPC;
+ return;
+ }
+ tprintf("[%08lx] ", ip);
+#elif defined(POWERPC)
+ long pc;
+
+ if (upeek(tcp, sizeof(unsigned long)*PT_NIP, &pc) < 0) {
+ PRINTBADPC;
+ return;
+ }
+# ifdef POWERPC64
+ tprintf("[%016lx] ", pc);
+# else
+ tprintf("[%08lx] ", pc);
+# endif
+#elif defined(M68K)
+ long pc;
+
+ if (upeek(tcp, 4*PT_PC, &pc) < 0) {
+ tprints("[????????] ");
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#elif defined(ALPHA)
+ long pc;
+
+ if (upeek(tcp, REG_PC, &pc) < 0) {
+ tprints("[????????????????] ");
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#elif defined(SPARC)
+ tprintf("[%08lx] ", regs.pc);
+#elif defined(SPARC64)
+ tprintf("[%08lx] ", regs.tpc);
+#elif defined(HPPA)
+ long pc;
+
+ if (upeek(tcp, PT_IAOQ0, &pc) < 0) {
+ tprints("[????????] ");
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#elif defined(MIPS)
+ long pc;
+
+ if (upeek(tcp, REG_EPC, &pc) < 0) {
+ tprints("[????????] ");
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#elif defined(SH)
+ long pc;
+
+ if (upeek(tcp, 4*REG_PC, &pc) < 0) {
+ tprints("[????????] ");
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#elif defined(SH64)
+ long pc;
+
+ if (upeek(tcp, REG_PC, &pc) < 0) {
+ tprints("[????????????????] ");
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#elif defined(ARM)
+ tprintf("[%08lx] ", regs.ARM_pc);
+/*#elif defined(AARCH64) ??? */
+#elif defined(AVR32)
+ tprintf("[%08lx] ", regs.pc);
+#elif defined(BFIN)
+ long pc;
+
+ if (upeek(tcp, PT_PC, &pc) < 0) {
+ PRINTBADPC;
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#elif defined(CRISV10)
+ long pc;
+
+ if (upeek(tcp, 4*PT_IRP, &pc) < 0) {
+ PRINTBADPC;
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#elif defined(CRISV32)
+ long pc;
+
+ if (upeek(tcp, 4*PT_ERP, &pc) < 0) {
+ PRINTBADPC;
+ return;
+ }
+ tprintf("[%08lx] ", pc);
+#endif /* architecture */
+}
+
+#ifndef get_regs
+long get_regs_error;
+void get_regs(pid_t pid)
+{
+# if defined(AVR32)
+ get_regs_error = ptrace(PTRACE_GETREGS, pid, NULL, ®s);
+# elif defined(I386)
+ get_regs_error = ptrace(PTRACE_GETREGS, pid, NULL, (long) &i386_regs);
+# elif defined(X86_64) || defined(X32)
+ get_regs_error = ptrace(PTRACE_GETREGS, pid, NULL, (long) &x86_64_regs);
+# elif defined(AARCH64)
+ /*aarch64_io.iov_base = &aarch64_regs; - already is */
+ aarch64_io.iov_len = sizeof(aarch64_regs);
+ get_regs_error = ptrace(PTRACE_GETREGSET, pid, NT_PRSTATUS, (void *)&aarch64_io);
+ if (get_regs_error)
+ return;
+ switch (aarch64_io.iov_len) {
+ case sizeof(regs):
+ /* We are in 32-bit mode */
+ memcpy(®s, &aarch64_regs, sizeof(regs));
+ break;
+ case sizeof(aarch64_regs):
+ /* We are in 64-bit mode */
+ /* Data is already in aarch64_regs */
+ break;
+ default:
+ get_regs_error = -1;
+ break;
+ }
+# elif defined(ARM)
+ get_regs_error = ptrace(PTRACE_GETREGS, pid, NULL, (void *)®s);
+# elif defined(SPARC) || defined(SPARC64)
+ get_regs_error = ptrace(PTRACE_GETREGS, pid, (char *)®s, 0);
+# endif
+}
+#endif
+
/* Returns:
* 0: "ignore this ptrace stop", bail out of trace_syscall_entering() silently.
* 1: ok, continue in trace_syscall_entering().
@@ -815,16 +981,11 @@
update_personality(tcp, currpers);
# endif
#elif defined(AVR32)
- /* Read complete register set in one go. */
- if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, ®s) < 0)
- return -1;
scno = regs.r8;
#elif defined(BFIN)
if (upeek(tcp, PT_ORIG_P0, &scno))
return -1;
#elif defined(I386)
- if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (long) &i386_regs) < 0)
- return -1;
scno = i386_regs.orig_eax;
#elif defined(X86_64) || defined(X32)
# ifndef __X32_SYSCALL_BIT
@@ -835,8 +996,6 @@
# endif
int currpers;
- if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (long) &x86_64_regs) < 0)
- return -1;
scno = x86_64_regs.orig_rax;
/* Check CS register value. On x86-64 linux it is:
@@ -924,33 +1083,19 @@
return -1;
}
#elif defined(AARCH64)
- struct iovec io;
- char buf[sizeof(aarch64_regs)];
- io.iov_base = &buf;
- io.iov_len = sizeof(aarch64_regs);
- if (ptrace(PTRACE_GETREGSET, tcp->pid, NT_PRSTATUS, (void *)&io) == -1)
- return -1;
- switch (io.iov_len) {
+ switch (aarch64_io.iov_len) {
case sizeof(aarch64_regs):
/* We are in 64-bit mode */
- memcpy(&aarch64_regs, buf, sizeof(aarch64_regs));
scno = aarch64_regs.regs[8];
update_personality(tcp, 1);
break;
case sizeof(regs):
/* We are in 32-bit mode */
- memcpy(®s, buf, sizeof(regs));
scno = regs.uregs[7];
update_personality(tcp, 0);
break;
- default:
- return -1;
}
#elif defined(ARM)
- /* Read complete register set in one go. */
- if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (void *)®s) == -1)
- return -1;
-
/*
* We only need to grab the syscall number on syscall entry.
*/
@@ -1055,10 +1200,6 @@
}
}
#elif defined(SPARC) || defined(SPARC64)
- /* Everything we need is in the current register set. */
- if (ptrace(PTRACE_GETREGS, tcp->pid, (char *)®s, 0) < 0)
- return -1;
-
/* Disassemble the syscall trap. */
/* Retrieve the syscall trap instruction. */
errno = 0;
@@ -1557,7 +1698,7 @@
}
#endif
- scno_good = res = get_scno(tcp);
+ scno_good = res = (get_regs_error ? -1 : get_scno(tcp));
if (res == 0)
return res;
if (res == 1) {
@@ -1661,18 +1802,14 @@
ppc_result = -ppc_result;
}
#elif defined(AVR32)
- /* Read complete register set in one go. */
- if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, ®s) < 0)
- return -1;
+ /* already done by get_regs */
#elif defined(BFIN)
if (upeek(tcp, PT_R0, &r0) < 0)
return -1;
#elif defined(I386)
- if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (long) &i386_regs) < 0)
- return -1;
+ /* already done by get_regs */
#elif defined(X86_64) || defined(X32)
- if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (long) &x86_64_regs) < 0)
- return -1;
+ /* already done by get_regs */
#elif defined(IA64)
# define IA64_PSR_IS ((long)1 << 34)
if (upeek(tcp, PT_CR_IPSR, &psr) >= 0)
@@ -1682,30 +1819,13 @@
if (upeek(tcp, PT_R10, &r10) < 0)
return -1;
#elif defined(AARCH64)
- struct iovec io;
- char buf[sizeof(aarch64_regs)];
- io.iov_base = &buf;
- io.iov_len = sizeof(aarch64_regs);
- if (ptrace(PTRACE_GETREGSET, tcp->pid, NT_PRSTATUS, (void *)&io) == -1)
- return -1;
- switch (io.iov_len) {
- case sizeof(aarch64_regs):
- /* We are in 64-bit mode */
- memcpy(&aarch64_regs, buf, sizeof(aarch64_regs));
- update_personality(tcp, 1);
- break;
- case sizeof(regs):
- /* We are in 32-bit mode */
- memcpy(®s, buf, sizeof(regs));
- update_personality(tcp, 0);
- break;
- default:
- return -1;
- }
+/* FIXME: uh, why do we do it on syscall *exit*? We did it on entry already... */
+ /* We are in 64-bit mode (personality 1) if register struct is aarch64_regs,
+ * else it's personality 0.
+ */
+ update_personality(tcp, aarch64_io.iov_len == sizeof(aarch64_regs));
#elif defined(ARM)
- /* Read complete ARM register set in one go. */
- if (ptrace(PTRACE_GETREGS, tcp->pid, NULL, (void *)®s) == -1)
- return -1;
+ /* already done by get_regs */
#elif defined(M68K)
if (upeek(tcp, 4*PT_D0, &d0) < 0)
return -1;
@@ -1727,14 +1847,18 @@
if (upeek(tcp, REG_R0, &r0) < 0)
return -1;
#elif defined(SPARC) || defined(SPARC64)
- /* Everything we need is in the current register set. */
- if (ptrace(PTRACE_GETREGS, tcp->pid, (char *)®s, 0) < 0)
- return -1;
+ /* already done by get_regs */
#elif defined(HPPA)
if (upeek(tcp, PT_GR28, &r28) < 0)
return -1;
#elif defined(SH)
+ /* new syscall ABI returns result in R0 */
+ if (upeek(tcp, 4*REG_REG0, (long *)&r0) < 0)
+ return -1;
#elif defined(SH64)
+ /* ABI defines result returned in r9 */
+ if (upeek(tcp, REG_GENERAL(9), (long *)&r9) < 0)
+ return -1;
#elif defined(CRISV10) || defined(CRISV32)
if (upeek(tcp, 4*PT_R10, &r10) < 0)
return -1;
@@ -1743,17 +1867,6 @@
if (upeek(tcp, 3 * 4, &r3) < 0)
return -1;
#endif
-
-#if defined(SH)
- /* new syscall ABI returns result in R0 */
- if (upeek(tcp, 4*REG_REG0, (long *)&r0) < 0)
- return -1;
-#elif defined(SH64)
- /* ABI defines result returned in r9 */
- if (upeek(tcp, REG_GENERAL(9), (long *)&r9) < 0)
- return -1;
-#endif
-
return 1;
}
@@ -2045,7 +2158,7 @@
#if SUPPORTED_PERSONALITIES > 1
update_personality(tcp, tcp->currpers);
#endif
- res = get_syscall_result(tcp);
+ res = (get_regs_error ? -1 : get_syscall_result(tcp));
if (res == 1) {
syscall_fixup_on_sysexit(tcp); /* never fails */
res = get_error(tcp); /* returns 1 or -1 */