x86 ptrace: unify syscall tracing
This unifies and cleans up the syscall tracing code on i386 and x86_64.
Using a single function for entry and exit tracing on 32-bit made the
do_syscall_trace() into some terrible spaghetti. The logic is clear and
simple using separate syscall_trace_enter() and syscall_trace_leave()
functions as on 64-bit.
The unification adds PTRACE_SYSEMU and PTRACE_SYSEMU_SINGLESTEP support
on x86_64, for 32-bit ptrace() callers and for 64-bit ptrace() callers
tracing either 32-bit or 64-bit tasks. It behaves just like 32-bit.
Changing syscall_trace_enter() to return the syscall number shortens
all the assembly paths, while adding the SYSEMU feature in a simple way.
Signed-off-by: Roland McGrath <roland@redhat.com>
diff --git a/include/asm-x86/calling.h b/include/asm-x86/calling.h
index f13e62e..2bc162e 100644
--- a/include/asm-x86/calling.h
+++ b/include/asm-x86/calling.h
@@ -104,7 +104,7 @@
.endif
.endm
- .macro LOAD_ARGS offset
+ .macro LOAD_ARGS offset, skiprax=0
movq \offset(%rsp), %r11
movq \offset+8(%rsp), %r10
movq \offset+16(%rsp), %r9
@@ -113,7 +113,10 @@
movq \offset+48(%rsp), %rdx
movq \offset+56(%rsp), %rsi
movq \offset+64(%rsp), %rdi
+ .if \skiprax
+ .else
movq \offset+72(%rsp), %rax
+ .endif
.endm
#define REST_SKIP 6*8
@@ -165,4 +168,3 @@
.macro icebp
.byte 0xf1
.endm
-
diff --git a/include/asm-x86/ptrace-abi.h b/include/asm-x86/ptrace-abi.h
index f224eb3..72e7b9d 100644
--- a/include/asm-x86/ptrace-abi.h
+++ b/include/asm-x86/ptrace-abi.h
@@ -73,11 +73,11 @@
#ifdef __x86_64__
# define PTRACE_ARCH_PRCTL 30
-#else
-# define PTRACE_SYSEMU 31
-# define PTRACE_SYSEMU_SINGLESTEP 32
#endif
+#define PTRACE_SYSEMU 31
+#define PTRACE_SYSEMU_SINGLESTEP 32
+
#define PTRACE_SINGLEBLOCK 33 /* resume execution until next branch */
#ifndef __ASSEMBLY__
diff --git a/include/asm-x86/thread_info.h b/include/asm-x86/thread_info.h
index fb8d3cd..b2702a1 100644
--- a/include/asm-x86/thread_info.h
+++ b/include/asm-x86/thread_info.h
@@ -75,9 +75,7 @@
#define TIF_NEED_RESCHED 3 /* rescheduling necessary */
#define TIF_SINGLESTEP 4 /* reenable singlestep on user return*/
#define TIF_IRET 5 /* force IRET */
-#ifdef CONFIG_X86_32
#define TIF_SYSCALL_EMU 6 /* syscall emulation active */
-#endif
#define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */
#define TIF_SECCOMP 8 /* secure computing */
#define TIF_MCE_NOTIFY 10 /* notify userspace of an MCE */
@@ -100,11 +98,7 @@
#define _TIF_SINGLESTEP (1 << TIF_SINGLESTEP)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_IRET (1 << TIF_IRET)
-#ifdef CONFIG_X86_32
#define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU)
-#else
-#define _TIF_SYSCALL_EMU 0
-#endif
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SECCOMP (1 << TIF_SECCOMP)
#define _TIF_MCE_NOTIFY (1 << TIF_MCE_NOTIFY)
@@ -121,11 +115,20 @@
#define _TIF_DS_AREA_MSR (1 << TIF_DS_AREA_MSR)
#define _TIF_BTS_TRACE_TS (1 << TIF_BTS_TRACE_TS)
+/* work to do in syscall_trace_enter() */
+#define _TIF_WORK_SYSCALL_ENTRY \
+ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU | \
+ _TIF_SYSCALL_AUDIT | _TIF_SECCOMP)
+
+/* work to do in syscall_trace_leave() */
+#define _TIF_WORK_SYSCALL_EXIT \
+ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SINGLESTEP)
+
/* work to do on interrupt/exception return */
#define _TIF_WORK_MASK \
(0x0000FFFF & \
~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT| \
- _TIF_SECCOMP|_TIF_SYSCALL_EMU))
+ _TIF_SINGLESTEP|_TIF_SECCOMP|_TIF_SYSCALL_EMU))
/* work to do on any return to user space */
#define _TIF_ALLWORK_MASK (0x0000FFFF & ~_TIF_SECCOMP)