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>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/asm-x86/ptrace-abi.h b/include/asm-x86/ptrace-abi.h
index f224eb3c3157..72e7b9db29bb 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__