From: Jeff Dike This implements using the new ptrace option SYSEMU_SINGLESTEP in UML (advanced sysemu) in SKAS and TT modes. To have a fast selection of the appropriate ptrace option to use next, a 2 dimensional arry is used and singlestepping() is modified to return 0,1 or 2: 0 = don't do singlestepping 1 = singlestep a syscall 2 = singlestep a "non syscall" instruction In do_syscall() writing of the syscall number is supressed, if the advanced sysemu is in use (that does it itself). Signed-off-by: Bodo Stroesser Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton --- 25-akpm/arch/um/include/ptrace_user.h | 7 +++++++ 25-akpm/arch/um/kernel/process_kern.c | 4 ++-- 25-akpm/arch/um/kernel/skas/process.c | 10 ++++------ 25-akpm/arch/um/kernel/tt/syscall_user.c | 4 ++++ 25-akpm/arch/um/kernel/tt/tracer.c | 18 +++++++----------- 5 files changed, 24 insertions(+), 19 deletions(-) diff -puN arch/um/include/ptrace_user.h~uml-use-sysemu_singlestep arch/um/include/ptrace_user.h --- 25/arch/um/include/ptrace_user.h~uml-use-sysemu_singlestep Fri Dec 3 13:50:43 2004 +++ 25-akpm/arch/um/include/ptrace_user.h Fri Dec 3 13:50:43 2004 @@ -29,4 +29,11 @@ void set_using_sysemu(int value); int get_using_sysemu(void); extern int sysemu_supported; +#define SELECT_PTRACE_OPERATION(sysemu_mode, singlestep_mode) \ + (((int[3][3] ) { \ + { PTRACE_SYSCALL, PTRACE_SYSCALL, PTRACE_SINGLESTEP }, \ + { PTRACE_SYSEMU, PTRACE_SYSEMU, PTRACE_SINGLESTEP }, \ + { PTRACE_SYSEMU, PTRACE_SYSEMU_SINGLESTEP, PTRACE_SYSEMU_SINGLESTEP }}) \ + [sysemu_mode][singlestep_mode]) + #endif diff -puN arch/um/kernel/process_kern.c~uml-use-sysemu_singlestep arch/um/kernel/process_kern.c --- 25/arch/um/kernel/process_kern.c~uml-use-sysemu_singlestep Fri Dec 3 13:50:43 2004 +++ 25-akpm/arch/um/kernel/process_kern.c Fri Dec 3 13:50:43 2004 @@ -464,9 +464,9 @@ int singlestepping(void * t) return(0); if (task->thread.singlestep_syscall) - return(0); + return(1); - return 1; + return 2; } /* diff -puN arch/um/kernel/skas/process.c~uml-use-sysemu_singlestep arch/um/kernel/skas/process.c --- 25/arch/um/kernel/skas/process.c~uml-use-sysemu_singlestep Fri Dec 3 13:50:43 2004 +++ 25-akpm/arch/um/kernel/skas/process.c Fri Dec 3 13:50:43 2004 @@ -140,15 +140,15 @@ void start_userspace(int cpu) void userspace(union uml_pt_regs *regs) { - int err, status, op, pt_syscall_parm, pid = userspace_pid[0]; + int err, status, op, pid = userspace_pid[0]; int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ restore_registers(regs); local_using_sysemu = get_using_sysemu(); - pt_syscall_parm = local_using_sysemu ? PTRACE_SYSEMU : PTRACE_SYSCALL; - err = ptrace(pt_syscall_parm, pid, 0, 0); + op = local_using_sysemu ? PTRACE_SYSEMU : PTRACE_SYSCALL; + err = ptrace(op, pid, 0, 0); if(err) panic("userspace - PTRACE_%s failed, errno = %d\n", @@ -196,10 +196,8 @@ void userspace(union uml_pt_regs *regs) /*Now we ended the syscall, so re-read local_using_sysemu.*/ local_using_sysemu = get_using_sysemu(); - pt_syscall_parm = local_using_sysemu ? PTRACE_SYSEMU : PTRACE_SYSCALL; - op = singlestepping(NULL) ? PTRACE_SINGLESTEP : - pt_syscall_parm; + op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL)); err = ptrace(op, pid, 0, 0); if(err) diff -puN arch/um/kernel/tt/syscall_user.c~uml-use-sysemu_singlestep arch/um/kernel/tt/syscall_user.c --- 25/arch/um/kernel/tt/syscall_user.c~uml-use-sysemu_singlestep Fri Dec 3 13:50:43 2004 +++ 25-akpm/arch/um/kernel/tt/syscall_user.c Fri Dec 3 13:50:43 2004 @@ -62,6 +62,10 @@ void do_syscall(void *task, int pid, int ((unsigned long *) PT_IP(proc_regs) <= &_etext)) tracer_panic("I'm tracing myself and I can't get out"); + /* advanced sysemu mode set syscall number to -1 automatically */ + if (local_using_sysemu==2) + return; + /* syscall number -1 in sysemu skips syscall restarting in host */ if(ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, local_using_sysemu ? -1 : __NR_getpid) < 0) diff -puN arch/um/kernel/tt/tracer.c~uml-use-sysemu_singlestep arch/um/kernel/tt/tracer.c --- 25/arch/um/kernel/tt/tracer.c~uml-use-sysemu_singlestep Fri Dec 3 13:50:43 2004 +++ 25-akpm/arch/um/kernel/tt/tracer.c Fri Dec 3 13:50:43 2004 @@ -186,7 +186,7 @@ int tracer(int (*init_proc)(void *), voi unsigned long eip = 0; int status, pid = 0, sig = 0, cont_type, tracing = 0, op = 0; int last_index, proc_id = 0, n, err, old_tracing = 0, strace = 0; - int pt_syscall_parm, local_using_sysemu = 0; + int local_using_sysemu = 0; signal(SIGPIPE, SIG_IGN); setup_tracer_winch(); @@ -391,18 +391,14 @@ int tracer(int (*init_proc)(void *), voi } local_using_sysemu = get_using_sysemu(); - pt_syscall_parm = local_using_sysemu ? PTRACE_SYSEMU : PTRACE_SYSCALL; - if(tracing){ - if(singlestepping(task)) - cont_type = PTRACE_SINGLESTEP; - else cont_type = pt_syscall_parm; - } - else cont_type = PTRACE_CONT; - - if((cont_type == PTRACE_CONT) && - (debugger_pid != -1) && strace) + if(tracing) + cont_type = SELECT_PTRACE_OPERATION(local_using_sysemu, + singlestepping(task)); + else if((debugger_pid != -1) && strace) cont_type = PTRACE_SYSCALL; + else + cont_type = PTRACE_CONT; if(ptrace(cont_type, pid, 0, sig) != 0){ tracer_panic("ptrace failed to continue " _