From: Adds /proc/sysemu to toggle SYSEMU usage. Signed-off-by: Paolo 'Blaisorblade' Giarrusso Signed-off-by: Andrew Morton --- 25-akpm/arch/um/kernel/process.c | 4 - 25-akpm/arch/um/kernel/skas/include/ptrace-skas.h | 4 + 25-akpm/arch/um/kernel/skas/process.c | 62 ++++++++++------------ 25-akpm/arch/um/kernel/skas/process_kern.c | 59 ++++++++++++++++++++ 4 files changed, 93 insertions(+), 36 deletions(-) diff -puN arch/um/kernel/process.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage arch/um/kernel/process.c --- 25/arch/um/kernel/process.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage 2004-07-05 16:00:45.667078000 -0700 +++ 25-akpm/arch/um/kernel/process.c 2004-07-05 16:00:45.684075416 -0700 @@ -246,7 +246,7 @@ void __init check_ptrace(void) printk("OK\n"); printk("Checking syscall emulation patch for ptrace..."); - use_sysemu = 0; + set_using_sysemu(0); pid = start_ptraced_child(&stack); if(ptrace(PTRACE_SYSEMU, pid, 0, 0) >= 0) { struct user_regs_struct regs; @@ -269,7 +269,7 @@ void __init check_ptrace(void) if (!force_sysemu_disabled) { printk("found\n"); - use_sysemu = 1; + set_using_sysemu(1); } else { printk("found but disabled\n"); } diff -puN arch/um/kernel/skas/include/ptrace-skas.h~uml-adds-proc-sysemu-to-toggle-sysemu-usage arch/um/kernel/skas/include/ptrace-skas.h --- 25/arch/um/kernel/skas/include/ptrace-skas.h~uml-adds-proc-sysemu-to-toggle-sysemu-usage 2004-07-05 16:00:45.678076328 -0700 +++ 25-akpm/arch/um/kernel/skas/include/ptrace-skas.h 2004-07-05 16:00:45.684075416 -0700 @@ -15,7 +15,9 @@ #ifndef PTRACE_SYSEMU #define PTRACE_SYSEMU 31 #endif -extern int use_sysemu; + +void set_using_sysemu(int value); +int get_using_sysemu(void); #include "skas_ptregs.h" diff -puN arch/um/kernel/skas/process.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage arch/um/kernel/skas/process.c --- 25/arch/um/kernel/skas/process.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage 2004-07-05 16:00:45.679076176 -0700 +++ 25-akpm/arch/um/kernel/skas/process.c 2004-07-05 16:00:45.686075112 -0700 @@ -28,10 +28,6 @@ #include "chan_user.h" #include "signal_user.h" -#ifdef PTRACE_SYSEMU -int use_sysemu = 0; -#endif - int is_skas_winch(int pid, int fd, void *data) { if(pid != getpid()) @@ -61,7 +57,8 @@ static void handle_segv(int pid) segv(fault.addr, 0, FAULT_WRITE(fault.is_write), 1, NULL); } -static void handle_trap(int pid, union uml_pt_regs *regs) +/*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/ +static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu) { int err, syscall_nr, status; @@ -72,27 +69,23 @@ static void handle_trap(int pid, union u return; } -#ifdef PTRACE_SYSEMU - if (!use_sysemu) + if (!local_using_sysemu) { -#endif - err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid); - if(err < 0) - panic("handle_trap - nullifying syscall failed errno = %d\n", - errno); + err = ptrace(PTRACE_POKEUSER, pid, PT_SYSCALL_NR_OFFSET, __NR_getpid); + if(err < 0) + panic("handle_trap - nullifying syscall failed errno = %d\n", + errno); + + err = ptrace(PTRACE_SYSCALL, pid, 0, 0); + if(err < 0) + panic("handle_trap - continuing to end of syscall failed, " + "errno = %d\n", errno); - err = ptrace(PTRACE_SYSCALL, pid, 0, 0); - if(err < 0) - panic("handle_trap - continuing to end of syscall failed, " - "errno = %d\n", errno); - - err = waitpid(pid, &status, WUNTRACED); - if((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) - panic("handle_trap - failed to wait at end of syscall, " - "errno = %d, status = %d\n", errno, status); -#ifdef PTRACE_SYSEMU + err = waitpid(pid, &status, WUNTRACED); + if((err < 0) || !WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP)) + panic("handle_trap - failed to wait at end of syscall, " + "errno = %d, status = %d\n", errno, status); } -#endif handle_syscall(regs); } @@ -147,15 +140,16 @@ void start_userspace(int cpu) void userspace(union uml_pt_regs *regs) { int err, status, op, pid = userspace_pid[0]; + int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/ restore_registers(regs); -#ifdef PTRACE_SYSEMU - if (use_sysemu) + local_using_sysemu = get_using_sysemu(); + + if (local_using_sysemu) err = ptrace(PTRACE_SYSEMU, pid, 0, 0); else -#endif - err = ptrace(PTRACE_SYSCALL, pid, 0, 0); + err = ptrace(PTRACE_SYSCALL, pid, 0, 0); if(err) panic("userspace - PTRACE_SYSCALL failed, errno = %d\n", errno); @@ -174,7 +168,7 @@ void userspace(union uml_pt_regs *regs) handle_segv(pid); break; case SIGTRAP: - handle_trap(pid, regs); + handle_trap(pid, regs, local_using_sysemu); break; case SIGIO: case SIGVTALRM: @@ -193,14 +187,16 @@ void userspace(union uml_pt_regs *regs) restore_registers(regs); -#ifdef PTRACE_SYSEMU - if (use_sysemu) + /*Now we ended the syscall, so re-read local_using_sysemu.*/ + local_using_sysemu = get_using_sysemu(); + + if (local_using_sysemu) op = singlestepping_skas() ? PTRACE_SINGLESTEP : PTRACE_SYSEMU; else -#endif - op = singlestepping_skas() ? PTRACE_SINGLESTEP : - PTRACE_SYSCALL; + op = singlestepping_skas() ? PTRACE_SINGLESTEP : + PTRACE_SYSCALL; + err = ptrace(op, pid, 0, 0); if(err) panic("userspace - PTRACE_SYSCALL failed, " diff -puN arch/um/kernel/skas/process_kern.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage arch/um/kernel/skas/process_kern.c --- 25/arch/um/kernel/skas/process_kern.c~uml-adds-proc-sysemu-to-toggle-sysemu-usage 2004-07-05 16:00:45.680076024 -0700 +++ 25-akpm/arch/um/kernel/skas/process_kern.c 2004-07-05 16:00:45.686075112 -0700 @@ -6,6 +6,12 @@ #include "linux/sched.h" #include "linux/slab.h" #include "linux/ptrace.h" +#include "linux/proc_fs.h" +#include "linux/file.h" +#include "linux/errno.h" +#include "linux/init.h" +#include "asm/uaccess.h" +#include "asm/atomic.h" #include "kern_util.h" #include "time_user.h" #include "signal_user.h" @@ -17,6 +23,59 @@ #include "kern.h" #include "mode.h" +#ifdef PTRACE_SYSEMU +static atomic_t using_sysemu; +#endif + +void set_using_sysemu(int value) +{ + atomic_set(&using_sysemu, value); +} + +int get_using_sysemu(void) +{ + return atomic_read(&using_sysemu); +} + +int proc_read_sysemu(char *buf, char **start, off_t offset, int size,int *eof, void *data) +{ + if (snprintf(buf, size, "%d\n", get_using_sysemu()) < size) /*No overflow*/ + *eof = 1; + + return strlen(buf); +} + +int proc_write_sysemu(struct file *file,const char *buf, unsigned long count,void *data) +{ + char tmp[2]; + + if (copy_from_user(tmp, buf, 1)) + return -EFAULT; + + if (tmp[0] == '0' || tmp[0] == '1') + set_using_sysemu(tmp[0] - '0'); + return count; /*We use the first char, but pretend to write everything*/ +} + +int __init make_proc_sysemu(void) +{ + struct proc_dir_entry *ent; + + ent = create_proc_entry("sysemu", 00600, &proc_root); + ent->read_proc = proc_read_sysemu; + ent->write_proc = proc_write_sysemu; + + if (ent == NULL) + { + printk("Failed to register /proc/sysemu\n"); + return(0); + } + + return 0; +} + +late_initcall(make_proc_sysemu); + int singlestepping_skas(void) { int ret = current->ptrace & PT_DTRACE; _