Extend the syscall tracing subsystem by adding a handler for compat tasks. For some architectures, where compat tasks' syscall numbers have an exclusive set of syscall numbers, this already works since the removal of syscall_nr. Architectures where the same syscall may use a different syscall number for compat tasks need to define ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP and define a method arch_trace_is_compat_syscall(struct pt_regs*) that tells if a current task is a compat one. For architectures that define ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP: - if an architecture defines NR_compat_syscalls, then the number of trace event files equals to NR_compat_syscalls + NR_syscalls - if an architecture doesn't define NR_compat_syscalls, the number of trace event files is calculated as 2*NR_syscalls Compat syscall trace events are identified by the syscall number offset by NR_syscalls. Signed-off-by: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/mips/kernel/ftrace.c | 4 +- arch/powerpc/kernel/ftrace.c | 2 +- include/linux/ftrace.h | 2 +- kernel/trace/trace.h | 17 +++++- kernel/trace/trace_syscalls.c | 137 +++++++++++++++++++++++++----------------- 5 files changed, 102 insertions(+), 60 deletions(-) diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index 30a3b75..dd3dae3 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -412,7 +412,7 @@ void prepare_ftrace_return(unsigned long *parent_ra_addr, unsigned long self_ra, #ifdef CONFIG_FTRACE_SYSCALLS #ifdef CONFIG_32BIT -unsigned long __init arch_syscall_addr(int nr) +unsigned long __init arch_syscall_addr(int nr, bool compat) { return (unsigned long)sys_call_table[nr - __NR_O32_Linux]; } @@ -420,7 +420,7 @@ unsigned long __init arch_syscall_addr(int nr) #ifdef CONFIG_64BIT -unsigned long __init arch_syscall_addr(int nr) +unsigned long __init arch_syscall_addr(int nr, bool compat) { #ifdef CONFIG_MIPS32_N32 if (nr >= __NR_N32_Linux && nr <= __NR_N32_Linux + __NR_N32_Linux_syscalls) diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c index a95639b..5bfb35f 100644 --- a/arch/powerpc/kernel/ftrace.c +++ b/arch/powerpc/kernel/ftrace.c @@ -604,7 +604,7 @@ unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip) #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ #if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) -unsigned long __init arch_syscall_addr(int nr) +unsigned long __init arch_syscall_addr(int nr, bool compat) { return sys_call_table[nr*2]; } diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index c45ed06..4d1ca1c 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -957,7 +957,7 @@ static inline void disable_trace_on_warning(void) { } #ifdef CONFIG_FTRACE_SYSCALLS -unsigned long arch_syscall_addr(int nr); +unsigned long arch_syscall_addr(int nr, bool compat); #endif /* CONFIG_FTRACE_SYSCALLS */ diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index fd24b1f..821ee82 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -237,8 +237,21 @@ struct trace_array { #ifdef CONFIG_FTRACE_SYSCALLS int sys_refcount_enter; int sys_refcount_exit; - struct trace_event_file __rcu *enter_syscall_files[NR_syscalls]; - struct trace_event_file __rcu *exit_syscall_files[NR_syscalls]; + +#if (defined ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP) && (defined CONFIG_COMPAT) + +#ifdef NR_compat_syscalls +#define FTRACE_SYSCALL_CNT (NR_syscalls + NR_compat_syscalls) +#else /* !NR_compat_syscalls */ +#define FTRACE_SYSCALL_CNT (2 * NR_syscalls) +#endif /* NR_compat_syscalls */ + +#else +#define FTRACE_SYSCALL_CNT (NR_syscalls) +#endif + + struct trace_event_file __rcu *enter_syscall_files[FTRACE_SYSCALL_CNT]; + struct trace_event_file __rcu *exit_syscall_files[FTRACE_SYSCALL_CNT]; #endif int stop_count; int clock_id; diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index f50563a..9065db3 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -44,37 +44,35 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name } #endif -#ifdef ARCH_TRACE_IGNORE_COMPAT_SYSCALLS +#ifdef ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP /* * Some architectures that allow for 32bit applications * to run on a 64bit kernel, do not map the syscalls for * the 32bit tasks the same as they do for 64bit tasks. * - * *cough*x86*cough* - * - * In such a case, instead of reporting the wrong syscalls, - * simply ignore them. - * - * For an arch to ignore the compat syscalls it needs to - * define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS as well as + * If a set of syscall numbers for 32-bit tasks overlaps + * the set of syscall numbers for 64-bit tasks, define + * ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP as well as * define the function arch_trace_is_compat_syscall() to let - * the tracing system know that it should ignore it. + * the tracing system know that a compat syscall is being handled. */ -static int -trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs) +static inline bool trace_is_compat_syscall(struct pt_regs *regs) { - if (unlikely(arch_trace_is_compat_syscall(regs))) - return -1; - - return syscall_get_nr(task, regs); + return arch_trace_is_compat_syscall(regs); } #else +static inline bool trace_is_compat_syscall(struct pt_regs *regs) +{ + return false; +} +#endif /* ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP */ + static inline int trace_get_syscall_nr(struct task_struct *task, struct pt_regs *regs) { return syscall_get_nr(task, regs); } -#endif /* ARCH_TRACE_IGNORE_COMPAT_SYSCALLS */ + static __init struct syscall_metadata * find_syscall_meta(unsigned long syscall) @@ -98,9 +96,9 @@ find_syscall_meta(unsigned long syscall) return NULL; } -static struct syscall_metadata *syscall_nr_to_meta(int nr) +static struct syscall_metadata *trace_syscall_nr_to_meta(int nr) { - if (!syscalls_metadata || nr >= NR_syscalls || nr < 0) + if (!syscalls_metadata || nr >= FTRACE_SYSCALL_CNT || nr < 0) return NULL; return syscalls_metadata[nr]; @@ -110,7 +108,7 @@ const char *get_syscall_name(int syscall) { struct syscall_metadata *entry; - entry = syscall_nr_to_meta(syscall); + entry = trace_syscall_nr_to_meta(syscall); if (!entry) return NULL; @@ -130,7 +128,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags, trace = (typeof(trace))ent; syscall = trace->nr; - entry = syscall_nr_to_meta(syscall); + entry = trace_syscall_nr_to_meta(syscall); if (!entry) goto end; @@ -176,7 +174,7 @@ print_syscall_exit(struct trace_iterator *iter, int flags, trace = (typeof(trace))ent; syscall = trace->nr; - entry = syscall_nr_to_meta(syscall); + entry = trace_syscall_nr_to_meta(syscall); if (!entry) { trace_seq_putc(s, '\n'); @@ -304,6 +302,26 @@ static int __init syscall_exit_define_fields(struct trace_event_call *call) return ret; } +static int ftrace_check_syscall_nr(struct pt_regs *regs) +{ + int syscall_nr; + + syscall_nr = trace_get_syscall_nr(current, regs); + if (syscall_nr < 0) + return -1; + + if (trace_is_compat_syscall(regs)) { + syscall_nr += NR_syscalls; + if (syscall_nr >= FTRACE_SYSCALL_CNT) + return -1; + } else { + if (syscall_nr > NR_syscalls) + return -1; + } + + return syscall_nr; +} + static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) { struct trace_array *tr = data; @@ -317,8 +335,8 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) int syscall_nr; int size; - syscall_nr = trace_get_syscall_nr(current, regs); - if (syscall_nr < 0 || syscall_nr >= NR_syscalls) + syscall_nr = ftrace_check_syscall_nr(regs); + if (syscall_nr < 0) return; /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */ @@ -329,7 +347,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) if (trace_trigger_soft_disabled(trace_file)) return; - sys_data = syscall_nr_to_meta(syscall_nr); + sys_data = trace_syscall_nr_to_meta(syscall_nr); if (!sys_data) return; @@ -364,8 +382,8 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) int pc; int syscall_nr; - syscall_nr = trace_get_syscall_nr(current, regs); - if (syscall_nr < 0 || syscall_nr >= NR_syscalls) + syscall_nr = ftrace_check_syscall_nr(regs); + if (syscall_nr < 0) return; /* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */ @@ -376,7 +394,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) if (trace_trigger_soft_disabled(trace_file)) return; - sys_data = syscall_nr_to_meta(syscall_nr); + sys_data = trace_syscall_nr_to_meta(syscall_nr); if (!sys_data) return; @@ -412,7 +430,7 @@ static int reg_event_syscall_enter(struct trace_event_file *file, goto out_unlock; } - for (num = 0; num < NR_syscalls; num++) { + for (num = 0; num < FTRACE_SYSCALL_CNT; num++) { if (syscalls_metadata[num] && (syscalls_metadata[num] == call->data)) rcu_assign_pointer(tr->enter_syscall_files[num], file); @@ -432,7 +450,7 @@ static void unreg_event_syscall_enter(struct trace_event_file *file, mutex_lock(&syscall_trace_lock); tr->sys_refcount_enter--; - for (num = 0; num < NR_syscalls; num++) { + for (num = 0; num < FTRACE_SYSCALL_CNT; num++) { if (syscalls_metadata[num] && (syscalls_metadata[num] == call->data)) RCU_INIT_POINTER(tr->enter_syscall_files[num], NULL); @@ -456,7 +474,7 @@ static int reg_event_syscall_exit(struct trace_event_file *file, goto out_unlock; } - for (num = 0; num < NR_syscalls; num++) { + for (num = 0; num < FTRACE_SYSCALL_CNT; num++) { if (syscalls_metadata[num] && (syscalls_metadata[num] == call->data)) rcu_assign_pointer(tr->exit_syscall_files[num], file); @@ -476,7 +494,7 @@ static void unreg_event_syscall_exit(struct trace_event_file *file, mutex_lock(&syscall_trace_lock); tr->sys_refcount_exit--; - for (num = 0; num < NR_syscalls; num++) { + for (num = 0; num < FTRACE_SYSCALL_CNT; num++) { if (syscalls_metadata[num] && (syscalls_metadata[num] == call->data)) RCU_INIT_POINTER(tr->exit_syscall_files[num], NULL); @@ -527,38 +545,47 @@ struct trace_event_class __refdata event_class_syscall_exit = { .raw_init = init_syscall_trace, }; -unsigned long __init __weak arch_syscall_addr(int nr) +unsigned long __init __weak arch_syscall_addr(int nr, bool compat) { return (unsigned long)sys_call_table[nr]; } -void __init init_ftrace_syscalls(void) +void __init init_ftrace_syscalls_meta(bool compat) { struct syscall_metadata *meta; unsigned long addr; int i; - syscalls_metadata = kcalloc(NR_syscalls, sizeof(*syscalls_metadata), - GFP_KERNEL); - if (!syscalls_metadata) { - WARN_ON(1); - return; - } - for (i = 0; i < NR_syscalls; i++) { - addr = arch_syscall_addr(i); + addr = arch_syscall_addr(i, compat); meta = find_syscall_meta(addr); if (!meta) continue; - syscalls_metadata[i] = meta; + syscalls_metadata[compat * NR_syscalls + i] = meta; } } +void __init init_ftrace_syscalls(void) +{ + syscalls_metadata = kcalloc(FTRACE_SYSCALL_CNT, + sizeof(*syscalls_metadata), GFP_KERNEL); + if (!syscalls_metadata) { + WARN_ON(1); + return; + } + + init_ftrace_syscalls_meta(false); +#ifdef ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP + if (IS_ENABLED(CONFIG_COMPAT)) + init_ftrace_syscalls_meta(true); +#endif +} + #ifdef CONFIG_PERF_EVENTS -static DECLARE_BITMAP(enabled_perf_enter_syscalls, NR_syscalls); -static DECLARE_BITMAP(enabled_perf_exit_syscalls, NR_syscalls); +static DECLARE_BITMAP(enabled_perf_enter_syscalls, FTRACE_SYSCALL_CNT); +static DECLARE_BITMAP(enabled_perf_exit_syscalls, FTRACE_SYSCALL_CNT); static int sys_perf_refcount_enter; static int sys_perf_refcount_exit; @@ -571,13 +598,14 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) int rctx; int size; - syscall_nr = trace_get_syscall_nr(current, regs); - if (syscall_nr < 0 || syscall_nr >= NR_syscalls) + syscall_nr = ftrace_check_syscall_nr(regs); + if (syscall_nr < 0) return; + if (!test_bit(syscall_nr, enabled_perf_enter_syscalls)) return; - sys_data = syscall_nr_to_meta(syscall_nr); + sys_data = trace_syscall_nr_to_meta(syscall_nr); if (!sys_data) return; @@ -616,7 +644,7 @@ static int perf_sysenter_enable(struct trace_event_call *call) } } - for (num = 0; num < NR_syscalls; num++) { + for (num = 0; num < FTRACE_SYSCALL_CNT; num++) { if (syscalls_metadata[num] && (syscalls_metadata[num] == call->data)) set_bit(num, enabled_perf_enter_syscalls); @@ -634,7 +662,7 @@ static void perf_sysenter_disable(struct trace_event_call *call) mutex_lock(&syscall_trace_lock); sys_perf_refcount_enter--; - for (num = 0; num < NR_syscalls; num++) { + for (num = 0; num < FTRACE_SYSCALL_CNT; num++) { if (syscalls_metadata[num] && (syscalls_metadata[num] == call->data)) clear_bit(num, enabled_perf_enter_syscalls); @@ -653,13 +681,14 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) int rctx; int size; - syscall_nr = trace_get_syscall_nr(current, regs); - if (syscall_nr < 0 || syscall_nr >= NR_syscalls) + syscall_nr = ftrace_check_syscall_nr(regs); + if (syscall_nr < 0) return; + if (!test_bit(syscall_nr, enabled_perf_exit_syscalls)) return; - sys_data = syscall_nr_to_meta(syscall_nr); + sys_data = trace_syscall_nr_to_meta(syscall_nr); if (!sys_data) return; @@ -695,7 +724,7 @@ static int perf_sysexit_enable(struct trace_event_call *call) } } - for (num = 0; num < NR_syscalls; num++) { + for (num = 0; num < FTRACE_SYSCALL_CNT; num++) { if (syscalls_metadata[num] && (syscalls_metadata[num] == call->data)) set_bit(num, enabled_perf_exit_syscalls); @@ -713,7 +742,7 @@ static void perf_sysexit_disable(struct trace_event_call *call) mutex_lock(&syscall_trace_lock); sys_perf_refcount_exit--; - for (num = 0; num < NR_syscalls; num++) { + for (num = 0; num < FTRACE_SYSCALL_CNT; num++) { if (syscalls_metadata[num] && (syscalls_metadata[num] == call->data)) clear_bit(num, enabled_perf_exit_syscalls); -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html