[PATCH v4 06/12] x86/tracing: fix compat syscall handling
From: Marcin Nowakowski <hidden>
Date: 2016-10-14 08:36:15
Also in:
lkml
Subsystem:
function hooks (ftrace), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Steven Rostedt, Masami Hiramatsu, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Adapt the arch-specific code to new syscall tracing interface: arch_trace_is_compat_syscall() now only indicates if a syscall is ia32, as x32 syscalls exist in the same syscall table as native 64 bit ones, so should not be treated as compat ones Add arch_trace_syscall_get_nr that removes the x32 bit from syscall numbers. Signed-off-by: Marcin Nowakowski <redacted> Cc: Steven Rostedt <redacted> Cc: Ingo Molnar <redacted> Cc: Thomas Gleixner <redacted> Cc: "H. Peter Anvin" <redacted> Cc: x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org --- arch/x86/include/asm/ftrace.h | 14 ++------------ arch/x86/include/asm/syscall.h | 9 +++++++++ arch/x86/kernel/ftrace.c | 23 +++++++++++++++++++++++ 3 files changed, 34 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index eccd0ac..69f1674 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h@@ -50,20 +50,10 @@ int ftrace_int3_handler(struct pt_regs *regs); #if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_IA32_EMULATION) #include <asm/compat.h> -/* - * Because ia32 syscalls do not map to x86_64 syscall numbers - * this screws up the trace output when tracing a ia32 task. - * Instead of reporting bogus syscalls, just do not trace them. - * - * If the user really wants these, then they should use the - * raw syscall tracepoints with filtering. - */ -#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS 1 +#define ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP 1 static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs) { - if (in_compat_syscall()) - return true; - return false; + return in_ia32_syscall(); } #endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_IA32_EMULATION */ #endif /* !__ASSEMBLY__ && !COMPILE_OFFSETS */
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index e3c95e8..732b5ab 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h@@ -239,4 +239,13 @@ static inline int syscall_get_arch(void) } #endif /* CONFIG_X86_32 */ +#ifdef CONFIG_FTRACE_SYSCALLS +static inline +int arch_trace_syscall_get_nr(struct task_struct *task, struct pt_regs *regs) +{ + return syscall_get_nr(task, regs) & __SYSCALL_MASK; +} +#define arch_trace_syscall_get_nr arch_trace_syscall_get_nr +#endif /* CONFIG_FTRACE_SYSCALLS */ + #endif /* _ASM_X86_SYSCALL_H */
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index 8639bb2..38032fc 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c@@ -28,6 +28,7 @@ #include <asm/kprobes.h> #include <asm/ftrace.h> #include <asm/nops.h> +#include <asm/syscall.h> #ifdef CONFIG_DYNAMIC_FTRACE
@@ -1035,3 +1036,25 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, } } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_FTRACE_SYSCALLS +#if defined(CONFIG_X86_64) && defined(CONFIG_IA32_EMULATION) +/* + * Because ia32 syscalls do not map to x86_64 syscall numbers + * we need to choose the right syscall table depending on the + * compat flag. + * + * Alternatively, it is also possible to use the raw syscall + * tracepoints with filtering. + */ + +unsigned long __init arch_syscall_addr(int nr, bool compat) +{ + if (compat) + return (unsigned long)ia32_sys_call_table[nr]; + + return (unsigned long)sys_call_table[nr]; +} + +#endif /* CONFIG_X86_64 && CONFIG_IA32_EMULATION */ +#endif /* CONFIG_FTRACE_SYSCALLS */
--
2.7.4