| Message ID | 1394705630-12384-8-git-send-email-takahiro.akashi@linaro.org |
|---|---|
| State | New |
| Headers | show |
On 03/14/2014 01:25 AM, Will Deacon wrote: > On Thu, Mar 13, 2014 at 10:13:50AM +0000, AKASHI Takahiro wrote: >> This patch allows system call entry or exit to be traced as ftrace events, >> ie. sys_enter_*/sys_exit_*, if CONFIG_FTRACE_SYSCALLS is enabled. >> Those events appear and can be controlled under >> ${sysfs}/tracing/events/syscalls/ >> >> Please note that we can't trace compat system calls here because >> AArch32 mode does not share the same syscall table with AArch64. >> Just define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS in order to avoid unexpected >> results (bogus syscalls reported or even hang-up). >> >> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> >> --- >> arch/arm64/Kconfig | 1 + >> arch/arm64/include/asm/ftrace.h | 20 ++++++++++++++++ >> arch/arm64/include/asm/syscall.h | 1 + >> arch/arm64/include/asm/unistd.h | 2 ++ >> arch/arm64/kernel/ptrace.c | 48 ++++++++++++++++++++++---------------- >> 5 files changed, 52 insertions(+), 20 deletions(-) >> >> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig >> index 6954959..b1dcdb4 100644 >> --- a/arch/arm64/Kconfig >> +++ b/arch/arm64/Kconfig >> @@ -43,6 +43,7 @@ config ARM64 >> select HAVE_MEMBLOCK >> select HAVE_PATA_PLATFORM >> select HAVE_PERF_EVENTS >> + select HAVE_SYSCALL_TRACEPOINTS >> select IRQ_DOMAIN >> select MODULES_USE_ELF_RELA >> select NO_BOOTMEM >> diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h >> index c44c4b1..4ef06f1 100644 >> --- a/arch/arm64/include/asm/ftrace.h >> +++ b/arch/arm64/include/asm/ftrace.h >> @@ -44,6 +44,26 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) >> #define CALLER_ADDR4 ((unsigned long)return_address(4)) >> #define CALLER_ADDR5 ((unsigned long)return_address(5)) >> #define CALLER_ADDR6 ((unsigned long)return_address(6)) >> + >> +#include <asm/compat.h> >> + >> +/* >> + * Because AArch32 mode does not share the same syscall table with AArch64, >> + * tracing compat syscalls may result in reporting bogus syscalls or even >> + * hang-up, so just do not trace them. >> + * See kernel/trace/trace_syscalls.c >> + * >> + * x86 code says: >> + * If the user realy wants these, then they should use the >> + * raw syscall tracepoints with filtering. > > Fair enough. > >> + */ >> +#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS 1 > > You don't need the '1' here. OK. >> +static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs) >> +{ >> + if (is_compat_task()) >> + return true; >> + return false; >> +} > > return is_compat_task(); Fix it. >> #endif /* ifndef __ASSEMBLY__ */ >> >> #endif /* __ASM_FTRACE_H */ >> diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h >> index 70ba9d4..383771e 100644 >> --- a/arch/arm64/include/asm/syscall.h >> +++ b/arch/arm64/include/asm/syscall.h >> @@ -18,6 +18,7 @@ >> >> #include <linux/err.h> >> >> +extern const void *sys_call_table[]; >> >> static inline int syscall_get_nr(struct task_struct *task, >> struct pt_regs *regs) >> diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h >> index 82ce217..c335479 100644 >> --- a/arch/arm64/include/asm/unistd.h >> +++ b/arch/arm64/include/asm/unistd.h >> @@ -28,3 +28,5 @@ >> #endif >> #define __ARCH_WANT_SYS_CLONE >> #include <uapi/asm/unistd.h> >> + >> +#define NR_syscalls (__NR_syscalls) >> diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c >> index 9993a8f..9c52b3e 100644 >> --- a/arch/arm64/kernel/ptrace.c >> +++ b/arch/arm64/kernel/ptrace.c >> @@ -41,6 +41,9 @@ >> #include <asm/traps.h> >> #include <asm/system_misc.h> >> >> +#define CREATE_TRACE_POINTS >> +#include <trace/events/syscalls.h> >> + >> /* >> * TODO: does not yet catch signals sent when the child dies. >> * in exit.c or in signal.c. >> @@ -1062,29 +1065,31 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs) >> { >> unsigned long saved_reg; >> >> - if (!test_thread_flag(TIF_SYSCALL_TRACE)) >> - return regs->syscallno; >> + if (test_thread_flag(TIF_SYSCALL_TRACE)) { >> + /* >> + * A scrach register (ip(r12) on AArch32, x7 on AArch64) is >> + * used to denote syscall entry/exit: >> + * 0 -> entry >> + */ >> + if (is_compat_task()) { > > if (arch_trace_is_compat_syscall()) I don't mind either way, but this part of code comes from the original syscall_trace() (ie. ptrace stuff), and has nothing to do with ftrace events. (You know, arch_trace_is_compat_syscall() is currently defined in asm/ftrace.h.) So I'd like to keep it unchanged unless you really want. > With those changes: > > Acked-by: Will Deacon <will.deacon@arm.com> Thank you, -Takahiro AKASHI > Will > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 6954959..b1dcdb4 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -43,6 +43,7 @@ config ARM64 select HAVE_MEMBLOCK select HAVE_PATA_PLATFORM select HAVE_PERF_EVENTS + select HAVE_SYSCALL_TRACEPOINTS select IRQ_DOMAIN select MODULES_USE_ELF_RELA select NO_BOOTMEM diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index c44c4b1..4ef06f1 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -44,6 +44,26 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) #define CALLER_ADDR4 ((unsigned long)return_address(4)) #define CALLER_ADDR5 ((unsigned long)return_address(5)) #define CALLER_ADDR6 ((unsigned long)return_address(6)) + +#include <asm/compat.h> + +/* + * Because AArch32 mode does not share the same syscall table with AArch64, + * tracing compat syscalls may result in reporting bogus syscalls or even + * hang-up, so just do not trace them. + * See kernel/trace/trace_syscalls.c + * + * x86 code says: + * If the user realy wants these, then they should use the + * raw syscall tracepoints with filtering. + */ +#define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS 1 +static inline bool arch_trace_is_compat_syscall(struct pt_regs *regs) +{ + if (is_compat_task()) + return true; + return false; +} #endif /* ifndef __ASSEMBLY__ */ #endif /* __ASM_FTRACE_H */ diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h index 70ba9d4..383771e 100644 --- a/arch/arm64/include/asm/syscall.h +++ b/arch/arm64/include/asm/syscall.h @@ -18,6 +18,7 @@ #include <linux/err.h> +extern const void *sys_call_table[]; static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs) diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h index 82ce217..c335479 100644 --- a/arch/arm64/include/asm/unistd.h +++ b/arch/arm64/include/asm/unistd.h @@ -28,3 +28,5 @@ #endif #define __ARCH_WANT_SYS_CLONE #include <uapi/asm/unistd.h> + +#define NR_syscalls (__NR_syscalls) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index 9993a8f..9c52b3e 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -41,6 +41,9 @@ #include <asm/traps.h> #include <asm/system_misc.h> +#define CREATE_TRACE_POINTS +#include <trace/events/syscalls.h> + /* * TODO: does not yet catch signals sent when the child dies. * in exit.c or in signal.c. @@ -1062,29 +1065,31 @@ asmlinkage int syscall_trace_enter(struct pt_regs *regs) { unsigned long saved_reg; - if (!test_thread_flag(TIF_SYSCALL_TRACE)) - return regs->syscallno; + if (test_thread_flag(TIF_SYSCALL_TRACE)) { + /* + * A scrach register (ip(r12) on AArch32, x7 on AArch64) is + * used to denote syscall entry/exit: + * 0 -> entry + */ + if (is_compat_task()) { + saved_reg = regs->regs[12]; + regs->regs[12] = 0; + } else { + saved_reg = regs->regs[7]; + regs->regs[7] = 0; + } - /* - * A scrach register (ip(r12) on AArch32, x7 on AArch64) is - * used to denote syscall entry/exit: - * 0 -> entry - */ - if (is_compat_task()) { - saved_reg = regs->regs[12]; - regs->regs[12] = 0; - } else { - saved_reg = regs->regs[7]; - regs->regs[7] = 0; - } + if (tracehook_report_syscall_entry(regs)) + regs->syscallno = ~0UL; - if (tracehook_report_syscall_entry(regs)) - regs->syscallno = ~0UL; + if (is_compat_task()) + regs->regs[12] = saved_reg; + else + regs->regs[7] = saved_reg; + } - if (is_compat_task()) - regs->regs[12] = saved_reg; - else - regs->regs[7] = saved_reg; + if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) + trace_sys_enter(regs, regs->syscallno); return regs->syscallno; } @@ -1093,6 +1098,9 @@ asmlinkage void syscall_trace_exit(struct pt_regs *regs) { unsigned long saved_reg; + if (test_thread_flag(TIF_SYSCALL_TRACEPOINT)) + trace_sys_exit(regs, regs_return_value(regs)); + if (!test_thread_flag(TIF_SYSCALL_TRACE)) return;
This patch allows system call entry or exit to be traced as ftrace events, ie. sys_enter_*/sys_exit_*, if CONFIG_FTRACE_SYSCALLS is enabled. Those events appear and can be controlled under ${sysfs}/tracing/events/syscalls/ Please note that we can't trace compat system calls here because AArch32 mode does not share the same syscall table with AArch64. Just define ARCH_TRACE_IGNORE_COMPAT_SYSCALLS in order to avoid unexpected results (bogus syscalls reported or even hang-up). Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/ftrace.h | 20 ++++++++++++++++ arch/arm64/include/asm/syscall.h | 1 + arch/arm64/include/asm/unistd.h | 2 ++ arch/arm64/kernel/ptrace.c | 48 ++++++++++++++++++++++---------------- 5 files changed, 52 insertions(+), 20 deletions(-)