From: Ian Munsie Date: Wed, 2 Feb 2011 17:27:24 +0000 (+0000) Subject: powerpc/ftrace: Implement raw syscall tracepoints on PowerPC X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=02424d8966d803e33cbe51469be56b5d177b4a37;p=openwrt%2Fstaging%2Fblogic.git powerpc/ftrace: Implement raw syscall tracepoints on PowerPC This patch implements the raw syscall tracepoints on PowerPC and exports them for ftrace syscalls to use. To minimise reworking existing code, I slightly re-ordered the thread info flags such that the new TIF_SYSCALL_TRACEPOINT bit would still fit within the 16 bits of the andi. instruction's UI field. The instructions in question are in /arch/powerpc/kernel/entry_{32,64}.S to and the _TIF_SYSCALL_T_OR_A with the thread flags to see if system call tracing is enabled. In the case of 64bit PowerPC, arch_syscall_addr and arch_syscall_match_sym_name are overridden to allow ftrace syscalls to work given the unusual system call table structure and symbol names that start with a period. Signed-off-by: Ian Munsie Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 423145a6f7ba..2f6a22e8e935 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -141,6 +141,7 @@ config PPC select GENERIC_IRQ_SHOW select GENERIC_IRQ_SHOW_LEVEL select HAVE_RCU_TABLE_FREE if SMP + select HAVE_SYSCALL_TRACEPOINTS config EARLY_PRINTK bool diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h index dde1296b8b41..169d039ed402 100644 --- a/arch/powerpc/include/asm/ftrace.h +++ b/arch/powerpc/include/asm/ftrace.h @@ -60,4 +60,18 @@ struct dyn_arch_ftrace { #endif +#if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) && !defined(__ASSEMBLY__) +#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME +static inline bool arch_syscall_match_sym_name(const char *sym, const char *name) +{ + /* + * Compare the symbol name with the system call name. Skip the .sys or .SyS + * prefix from the symbol name and the sys prefix from the system call name and + * just match the rest. This is only needed on ppc64 since symbol names on + * 32bit do not start with a period so the generic function will work. + */ + return !strcmp(sym + 4, name + 3); +} +#endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_PPC64 && !__ASSEMBLY__ */ + #endif /* _ASM_POWERPC_FTRACE */ diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h index 23913e902fc3..b54b2add07be 100644 --- a/arch/powerpc/include/asm/syscall.h +++ b/arch/powerpc/include/asm/syscall.h @@ -15,6 +15,11 @@ #include +/* ftrace syscalls requires exporting the sys_call_table */ +#ifdef CONFIG_FTRACE_SYSCALLS +extern const unsigned long *sys_call_table; +#endif /* CONFIG_FTRACE_SYSCALLS */ + static inline long syscall_get_nr(struct task_struct *task, struct pt_regs *regs) { diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h index 37c353e8af7c..836f231ec1f0 100644 --- a/arch/powerpc/include/asm/thread_info.h +++ b/arch/powerpc/include/asm/thread_info.h @@ -110,7 +110,8 @@ static inline struct thread_info *current_thread_info(void) #define TIF_NOERROR 12 /* Force successful syscall return */ #define TIF_NOTIFY_RESUME 13 /* callback before returning to user */ #define TIF_FREEZE 14 /* Freezing for suspend */ -#define TIF_RUNLATCH 15 /* Is the runlatch enabled? */ +#define TIF_SYSCALL_TRACEPOINT 15 /* syscall tracepoint instrumentation */ +#define TIF_RUNLATCH 16 /* Is the runlatch enabled? */ /* as above, but as bit values */ #define _TIF_SYSCALL_TRACE (1< #include #include +#include #ifdef CONFIG_DYNAMIC_FTRACE @@ -600,3 +601,10 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) } } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#if defined(CONFIG_FTRACE_SYSCALLS) && defined(CONFIG_PPC64) +unsigned long __init arch_syscall_addr(int nr) +{ + return sys_call_table[nr*2]; +} +#endif /* CONFIG_FTRACE_SYSCALLS && CONFIG_PPC64 */ diff --git a/arch/powerpc/kernel/ptrace.c b/arch/powerpc/kernel/ptrace.c index a6ae1cfad86c..cb22024f2b42 100644 --- a/arch/powerpc/kernel/ptrace.c +++ b/arch/powerpc/kernel/ptrace.c @@ -29,6 +29,7 @@ #include #include #include +#include #ifdef CONFIG_PPC32 #include #endif @@ -40,6 +41,9 @@ #include #include +#define CREATE_TRACE_POINTS +#include + /* * The parameter save area on the stack is used to store arguments being passed * to callee function and is located at fixed offset from stack pointer. @@ -1710,6 +1714,9 @@ long do_syscall_trace_enter(struct pt_regs *regs) */ ret = -1L; + if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) + trace_sys_enter(regs, regs->gpr[0]); + if (unlikely(current->audit_context)) { #ifdef CONFIG_PPC64 if (!is_32bit_task()) @@ -1738,6 +1745,9 @@ void do_syscall_trace_leave(struct pt_regs *regs) audit_syscall_exit((regs->ccr&0x10000000)?AUDITSC_FAILURE:AUDITSC_SUCCESS, regs->result); + if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT))) + trace_sys_exit(regs, regs->result); + step = test_thread_flag(TIF_SINGLESTEP); if (step || test_thread_flag(TIF_SYSCALL_TRACE)) tracehook_report_syscall_exit(regs, step);