From 4e491d14f2506b218d678935c25a7027b79178b1 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 14 May 2008 23:49:44 -0400 Subject: ftrace: support for PowerPC This patch adds full support for ftrace for PowerPC (both 64 and 32 bit). This includes dynamic tracing and function filtering. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- arch/powerpc/kernel/ftrace.c | 165 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 165 insertions(+) create mode 100644 arch/powerpc/kernel/ftrace.c (limited to 'arch/powerpc/kernel/ftrace.c') diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c new file mode 100644 index 00000000000..5a4993fefa4 --- /dev/null +++ b/arch/powerpc/kernel/ftrace.c @@ -0,0 +1,165 @@ +/* + * Code for replacing ftrace calls with jumps. + * + * Copyright (C) 2007-2008 Steven Rostedt + * + * Thanks goes out to P.A. Semi, Inc for supplying me with a PPC64 box. + * + */ + +#include +#include +#include +#include +#include +#include + +#include + +#define CALL_BACK 4 + +static unsigned int ftrace_nop = 0x60000000; + +#ifdef CONFIG_PPC32 +# define GET_ADDR(addr) addr +#else +/* PowerPC64's functions are data that points to the functions */ +# define GET_ADDR(addr) *(unsigned long *)addr +#endif + +notrace int ftrace_ip_converted(unsigned long ip) +{ + unsigned int save; + + ip -= CALL_BACK; + save = *(unsigned int *)ip; + + return save == ftrace_nop; +} + +static unsigned int notrace ftrace_calc_offset(long ip, long addr) +{ + return (int)((addr + CALL_BACK) - ip); +} + +notrace unsigned char *ftrace_nop_replace(void) +{ + return (char *)&ftrace_nop; +} + +notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr) +{ + static unsigned int op; + + addr = GET_ADDR(addr); + + /* Set to "bl addr" */ + op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffe); + + /* + * No locking needed, this must be called via kstop_machine + * which in essence is like running on a uniprocessor machine. + */ + return (unsigned char *)&op; +} + +#ifdef CONFIG_PPC64 +# define _ASM_ALIGN " .align 3 " +# define _ASM_PTR " .llong " +#else +# define _ASM_ALIGN " .align 2 " +# define _ASM_PTR " .long " +#endif + +notrace int +ftrace_modify_code(unsigned long ip, unsigned char *old_code, + unsigned char *new_code) +{ + unsigned replaced; + unsigned old = *(unsigned *)old_code; + unsigned new = *(unsigned *)new_code; + int faulted = 0; + + /* move the IP back to the start of the call */ + ip -= CALL_BACK; + + /* + * Note: Due to modules and __init, code can + * disappear and change, we need to protect against faulting + * as well as code changing. + * + * No real locking needed, this code is run through + * kstop_machine. + */ + asm volatile ( + "1: lwz %1, 0(%2)\n" + " cmpw %1, %5\n" + " bne 2f\n" + " stwu %3, 0(%2)\n" + "2:\n" + ".section .fixup, \"ax\"\n" + "3: li %0, 1\n" + " b 2b\n" + ".previous\n" + ".section __ex_table,\"a\"\n" + _ASM_ALIGN "\n" + _ASM_PTR "1b, 3b\n" + ".previous" + : "=r"(faulted), "=r"(replaced) + : "r"(ip), "r"(new), + "0"(faulted), "r"(old) + : "memory"); + + if (replaced != old && replaced != new) + faulted = 2; + + if (!faulted) + flush_icache_range(ip, ip + 8); + + return faulted; +} + +notrace int ftrace_update_ftrace_func(ftrace_func_t func) +{ + unsigned long ip = (unsigned long)(&ftrace_call); + unsigned char old[4], *new; + int ret; + + ip += CALL_BACK; + + memcpy(old, &ftrace_call, 4); + new = ftrace_call_replace(ip, (unsigned long)func); + ret = ftrace_modify_code(ip, old, new); + + return ret; +} + +notrace int ftrace_mcount_set(unsigned long *data) +{ + unsigned long ip = (long)(&mcount_call); + unsigned long *addr = data; + unsigned char old[4], *new; + + /* ip is at the location, but modify code will subtact this */ + ip += CALL_BACK; + + /* + * Replace the mcount stub with a pointer to the + * ip recorder function. + */ + memcpy(old, &mcount_call, 4); + new = ftrace_call_replace(ip, *addr); + *addr = ftrace_modify_code(ip, old, new); + + return 0; +} + +int __init ftrace_dyn_arch_init(void *data) +{ + /* This is running in kstop_machine */ + + ftrace_mcount_set(data); + + return 0; +} + -- cgit v1.2.3 From ccbfac2923c9febaeaf07a50054027a92b502718 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 22 May 2008 14:31:07 -0400 Subject: ftrace: powerpc clean ups This patch cleans up the ftrace code in PowerPC based on the comments from Michael Ellerman. Signed-off-by: Steven Rostedt Cc: Michael Ellerman Cc: proski@gnu.org Cc: a.p.zijlstra@chello.nl Cc: Pekka Paalanen Cc: Steven Rostedt Cc: linuxppc-dev@ozlabs.org Cc: Soeren Sandmann Pedersen Cc: paulus@samba.org Signed-off-by: Thomas Gleixner --- arch/powerpc/kernel/ftrace.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/ftrace.c') diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c index 5a4993fefa4..69ed4122346 100644 --- a/arch/powerpc/kernel/ftrace.c +++ b/arch/powerpc/kernel/ftrace.c @@ -51,10 +51,16 @@ notrace unsigned char *ftrace_call_replace(unsigned long ip, unsigned long addr) { static unsigned int op; + /* + * It would be nice to just use create_function_call, but that will + * update the code itself. Here we need to just return the + * instruction that is going to be modified, without modifying the + * code. + */ addr = GET_ADDR(addr); /* Set to "bl addr" */ - op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffe); + op = 0x48000001 | (ftrace_calc_offset(ip, addr) & 0x03fffffc); /* * No locking needed, this must be called via kstop_machine -- cgit v1.2.3 From 1d74f2a0f64b4091e5e91b55ac1b17dff93f4b59 Mon Sep 17 00:00:00 2001 From: Abhishek Sagar Date: Sun, 1 Jun 2008 21:47:42 +0530 Subject: ftrace: remove ftrace_ip_converted() Remove the unneeded function ftrace_ip_converted(). Signed-off-by: Abhishek Sagar Signed-off-by: Ingo Molnar --- arch/powerpc/kernel/ftrace.c | 10 ---------- 1 file changed, 10 deletions(-) (limited to 'arch/powerpc/kernel/ftrace.c') diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c index 69ed4122346..e12c593ab9c 100644 --- a/arch/powerpc/kernel/ftrace.c +++ b/arch/powerpc/kernel/ftrace.c @@ -27,16 +27,6 @@ static unsigned int ftrace_nop = 0x60000000; # define GET_ADDR(addr) *(unsigned long *)addr #endif -notrace int ftrace_ip_converted(unsigned long ip) -{ - unsigned int save; - - ip -= CALL_BACK; - save = *(unsigned int *)ip; - - return save == ftrace_nop; -} - static unsigned int notrace ftrace_calc_offset(long ip, long addr) { return (int)((addr + CALL_BACK) - ip); -- cgit v1.2.3 From 395a59d0f8e86bb39cd700c3d185d30c670bb958 Mon Sep 17 00:00:00 2001 From: Abhishek Sagar Date: Sat, 21 Jun 2008 23:47:27 +0530 Subject: ftrace: store mcount address in rec->ip Record the address of the mcount call-site. Currently all archs except sparc64 record the address of the instruction following the mcount call-site. Some general cleanups are entailed. Storing mcount addresses in rec->ip enables looking them up in the kprobe hash table later on to check if they're kprobe'd. Signed-off-by: Abhishek Sagar Cc: davem@davemloft.net Cc: Steven Rostedt Signed-off-by: Ingo Molnar --- arch/powerpc/kernel/ftrace.c | 21 +++++++-------------- 1 file changed, 7 insertions(+), 14 deletions(-) (limited to 'arch/powerpc/kernel/ftrace.c') diff --git a/arch/powerpc/kernel/ftrace.c b/arch/powerpc/kernel/ftrace.c index e12c593ab9c..3855ceb937b 100644 --- a/arch/powerpc/kernel/ftrace.c +++ b/arch/powerpc/kernel/ftrace.c @@ -15,8 +15,8 @@ #include #include +#include -#define CALL_BACK 4 static unsigned int ftrace_nop = 0x60000000; @@ -27,9 +27,10 @@ static unsigned int ftrace_nop = 0x60000000; # define GET_ADDR(addr) *(unsigned long *)addr #endif + static unsigned int notrace ftrace_calc_offset(long ip, long addr) { - return (int)((addr + CALL_BACK) - ip); + return (int)(addr - ip); } notrace unsigned char *ftrace_nop_replace(void) @@ -76,9 +77,6 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code, unsigned new = *(unsigned *)new_code; int faulted = 0; - /* move the IP back to the start of the call */ - ip -= CALL_BACK; - /* * Note: Due to modules and __init, code can * disappear and change, we need to protect against faulting @@ -118,12 +116,10 @@ ftrace_modify_code(unsigned long ip, unsigned char *old_code, notrace int ftrace_update_ftrace_func(ftrace_func_t func) { unsigned long ip = (unsigned long)(&ftrace_call); - unsigned char old[4], *new; + unsigned char old[MCOUNT_INSN_SIZE], *new; int ret; - ip += CALL_BACK; - - memcpy(old, &ftrace_call, 4); + memcpy(old, &ftrace_call, MCOUNT_INSN_SIZE); new = ftrace_call_replace(ip, (unsigned long)func); ret = ftrace_modify_code(ip, old, new); @@ -134,16 +130,13 @@ notrace int ftrace_mcount_set(unsigned long *data) { unsigned long ip = (long)(&mcount_call); unsigned long *addr = data; - unsigned char old[4], *new; - - /* ip is at the location, but modify code will subtact this */ - ip += CALL_BACK; + unsigned char old[MCOUNT_INSN_SIZE], *new; /* * Replace the mcount stub with a pointer to the * ip recorder function. */ - memcpy(old, &mcount_call, 4); + memcpy(old, &mcount_call, MCOUNT_INSN_SIZE); new = ftrace_call_replace(ip, *addr); *addr = ftrace_modify_code(ip, old, new); -- cgit v1.2.3