From 046199cae714a7f9e88f5a7940b077f4515f48cb Mon Sep 17 00:00:00 2001 From: Wu Zhangjin Date: Fri, 20 Nov 2009 20:34:36 +0800 Subject: MIPS: Tracing: Make ftrace for MIPS work without -fno-omit-frame-pointer When remove the -fno-omit-frame-pointer, gcc will not save the frame pointer for us, we need to save one ourselves. Signed-off-by: Wu Zhangjin Cc: Steven Rostedt Cc: Nicholas Mc Guire Cc: zhangfx@lemote.com Cc: Wu Zhangjin Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Frederic Weisbecker Cc: linux-kernel@vger.kernel.org Cc: linux-mips@linux-mips.org Patchwork: http://patchwork.linux-mips.org/patch/679/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/ftrace.h | 57 ++++++++++++++++++++++++++++++++++++++++++ arch/mips/kernel/ftrace.c | 56 ++++++++++++++++++++++++++++++----------- arch/mips/kernel/mcount.S | 8 ++++++ 3 files changed, 106 insertions(+), 15 deletions(-) (limited to 'arch') diff --git a/arch/mips/include/asm/ftrace.h b/arch/mips/include/asm/ftrace.h index 7094a40b96d..3986cd8704f 100644 --- a/arch/mips/include/asm/ftrace.h +++ b/arch/mips/include/asm/ftrace.h @@ -19,6 +19,62 @@ extern void _mcount(void); #define mcount _mcount +#define safe_load(load, src, dst, error) \ +do { \ + asm volatile ( \ + "1: " load " %[" STR(dst) "], 0(%[" STR(src) "])\n"\ + " li %[" STR(error) "], 0\n" \ + "2:\n" \ + \ + ".section .fixup, \"ax\"\n" \ + "3: li %[" STR(error) "], 1\n" \ + " j 2b\n" \ + ".previous\n" \ + \ + ".section\t__ex_table,\"a\"\n\t" \ + STR(PTR) "\t1b, 3b\n\t" \ + ".previous\n" \ + \ + : [dst] "=&r" (dst), [error] "=r" (error)\ + : [src] "r" (src) \ + : "memory" \ + ); \ +} while (0) + +#define safe_store(store, src, dst, error) \ +do { \ + asm volatile ( \ + "1: " store " %[" STR(src) "], 0(%[" STR(dst) "])\n"\ + " li %[" STR(error) "], 0\n" \ + "2:\n" \ + \ + ".section .fixup, \"ax\"\n" \ + "3: li %[" STR(error) "], 1\n" \ + " j 2b\n" \ + ".previous\n" \ + \ + ".section\t__ex_table,\"a\"\n\t"\ + STR(PTR) "\t1b, 3b\n\t" \ + ".previous\n" \ + \ + : [error] "=r" (error) \ + : [dst] "r" (dst), [src] "r" (src)\ + : "memory" \ + ); \ +} while (0) + +#define safe_load_code(dst, src, error) \ + safe_load(STR(lw), src, dst, error) +#define safe_store_code(src, dst, error) \ + safe_store(STR(sw), src, dst, error) + +#define safe_load_stack(dst, src, error) \ + safe_load(STR(PTR_L), src, dst, error) + +#define safe_store_stack(src, dst, error) \ + safe_store(STR(PTR_S), src, dst, error) + + #ifdef CONFIG_DYNAMIC_FTRACE static inline unsigned long ftrace_call_adjust(unsigned long addr) { @@ -27,6 +83,7 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) struct dyn_arch_ftrace { }; + #endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* __ASSEMBLY__ */ #endif /* CONFIG_FUNCTION_TRACER */ diff --git a/arch/mips/kernel/ftrace.c b/arch/mips/kernel/ftrace.c index e981a497c98..e363fc69aab 100644 --- a/arch/mips/kernel/ftrace.c +++ b/arch/mips/kernel/ftrace.c @@ -27,7 +27,13 @@ static unsigned int ftrace_nop = 0x00000000; static int ftrace_modify_code(unsigned long ip, unsigned int new_code) { - *(unsigned int *)ip = new_code; + int faulted; + + /* *(unsigned int *)ip = new_code; */ + safe_store_code(new_code, ip, faulted); + + if (unlikely(faulted)) + return -EFAULT; flush_icache_range(ip, ip + 8); @@ -41,14 +47,20 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, unsigned long addr) { unsigned int new; + int faulted; unsigned long ip = rec->ip; /* We have compiled module with -mlong-calls, but compiled the kernel * without it, we need to cope with them respectively. */ if (ip & 0x40000000) { /* record it for ftrace_make_call */ - if (lui_v1 == 0) - lui_v1 = *(unsigned int *)ip; + if (lui_v1 == 0) { + /* lui_v1 = *(unsigned int *)ip; */ + safe_load_code(lui_v1, ip, faulted); + + if (unlikely(faulted)) + return -EFAULT; + } /* lui v1, hi_16bit_of_mcount --> b 1f (0x10000004) * addiu v1, v1, low_16bit_of_mcount @@ -147,6 +159,7 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, { unsigned long sp, ip, ra; unsigned int code; + int faulted; /* in module or kernel? */ if (self_addr & 0x40000000) { @@ -162,8 +175,11 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, do { ip -= 4; - /* get the code at "ip" */ - code = *(unsigned int *)ip; + /* get the code at "ip": code = *(unsigned int *)ip; */ + safe_load_code(code, ip, faulted); + + if (unlikely(faulted)) + return 0; /* If we hit the non-store instruction before finding where the * ra is stored, then this is a leaf function and it does not @@ -174,11 +190,14 @@ unsigned long ftrace_get_parent_addr(unsigned long self_addr, } while (((code & S_RA_SP) != S_RA_SP)); sp = fp + (code & OFFSET_MASK); - ra = *(unsigned long *)sp; + + /* ra = *(unsigned long *)sp; */ + safe_load_stack(ra, sp, faulted); + if (unlikely(faulted)) + return 0; if (ra == parent) return sp; - return 0; } @@ -193,6 +212,7 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, struct ftrace_graph_ent trace; unsigned long return_hooker = (unsigned long) &return_to_handler; + int faulted; if (unlikely(atomic_read(¤t->tracing_graph_pause))) return; @@ -206,21 +226,23 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, * ftrace_get_parent_addr() does it! */ - old = *parent; + /* old = *parent; */ + safe_load_stack(old, parent, faulted); + if (unlikely(faulted)) + goto out; parent = (unsigned long *)ftrace_get_parent_addr(self_addr, old, (unsigned long)parent, fp); - /* If fails when getting the stack address of the non-leaf function's * ra, stop function graph tracer and return */ - if (parent == 0) { - ftrace_graph_stop(); - WARN_ON(1); - return; - } + if (parent == 0) + goto out; - *parent = return_hooker; + /* *parent = return_hooker; */ + safe_store_stack(return_hooker, parent, faulted); + if (unlikely(faulted)) + goto out; if (ftrace_push_return_trace(old, self_addr, &trace.depth, fp) == -EBUSY) { @@ -235,5 +257,9 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, current->curr_ret_stack--; *parent = old; } + return; +out: + ftrace_graph_stop(); + WARN_ON(1); } #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S index 98d46903250..bdfef2c24f1 100644 --- a/arch/mips/kernel/mcount.S +++ b/arch/mips/kernel/mcount.S @@ -139,7 +139,15 @@ NESTED(ftrace_graph_caller, PT_SIZE, ra) #endif PTR_LA a0, PT_R1(sp) /* arg1: &AT -> a0 */ jal prepare_ftrace_return +#ifdef CONFIG_FRAME_POINTER move a2, fp /* arg3: frame pointer */ +#else +#ifdef CONFIG_64BIT + PTR_LA a2, PT_SIZE(sp) +#else + PTR_LA a2, (PT_SIZE+8)(sp) +#endif +#endif MCOUNT_RESTORE_REGS RETURN_BACK -- cgit v1.2.3