From 366dd4ea9d5f0eb78fdf4982d76506f99480ec0a Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Wed, 13 Apr 2016 22:27:22 +0200 Subject: [PATCH] parisc: Fix ftrace function tracer Fix the FTRACE function tracer for 32- and 64-bit kernel. The former code was horribly broken. Reimplement most coding in assembly and utilize optimizations, e.g. put mcount() and ftrace_stub() into one L1 cacheline. Signed-off-by: Helge Deller --- arch/parisc/Kconfig | 4 +- arch/parisc/Kconfig.debug | 4 + arch/parisc/Makefile | 4 +- arch/parisc/include/asm/ftrace.h | 18 +--- arch/parisc/kernel/Makefile | 4 - arch/parisc/kernel/entry.S | 93 ++++++++++++++++---- arch/parisc/kernel/ftrace.c | 146 +++++-------------------------- arch/parisc/kernel/head.S | 9 ++ 8 files changed, 114 insertions(+), 168 deletions(-) diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 14f655cf542e..86167bf85aa1 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -4,8 +4,8 @@ config PARISC select ARCH_MIGHT_HAVE_PC_PARPORT select HAVE_IDE select HAVE_OPROFILE - select HAVE_FUNCTION_TRACER if 64BIT - select HAVE_FUNCTION_GRAPH_TRACER if 64BIT + select HAVE_FUNCTION_TRACER + select HAVE_FUNCTION_GRAPH_TRACER select ARCH_WANT_FRAME_POINTERS select RTC_CLASS select RTC_DRV_GENERIC diff --git a/arch/parisc/Kconfig.debug b/arch/parisc/Kconfig.debug index bc989e522a04..68b7cbd0810a 100644 --- a/arch/parisc/Kconfig.debug +++ b/arch/parisc/Kconfig.debug @@ -2,9 +2,13 @@ menu "Kernel hacking" source "lib/Kconfig.debug" +config TRACE_IRQFLAGS_SUPPORT + def_bool y + config DEBUG_RODATA bool "Write protect kernel read-only data structures" depends on DEBUG_KERNEL + default y help Mark the kernel read-only data as write-protected in the pagetables, in order to catch accidental (and incorrect) writes to such const diff --git a/arch/parisc/Makefile b/arch/parisc/Makefile index 965a0999fc4c..75cb451b1f03 100644 --- a/arch/parisc/Makefile +++ b/arch/parisc/Makefile @@ -62,9 +62,7 @@ cflags-y += -mdisable-fpregs # Without this, "ld -r" results in .text sections that are too big # (> 0x40000) for branches to reach stubs. -ifndef CONFIG_FUNCTION_TRACER - cflags-y += -ffunction-sections -endif +cflags-y += -ffunction-sections # Use long jumps instead of long branches (needed if your linker fails to # link a too big vmlinux executable). Not enabled for building modules. diff --git a/arch/parisc/include/asm/ftrace.h b/arch/parisc/include/asm/ftrace.h index 544ed8ef87eb..24cd81d58d70 100644 --- a/arch/parisc/include/asm/ftrace.h +++ b/arch/parisc/include/asm/ftrace.h @@ -4,23 +4,7 @@ #ifndef __ASSEMBLY__ extern void mcount(void); -/* - * Stack of return addresses for functions of a thread. - * Used in struct thread_info - */ -struct ftrace_ret_stack { - unsigned long ret; - unsigned long func; - unsigned long long calltime; -}; - -/* - * Primary handler of a function return. - * It relays on ftrace_return_to_handler. - * Defined in entry.S - */ -extern void return_to_handler(void); - +#define MCOUNT_INSN_SIZE 4 extern unsigned long return_address(unsigned int); diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile index ff87b4603e3d..69a11183d48d 100644 --- a/arch/parisc/kernel/Makefile +++ b/arch/parisc/kernel/Makefile @@ -15,11 +15,7 @@ ifdef CONFIG_FUNCTION_TRACER # Do not profile debug and lowlevel utilities CFLAGS_REMOVE_ftrace.o = -pg CFLAGS_REMOVE_cache.o = -pg -CFLAGS_REMOVE_irq.o = -pg -CFLAGS_REMOVE_pacache.o = -pg CFLAGS_REMOVE_perf.o = -pg -CFLAGS_REMOVE_traps.o = -pg -CFLAGS_REMOVE_unaligned.o = -pg CFLAGS_REMOVE_unwind.o = -pg endif diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S index 623496c11756..39127d3e70e5 100644 --- a/arch/parisc/kernel/entry.S +++ b/arch/parisc/kernel/entry.S @@ -1970,43 +1970,98 @@ pt_regs_ok: b intr_restore copy %r25,%r16 - .import schedule,code syscall_do_resched: - BL schedule,%r2 + load32 syscall_check_resched,%r2 /* if resched, we start over again */ + load32 schedule,%r19 + bv %r0(%r19) /* jumps to schedule() */ #ifdef CONFIG_64BIT ldo -16(%r30),%r29 /* Reference param save area */ #else nop #endif - b syscall_check_resched /* if resched, we start over again */ - nop ENDPROC(syscall_exit) #ifdef CONFIG_FUNCTION_TRACER + .import ftrace_function_trampoline,code -ENTRY(_mcount) - copy %r3, %arg2 + .align L1_CACHE_BYTES + .globl mcount + .type mcount, @function +ENTRY(mcount) +_mcount: + .export _mcount,data + .proc + .callinfo caller,frame=0 + .entry + /* + * The 64bit mcount() function pointer needs 4 dwords, of which the + * first two are free. We optimize it here and put 2 instructions for + * calling mcount(), and 2 instructions for ftrace_stub(). That way we + * have all on one L1 cacheline. + */ b ftrace_function_trampoline + copy %r3, %arg2 /* caller original %sp */ +ftrace_stub: + .globl ftrace_stub + .type ftrace_stub, @function +#ifdef CONFIG_64BIT + bve (%rp) +#else + bv %r0(%rp) +#endif nop -ENDPROC(_mcount) +#ifdef CONFIG_64BIT + .dword mcount + .dword 0 /* code in head.S puts value of global gp here */ +#endif + .exit + .procend +ENDPROC(mcount) + .align 8 + .globl return_to_handler + .type return_to_handler, @function ENTRY(return_to_handler) - load32 return_trampoline, %rp - copy %ret0, %arg0 - copy %ret1, %arg1 - b ftrace_return_to_handler - nop -return_trampoline: - copy %ret0, %rp - copy %r23, %ret0 - copy %r24, %ret1 + .proc + .callinfo caller,frame=FRAME_SIZE + .entry + .export parisc_return_to_handler,data +parisc_return_to_handler: + copy %r3,%r1 + STREG %r0,-RP_OFFSET(%sp) /* store 0 as %rp */ + copy %sp,%r3 + STREGM %r1,FRAME_SIZE(%sp) + STREG %ret0,8(%r3) + STREG %ret1,16(%r3) -.globl ftrace_stub -ftrace_stub: +#ifdef CONFIG_64BIT + loadgp +#endif + + /* call ftrace_return_to_handler(0) */ +#ifdef CONFIG_64BIT + ldo -16(%sp),%ret1 /* Reference param save area */ +#endif + BL ftrace_return_to_handler,%r2 + ldi 0,%r26 + copy %ret0,%rp + + /* restore original return values */ + LDREG 8(%r3),%ret0 + LDREG 16(%r3),%ret1 + + /* return from function */ +#ifdef CONFIG_64BIT + bve (%rp) +#else bv %r0(%rp) - nop +#endif + LDREGM -FRAME_SIZE(%sp),%r3 + .exit + .procend ENDPROC(return_to_handler) + #endif /* CONFIG_FUNCTION_TRACER */ #ifdef CONFIG_IRQSTACKS diff --git a/arch/parisc/kernel/ftrace.c b/arch/parisc/kernel/ftrace.c index 559d400f9385..b13f9ec6f294 100644 --- a/arch/parisc/kernel/ftrace.c +++ b/arch/parisc/kernel/ftrace.c @@ -1,6 +1,6 @@ /* * Code for tracing calls in Linux kernel. - * Copyright (C) 2009 Helge Deller + * Copyright (C) 2009-2016 Helge Deller * * based on code for x86 which is: * Copyright (C) 2007-2008 Steven Rostedt @@ -13,104 +13,21 @@ #include #include +#include #include #include - #ifdef CONFIG_FUNCTION_GRAPH_TRACER - -/* Add a function return address to the trace stack on thread info.*/ -static int push_return_trace(unsigned long ret, unsigned long long time, - unsigned long func, int *depth) -{ - int index; - - if (!current->ret_stack) - return -EBUSY; - - /* The return trace stack is full */ - if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) { - atomic_inc(¤t->trace_overrun); - return -EBUSY; - } - - index = ++current->curr_ret_stack; - barrier(); - current->ret_stack[index].ret = ret; - current->ret_stack[index].func = func; - current->ret_stack[index].calltime = time; - *depth = index; - - return 0; -} - -/* Retrieve a function return address to the trace stack on thread info.*/ -static void pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret) -{ - int index; - - index = current->curr_ret_stack; - - if (unlikely(index < 0)) { - ftrace_graph_stop(); - WARN_ON(1); - /* Might as well panic, otherwise we have no where to go */ - *ret = (unsigned long) - dereference_function_descriptor(&panic); - return; - } - - *ret = current->ret_stack[index].ret; - trace->func = current->ret_stack[index].func; - trace->calltime = current->ret_stack[index].calltime; - trace->overrun = atomic_read(¤t->trace_overrun); - trace->depth = index; - barrier(); - current->curr_ret_stack--; - -} - -/* - * Send the trace to the ring-buffer. - * @return the original return address. - */ -unsigned long ftrace_return_to_handler(unsigned long retval0, - unsigned long retval1) -{ - struct ftrace_graph_ret trace; - unsigned long ret; - - pop_return_trace(&trace, &ret); - trace.rettime = local_clock(); - ftrace_graph_return(&trace); - - if (unlikely(!ret)) { - ftrace_graph_stop(); - WARN_ON(1); - /* Might as well panic. What else to do? */ - ret = (unsigned long) - dereference_function_descriptor(&panic); - } - - /* HACK: we hand over the old functions' return values - in %r23 and %r24. Assembly in entry.S will take care - and move those to their final registers %ret0 and %ret1 */ - asm( "copy %0, %%r23 \n\t" - "copy %1, %%r24 \n" : : "r" (retval0), "r" (retval1) ); - - return ret; -} - /* * Hook the return address and push it in the stack of return addrs * in current thread info. */ -void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) +static void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) { unsigned long old; - unsigned long long calltime; struct ftrace_graph_ent trace; + extern int parisc_return_to_handler; if (unlikely(ftrace_graph_is_dead())) return; @@ -119,64 +36,47 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr) return; old = *parent; - *parent = (unsigned long) - dereference_function_descriptor(&return_to_handler); - if (unlikely(!__kernel_text_address(old))) { - ftrace_graph_stop(); - *parent = old; - WARN_ON(1); - return; - } - - calltime = local_clock(); + trace.func = self_addr; + trace.depth = current->curr_ret_stack + 1; - if (push_return_trace(old, calltime, - self_addr, &trace.depth) == -EBUSY) { - *parent = old; + /* Only trace if the calling function expects to */ + if (!ftrace_graph_entry(&trace)) return; - } - trace.func = self_addr; + if (ftrace_push_return_trace(old, self_addr, &trace.depth, + 0 ) == -EBUSY) + return; - /* Only trace if the calling function expects to */ - if (!ftrace_graph_entry(&trace)) { - current->curr_ret_stack--; - *parent = old; - } + /* activate parisc_return_to_handler() as return point */ + *parent = (unsigned long) &parisc_return_to_handler; } - #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ - -void ftrace_function_trampoline(unsigned long parent, +void notrace ftrace_function_trampoline(unsigned long parent, unsigned long self_addr, unsigned long org_sp_gr3) { - extern ftrace_func_t ftrace_trace_function; + extern ftrace_func_t ftrace_trace_function; /* depends on CONFIG_DYNAMIC_FTRACE */ + extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace); if (ftrace_trace_function != ftrace_stub) { - ftrace_trace_function(parent, self_addr); + /* struct ftrace_ops *op, struct pt_regs *regs); */ + ftrace_trace_function(parent, self_addr, NULL, NULL); return; } + #ifdef CONFIG_FUNCTION_GRAPH_TRACER - if (ftrace_graph_entry && ftrace_graph_return) { - unsigned long sp; + if (ftrace_graph_return != (trace_func_graph_ret_t) ftrace_stub || + ftrace_graph_entry != ftrace_graph_entry_stub) { unsigned long *parent_rp; - asm volatile ("copy %%r30, %0" : "=r"(sp)); - /* sanity check: is stack pointer which we got from - assembler function in entry.S in a reasonable - range compared to current stack pointer? */ - if ((sp - org_sp_gr3) > 0x400) - return; - /* calculate pointer to %rp in stack */ - parent_rp = (unsigned long *) org_sp_gr3 - 0x10; + parent_rp = (unsigned long *) (org_sp_gr3 - RP_OFFSET); /* sanity check: parent_rp should hold parent */ if (*parent_rp != parent) return; - + prepare_ftrace_return(parent_rp, self_addr); return; } diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S index 75aa0db9f69e..bbbe360b458f 100644 --- a/arch/parisc/kernel/head.S +++ b/arch/parisc/kernel/head.S @@ -129,6 +129,15 @@ $pgt_fill_loop: /* And the stack pointer too */ ldo THREAD_SZ_ALGN(%r6),%sp +#if defined(CONFIG_64BIT) && defined(CONFIG_FUNCTION_TRACER) + .import _mcount,data + /* initialize mcount FPTR */ + /* Get the global data pointer */ + loadgp + load32 PA(_mcount), %r10 + std %dp,0x18(%r10) +#endif + #ifdef CONFIG_SMP /* Set the smp rendezvous address into page zero. ** It would be safer to do this in init_smp_config() but -- 2.34.1