X-Git-Url: http://git.liburcu.org/?p=lttng-modules.git;a=blobdiff_plain;f=lttng-context-callstack.c;h=195990a6e3e1292bebce8277a7b3bdefbd0d5acb;hp=432fadb652f349566ae1eee7e646ed29f83b507b;hb=436f640717bab63240d9a624846d947e150a2cee;hpb=b874d3f33576e84221ae1be02505c47c0e7899bf diff --git a/lttng-context-callstack.c b/lttng-context-callstack.c index 432fadb6..195990a6 100644 --- a/lttng-context-callstack.c +++ b/lttng-context-callstack.c @@ -1,4 +1,5 @@ -/* +/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1) + * * lttng-context-callstack.c * * LTTng callstack event context. @@ -6,20 +7,6 @@ * Copyright (C) 2014 Mathieu Desnoyers * Copyright (C) 2014 Francis Giraldeau * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; only - * version 2.1 of the License. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - * * The callstack context can be added to any kernel event. It records * either the kernel or the userspace callstack, up to a max depth. The * context is a CTF sequence, such that it uses only the space required @@ -62,182 +49,11 @@ #include "wrapper/vmalloc.h" #include "lttng-tracer.h" -#define MAX_ENTRIES 128 - -enum lttng_cs_ctx_modes { - CALLSTACK_KERNEL = 0, - CALLSTACK_USER = 1, - NR_CALLSTACK_MODES, -}; - -struct lttng_cs_dispatch { - struct stack_trace stack_trace; - unsigned long entries[MAX_ENTRIES]; -}; - -struct lttng_cs { - struct lttng_cs_dispatch dispatch[RING_BUFFER_MAX_NESTING]; -}; - -struct field_data { - struct lttng_cs __percpu *cs_percpu; - enum lttng_cs_ctx_modes mode; -}; - -struct lttng_cs_type { - const char *name; - const char *save_func_name; - void (*save_func)(struct stack_trace *trace); -}; - -static struct lttng_cs_type cs_types[] = { - { - .name = "callstack_kernel", - .save_func_name = "save_stack_trace", - .save_func = NULL, - }, - { - .name = "callstack_user", - .save_func_name = "save_stack_trace_user", - .save_func = NULL, - }, -}; - -static -int init_type(enum lttng_cs_ctx_modes mode) -{ - unsigned long func; - - if (cs_types[mode].save_func) - return 0; - func = kallsyms_lookup_funcptr(cs_types[mode].save_func_name); - if (!func) { - printk(KERN_WARNING "LTTng: symbol lookup failed: %s\n", - cs_types[mode].save_func_name); - return -EINVAL; - } - cs_types[mode].save_func = (void *) func; - return 0; -} - -/* Keep track of nesting inside userspace callstack context code */ -DEFINE_PER_CPU(int, callstack_user_nesting); - -static -struct stack_trace *stack_trace_context(struct lttng_ctx_field *field, - struct lib_ring_buffer_ctx *ctx) -{ - int buffer_nesting, cs_user_nesting; - struct lttng_cs *cs; - struct field_data *fdata = field->priv; - - /* - * Do not gather the userspace callstack context when the event was - * triggered by the userspace callstack context saving mechanism. - */ - cs_user_nesting = per_cpu(callstack_user_nesting, ctx->cpu); - - if (fdata->mode == CALLSTACK_USER && cs_user_nesting >= 1) - return NULL; - - /* - * get_cpu() is not required, preemption is already - * disabled while event is written. - * - * max nesting is checked in lib_ring_buffer_get_cpu(). - * Check it again as a safety net. - */ - cs = per_cpu_ptr(fdata->cs_percpu, ctx->cpu); - buffer_nesting = per_cpu(lib_ring_buffer_nesting, ctx->cpu) - 1; - if (buffer_nesting >= RING_BUFFER_MAX_NESTING) - return NULL; - - return &cs->dispatch[buffer_nesting].stack_trace; -} - -/* - * In order to reserve the correct size, the callstack is computed. The - * resulting callstack is saved to be accessed in the record step. - */ -static -size_t lttng_callstack_get_size(size_t offset, struct lttng_ctx_field *field, - struct lib_ring_buffer_ctx *ctx, - struct lttng_channel *chan) -{ - struct stack_trace *trace; - struct field_data *fdata = field->priv; - size_t orig_offset = offset; - - /* do not write data if no space is available */ - trace = stack_trace_context(field, ctx); - if (unlikely(!trace)) { - offset += lib_ring_buffer_align(offset, lttng_alignof(unsigned int)); - offset += sizeof(unsigned int); - offset += lib_ring_buffer_align(offset, lttng_alignof(unsigned long)); - return offset - orig_offset; - } - - /* reset stack trace, no need to clear memory */ - trace->nr_entries = 0; - - if (fdata->mode == CALLSTACK_USER) - ++per_cpu(callstack_user_nesting, ctx->cpu); - - /* do the real work and reserve space */ - cs_types[fdata->mode].save_func(trace); - - if (fdata->mode == CALLSTACK_USER) - per_cpu(callstack_user_nesting, ctx->cpu)--; - - /* - * Remove final ULONG_MAX delimiter. If we cannot find it, add - * our own marker to show that the stack is incomplete. This is - * more compact for a trace. - */ - if (trace->nr_entries > 0 - && trace->entries[trace->nr_entries - 1] == ULONG_MAX) { - trace->nr_entries--; - } - offset += lib_ring_buffer_align(offset, lttng_alignof(unsigned int)); - offset += sizeof(unsigned int); - offset += lib_ring_buffer_align(offset, lttng_alignof(unsigned long)); - offset += sizeof(unsigned long) * trace->nr_entries; - /* Add our own ULONG_MAX delimiter to show incomplete stack. */ - if (trace->nr_entries == trace->max_entries) - offset += sizeof(unsigned long); - return offset - orig_offset; -} - -static -void lttng_callstack_record(struct lttng_ctx_field *field, - struct lib_ring_buffer_ctx *ctx, - struct lttng_channel *chan) -{ - struct stack_trace *trace = stack_trace_context(field, ctx); - unsigned int nr_seq_entries; - - if (unlikely(!trace)) { - nr_seq_entries = 0; - lib_ring_buffer_align_ctx(ctx, lttng_alignof(unsigned int)); - chan->ops->event_write(ctx, &nr_seq_entries, sizeof(unsigned int)); - lib_ring_buffer_align_ctx(ctx, lttng_alignof(unsigned long)); - return; - } - lib_ring_buffer_align_ctx(ctx, lttng_alignof(unsigned int)); - nr_seq_entries = trace->nr_entries; - if (trace->nr_entries == trace->max_entries) - nr_seq_entries++; - chan->ops->event_write(ctx, &nr_seq_entries, sizeof(unsigned int)); - lib_ring_buffer_align_ctx(ctx, lttng_alignof(unsigned long)); - chan->ops->event_write(ctx, trace->entries, - sizeof(unsigned long) * trace->nr_entries); - /* Add our own ULONG_MAX delimiter to show incomplete stack. */ - if (trace->nr_entries == trace->max_entries) { - unsigned long delim = ULONG_MAX; - - chan->ops->event_write(ctx, &delim, sizeof(unsigned long)); - } -} +#ifdef CONFIG_ARCH_STACKWALK +#include "lttng-context-callstack-stackwalk-impl.h" +#else +#include "lttng-context-callstack-legacy-impl.h" +#endif static void field_data_free(struct field_data *fdata) @@ -251,7 +67,6 @@ void field_data_free(struct field_data *fdata) static struct field_data __percpu *field_data_create(enum lttng_cs_ctx_modes mode) { - int cpu, i; struct lttng_cs __percpu *cs_set; struct field_data *fdata; @@ -261,20 +76,8 @@ struct field_data __percpu *field_data_create(enum lttng_cs_ctx_modes mode) cs_set = alloc_percpu(struct lttng_cs); if (!cs_set) goto error_alloc; - + lttng_cs_set_init(cs_set); fdata->cs_percpu = cs_set; - for_each_possible_cpu(cpu) { - struct lttng_cs *cs; - - cs = per_cpu_ptr(cs_set, cpu); - for (i = 0; i < RING_BUFFER_MAX_NESTING; i++) { - struct lttng_cs_dispatch *dispatch; - - dispatch = &cs->dispatch[i]; - dispatch->stack_trace.entries = dispatch->entries; - dispatch->stack_trace.max_entries = MAX_ENTRIES; - } - } fdata->mode = mode; return fdata; @@ -295,7 +98,7 @@ static int __lttng_add_callstack_generic(struct lttng_ctx **ctx, enum lttng_cs_ctx_modes mode) { - const char *ctx_name = cs_types[mode].name; + const char *ctx_name = lttng_cs_ctx_mode_name(mode); struct lttng_ctx_field *field; struct field_data *fdata; int ret; @@ -376,7 +179,3 @@ int lttng_add_callstack_to_ctx(struct lttng_ctx **ctx, int type) } } EXPORT_SYMBOL_GPL(lttng_add_callstack_to_ctx); - -MODULE_LICENSE("GPL and additional rights"); -MODULE_AUTHOR("Francis Giraldeau"); -MODULE_DESCRIPTION("Linux Trace Toolkit Callstack Support");