--- /dev/null
+/* SPDX-License-Identifier: (GPL-2.0 or LGPL-2.1)
+ *
+ * lttng-context-callstack-legacy-impl.h
+ *
+ * LTTng callstack event context, legacy implementation. Targets
+ * kernels and architectures not yet using the stacktrace common
+ * infrastructure introduced in the upstream Linux kernel by commit
+ * 214d8ca6ee "stacktrace: Provide common infrastructure" (merged in
+ * Linux 5.2, then gradually introduced within architectures).
+ *
+ * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2014 Francis Giraldeau <francis.giraldeau@gmail.com>
+ */
+
+#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));
+ }
+}
#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));
- }
-}
+#include "lttng-context-callstack-legacy-impl.h"
static
void field_data_free(struct field_data *fdata)
projects / lttng-modules.git / commitdiff
