PERF_SAMPLE_RAW = 1U << 10,
PERF_SAMPLE_BRANCH_STACK = 1U << 11,
PERF_SAMPLE_REGS_USER = 1U << 12,
+ PERF_SAMPLE_STACK_USER = 1U << 13,
- PERF_SAMPLE_MAX = 1U << 13, /* non-ABI */
+ PERF_SAMPLE_MAX = 1U << 14, /* non-ABI */
};
/*
#define PERF_ATTR_SIZE_VER1 72 /* add: config2 */
#define PERF_ATTR_SIZE_VER2 80 /* add: branch_sample_type */
#define PERF_ATTR_SIZE_VER3 88 /* add: sample_regs_user */
+#define PERF_ATTR_SIZE_VER4 96 /* add: sample_stack_user */
/*
* Hardware event_id to monitor via a performance monitoring event:
* See asm/perf_regs.h for details.
*/
__u64 sample_regs_user;
+
+ /*
+ * Defines size of the user stack to dump on samples.
+ */
+ __u32 sample_stack_user;
+
+ /* Align to u64. */
+ __u32 __reserved_2;
};
/*
*
* { u64 abi; # enum perf_sample_regs_abi
* u64 regs[weight(mask)]; } && PERF_SAMPLE_REGS_USER
+ *
+ * { u64 size;
+ * char data[size];
+ * u64 dyn_size; } && PERF_SAMPLE_STACK_USER
* };
*/
PERF_RECORD_SAMPLE = 9,
struct perf_raw_record *raw;
struct perf_branch_stack *br_stack;
struct perf_regs_user regs_user;
+ u64 stack_user_size;
};
static inline void perf_sample_data_init(struct perf_sample_data *data,
data->period = period;
data->regs_user.abi = PERF_SAMPLE_REGS_ABI_NONE;
data->regs_user.regs = NULL;
+ data->stack_user_size = 0;
}
extern void perf_output_sample(struct perf_output_handle *handle,
#include <linux/perf_event.h>
#include <linux/ftrace_event.h>
#include <linux/hw_breakpoint.h>
+#include <linux/mm_types.h>
#include "internal.h"
}
}
+/*
+ * Get remaining task size from user stack pointer.
+ *
+ * It'd be better to take stack vma map and limit this more
+ * precisly, but there's no way to get it safely under interrupt,
+ * so using TASK_SIZE as limit.
+ */
+static u64 perf_ustack_task_size(struct pt_regs *regs)
+{
+ unsigned long addr = perf_user_stack_pointer(regs);
+
+ if (!addr || addr >= TASK_SIZE)
+ return 0;
+
+ return TASK_SIZE - addr;
+}
+
+static u16
+perf_sample_ustack_size(u16 stack_size, u16 header_size,
+ struct pt_regs *regs)
+{
+ u64 task_size;
+
+ /* No regs, no stack pointer, no dump. */
+ if (!regs)
+ return 0;
+
+ /*
+ * Check if we fit in with the requested stack size into the:
+ * - TASK_SIZE
+ * If we don't, we limit the size to the TASK_SIZE.
+ *
+ * - remaining sample size
+ * If we don't, we customize the stack size to
+ * fit in to the remaining sample size.
+ */
+
+ task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
+ stack_size = min(stack_size, (u16) task_size);
+
+ /* Current header size plus static size and dynamic size. */
+ header_size += 2 * sizeof(u64);
+
+ /* Do we fit in with the current stack dump size? */
+ if ((u16) (header_size + stack_size) < header_size) {
+ /*
+ * If we overflow the maximum size for the sample,
+ * we customize the stack dump size to fit in.
+ */
+ stack_size = USHRT_MAX - header_size - sizeof(u64);
+ stack_size = round_up(stack_size, sizeof(u64));
+ }
+
+ return stack_size;
+}
+
+static void
+perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
+ struct pt_regs *regs)
+{
+ /* Case of a kernel thread, nothing to dump */
+ if (!regs) {
+ u64 size = 0;
+ perf_output_put(handle, size);
+ } else {
+ unsigned long sp;
+ unsigned int rem;
+ u64 dyn_size;
+
+ /*
+ * We dump:
+ * static size
+ * - the size requested by user or the best one we can fit
+ * in to the sample max size
+ * data
+ * - user stack dump data
+ * dynamic size
+ * - the actual dumped size
+ */
+
+ /* Static size. */
+ perf_output_put(handle, dump_size);
+
+ /* Data. */
+ sp = perf_user_stack_pointer(regs);
+ rem = __output_copy_user(handle, (void *) sp, dump_size);
+ dyn_size = dump_size - rem;
+
+ perf_output_skip(handle, rem);
+
+ /* Dynamic size. */
+ perf_output_put(handle, dyn_size);
+ }
+}
+
static void __perf_event_header__init_id(struct perf_event_header *header,
struct perf_sample_data *data,
struct perf_event *event)
mask);
}
}
+
+ if (sample_type & PERF_SAMPLE_STACK_USER)
+ perf_output_sample_ustack(handle,
+ data->stack_user_size,
+ data->regs_user.regs);
}
void perf_prepare_sample(struct perf_event_header *header,
header->size += size;
}
+
+ if (sample_type & PERF_SAMPLE_STACK_USER) {
+ /*
+ * Either we need PERF_SAMPLE_STACK_USER bit to be allways
+ * processed as the last one or have additional check added
+ * in case new sample type is added, because we could eat
+ * up the rest of the sample size.
+ */
+ struct perf_regs_user *uregs = &data->regs_user;
+ u16 stack_size = event->attr.sample_stack_user;
+ u16 size = sizeof(u64);
+
+ if (!uregs->abi)
+ perf_sample_regs_user(uregs, regs);
+
+ stack_size = perf_sample_ustack_size(stack_size, header->size,
+ uregs->regs);
+
+ /*
+ * If there is something to dump, add space for the dump
+ * itself and for the field that tells the dynamic size,
+ * which is how many have been actually dumped.
+ */
+ if (stack_size)
+ size += sizeof(u64) + stack_size;
+
+ data->stack_user_size = stack_size;
+ header->size += size;
+ }
}
static void perf_event_output(struct perf_event *event,
}
}
- if (attr->sample_type & PERF_SAMPLE_REGS_USER)
+ if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
ret = perf_reg_validate(attr->sample_regs_user);
+ if (ret)
+ return ret;
+ }
+
+ if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
+ if (!arch_perf_have_user_stack_dump())
+ return -ENOSYS;
+
+ /*
+ * We have __u32 type for the size, but so far
+ * we can only use __u16 as maximum due to the
+ * __u16 sample size limit.
+ */
+ if (attr->sample_stack_user >= USHRT_MAX)
+ ret = -EINVAL;
+ else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
+ ret = -EINVAL;
+ }
out:
return ret;
projects / linux-beck.git / commitdiff