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/*
* Oracle Linux DTrace.
* Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
#ifndef _DT_DCTX_H
#define _DT_DCTX_H
#include <stdint.h>
#include <linux/bpf.h>
#include <bpf_asm.h>
#include <dt_pt_regs.h>
#include <dt_state.h>
/*
* Static probe IDs for the dtrace provider.
*/
#define DTRACE_BEGIN_ID 1
#define DTRACE_END_ID 2
#define DTRACE_ERROR_ID 3
/*
* The DTrace machine state.
*/
typedef struct dt_mstate {
uint32_t prid; /* Probe ID */
uint32_t stid; /* Statement ID */
uint32_t tag; /* Tag (for future use) */
uint32_t scratch_top; /* Current top of scratch space */
int32_t syscall_errno; /* syscall errno */
uint64_t specsize; /* speculation size */
uint64_t scalarizer; /* used to scalarize pointers */
uint64_t fault; /* DTrace fault flags */
uint64_t tstamp; /* cached timestamp value */
dt_pt_regs regs; /* CPU registers */
uint64_t argv[10]; /* Probe arguments */
uint64_t orig_argv[10]; /* Original (underlying) probe args */
uint64_t saved_argv[6]; /* Saved arguments */
} dt_mstate_t;
#define DMST_PRID offsetof(dt_mstate_t, prid)
#define DMST_STID offsetof(dt_mstate_t, stid)
#define DMST_TAG offsetof(dt_mstate_t, tag)
#define DMST_SCRATCH_TOP offsetof(dt_mstate_t, scratch_top)
#define DMST_ERRNO offsetof(dt_mstate_t, syscall_errno)
#define DMST_SPECSIZE offsetof(dt_mstate_t, specsize)
#define DMST_SCALARIZER offsetof(dt_mstate_t, scalarizer)
#define DMST_FAULT offsetof(dt_mstate_t, fault)
#define DMST_TSTAMP offsetof(dt_mstate_t, tstamp)
#define DMST_REGS offsetof(dt_mstate_t, regs)
#define DMST_ARG(n) offsetof(dt_mstate_t, argv[n])
#define DMST_ORIG_ARG(n) offsetof(dt_mstate_t, orig_argv[n])
/*
* The DTrace context.
*/
typedef struct dt_dctx {
void *ctx; /* BPF context */
dt_activity_t *act; /* pointer to activity state */
dt_mstate_t *mst; /* DTrace machine state */
char *buf; /* Output buffer scratch memory */
char *mem; /* General scratch memory */
char *scratchmem; /* Scratch space for alloca, etc */
char *strtab; /* String constant table */
char *rodata; /* Read-only data */
char *agg; /* Aggregation data */
char *gvars; /* Global variables */
char *lvars; /* Local variables */
} dt_dctx_t;
#define DCTX_CTX offsetof(dt_dctx_t, ctx)
#define DCTX_ACT offsetof(dt_dctx_t, act)
#define DCTX_MST offsetof(dt_dctx_t, mst)
#define DCTX_BUF offsetof(dt_dctx_t, buf)
#define DCTX_MEM offsetof(dt_dctx_t, mem)
#define DCTX_SCRATCHMEM offsetof(dt_dctx_t, scratchmem)
#define DCTX_STRTAB offsetof(dt_dctx_t, strtab)
#define DCTX_RODATA offsetof(dt_dctx_t, rodata)
#define DCTX_AGG offsetof(dt_dctx_t, agg)
#define DCTX_GVARS offsetof(dt_dctx_t, gvars)
#define DCTX_LVARS offsetof(dt_dctx_t, lvars)
#define DCTX_SIZE ((int16_t)sizeof(dt_dctx_t))
/*
* The dctx->buf pointer references a block of memory that contains:
*
* +----------------+
* 0 -> | size |
* +----------------+
* 4 -> | Speculation ID |
* +----------------+
* 8 -> | PRID |
* +----------------+
* 12 -> | STID |
* +----------------+
* 16 -> | Trace Data |
* | ... |
* +----------------+
*/
#define DBUF_SIZE 0
#define DBUF_SPECID 4
#define DBUF_PRID 8
#define DBUF_STID 12
#define DBUF_DATA 16
/*
* The dctx->mem pointer references a block of memory that contains:
*
* +----------------+----------------+
* 0 -> | tstring storage | \
* +----------------+----------------+ |
* DMEM_STRTOK -> | strtok() internal state | |
* +---------------------------------+ > DMEM_SIZE
* DMEM_STACK -> | stack storage | |
* +---------------------------------+ |
* DMEM_TUPLE -> | tuple assembly area | /
* +---------------------------------+
*/
/*
* Macros for the sizes of the components of dctx->mem.
*
* CAUTION: DMEM_TUPLE_SZ(dtp) depends on data collected during code generation
* and therefore cannot be used until all code generation has
* completed.
*/
#define DMEM_STACK_SZ(dtp) \
(4 * sizeof(uint32_t) + \
(dtp)->dt_options[DTRACEOPT_MAXFRAMES] * sizeof(uint64_t))
#define DMEM_TSTR_SZ(dtp) \
(DT_TSTRING_SLOTS * DT_TSTRING_SIZE(dtp))
#define DMEM_STRTOK_SZ(dtp) \
(sizeof(uint64_t) + (dtp)->dt_options[DTRACEOPT_STRSIZE] + 1)
#define DMEM_TUPLE_SZ(dtp) \
((dtp)->dt_maxtuplesize)
/*
* Macros to determine the offset of the components of dctx->mem.
*/
#define DMEM_STRTOK(dtp) \
DMEM_TSTR_SZ(dtp)
#define DMEM_STACK(dtp) \
(DMEM_STRTOK(dtp) + DMEM_STRTOK_SZ(dtp))
#define DMEM_TUPLE(dtp) \
(DMEM_STACK(dtp) + DMEM_STACK_SZ(dtp))
/*
* Macro to determine the total size of the mem area.
*
* CAUTION: DMEM_SIZE(dtp) depends on data collected during code generation
* and therefore cannot be used until all code generation has
* completed.
*/
#define DMEM_SIZE(dtp) (DMEM_TUPLE(dtp) + DMEM_TUPLE_SZ(dtp))
/*
* The stack layout for BPF programs that are generated as trampolines for
* D clauses.
*
* Note: The BPF frame pointer points to the address of the first byte past the
* end of the stack. 8-byte values are properly aligned at offsets -8,
* -16, -24, -32, etc. -- that is, negative multiples of sizeof(uint64_t).
*
* +----------------+
* SP_SLOT(n) | |
* +----------------+
* | ... |
* +----------------+
* SP_SLOT(1) | |
* +----------------+
* SP_BASE = SP_SLOT(0) | |
* +----------------+
* DCTX | DTrace Context |
* +----------------+
*/
#define DT_STK_BASE ((int16_t)0)
#define DT_STK_SLOT_SZ ((int16_t)sizeof(uint64_t))
#define DT_TRAMP_SP_BASE (DT_STK_BASE - DCTX_SIZE - DT_STK_SLOT_SZ)
#define DT_TRAMP_SP_SLOT(n) (DT_TRAMP_SP_BASE - (n) * DT_STK_SLOT_SZ)
/*
* DTrace clause functions can use all BPF registers except for the %fp (frame
* pointer) register and the highest numbered register (currently %r9) that is
* used to store the base pointer for the trace output record.
*/
#define DT_STK_NREGS (MAX_BPF_REG - 2)
/*
* The stack layout for functions that implement a D clause is encoded with the
* following constants.
*
* Note: The BPF frame pointer points to the address of the first byte past the
* end of the stack. 8-byte values are properly aligned at offsets -8,
* -16, -24, -32, etc. -- that is, negative multiples of sizeof(uint64_t).
*
* +----------------+
* | ... |
* +----------------+
* SP_BASE = SP_SLOT(0) | |<--+
* +----------------+ |
* SPILL(n) | %r8 | (n = DT_STK_NREGS - 1 = 8)
* +----------------+ |
* | ... | |
* +----------------+ |
* SPILL(1) | %r1 | |
* +----------------+ |
* SPILL_BASE = SPILL(0) | %r0 | |
* +----------------+ |
* SP | o------------+ (initial value)
* +----------------+
* DCTX | Ptr to dctx |
* +----------------+
*/
#define DT_STK_DCTX (DT_STK_BASE - DT_STK_SLOT_SZ)
#define DT_STK_SP (DT_STK_DCTX - DT_STK_SLOT_SZ)
#define DT_STK_SPILL_BASE (DT_STK_SP - DT_STK_SLOT_SZ)
#define DT_STK_SPILL(n) (DT_STK_SPILL_BASE - (n) * DT_STK_SLOT_SZ)
#define DT_STK_SP_BASE DT_STK_SPILL(DT_STK_NREGS)
#define DT_STK_SP_SLOT(n) (DT_STK_SP_BASE - (n) * DT_STK_SLOT_SZ)
#endif /* _DT_DCTX_H */
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