ref: e15b1b8930550b14938e94f01a5109f9417e0506
parent: a7f5ecaf636e38f407c951d0e86dcc4c4f424bd6
author: aiju <devnull@localhost>
date: Sat Nov 10 15:01:19 EST 2018
add dtracy.h
--- /dev/null
+++ b/sys/include/dtracy.h
@@ -1,0 +1,245 @@
+#pragma lib "libdtracy.a"
+#pragma src "/sys/src/libdtracy"
+
+/*
+ triggered probes run in "probe context", which involves grabbing a per-CPU lock using dtmachlock/dtmachunlock.
+ everything else in the library assumes that the calling code has grabbed a global lock (which is done in 9/port/devtracy.c).
+*/
+
+enum {+ DTSTRMAX = 256,
+ DTRECMAX = 1024,
+};
+
+typedef struct DTName DTName;
+typedef struct DTProbe DTProbe;
+typedef struct DTExprState DTExprState;
+typedef struct DTAct DTAct;
+typedef struct DTActGr DTActGr;
+typedef struct DTClause DTClause;
+typedef struct DTEnab DTEnab;
+typedef struct DTChan DTChan;
+typedef struct DTExpr DTExpr;
+typedef struct DTProvider DTProvider;
+typedef struct DTBuf DTBuf;
+
+struct DTName {+ char *provider;
+ char *function;
+ char *name;
+};
+
+/*
+ we assign all pairs (probe,action-group) (called an enabling or DTEnab) a unique ID.
+ we could also use probe IDs and action group IDs but using a single 32-bit ID for both is more flexible/efficient.
+*/
+struct DTEnab {+ u32int epid;
+ DTActGr *gr;
+ DTEnab *probnext, *probprev;
+ DTEnab *channext;
+ DTProbe *prob;
+};
+
+/* probes are never freed */
+struct DTProbe {+ int nenable;
+ DTName;
+ DTEnab enablist;
+ DTProvider *prov;
+ void *aux; /* for the provider */
+ DTProbe *provnext;
+};
+
+struct DTProvider {+ char *name;
+ /*
+ provide() is called when the user asks for a probe that doesn't exist.
+ provide() should call dtpnew() to create probes.
+ it can use the DTName as a hint or just create all probes that it knows about.
+ the provider has to ensure not to create the same probe multiple times.
+ */
+ void (*provide)(DTProvider *, DTName);
+ int (*enable)(DTProbe *); /* enable the probe. return >= 0 for success and < 0 for failure */
+ void (*disable)(DTProbe *); /* disable the probe */
+
+ /* for the library, not the provider */
+ DTProbe *probes;
+};
+
+/*
+ the dtracy vm is a simple RISC machine with (currently) 16 64-bit registers.
+ all operations are 64-bit.
+
+ instruction encoding:
+ 31:24 opcode
+ 23:16 a
+ 15:8 b
+ 7:0 c
+*/
+
+enum {+ /* Rc = Ra (op) Rb */
+ DTE_ADD = 0x00,
+ DTE_SUB = 0x01,
+ DTE_MUL = 0x02,
+ DTE_SDIV = 0x03,
+ DTE_SMOD = 0x04,
+ DTE_UDIV = 0x05,
+ DTE_UMOD = 0x06,
+ DTE_AND = 0x07,
+ DTE_OR = 0x08,
+ DTE_XOR = 0x09,
+ DTE_XNOR = 0x0A,
+ DTE_LSL = 0x0B, /* logical shift left */
+ DTE_LSR = 0x0C, /* logical shift right */
+ DTE_ASR = 0x0D, /* arithmetic shift right */
+ DTE_SEQ = 0x10, /* set if equal */
+ DTE_SNE = 0x11, /* set if not equal */
+ DTE_SLT = 0x12, /* set if less than */
+ DTE_SLE = 0x13, /* set if less or equal */
+
+ /* immediate operations, const = 10 top bits of ab, sign extended and shifted left by 6 bottom bits */
+ DTE_LDI = 0x20, /* Rc = const */
+ DTE_XORI = 0x21, /* Rc = Rc ^ const */
+
+ /* if(Ra (op) Rb) PC += c; */
+ DTE_BEQ = 0x30,
+ DTE_BNE = 0x31,
+ DTE_BLT = 0x32,
+ DTE_BLE = 0x33,
+
+ DTE_LDV = 0x40, /* R[b] = Var[a] */
+
+ DTE_ZXT = 0x50, /* R[c] = lower b bits of R[a], zero extended, 0 < b <= 64 */
+ DTE_SXT = 0x51, /* R[c] = lower b bits of R[a], sign extended, 0 < b <= 64 */
+
+ DTE_RET = 0xF0, /* RET Ra */
+};
+#define DTE(op,a,b,c) ((op)<<24|(a)<<16|(b)<<8|(c))
+
+struct DTExpr {+ int n;
+ u32int *b;
+};
+
+/* an action is an expression, plus info about what to do with the result */
+struct DTAct {+ enum {+ ACTTRACE, /* record the result. size is the number of bytes used. 0 <= size <= 8 */
+ ACTTRACESTR, /* take the result to be a pointer to a null-terminated string. store it as zero-padded char[size]. */
+ } type;
+ DTExpr *p;
+ int size;
+};
+
+/* an action group is an optional predicate and a set of actions. */
+struct DTActGr {+ u32int id;
+ int ref;
+ DTExpr *pred; /* if non-nil and evaluates to 0, skip the actions. */
+ int nact;
+ DTAct *acts;
+ DTChan *chan;
+ int reclen; /* record size, including 12-byte header */
+};
+
+/* a clause list probe wildcard expressions and an action group. only used during set-up. */
+struct DTClause {+ int nprob;
+ char **probs;
+ DTActGr *gr;
+};
+
+enum { DTBUFSZ = 65536 };+struct DTBuf {+ int wr;
+ uchar data[DTBUFSZ];
+};
+
+/* a chan is the kernel representation of a client. */
+struct DTChan {+ enum {+ DTCSTOP,
+ DTCGO,
+ DTCFAULT,
+ } state;
+ char errstr[64];
+ u32int epidalloc; /* lowest unused EPID */
+
+ /* we have 2 buffers per cpu, one for writing and one for reading. dtcread() swaps them if empty. */
+ DTBuf **wrbufs;
+ DTBuf **rdbufs;
+
+ /* list of enablings. */
+ DTEnab *enab;
+};
+
+void dtinit(int);
+void dtsync(void);
+
+/* probe functions */
+DTProbe *dtpnew(DTName, DTProvider *, void *aux);
+int dtpmatch(DTName, DTProbe ***);
+void dtptrigger(DTProbe *, int, uvlong, uvlong, uvlong, uvlong);
+
+/* expression functions */
+int dteverify(DTExpr *);
+int dtefmt(Fmt *);
+#pragma varargck type "I" u32int
+
+/* action group functions */
+void dtgpack(Fmt *, DTActGr *);
+char *dtgunpack(char *, DTActGr **);
+int dtgverify(DTActGr *);
+void dtgfree(DTActGr *);
+
+/* clause functions */
+void dtclpack(Fmt *, DTClause *);
+char *dtclunpack(char *, DTClause **);
+void dtclfree(DTClause *);
+
+/* chan functions */
+DTChan *dtcnew(void);
+void dtcfree(DTChan *);
+int dtcaddgr(DTChan *, DTName, DTActGr *);
+int dtcaddcl(DTChan *, DTClause *);
+int dtcread(DTChan *, void *, int);
+void dtcreset(DTChan *);
+void dtcrun(DTChan *, int);
+
+extern DTProvider *dtproviders[];
+extern int dtnmach;
+
+/* helper */
+char *dtstrdup(char *);
+
+/* these functions are provided by the kernel interface */
+uvlong dttime(void); /* return current timestamp */
+void *dtrealloc(void *, ulong);
+void dtfree(void *);
+void *dtmalloc(ulong);
+void dtmachlock(int); /* lock the per-cpu lock */
+void dtmachunlock(int); /* unlock the per-cpu lock */
+void dtcoherence(void); /* memory barrier */
+uvlong dtgetvar(int); /* return the value of a variable */
+int dtpeek(uvlong, void*, int); /* safe memmemove(). returns -1 on error. */
+
+enum {+ DTV_ARG0,
+ DTV_ARG1,
+ DTV_ARG2,
+ DTV_ARG3,
+ DTV_ARG4,
+ DTV_ARG5,
+ DTV_ARG6,
+ DTV_ARG7,
+ DTV_ARG8,
+ DTV_ARG9,
+ DTV_PID,
+ DTV_MACHNO,
+ DTV_TIME,
+ DTV_PROBE,
+ DTNVARS,
+};
+extern char *dtvarnames[DTNVARS];