Date:	Fri, 28 Mar 2014 10:45:03 -0400
From:	Jovi Zhangwei <jovi.zhangwei@...il.com>
To:	Ingo Molnar <mingo@...hat.com>,
	Steven Rostedt <rostedt@...dmis.org>
Cc:	linux-kernel@...r.kernel.org,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Andi Kleen <andi@...stfloor.org>,
	Jovi Zhangwei <jovi.zhangwei@...il.com>
Subject: [PATCH v2 08/29] ktap: add bytecode reader(kernel/trace/ktap/kp_bcread.[c|h])

Exposed function:
ktap_proto_t *kp_bcread(ktap_state_t *ks, unsigned char *buff, int len)

Function kp_bcread read bytecode from buff, and return
ktap top-level function prototype.

Signed-off-by: Jovi Zhangwei <jovi.zhangwei@...il.com>
---
 kernel/trace/ktap/kp_bcread.c | 429 ++++++++++++++++++++++++++++++++++++++++++
 kernel/trace/ktap/kp_bcread.h |   6 +
 2 files changed, 435 insertions(+)
 create mode 100644 kernel/trace/ktap/kp_bcread.c
 create mode 100644 kernel/trace/ktap/kp_bcread.h

diff --git a/kernel/trace/ktap/kp_bcread.c b/kernel/trace/ktap/kp_bcread.c
new file mode 100644
index 0000000..b51b622
--- /dev/null
+++ b/kernel/trace/ktap/kp_bcread.c
@@ -0,0 +1,429 @@
+/*
+ * Bytecode reader.
+ *
+ * This file is part of ktap by Jovi Zhangwei.
+ *
+ * Copyright (C) 2012-2014 Jovi Zhangwei <jovi.zhangwei@...il.com>.
+ *
+ * Adapted from luajit and lua interpreter.
+ * Copyright (C) 2005-2014 Mike Pall.
+ * Copyright (C) 1994-2008 Lua.org, PUC-Rio.
+ *
+ * ktap is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * ktap is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <uapi/ktap/ktap_types.h>
+#include <uapi/ktap/ktap_bc.h>
+#include <uapi/ktap/ktap_err.h>
+#include "ktap.h"
+#include "kp_obj.h"
+#include "kp_vm.h"
+#include "kp_str.h"
+#include "kp_tab.h"
+
+
+/* Context for bytecode reader. */
+typedef struct BCReadCtx {
+	ktap_state_t *ks;
+	int flags;
+	char *start;
+	char *p;
+	char *pe;
+	ktap_str_t *chunkname;
+	ktap_val_t *savetop;
+} BCReadCtx;
+
+
+#define bcread_flags(ctx)	(ctx)->flags
+#define bcread_swap(ctx) \
+	((bcread_flags(ctx) & BCDUMP_F_BE) != KP_BE*BCDUMP_F_BE)
+#define bcread_oldtop(ctx)		(ctx)->savetop
+#define bcread_savetop(ctx)	(ctx)->savetop = (ctx)->ks->top;
+
+static inline uint32_t bswap(uint32_t x)
+{
+	return (uint32_t)__builtin_bswap32((int32_t)x);
+}
+
+/* -- Input buffer handling ----------------------------------------------- */
+
+/* Throw reader error. */
+static void bcread_error(BCReadCtx *ctx, ErrMsg em)
+{
+	kp_error(ctx->ks, "%s\n", err2msg(em));
+}
+
+/* Return memory block from buffer. */
+static inline uint8_t *bcread_mem(BCReadCtx *ctx, int len)
+{
+	uint8_t *p = (uint8_t *)ctx->p;
+	ctx->p += len;
+	kp_assert(ctx->p <= ctx->pe);
+	return p;
+}
+
+/* Copy memory block from buffer. */
+static void bcread_block(BCReadCtx *ctx, void *q, int len)
+{
+	memcpy(q, bcread_mem(ctx, len), len);
+}
+
+/* Read byte from buffer. */
+static inline uint32_t bcread_byte(BCReadCtx *ctx)
+{
+	kp_assert(ctx->p < ctx->pe);
+	return (uint32_t)(uint8_t)*ctx->p++;
+}
+
+/* Read ULEB128 value from buffer. */
+static inline uint32_t bcread_uint32(BCReadCtx *ctx)
+{
+	uint32_t v;
+	bcread_block(ctx, &v, sizeof(uint32_t));
+	kp_assert(ctx->p <= ctx->pe);
+	return v;
+}
+
+/* -- Bytecode reader ----------------------------------------------------- */
+
+/* Read debug info of a prototype. */
+static void bcread_dbg(BCReadCtx *ctx, ktap_proto_t *pt, int sizedbg)
+{
+	void *lineinfo = (void *)proto_lineinfo(pt);
+
+	bcread_block(ctx, lineinfo, sizedbg);
+	/* Swap lineinfo if the endianess differs. */
+	if (bcread_swap(ctx) && pt->numline >= 256) {
+		int i, n = pt->sizebc-1;
+		if (pt->numline < 65536) {
+			uint16_t *p = (uint16_t *)lineinfo;
+			for (i = 0; i < n; i++)
+				p[i] = (uint16_t)((p[i] >> 8)|(p[i] << 8));
+		} else {
+			uint32_t *p = (uint32_t *)lineinfo;
+			for (i = 0; i < n; i++)
+				p[i] = bswap(p[i]);
+		}
+	}
+}
+
+/* Find pointer to varinfo. */
+static const void *bcread_varinfo(ktap_proto_t *pt)
+{
+	const uint8_t *p = proto_uvinfo(pt);
+	int n = pt->sizeuv;
+	if (n)
+		while (*p++ || --n) ;
+	return p;
+}
+
+/* Read a single constant key/value of a template table. */
+static int bcread_ktabk(BCReadCtx *ctx, ktap_val_t *o)
+{
+	int tp = bcread_uint32(ctx);
+	if (tp >= BCDUMP_KTAB_STR) {
+		int len = tp - BCDUMP_KTAB_STR;
+		const char *p = (const char *)bcread_mem(ctx, len);
+		ktap_str_t *ts = kp_str_new(ctx->ks, p, len);
+		if (unlikely(!ts))
+			return -ENOMEM;
+
+		set_string(o, ts);
+	} else if (tp == BCDUMP_KTAB_NUM) {
+		set_number(o, *(ktap_number *)bcread_mem(ctx,
+					sizeof(ktap_number)));
+	} else {
+ 		kp_assert(tp <= BCDUMP_KTAB_TRUE);
+		setitype(o, ~tp);
+	}
+	return 0;
+}
+
+/* Read a template table. */
+static ktap_tab_t *bcread_ktab(BCReadCtx *ctx)
+{
+	int narray = bcread_uint32(ctx);
+	int nhash = bcread_uint32(ctx);
+
+	ktap_tab_t *t = kp_tab_new(ctx->ks, narray, hsize2hbits(nhash));
+	if (!t)
+		return NULL;
+
+	if (narray) {  /* Read array entries. */
+		int i;
+		ktap_val_t *o = t->array;
+		for (i = 0; i < narray; i++, o++) 
+			if (bcread_ktabk(ctx, o))
+				return NULL;
+	}
+	if (nhash) {  /* Read hash entries. */
+		int i;
+		for (i = 0; i < nhash; i++) {
+			ktap_val_t key;
+			ktap_val_t val;
+			if (bcread_ktabk(ctx, &key))
+				return NULL;
+			kp_assert(!is_nil(&key));
+			if (bcread_ktabk(ctx, &val))
+				return NULL;
+			kp_tab_set(ctx->ks, t, &key, &val);
+		}
+	}
+	return t;
+}
+
+/* Read GC constants(string, table, child proto) of a prototype. */
+static int bcread_kgc(BCReadCtx *ctx, ktap_proto_t *pt, int sizekgc)
+{
+	ktap_obj_t **kr = (ktap_obj_t **)pt->k - (ptrdiff_t)sizekgc;
+	int i;
+
+	for (i = 0; i < sizekgc; i++, kr++) {
+		int tp = bcread_uint32(ctx);
+		if (tp >= BCDUMP_KGC_STR) {
+			int len = tp - BCDUMP_KGC_STR;
+			const char *p = (const char *)bcread_mem(ctx, len);
+			*kr =(ktap_obj_t *)kp_str_new(ctx->ks, p, len);
+			if (unlikely(!*kr))
+				return -1;
+		} else if (tp == BCDUMP_KGC_TAB) {
+			*kr = (ktap_obj_t *)bcread_ktab(ctx);
+			if (unlikely(!*kr))
+				return -1;
+		} else if (tp == BCDUMP_KGC_CHILD){
+			ktap_state_t *ks = ctx->ks;
+			if (ks->top <= bcread_oldtop(ctx)) {
+				bcread_error(ctx, KP_ERR_BCBAD);
+				return -1;
+			}
+			ks->top--;
+			*kr = (ktap_obj_t *)ptvalue(ks->top);
+		} else {
+			bcread_error(ctx, KP_ERR_BCBAD);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+/* Read number constants of a prototype. */
+static void bcread_knum(BCReadCtx *ctx, ktap_proto_t *pt, int sizekn)
+{
+	int i;
+	ktap_val_t *o = pt->k;
+
+	for (i = 0; i < sizekn; i++, o++) {
+		set_number(o, *(ktap_number *)bcread_mem(ctx,
+					sizeof(ktap_number)));
+	}
+}
+
+/* Read bytecode instructions. */
+static void bcread_bytecode(BCReadCtx *ctx, ktap_proto_t *pt, int sizebc)
+{
+	BCIns *bc = proto_bc(pt);
+	bc[0] = BCINS_AD((pt->flags & PROTO_VARARG) ? BC_FUNCV : BC_FUNCF,
+			  pt->framesize, 0);
+	bcread_block(ctx, bc+1, (sizebc-1)*(int)sizeof(BCIns));
+	/* Swap bytecode instructions if the endianess differs. */
+	if (bcread_swap(ctx)) {
+		int i;
+		for (i = 1; i < sizebc; i++) bc[i] = bswap(bc[i]);
+	}
+}
+
+/* Read upvalue refs. */
+static void bcread_uv(BCReadCtx *ctx, ktap_proto_t *pt, int sizeuv)
+{
+	if (sizeuv) {
+		uint16_t *uv = proto_uv(pt);
+		bcread_block(ctx, uv, sizeuv*2);
+		/* Swap upvalue refs if the endianess differs. */
+		if (bcread_swap(ctx)) {
+			int i;
+			for (i = 0; i < sizeuv; i++)
+				uv[i] = (uint16_t)((uv[i] >> 8)|(uv[i] << 8));
+		}
+	}
+}
+
+/* Read a prototype. */
+static ktap_proto_t *bcread_proto(BCReadCtx *ctx)
+{
+	ktap_proto_t *pt;
+	int framesize, numparams, flags;
+	int sizeuv, sizekgc, sizekn, sizebc, sizept;
+	int ofsk, ofsuv, ofsdbg;
+	int sizedbg = 0;
+	BCLine firstline = 0, numline = 0;
+
+	/* Read prototype header. */
+	flags = bcread_byte(ctx);
+	numparams = bcread_byte(ctx);
+	framesize = bcread_byte(ctx);
+	sizeuv = bcread_byte(ctx);
+	sizekgc = bcread_uint32(ctx);
+	sizekn = bcread_uint32(ctx);
+	sizebc = bcread_uint32(ctx) + 1;
+	if (!(bcread_flags(ctx) & BCDUMP_F_STRIP)) {
+		sizedbg = bcread_uint32(ctx);
+		if (sizedbg) {
+			firstline = bcread_uint32(ctx);
+			numline = bcread_uint32(ctx);
+		}
+	}
+
+	/* Calculate total size of prototype including all colocated arrays. */
+	sizept = (int)sizeof(ktap_proto_t) + sizebc * (int)sizeof(BCIns) +
+			sizekgc * (int)sizeof(ktap_obj_t *);
+	sizept = (sizept + (int)sizeof(ktap_val_t)-1) &
+			~((int)sizeof(ktap_val_t)-1);
+	ofsk = sizept; sizept += sizekn*(int)sizeof(ktap_val_t);
+	ofsuv = sizept; sizept += ((sizeuv+1)&~1)*2;
+	ofsdbg = sizept; sizept += sizedbg;
+
+	/* Allocate prototype object and initialize its fields. */
+	pt = (ktap_proto_t *)kp_obj_new(ctx->ks, (int)sizept);
+	pt->gct = ~KTAP_TPROTO;
+	pt->numparams = (uint8_t)numparams;
+	pt->framesize = (uint8_t)framesize;
+	pt->sizebc = sizebc;
+	pt->k = (char *)pt + ofsk;
+	pt->uv = (char *)pt + ofsuv;
+	pt->sizekgc = 0;  /* Set to zero until fully initialized. */
+	pt->sizekn = sizekn;
+	pt->sizept = sizept;
+	pt->sizeuv = (uint8_t)sizeuv;
+	pt->flags = (uint8_t)flags;
+	pt->chunkname = ctx->chunkname;
+
+	/* Close potentially uninitialized gap between bc and kgc. */
+	*(uint32_t *)((char *)pt + ofsk - sizeof(ktap_obj_t *)*(sizekgc+1))
+									= 0;
+
+	/* Read bytecode instructions and upvalue refs. */
+	bcread_bytecode(ctx, pt, sizebc);
+	bcread_uv(ctx, pt, sizeuv);
+
+	/* Read constants. */
+	if (bcread_kgc(ctx, pt, sizekgc))
+		return NULL;
+	pt->sizekgc = sizekgc;
+	bcread_knum(ctx, pt, sizekn);
+
+	/* Read and initialize debug info. */
+	pt->firstline = firstline;
+	pt->numline = numline;
+	if (sizedbg) {
+		int sizeli = (sizebc-1) << (numline < 256 ? 0 :
+					numline < 65536 ? 1 : 2);
+		pt->lineinfo = (char *)pt + ofsdbg;
+		pt->uvinfo = (char *)pt + ofsdbg + sizeli;
+		bcread_dbg(ctx, pt, sizedbg);
+		pt->varinfo = (void *)bcread_varinfo(pt);
+	} else {
+		pt->lineinfo = NULL;
+		pt->uvinfo = NULL;
+		pt->varinfo = NULL;
+	}
+	return pt;
+}
+
+/* Read and check header of bytecode dump. */
+static int bcread_header(BCReadCtx *ctx)
+{
+	uint32_t flags;
+
+	if (bcread_byte(ctx) != BCDUMP_HEAD1 ||
+		bcread_byte(ctx) != BCDUMP_HEAD2 ||
+		bcread_byte(ctx) != BCDUMP_HEAD3 ||
+		bcread_byte(ctx) != BCDUMP_VERSION)
+		return -1;
+
+	bcread_flags(ctx) = flags = bcread_byte(ctx);
+
+	if ((flags & ~(BCDUMP_F_KNOWN)) != 0)
+		return -1;
+
+	if ((flags & BCDUMP_F_FFI)) {
+		return -1;
+	}
+
+	if ((flags & BCDUMP_F_STRIP)) {
+		ctx->chunkname = kp_str_newz(ctx->ks, "striped");
+	} else {
+		int len = bcread_uint32(ctx);
+		ctx->chunkname = kp_str_new(ctx->ks,
+				(const char *)bcread_mem(ctx, len), len);
+	}
+
+	if (unlikely(!ctx->chunkname))
+		return -1;
+
+	return 0;
+}
+
+/* Read a bytecode dump. */
+ktap_proto_t *kp_bcread(ktap_state_t *ks, unsigned char *buff, int len)
+{
+	BCReadCtx ctx;
+
+	ctx.ks = ks;
+	ctx.p = buff;
+	ctx.pe = buff + len;
+
+	ctx.start = buff;
+
+	bcread_savetop(&ctx);
+	/* Check for a valid bytecode dump header. */
+	if (bcread_header(&ctx)) {
+		bcread_error(&ctx, KP_ERR_BCFMT);
+		return NULL;
+	}
+
+	for (;;) {  /* Process all prototypes in the bytecode dump. */
+		ktap_proto_t *pt;
+		int len;
+		const char *startp;
+		/* Read length. */
+		if (ctx.p < ctx.pe && ctx.p[0] == 0) {  /* Shortcut EOF. */
+			ctx.p++;
+			break;
+		}
+		len = bcread_uint32(&ctx);
+		if (!len)
+			break;  /* EOF */
+		startp = ctx.p;
+		pt = bcread_proto(&ctx);
+		if (!pt)
+			return NULL;
+		if (ctx.p != startp + len) {
+			bcread_error(&ctx, KP_ERR_BCBAD);
+			return NULL;
+		}
+		set_proto(ks->top, pt);
+		incr_top(ks);
+	}
+	if ((int32_t)(2*(uint32_t)(ctx.pe - ctx.p)) > 0 ||
+			ks->top-1 != bcread_oldtop(&ctx)) {
+		bcread_error(&ctx, KP_ERR_BCBAD);
+		return NULL;
+	}
+
+	/* Pop off last prototype. */
+	ks->top--;
+	return ptvalue(ks->top);
+}
+
diff --git a/kernel/trace/ktap/kp_bcread.h b/kernel/trace/ktap/kp_bcread.h
new file mode 100644
index 0000000..ea2dde2
--- /dev/null
+++ b/kernel/trace/ktap/kp_bcread.h
@@ -0,0 +1,6 @@
+#ifndef __KTAP_BCREAD_H__
+#define __KTAP_BCREAD_H__
+
+ktap_proto_t *kp_bcread(ktap_state_t *ks, unsigned char *buff, int len);
+
+#endif /* __KTAP_BCREAD_H__ */
-- 
1.8.1.4

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