Re: [PATCH]KGTP (Linux Kernel debugger and tracer) lite patch forreview

From: Hui Zhu
Date: Thu May 10 2012 - 08:15:58 EST

On 05/09/12 22:05, Andi Kleen wrote:
Please provide better explanation of the use case for this module.
One paragraph why someone would want it in their kernel.

sudo insmod kernel/gtp.ko
sudo gdb ./vmlinux
#Connect KGTP interface
(gdb) target remote /sys/kernel/debug/gtp
Remote debugging using /sys/kernel/debug/gtp
0x0000000000000000 in irq_stack_union ()
#Access memory directly
(gdb) p jiffies_64
$1 = 4332444293
(gdb) p jiffies_64
$2 = 4332444591
(gdb) p *((struct module *)((char *)modules->next - ((size_t) &(((struct module *)0)->list))))
$3 = {state = MODULE_STATE_LIVE, list = {next = 0xffffffffa0964188, prev = 0xffffffff81c345f0},
name = "gtp", '\000' <repeats 52 times>, mkobj = {kobj = {name = 0xffff88011f5c49c8 "gtp", entry = {
next = 0xffff880221cd6420, prev = 0xffffffffa09641d8}, parent = 0xffff880221cd6438, kset = 0xffff880221cd6420,
...
(gdb) p *(struct device *)(__per_cpu_offset[0]+(uint64_t)(&mce_device))
$4 = {parent = 0xffff8802212f8000, p = 0x1fe, kobj = {name = 0x0, entry = {next = 0x0, prev = 0xffffffff8102ae70},
parent = 0x0, kset = 0x0, ktype = 0x0, sd = 0x0, kref = {refcount = {counter = 0}}, state_initialized = 0,
...
#Set tracepoint to collect the register info of function vfs_read
(gdb) trace vfs_read
Tracepoint 1 at 0xffffffff8117a3d0: file /home/teawater/kernel2/linux/fs/read_write.c, line 365.
(gdb) actions
Enter actions for tracepoint 1, one per line.
End with a line saying just "end".
collect $reg
end
(gdb) tstart
(gdb) tstop
(gdb) tfind
Found trace frame 0, tracepoint 1
#0 vfs_read (file=0xffff880070bb6100,
buf=0x31cb8f0 "$2aa6178136313733#331bb700088ffff481fe4450188ffff002", '0' <repeats 13 times>, "f0b81c03000000000061bb700088ffff781fe4450188ffff301fe4450188ffff606944030000000058f19a010288ffff01", '0' <repeats 14 times>, "4602", '0' <repeats 12 times>, "f0b81c0"..., count=8192, pos=0xffff880145e41f48) at /home/teawater/kernel2/linux/fs/read_write.c:365
365 {
(gdb) info reg
rax 0x0 0
rbx 0xffff880070bb6100 -131939504004864
rcx 0xffff880145e41f48 -131935927787704
rdx 0x2000 8192
rsi 0x31cb8f0 52214000
rdi 0xffff880070bb6100 -131939504004864
rbp 0xffff880145e41f78 0xffff880145e41f78
rsp 0xffff880145e41f30 0xffff880145e41f30
r8 0x3446960 54815072
r9 0xffff8802019af158 -131932778466984
r10 0x1 1
r11 0x246 582
r12 0x31cb8f0 52214000
r13 0x2000 8192
r14 0xa 10
r15 0xa 10
rip 0xffffffff8117a3d0 0xffffffff8117a3d0 <vfs_read>
eflags 0x286 [ PF SF IF ]
cs 0x10 16
ss 0x18 24
ds *value not available*
es *value not available*
fs *value not available*
gs *value not available*

Because this is a lite patch, so this patch doesn't support other functions of KGTP.


+++ b/arch/arm/include/asm/gtp.h
@@ -0,0 +1,34 @@
+#ifndef _ASM_ARM_GTP_H_
+#define _ASM_ARM_GTP_H_
+
+#define ULONGEST uint64_t

So u64 in kernel. Just use that.

+#define CORE_ADDR unsigned long

In linux kernel CORE_ADDR is always unsigned long. Use that.


ULONGEST and CORE_ADDR is the type from GDB rsp packet. I use it to parse the package from GDB. Then want to add add a new arch to KGTP, just need set this two type same with GDB. So do you mind I keep it?

+
+#define GTP_REG_ASCII_SIZE 336
+
+static inline void
+gtp_regs2ascii(struct pt_regs *regs, char *buf)
+{
+#ifdef __LITTLE_ENDIAN
+#define SWAB(a) swab32(a)
+#else
+#define SWAB(a) (a)
+#endif

That's just ntohl()? Just use that

It is fixed in new patch.


Linux already has macros for this:
+ int i;
+
+ for (i = 0; i < 16; i++) {
+ sprintf(buf, "%08lx", (unsigned long) SWAB(regs->uregs[i]));

Is the gdb protocol really big endian in ASCII?

Yes, I tested this part of code in before. GDB need it in this format.

Also could you share code on this with the in kernel gdbstub?

Most of this part of code is deep inside the kgdb c code. Share these code need change this part of code out of kgdb and something else.


+#include <linux/slab.h>
+#include <asm/gtp.h>
+
+#define GTP_DEBUG KERN_WARNING

You should use the pr_* macros now

OK. I changed all of them to pr_devel.


+static int gtp_disconnected_tracing;
+static int gtp_circular;
+
+static DEFINE_SPINLOCK(gtp_frame_lock);

Every spinlock needs a comment that describes what it protects.
I believe checkpatch warns about that. Did you run it?

I use it with the patch but didn't get the warn. It is fixed in the new patch.


+
+ tmp = gtp_frame_alloc(GTP_FRAME_REG_SIZE);
+ if (!tmp)
+ return NULL;
+
+ *next = tmp;
+ tmp[0] = 'r';
+ freg = (struct gtp_frame_reg *) (tmp + 1);
+ memcpy(&freg->regs, regs, sizeof(struct pt_regs));
+#if !defined CONFIG_X86_32 && !defined CONFIG_X86_64
+ freg->regs.sp = (unsigned long)&regs->sp;
+#endif /* CONFIG_X86_32 CONFIG_X86_64 */

That looks weird. What does that do?

Oops, this part of code is worng.(I copy this function from a very old version of KGTP.)
Fixed in new patch.


+gtp_action_alloc(char type)
+{
+ struct action *ret;
+
+ ret = kmalloc(sizeof(struct action), GFP_KERNEL);

kzalloc

All fixed.

Same problem in others.

+static int
+hex2int(char hex, int *i)

I'm sure we have code for this. strtoul et.al.?

OK. I changed hex2ulongest to simple_strtoull in new patch.
But I meet a issue is checkpatch told me that "simple_strtoull is obsolete, use kstrtoull instead". But kstrtoull cannot get the address that where this convert stop at. Do you have some comments on it?


Didn't read further so far.


-Andi


Thanks for your help.
I post a new patch according to your comments. Please help me review it.

Thanks,
Hui

Signed-off-by: Hui Zhu <teawater@xxxxxxxxx>
---
arch/arm/include/asm/gtp.h | 28 +
arch/mips/include/asm/gtp.h | 64 +++
arch/x86/include/asm/gtp.h | 96 ++++
kernel/Makefile | 2
kernel/gtp.c | 914 ++++++++++++++++++++++++++++++++++++++++++++
lib/Kconfig.debug | 8
6 files changed, 1112 insertions(+)

--- /dev/null
+++ b/arch/arm/include/asm/gtp.h
@@ -0,0 +1,28 @@
+#ifndef _ASM_ARM_GTP_H_
+#define _ASM_ARM_GTP_H_
+
+#define ULONGEST uint64_t
+#define CORE_ADDR unsigned long
+
+#define GTP_REG_ASCII_SIZE 336
+
+static inline void
+gtp_regs2ascii(struct pt_regs *regs, char *buf)
+{
+ int i;
+
+ for (i = 0; i < 16; i++) {
+ sprintf(buf, "%08lx", (unsigned long) ntohl(regs->uregs[i]));
+ buf += 8;
+ }
+
+ /* f0-f7 fps */
+ memset(buf, '0', 200);
+ buf += 200;
+
+ sprintf(buf, "%08lx",
+ (unsigned long) ntohl(regs->uregs[16]));
+ buf += 8;
+}
+
+#endif
--- /dev/null
+++ b/arch/mips/include/asm/gtp.h
@@ -0,0 +1,64 @@
+#ifndef _ASM_MIPS_GTP_H_
+#define _ASM_MIPS_GTP_H_
+
+#define ULONGEST uint64_t
+#define CORE_ADDR unsigned long
+
+#ifdef CONFIG_32BIT
+#define GTP_REG_ASCII_SIZE 304
+#else
+#define GTP_REG_ASCII_SIZE 608
+#endif
+
+#define GTP_SP_NUM 29
+
+static inline void
+gtp_regs2ascii(struct pt_regs *regs, char *buf)
+{
+#ifdef CONFIG_32BIT
+#define OUTFORMAT "%08lx"
+#define REGSIZE 8
+#define SWAB(a) ntohl(a)
+#else
+#define OUTFORMAT "%016lx"
+#define REGSIZE 16
+#ifdef __LITTLE_ENDIAN
+#define SWAB(a) swab64(a)
+#else
+#define SWAB(a) (a)
+#endif
+#endif
+ {
+ int i;
+
+ for (i = 0; i < 32; i++) {
+ sprintf(buf, OUTFORMAT,
+ (unsigned long) SWAB(regs->regs[i]));
+ buf += REGSIZE;
+ }
+ }
+
+ sprintf(buf, OUTFORMAT,
+ (unsigned long) SWAB(regs->cp0_status));
+ buf += REGSIZE;
+ sprintf(buf, OUTFORMAT,
+ (unsigned long) SWAB(regs->lo));
+ buf += REGSIZE;
+ sprintf(buf, OUTFORMAT,
+ (unsigned long) SWAB(regs->hi));
+ buf += REGSIZE;
+ sprintf(buf, OUTFORMAT,
+ (unsigned long) SWAB(regs->cp0_badvaddr));
+ buf += REGSIZE;
+ sprintf(buf, OUTFORMAT,
+ (unsigned long) SWAB(regs->cp0_cause));
+ buf += REGSIZE;
+ sprintf(buf, OUTFORMAT,
+ (unsigned long) SWAB(regs->cp0_epc));
+ buf += REGSIZE;
+#undef OUTFORMAT
+#undef REGSIZE
+#undef SWAB
+}
+
+#endif
--- /dev/null
+++ b/arch/x86/include/asm/gtp.h
@@ -0,0 +1,96 @@
+#ifndef _ASM_X86_GTP_H_
+#define _ASM_X86_GTP_H_
+
+#define ULONGEST uint64_t
+#define CORE_ADDR unsigned long
+
+#ifdef CONFIG_X86_32
+#define GTP_REG_ASCII_SIZE 128
+#else
+#define GTP_REG_ASCII_SIZE 296
+#endif
+
+static inline void
+gtp_regs2ascii(struct pt_regs *regs, char *buf)
+{
+#ifdef CONFIG_X86_32
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->ax));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->cx));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->dx));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->bx));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->sp));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->bp));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->si));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->di));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->ip));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->flags));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->cs));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->ss));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->ds));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->es));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->fs));
+ buf += 8;
+ sprintf(buf, "%08x", (unsigned int) swab32(regs->gs));
+ buf += 8;
+#else
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->ax));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->bx));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->cx));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->dx));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->si));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->di));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->bp));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->sp));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->r8));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->r9));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->r10));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->r11));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->r12));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->r13));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->r14));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->r15));
+ buf += 16;
+ sprintf(buf, "%016lx", (unsigned long) swab64(regs->ip));
+ buf += 16;
+ sprintf(buf, "%08x",
+ (unsigned int) swab32((unsigned int)regs->flags));
+ buf += 8;
+ sprintf(buf, "%08x",
+ (unsigned int) swab32((unsigned int)regs->cs));
+ buf += 8;
+ sprintf(buf, "%08x",
+ (unsigned int) swab32((unsigned int)regs->ss));
+ buf += 8;
+#endif
+}
+
+#endif
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -107,6 +107,8 @@ obj-$(CONFIG_PADATA) += padata.o
obj-$(CONFIG_CRASH_DUMP) += crash_dump.o
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
+obj-$(CONFIG_GTP) += gtp.o
+
$(obj)/configs.o: $(obj)/config_data.h
# config_data.h contains the same information as ikconfig.h but gzipped.
--- /dev/null
+++ b/kernel/gtp.c
@@ -0,0 +1,914 @@
+/*
+ * Kernel GDB tracepoint module.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright(C) KGTP team (https://code.google.com/p/kgtp/), 2010, 2011, 2012
+ *
+ */
+
+#include <linux/version.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/poll.h>
+#include <linux/kprobes.h>
+#include <linux/interrupt.h>
+#include <linux/debugfs.h>
+#include <linux/slab.h>
+#include <asm/gtp.h>
+
+#define GTP_RW_MAX 16384
+
+#define GTP_FRAME_SIZE 5242880
+#define GTP_FRAME_HEAD_SIZE (1 + sizeof(struct gtp_frame_head))
+#define GTP_FRAME_REG_SIZE (1 + sizeof(struct gtp_frame_reg))
+
+#define TOHEX(h) ((h) > 9 ? (h) + 'a' - 10 : (h) + '0')
+
+struct action {
+ struct action *next;
+ char type;
+ union {
+ ULONGEST reg_mask;
+ } u;
+};
+
+struct gtp_entry {
+ struct gtp_entry *next;
+ ULONGEST num;
+ ULONGEST addr;
+ ULONGEST step;
+ ULONGEST pass;
+ int nopass;
+ int kpreg;
+ struct kprobe kp;
+ struct action *action_list;
+ struct action *action_list_tail;
+} *gtp_list = NULL, *gtp_list_tail = NULL;
+
+struct gtp_frame_head {
+ int frame_num;
+ ULONGEST trace_num;
+ char *next;
+};
+
+struct gtp_frame_reg {
+ struct pt_regs regs;
+ char *next;
+};
+
+static atomic_t gtp_count;
+static char gtp_read_ack;
+static char *gtp_rw_buf;
+static char *gtp_rw_bufp;
+static size_t gtp_rw_size;
+
+static int gtp_start;
+
+static int gtp_disconnected_tracing;
+static int gtp_circular;
+
+/* This spin_lock protects the gtp_frame. */
+static DEFINE_SPINLOCK(gtp_frame_lock);
+static int gtp_frame_num;
+static char *gtp_frame;
+static char *gtp_frame_r_start;
+static char *gtp_frame_w_start;
+static char *gtp_frame_w_end;
+static char *gtp_frame_r_cache;
+static int gtp_frame_is_circular;
+static struct gtp_frame_head *gtp_frame_current;
+
+static char *
+gtp_frame_alloc(size_t size)
+{
+ char *ret = NULL;
+
+ if (size > GTP_FRAME_SIZE)
+ return NULL;
+
+ spin_lock(&gtp_frame_lock);
+
+ if (gtp_frame_w_start + size > gtp_frame_w_end) {
+ if (gtp_circular) {
+ gtp_frame_is_circular = 1;
+ gtp_frame_w_start = gtp_frame;
+ gtp_frame_r_start = gtp_frame;
+ } else
+ goto out;
+ }
+
+ if (gtp_frame_is_circular) {
+ /* Release some frame entry to get some place.
+ XXX: When support new frame type, need add new handler
+ to switch. */
+ while (gtp_frame_w_start + size > gtp_frame_r_start) {
+ switch (gtp_frame_r_start[0]) {
+ case 'h':
+ gtp_frame_r_start += GTP_FRAME_HEAD_SIZE;
+ break;
+ case 'r':
+ gtp_frame_r_start += GTP_FRAME_REG_SIZE;
+ break;
+ default:
+ goto out;
+ }
+ }
+ }
+
+ ret = gtp_frame_w_start;
+ gtp_frame_w_start += size;
+
+out:
+ spin_unlock(&gtp_frame_lock);
+ return ret;
+}
+
+static inline char **
+gtp_action_r(struct pt_regs *regs, struct action *ae, char **next)
+{
+ struct gtp_frame_reg *freg;
+ char *tmp;
+
+ tmp = gtp_frame_alloc(GTP_FRAME_REG_SIZE);
+ if (!tmp)
+ return NULL;
+
+ *next = tmp;
+ tmp[0] = 'r';
+ freg = (struct gtp_frame_reg *) (tmp + 1);
+ memcpy(&freg->regs, regs, sizeof(struct pt_regs));
+#ifdef CONFIG_X86_32
+ freg->regs.sp = (unsigned long)&regs->sp;
+#endif /* CONFIG_X86_32 */
+#ifdef CONFIG_X86
+ freg->regs.ip -= 1;
+#endif /* CONFIG_X86 */
+ freg->next = NULL;
+
+ return &freg->next;
+}
+
+static int
+gtp_kp_pre_handler(struct kprobe *p, struct pt_regs *regs)
+{
+ struct gtp_entry *tpe = container_of(p, struct gtp_entry, kp);
+ struct gtp_frame_head *head;
+ char *tmp;
+ struct action *ae;
+ char **next;
+
+ pr_devel("gtp_kp_pre_handler: tracepoint %d\n", (int)tpe->num);
+
+ /* Get the head. */
+ tmp = gtp_frame_alloc(GTP_FRAME_HEAD_SIZE);
+ if (!tmp)
+ goto no_memory;
+ tmp[0] = 'h';
+ head = (struct gtp_frame_head *) (tmp + 1);
+ /* Get a new frame num from gtp_frame_num. */
+ spin_lock(&gtp_frame_lock);
+ if (gtp_frame_num < 0)
+ gtp_frame_num = head->frame_num = 0;
+ else
+ head->frame_num = gtp_frame_num++;
+ spin_unlock(&gtp_frame_lock);
+ head->trace_num = tpe->num;
+ head->next = NULL;
+ next = &head->next;
+
+ /* Handle actions. */
+ for (ae = tpe->action_list; ae; ae = ae->next) {
+ switch (ae->type) {
+ case 'r':
+ next = gtp_action_r(regs, ae, next);
+ if (!next)
+ goto no_memory;
+ break;
+ }
+ }
+
+ return 0;
+
+no_memory:
+ pr_devel("gtp_kp_pre_handler: tracepoint %d no memory.\n",
+ (int)tpe->num);
+ return 0;
+}
+
+static struct action *
+gtp_action_alloc(char type)
+{
+ struct action *ret;
+
+ ret = kzalloc(sizeof(struct action), GFP_KERNEL);
+ if (!ret)
+ goto out;
+
+ ret->type = type;
+
+out:
+ return ret;
+}
+
+static void
+gtp_action_release(struct action *ae)
+{
+ struct action *ae2;
+
+ while (ae) {
+ ae2 = ae;
+ ae = ae->next;
+ /* Release ae2. */
+ kfree(ae2);
+ }
+}
+
+static struct gtp_entry *
+gtp_list_add(ULONGEST num, ULONGEST addr)
+{
+ struct gtp_entry *ret = kzalloc(sizeof(struct gtp_entry),
+ GFP_KERNEL);
+
+ if (!ret)
+ goto out;
+ ret->num = num;
+ ret->addr = addr;
+ ret->kp.addr = (kprobe_opcode_t *) (CORE_ADDR)addr;
+ ret->kp.pre_handler = gtp_kp_pre_handler;
+
+ /* Add to gtp_list. */
+ if (!gtp_list) {
+ gtp_list = ret;
+ gtp_list_tail = ret;
+ } else {
+ gtp_list_tail->next = ret;
+ gtp_list_tail = ret;
+ }
+
+out:
+ return ret;
+}
+
+static struct gtp_entry *
+gtp_list_find(ULONGEST num, ULONGEST addr)
+{
+ struct gtp_entry *tpe;
+
+ for (tpe = gtp_list; tpe; tpe = tpe->next) {
+ if (tpe->num == num && tpe->addr == addr)
+ return tpe;
+ }
+
+ return NULL;
+}
+
+static void
+gtp_list_release(void)
+{
+ struct gtp_entry *tpe, *tpe2;
+
+ tpe = gtp_list;
+ while (tpe) {
+ tpe2 = tpe;
+ tpe = tpe->next;
+ /* Release tpe2. */
+ gtp_action_release(tpe2->action_list);
+ kfree(tpe2);
+ }
+ gtp_list = NULL;
+ gtp_list_tail = NULL;
+}
+
+static void
+gtp_frame_reset(void)
+{
+ gtp_frame_num = 0;
+ gtp_frame_r_start = gtp_frame;
+ gtp_frame_w_start = gtp_frame;
+ gtp_frame_w_end = gtp_frame + GTP_FRAME_SIZE;
+ gtp_frame_is_circular = 0;
+ gtp_frame_r_cache = NULL;
+ gtp_frame_current = NULL;
+}
+
+static int
+gtp_gdbrsp_qtinit(void)
+{
+ if (gtp_start)
+ return -EBUSY;
+
+ gtp_list_release();
+
+ if (gtp_frame)
+ gtp_frame_reset();
+
+ return 0;
+}
+
+static int
+gtp_gdbrsp_qtdp(char *pkg)
+{
+ int addnew = 1;
+ ULONGEST num, addr;
+ struct gtp_entry *tpe;
+
+ pr_devel("gtp_gdbrsp_qtdp: %s\n", pkg);
+
+ if (gtp_start)
+ return -EBUSY;
+
+ if (pkg[0] == '-') {
+ pkg++;
+ addnew = 0;
+ }
+
+ /* Get num and addr. */
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ num = simple_strtoull(pkg, &pkg, 16);
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ pkg++;
+ addr = simple_strtoull(pkg, &pkg, 16);
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ pkg++;
+
+ tpe = gtp_list_find(num, addr);
+ if (addnew) {
+ if (tpe)
+ return -EINVAL;
+ if (pkg[0] == 'D')
+ return 0;
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ pkg++;
+
+ tpe = gtp_list_add(num, addr);
+ if (tpe == NULL)
+ return -ENOMEM;
+
+ /* Get step and pass. */
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ pkg++;
+ tpe->step = simple_strtoull(pkg, &pkg, 16);
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ pkg++;
+ tpe->pass = simple_strtoull(pkg, &pkg, 16);
+ if (tpe->pass == 0)
+ tpe->nopass = 1;
+ } else if (tpe) {
+ /* Add action to tpe. */
+ int step_action = 0;
+
+ if (pkg[0] == 'S') {
+ pkg++;
+ step_action = 1;
+ /* XXX: Still not support step. */
+ return 1;
+ }
+ while (pkg[0]) {
+ struct action *ae;
+
+ switch (pkg[0]) {
+ case 'R':
+ /* XXX: reg_mask is ignore. */
+ ae = gtp_action_alloc(pkg[0]);
+ if (!ae)
+ return -ENOMEM;
+ pkg++;
+ ae->type = 'r';
+ ae->u.reg_mask = simple_strtoull(pkg, &pkg, 16);
+ break;
+ default:
+ /* XXX: Not support. */
+ return 1;
+ }
+
+ if (ae) {
+ /* Add ae to tpe. */
+ if (!tpe->action_list) {
+ tpe->action_list = ae;
+ tpe->action_list_tail = ae;
+ } else {
+ tpe->action_list_tail->next = ae;
+ tpe->action_list_tail = ae;
+ }
+ }
+ }
+ } else
+ return -EINVAL;
+
+ return 0;
+}
+
+static int
+gtp_gdbrsp_qtdisconnected(char *pkg)
+{
+ ULONGEST setting;
+
+ if (gtp_start)
+ return -EBUSY;
+ if (pkg[0] == '\0')
+ return -EINVAL;
+
+ setting = simple_strtoull(pkg, NULL, 16);
+ gtp_disconnected_tracing = (int) setting;
+
+ return 0;
+}
+
+static int
+gtp_gdbrsp_qtbuffer(char *pkg)
+{
+ if (strncmp("circular:", pkg, 9) == 0) {
+ ULONGEST setting;
+
+ pkg += 9;
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ setting = simple_strtoull(pkg, NULL, 16);
+ gtp_circular = (int)setting;
+
+ return 0;
+ }
+
+ return 1;
+}
+
+static struct gtp_frame_head *
+gtp_frame_head_find(int num)
+{
+ struct gtp_frame_head *ret = NULL;
+ char *tmp;
+
+ if (gtp_frame_r_cache) {
+ tmp = gtp_frame_r_cache;
+
+ while (tmp < gtp_frame_w_start) {
+ switch (tmp[0]) {
+ case 'h':
+ ret = (struct gtp_frame_head *)(tmp + 1);
+ goto cache_check;
+ break;
+ case 'r':
+ tmp += GTP_FRAME_REG_SIZE;
+ break;
+ default:
+ goto cache_check;
+ break;
+ }
+ }
+
+cache_check:
+ if (ret && ret->frame_num == num)
+ goto out;
+ }
+
+ tmp = gtp_frame_r_start;
+ while (tmp < gtp_frame_w_start) {
+ switch (tmp[0]) {
+ case 'h':
+ ret = (struct gtp_frame_head *) (tmp + 1);
+ if (ret->frame_num == num)
+ goto out;
+ ret = NULL;
+ tmp += GTP_FRAME_HEAD_SIZE;
+ break;
+ case 'r':
+ tmp += GTP_FRAME_REG_SIZE;
+ break;
+ default:
+ goto out;
+ }
+ }
+
+out:
+ return ret;
+}
+
+static int
+gtp_gdbrsp_qtframe(char *pkg)
+{
+ if (gtp_start)
+ return -EBUSY;
+
+ if (strncmp(pkg, "pc:", 3) == 0) /* XXX */
+ return 1;
+ else if (strncmp(pkg, "tdp:", 4) == 0) /* XXX */
+ return 1;
+ else if (strncmp(pkg, "range:", 6) == 0) /* XXX */
+ return 1;
+ else if (strncmp(pkg, "outside:", 8) == 0) /* XXX */
+ return 1;
+ else {
+ ULONGEST num;
+ struct gtp_frame_head *ret;
+
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ num = simple_strtoull(pkg, NULL, 16);
+
+ pr_devel("gtp_gdbrsp_qtframe: %d\n", (int) num);
+
+ if (((int) num) < 0) {
+ /* Return to current. */
+ gtp_frame_current = NULL;
+
+ return 0;
+ }
+ ret = gtp_frame_head_find((int) num);
+ if (ret) {
+ gtp_frame_current = ret;
+ gtp_frame_r_cache = (char *)ret;
+ gtp_frame_r_cache += sizeof(struct gtp_frame_head);
+ sprintf(gtp_rw_bufp, "F%xT%x",
+ gtp_frame_current->frame_num,
+ (unsigned int)gtp_frame_current->trace_num);
+ gtp_rw_size += strlen(gtp_rw_bufp);
+ gtp_rw_bufp += strlen(gtp_rw_bufp);
+ } else {
+ strcpy(gtp_rw_bufp, "F-1");
+ gtp_rw_bufp += 3;
+ gtp_rw_size += 3;
+ }
+ }
+
+ return 1;
+}
+
+static int
+gtp_gdbrsp_qtstop(void)
+{
+ struct gtp_entry *tpe;
+
+ if (!gtp_start)
+ return -EBUSY;
+
+ for (tpe = gtp_list; tpe; tpe = tpe->next) {
+ if (tpe->kpreg) {
+ unregister_kprobe(&tpe->kp);
+ tpe->kpreg = 0;
+ }
+ }
+
+ gtp_start = 0;
+
+ return 0;
+}
+
+static int
+gtp_gdbrsp_qtstart(void)
+{
+ struct gtp_entry *tpe;
+
+ if (gtp_start)
+ return -EBUSY;
+
+ if (!gtp_frame) {
+ gtp_frame = vmalloc(GTP_FRAME_SIZE);
+ if (!gtp_frame)
+ return -ENOMEM;
+
+ gtp_frame_reset();
+ }
+
+ for (tpe = gtp_list; tpe; tpe = tpe->next) {
+ if (tpe->action_list) {
+ int ret = register_kprobe(&tpe->kp);
+ if (ret < 0) {
+ gtp_gdbrsp_qtstop();
+ return ret;
+ }
+ tpe->kpreg = 1;
+ }
+ }
+
+ gtp_start = 1;
+
+ return 0;
+}
+
+static int
+gtp_gdbrsp_QT(char *pkg)
+{
+ int ret = 1;
+
+ pr_devel("gtp_gdbrsp_QT: %s\n", pkg);
+
+ if (strcmp("init", pkg) == 0)
+ ret = gtp_gdbrsp_qtinit();
+ else if (strncmp("DP:", pkg, 3) == 0)
+ ret = gtp_gdbrsp_qtdp(pkg + 3);
+ else if (strncmp("Disconnected:", pkg, 13) == 0)
+ ret = gtp_gdbrsp_qtdisconnected(pkg + 13);
+ else if (strncmp("Buffer:", pkg, 7) == 0)
+ ret = gtp_gdbrsp_qtbuffer(pkg + 7);
+ else if (strncmp("Frame:", pkg, 6) == 0)
+ ret = gtp_gdbrsp_qtframe(pkg + 6);
+ else if (strcmp("Start", pkg) == 0)
+ ret = gtp_gdbrsp_qtstart();
+ else if (strcmp("Stop", pkg) == 0)
+ ret = gtp_gdbrsp_qtstop();
+
+ return ret;
+}
+
+static unsigned char gtp_m_buffer[0xffff];
+
+static int
+gtp_gdbrsp_m(char *pkg)
+{
+ int i;
+ ULONGEST addr, len;
+
+ /* Get add and len. */
+ if (pkg[0] == '\0')
+ return -EINVAL;
+ addr = simple_strtoull(pkg, &pkg, 16);
+ if (pkg[0] != ',')
+ return -EINVAL;
+ pkg++;
+ len = simple_strtoull(pkg, &pkg, 16);
+ if (len == 0)
+ return -EINVAL;
+ len &= 0xffff;
+ len = (ULONGEST) min((int)((GTP_RW_MAX - 4 - gtp_rw_size) / 2),
+ (int)len);
+
+ pr_devel("gtp_gdbrsp_m: addr = 0x%lx len = %d\n",
+ (unsigned long) addr, (int) len);
+
+ if (probe_kernel_read(gtp_m_buffer, (void *)(CORE_ADDR)addr,
+ (size_t)len))
+ return -EFAULT;
+
+ for (i = 0; i < (int)len; i++) {
+ sprintf(gtp_rw_bufp, "%02x", gtp_m_buffer[i]);
+ gtp_rw_bufp += 2;
+ gtp_rw_size += 2;
+ }
+
+ return 1;
+}
+
+static int
+gtp_gdbrsp_g(void)
+{
+ char *next;
+ struct gtp_frame_reg *fr = NULL;
+
+ if (GTP_RW_MAX - 4 - gtp_rw_size < GTP_REG_ASCII_SIZE)
+ return -E2BIG;
+
+ if (gtp_start || !gtp_frame_current)
+ goto check;
+
+ /* Get the fr. */
+ next = gtp_frame_current->next;
+ while (next) {
+ switch (next[0]) {
+ case 'r':
+ fr = (struct gtp_frame_reg *) (next + 1);
+ goto check;
+ break;
+ default:
+ next = NULL;
+ break;
+ }
+ }
+check:
+ if (fr)
+ gtp_regs2ascii(&fr->regs, gtp_rw_bufp);
+ else
+ memset(gtp_rw_bufp, '0', GTP_REG_ASCII_SIZE);
+ gtp_rw_bufp += GTP_REG_ASCII_SIZE;
+ gtp_rw_size += GTP_REG_ASCII_SIZE;
+ return 1;
+}
+
+static int
+gtp_open(struct inode *inode, struct file *file)
+{
+ if (atomic_inc_return(&gtp_count) > 1) {
+ atomic_dec(&gtp_count);
+ return -EBUSY;
+ }
+
+ gtp_read_ack = 0;
+ gtp_rw_buf = vmalloc(GTP_RW_MAX);
+ if (!gtp_rw_buf)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static int
+gtp_release(struct inode *inode, struct file *file)
+{
+ vfree(gtp_rw_buf);
+
+ /* XXX: not handle gtp_disconnected_tracing. */
+ gtp_gdbrsp_qtstop();
+ gtp_gdbrsp_qtinit();
+ vfree(gtp_frame);
+ gtp_frame = NULL;
+
+ atomic_dec(&gtp_count);
+
+ return 0;
+}
+
+static long
+gtp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ /* This function will make GDB happy. */
+ pr_devel("gtp_ioctl: %x\n", cmd);
+
+ return 0;
+}
+
+static ssize_t
+gtp_write(struct file *file, const char __user *buf, size_t size,
+ loff_t *ppos)
+{
+ char *rsppkg = NULL;
+ int i, ret;
+ unsigned char csum = 0;
+
+ size = min_t(size_t, size, GTP_RW_MAX);
+ if (copy_from_user(gtp_rw_buf, buf, size))
+ return -EFAULT;
+
+ if (gtp_rw_buf[0] == '+' || gtp_rw_buf[0] == '-'
+ || gtp_rw_buf[0] == '\3')
+ goto out;
+
+ /* Check format and crc and get the rsppkg. */
+ for (i = 0; i < size - 2; i++) {
+ if (rsppkg == NULL) {
+ if (gtp_rw_buf[i] == '$')
+ rsppkg = gtp_rw_buf + i + 1;
+ } else {
+ if (gtp_rw_buf[i] == '#')
+ break;
+ else
+ csum += gtp_rw_buf[i];
+ }
+ }
+ if (rsppkg && gtp_rw_buf[i] == '#') {
+ /* Format is OK. Check crc. */
+ unsigned char c1, c2;
+
+ gtp_rw_buf[i] = '\0';
+
+ c1 = gtp_rw_buf[i+1];
+ c2 = gtp_rw_buf[i+2];
+ if (csum == (c1 << 4) + c2) {
+ pr_devel("gtp_write: crc error\n");
+ gtp_read_ack = '-';
+ goto out;
+ }
+ } else {
+ pr_devel("gtp_write: format error\n");
+ gtp_read_ack = '-';
+ goto out;
+ }
+ gtp_read_ack = '+';
+
+ pr_devel("gtp_write: %s\n", rsppkg);
+
+ /* Handle rsppkg and put return to gtp_rw_buf. */
+ gtp_rw_buf[0] = '$';
+ gtp_rw_bufp = gtp_rw_buf + 1;
+ gtp_rw_size = 0;
+ ret = 1;
+ switch (rsppkg[0]) {
+ case '?':
+ strcpy(gtp_rw_bufp, "S05");
+ gtp_rw_bufp += 3;
+ gtp_rw_size += 3;
+ break;
+ case 'g':
+ ret = gtp_gdbrsp_g();
+ break;
+ case 'm':
+ ret = gtp_gdbrsp_m(rsppkg + 1);
+ break;
+ case 'Q':
+ if (rsppkg[1] == 'T')
+ ret = gtp_gdbrsp_QT(rsppkg + 2);
+ break;
+ }
+ if (ret == 0) {
+ strcpy(gtp_rw_bufp, "OK");
+ gtp_rw_bufp += 2;
+ gtp_rw_size += 2;
+ } else if (ret < 0) {
+ sprintf(gtp_rw_bufp, "E%02x", -ret);
+ gtp_rw_bufp += 3;
+ gtp_rw_size += 3;
+ }
+
+ gtp_rw_bufp[0] = '#';
+ csum = 0;
+ for (i = 1; i < gtp_rw_size + 1; i++)
+ csum += gtp_rw_buf[i];
+ gtp_rw_bufp[1] = TOHEX(csum >> 4);
+ gtp_rw_bufp[2] = TOHEX(csum & 0x0f);
+ gtp_rw_bufp = gtp_rw_buf;
+ gtp_rw_size += 4;
+
+out:
+ return size;
+}
+
+static ssize_t
+gtp_read(struct file *file, char __user *buf, size_t size,
+ loff_t *ppos)
+{
+ if (gtp_read_ack) {
+ int err = put_user(gtp_read_ack, buf);
+ if (err)
+ return -err;
+ gtp_read_ack = 0;
+ return 1;
+ }
+
+ size = min(gtp_rw_size, size);
+
+ if (copy_to_user(buf, gtp_rw_bufp, size))
+ return -EFAULT;
+ gtp_rw_bufp += size;
+ gtp_rw_size -= size;
+
+ return size;
+}
+
+static const struct file_operations gtp_operations = {
+ .owner = THIS_MODULE,
+ .open = gtp_open,
+ .release = gtp_release,
+ .unlocked_ioctl = gtp_ioctl,
+ .compat_ioctl = gtp_ioctl,
+ .read = gtp_read,
+ .write = gtp_write,
+};
+
+struct dentry *gtp_dir;
+
+static int __init gtp_init(void)
+{
+ atomic_set(&gtp_count, 0);
+ gtp_read_ack = 0;
+ gtp_rw_buf = NULL;
+ gtp_rw_bufp = NULL;
+ gtp_rw_size = 0;
+ gtp_start = 0;
+ gtp_disconnected_tracing = 0;
+ gtp_circular = 0;
+ gtp_frame_num = 0;
+ gtp_frame = NULL;
+ gtp_frame_r_start = NULL;
+ gtp_frame_w_start = NULL;
+ gtp_frame_w_end = NULL;
+ gtp_frame_r_cache = NULL;
+ gtp_frame_is_circular = 0;
+ gtp_frame_current = NULL;
+
+ gtp_dir = debugfs_create_file("gtp", S_IFIFO | S_IRUSR | S_IWUSR, NULL,
+ NULL, &gtp_operations);
+ if (gtp_dir == NULL || gtp_dir == ERR_PTR(-ENODEV))
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void __exit gtp_exit(void)
+{
+ if (gtp_dir)
+ debugfs_remove_recursive(gtp_dir);
+}
+
+module_init(gtp_init)
+module_exit(gtp_exit)
+
+MODULE_AUTHOR("Hui Zhu <teawater@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1289,6 +1289,14 @@ config ASYNC_RAID6_TEST
If unsure, say N.
+config GTP
+ tristate "GDB tracepoint support"
+ depends on X86 || ARM || MIPS
+ select KPROBES
+ select DEBUG_FS
+ ---help---
+ Supply GDB tracepoint interface in /sys/kernel/debug/gtp.
+
source "samples/Kconfig"
source "lib/Kconfig.kgdb"
--
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