[PATCH][6/6] A different KGDB stub

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Date:	Wed, 11 Feb 2004 17:04:08 -0700
To: Andrew Morton <akpm@osdl.org>, Kernel Mailing List <linux-kernel@vger.kernel.org>

The following is the x86_64-specific bits to this KGDB stub.

 arch/x86_64/Kconfig | 5
 arch/x86_64/kernel/Makefile | 1
 arch/x86_64/kernel/entry.S | 41 ++-
 arch/x86_64/kernel/irq.c | 2
 arch/x86_64/kernel/nmi.c | 16 +
 arch/x86_64/kernel/traps.c | 6
 arch/x86_64/kernel/x86_64-stub.c | 523 +++++++++++++++++++++++++++++++++++++++
 arch/x86_64/mm/fault.c | 8
 include/asm-x86_64/dwarf2.h | 2
 include/asm-x86_64/kgdb.h | 57 ++++
 include/asm-x86_64/processor.h | 1
 include/asm-x86_64/system.h | 50 +++
 12 files changed, 703 insertions(+), 9 deletions(-)
--- a/arch/x86_64/Kconfig Wed Feb 11 15:42:06 2004
+++ b/arch/x86_64/Kconfig Wed Feb 11 15:42:06 2004
@@ -463,10 +463,7 @@
          Add a simple leak tracer to the IOMMU code. This is useful when you
          are debugging a buggy device driver that leaks IOMMU mappings.
        
-#config X86_REMOTE_DEBUG
-# bool "kgdb debugging stub"
-
-endmenu
+source "kernel/Kconfig.kgdb"
 
 source "security/Kconfig"
 
--- a/arch/x86_64/kernel/Makefile Wed Feb 11 15:42:06 2004
+++ b/arch/x86_64/kernel/Makefile Wed Feb 11 15:42:06 2004
@@ -24,6 +24,7 @@
 obj-$(CONFIG_DUMMY_IOMMU) += pci-nommu.o pci-dma.o
 
 obj-$(CONFIG_MODULES) += module.o
+obj-$(CONFIG_KGDB) += x86_64-stub.o
 
 obj-y += topology.o
 
--- a/arch/x86_64/kernel/entry.S Wed Feb 11 15:42:06 2004
+++ b/arch/x86_64/kernel/entry.S Wed Feb 11 15:42:06 2004
@@ -219,7 +219,7 @@
         jnc sysret_signal
         sti
         pushq %rdi
- call schedule
+ call user_schedule
         popq %rdi
         jmp sysret_check
 
@@ -288,7 +288,7 @@
         jnc int_very_careful
         sti
         pushq %rdi
- call schedule
+ call user_schedule
         popq %rdi
         jmp int_with_check
 
@@ -482,7 +482,7 @@
         jnc retint_signal
         sti
         pushq %rdi
- call schedule
+ call user_schedule
         popq %rdi
         GET_THREAD_INFO(%rcx)
         cli
@@ -868,3 +868,38 @@
 ENTRY(call_debug)
        zeroentry do_call_debug
 
+#ifdef CONFIG_KGDB_THREAD
+ENTRY(kern_schedule)
+ subq $21*8,%rsp
+ movq %rax,10*8(%rsp)
+
+ movq %rsp,%rax
+ addq $21*8,%rax
+ movq %rax, 19*8(%rsp)
+
+ pushfq
+ popq 18*8(%rsp)
+
+ movq 21*8(%rsp),%rax
+ movq %rax,16*8(%rsp)
+
+ movq %rdi,14*8(%rsp)
+ movq %rsi,13*8(%rsp)
+ movq %rdx,12*8(%rsp)
+ movq %rcx,11*8(%rsp)
+
+ movq %r8, 9*8(%rsp)
+ movq %r9, 8*8(%rsp)
+ movq %r10,7*8(%rsp)
+ movq %r11,6*8(%rsp)
+ movq %rbx,5*8(%rsp)
+ movq %rbp,4*8(%rsp)
+ movq %r12,3*8(%rsp)
+ movq %r13,2*8(%rsp)
+ movq %r14,1*8(%rsp)
+ movq %r15,(%rsp)
+ call kern_do_schedule
+ movq 10*8(%rsp), %rax
+ addq $21*8,%rsp
+ ret
+#endif
--- a/arch/x86_64/kernel/irq.c Wed Feb 11 15:42:06 2004
+++ b/arch/x86_64/kernel/irq.c Wed Feb 11 15:42:06 2004
@@ -405,6 +405,8 @@
         spin_unlock(&desc->lock);
 
         irq_exit();
+
+ kgdb_process_breakpoint();
         return 1;
 }
 
--- a/arch/x86_64/kernel/nmi.c Wed Feb 11 15:42:06 2004
+++ b/arch/x86_64/kernel/nmi.c Wed Feb 11 15:42:06 2004
@@ -24,6 +24,7 @@
 #include <linux/module.h>
 #include <linux/sysdev.h>
 #include <linux/nmi.h>
+#include <linux/debugger.h>
 
 #include <asm/smp.h>
 #include <asm/mtrr.h>
@@ -317,13 +318,26 @@
                 return;
 
         sum = read_pda(apic_timer_irqs);
- if (last_irq_sums[cpu] == sum) {
+ if (atomic_read(&debugger_active)) {
+
+ /*
+ * The machine is in debugger, hold this cpu if already
+ * not held.
+ */
+ debugger_nmihook(cpu, regs);
+ alert_counter[cpu] = 0;
+
+ } else if (last_irq_sums[cpu] == sum) {
+
                 /*
                  * Ayiee, looks like this CPU is stuck ...
                  * wait a few IRQs (5 seconds) before doing the oops ...
                  */
                 alert_counter[cpu]++;
                 if (alert_counter[cpu] == 5*nmi_hz) {
+
+ CHK_DEBUGGER(2,SIGSEGV,0,regs,)
+
                         if (notify_die(DIE_NMI, "nmi", regs, reason, 2, SIGINT) == NOTIFY_BAD) {
                                 alert_counter[cpu] = 0;
                                 return;
--- a/arch/x86_64/kernel/traps.c Wed Feb 11 15:42:06 2004
+++ b/arch/x86_64/kernel/traps.c Wed Feb 11 15:42:06 2004
@@ -28,6 +28,7 @@
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/debugger.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -363,6 +364,7 @@
 
 void die(const char * str, struct pt_regs * regs, long err)
 {
+ CHK_DEBUGGER(1,SIGTRAP,err,regs,)
         oops_begin();
         handle_BUG(regs);
         __die(str, regs, err);
@@ -436,6 +438,7 @@
 #define DO_ERROR(trapnr, signr, str, name) \
 asmlinkage void do_##name(struct pt_regs * regs, long error_code) \
 { \
+ CHK_DEBUGGER(1,SIGTRAP,error_code,regs,return) \
         if (notify_die(DIE_TRAP, str, regs, error_code, trapnr, signr) == NOTIFY_BAD) \
                 return; \
         do_trap(trapnr, signr, str, regs, error_code, NULL); \
@@ -614,7 +617,7 @@
         tsk->thread.debugreg6 = condition;
 
         /* Mask out spurious TF errors due to lazy TF clearing */
- if (condition & DR_STEP) {
+ if (condition & DR_STEP && !debugger_step) {
                 /*
                  * The TF error should be masked out only if the current
                  * process is not traced and if the TRAP flag has been set
@@ -643,6 +646,7 @@
         force_sig_info(SIGTRAP, &info, tsk);
 clear_dr7:
         asm volatile("movq %0,%%db7"::"r"(0UL));
+ CHK_DEBUGGER(1,SIGTRAP,error_code,regs,return)
         notify_die(DIE_DEBUG, "debug", regs, error_code, 1, SIGTRAP);
         return;
 
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/arch/x86_64/kernel/x86_64-stub.c Wed Feb 11 15:42:06 2004
@@ -0,0 +1,523 @@
+/*
+ *
+ * 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, 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.
+ *
+ */
+
+/*
+ * Copyright (C) 2004 Amit S. Kale
+ * Copyright (C) 2000-2001 VERITAS Software Corporation.
+ * Copyright (C) 2002 Andi Kleen, SuSE Labs
+ */
+/****************************************************************************
+ * Header: remcom.c,v 1.34 91/03/09 12:29:49 glenne Exp $
+ *
+ * Module name: remcom.c $
+ * Revision: 1.34 $
+ * Date: 91/03/09 12:29:49 $
+ * Contributor: Lake Stevens Instrument Division$
+ *
+ * Description: low level support for gdb debugger. $
+ *
+ * Considerations: only works on target hardware $
+ *
+ * Written by: Glenn Engel $
+ * Updated by: Amit Kale<akale@veritas.com>
+ * ModuleState: Experimental $
+ *
+ * NOTES: See Below $
+ *
+ * Modified for 386 by Jim Kingdon, Cygnus Support.
+ * Origianl kgdb, compatibility with 2.1.xx kernel by David Grothe <dave@gcom.com>
+ * Integrated into 2.2.5 kernel by Tigran Aivazian <tigran@sco.com>
+ * thread support,
+ * support for multiple processors,
+ * support for ia-32(x86) hardware debugging,
+ * Console support,
+ * handling nmi watchdog
+ * Amit S. Kale ( amitkale@emsyssoft.com )
+ *
+ * X86_64 changes from Andi Kleen's patch merged by Jim Houston
+ *
+ *
+ * To enable debugger support, two things need to happen. One, a
+ * call to set_debug_traps() is necessary in order to allow any breakpoints
+ * or error conditions to be properly intercepted and reported to gdb.
+ * Two, a breakpoint needs to be generated to begin communication. This
+ * is most easily accomplished by a call to breakpoint(). Breakpoint()
+ * simulates a breakpoint by executing an int 3.
+ *
+ *************
+ *
+ * The following gdb commands are supported:
+ *
+ * command function Return value
+ *
+ * g return the value of the CPU registers hex data or ENN
+ * G set the value of the CPU registers OK or ENN
+ *
+ * mAA..AA,LLLL Read LLLL bytes at address AA..AA hex data or ENN
+ * MAA..AA,LLLL: Write LLLL bytes at address AA.AA OK or ENN
+ *
+ * c Resume at current address SNN ( signal NN)
+ * cAA..AA Continue at address AA..AA SNN
+ *
+ * s Step one instruction SNN
+ * sAA..AA Step one instruction from AA..AA SNN
+ *
+ * k kill
+ *
+ * ? What was the last sigval ? SNN (signal NN)
+ *
+ * All commands and responses are sent with a packet which includes a
+ * checksum. A packet consists of
+ *
+ * $<packet info>#<checksum>.
+ *
+ * where
+ * <packet info> :: <characters representing the command or response>
+ * <checksum> :: < two hex digits computed as modulo 256 sum of <packetinfo>>
+ *
+ * When a packet is received, it is first acknowledged with either '+' or '-'.
+ * '+' indicates a successful transfer. '-' indicates a failed transfer.
+ *
+ * Example:
+ *
+ * Host: Reply:
+ * $m0,10#2a +$00010203040506070809101112131415#42
+ *
+ ****************************************************************************/
+
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/spinlock.h>
+#include <linux/delay.h>
+#include <asm/system.h>
+#include <asm/ptrace.h> /* for linux pt_regs struct */
+#include <linux/kgdb.h>
+#ifdef CONFIG_GDB_CONSOLE
+#include <linux/console.h>
+#endif
+#include <linux/init.h>
+#include <linux/debugger.h>
+
+/* Put the error code here just in case the user cares. */
+int gdb_x86_64errcode;
+/* Likewise, the vector number here (since GDB only gets the signal
+ number through the usual means, and that's not very specific). */
+int gdb_x86_64vector = -1;
+
+#if KGDB_MAX_NO_CPUS != 8
+#error change the definition of slavecpulocks
+#endif
+
+void regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ gdb_regs[_RAX] = regs->rax;
+ gdb_regs[_RBX] = regs->rbx;
+ gdb_regs[_RCX] = regs->rcx;
+ gdb_regs[_RDX] = regs->rdx;
+ gdb_regs[_RSI] = regs->rsi;
+ gdb_regs[_RDI] = regs->rdi;
+ gdb_regs[_RBP] = regs->rbp;
+ gdb_regs[ _PS] = regs->eflags;
+ gdb_regs[ _PC] = regs->rip;
+ gdb_regs[ _R8] = regs->r8;
+ gdb_regs[ _R9] = regs->r9;
+ gdb_regs[_R10] = regs->r10;
+ gdb_regs[_R11] = regs->r11;
+ gdb_regs[_R12] = regs->r12;
+ gdb_regs[_R13] = regs->r13;
+ gdb_regs[_R14] = regs->r14;
+ gdb_regs[_R15] = regs->r15;
+ gdb_regs[_RSP] = regs->rsp;
+}
+
+struct task_struct *__switch_to(struct task_struct *prev_p,
+ struct task_struct *next_p);
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+ gdb_regs[_RAX] = 0;
+ gdb_regs[_RBX] = 0;
+ gdb_regs[_RCX] = 0;
+ gdb_regs[_RDX] = 0;
+ gdb_regs[_RSI] = 0;
+ gdb_regs[_RDI] = 0;
+ gdb_regs[_RBP] = 0;
+ gdb_regs[ _PS] = 0;
+ gdb_regs[ _PC] = (unsigned long) __switch_to;
+ gdb_regs[ _R8] = 0;
+ gdb_regs[ _R9] = 0;
+ gdb_regs[_R10] = 0;
+ gdb_regs[_R11] = 0;
+ gdb_regs[_R12] = 0;
+ gdb_regs[_R13] = 0;
+ gdb_regs[_R14] = 0;
+ gdb_regs[_R15] = 0;
+ gdb_regs[_RSP] = p->thread.rsp;
+}
+
+void gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ regs->rax = gdb_regs[_RAX] ;
+ regs->rbx = gdb_regs[_RBX] ;
+ regs->rcx = gdb_regs[_RCX] ;
+ regs->rdx = gdb_regs[_RDX] ;
+ regs->rsi = gdb_regs[_RSI] ;
+ regs->rdi = gdb_regs[_RDI] ;
+ regs->rbp = gdb_regs[_RBP] ;
+ regs->eflags= gdb_regs[ _PS] ;
+ regs->rip = gdb_regs[ _PC] ;
+ regs->r8 = gdb_regs[ _R8] ;
+ regs->r9 = gdb_regs[ _R9] ;
+ regs->r10 = gdb_regs[ _R10] ;
+ regs->r11 = gdb_regs[ _R11] ;
+ regs->r12 = gdb_regs[ _R12] ;
+ regs->r13 = gdb_regs[ _R13] ;
+ regs->r14 = gdb_regs[ _R14] ;
+ regs->r15 = gdb_regs[ _R15] ;
+#if 0 /* can't change these */
+ regs->rsp = gdb_regs[_RSP] ;
+ regs->ss = gdb_regs[ _SS] ;
+ regs->fs = gdb_regs[ _FS] ;
+ regs->gs = gdb_regs[ _GS] ;
+#endif
+
+} /* gdb_regs_to_regs */
+
+
+struct hw_breakpoint {
+ unsigned enabled;
+ unsigned type;
+ unsigned len;
+ unsigned long addr;
+} breakinfo[4] = { {
+enabled:0}, {
+enabled:0}, {
+enabled:0}, {
+enabled:0}};
+
+void kgdb_correct_hw_break(void)
+{
+ int breakno;
+ int correctit;
+ int breakbit;
+ unsigned long dr7;
+
+ asm volatile ("movq %%db7, %0\n":"=r" (dr7) :);
+ do {
+ unsigned long addr0, addr1, addr2, addr3;
+ asm volatile ("movq %%db0, %0\n"
+ "movq %%db1, %1\n"
+ "movq %%db2, %2\n"
+ "movq %%db3, %3\n":"=r" (addr0), "=r"(addr1),
+ "=r"(addr2), "=r"(addr3):);
+ } while (0);
+ correctit = 0;
+ for (breakno = 0; breakno < 3; breakno++) {
+ breakbit = 2 << (breakno << 1);
+ if (!(dr7 & breakbit) && breakinfo[breakno].enabled) {
+ correctit = 1;
+ dr7 |= breakbit;
+ dr7 &= ~(0xf0000 << (breakno << 2));
+ dr7 |= (((breakinfo[breakno].len << 2) |
+ breakinfo[breakno].type) << 16) <<
+ (breakno << 2);
+ switch (breakno) {
+ case 0:
+ asm volatile ("movq %0, %%dr0\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 1:
+ asm volatile ("movq %0, %%dr1\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 2:
+ asm volatile ("movq %0, %%dr2\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 3:
+ asm volatile ("movq %0, %%dr3\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+ }
+ } else if ((dr7 & breakbit) && !breakinfo[breakno].enabled) {
+ correctit = 1;
+ dr7 &= ~breakbit;
+ dr7 &= ~(0xf0000 << (breakno << 2));
+ }
+ }
+ if (correctit) {
+ asm volatile ("movq %0, %%db7\n"::"r" (dr7));
+ }
+}
+
+int kgdb_remove_hw_break(unsigned long addr, int type)
+{
+ int i, idx = -1;
+ for (i = 0; i < 4; i ++) {
+ if (breakinfo[i].addr == addr && breakinfo[i].enabled) {
+ idx = i;
+ break;
+ }
+ }
+ if (idx == -1)
+ return -1;
+
+ breakinfo[idx].enabled = 0;
+ return 0;
+}
+
+int kgdb_set_hw_break(unsigned long addr, int type)
+{
+ int i, idx = -1;
+ for (i = 0; i < 4; i ++) {
+ if (!breakinfo[i].enabled) {
+ idx = i;
+ break;
+ }
+ }
+ if (idx == -1)
+ return -1;
+
+ breakinfo[idx].enabled = 1;
+ breakinfo[idx].type = type;
+ breakinfo[idx].len = 1;
+ breakinfo[idx].addr = addr;
+ return 0;
+}
+
+int remove_hw_break(unsigned breakno)
+{
+ if (!breakinfo[breakno].enabled) {
+ return -1;
+ }
+ breakinfo[breakno].enabled = 0;
+ return 0;
+}
+
+int set_hw_break(unsigned breakno,
+ unsigned type, unsigned len, unsigned addr)
+{
+ if (breakinfo[breakno].enabled) {
+ return -1;
+ }
+ breakinfo[breakno].enabled = 1;
+ breakinfo[breakno].type = type;
+ breakinfo[breakno].len = len;
+ breakinfo[breakno].addr = addr;
+ return 0;
+}
+
+void kgdb_printexceptioninfo(int exceptionNo, int errorcode, char *buffer)
+{
+ unsigned long dr6;
+ int i;
+ switch (exceptionNo) {
+ case 1: /* debug exception */
+ break;
+ case 3: /* breakpoint */
+ sprintf(buffer, "Software breakpoint");
+ return;
+ default:
+ sprintf(buffer, "Details not available");
+ return;
+ }
+ asm volatile ("movq %%db6, %0\n":"=r" (dr6)
+ :);
+ if (dr6 & 0x4000) {
+ sprintf(buffer, "Single step");
+ return;
+ }
+ for (i = 0; i < 4; ++i) {
+ if (dr6 & (1 << i)) {
+ sprintf(buffer, "Hardware breakpoint %d", i);
+ return;
+ }
+ }
+ sprintf(buffer, "Unknown trap");
+ return;
+}
+
+void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+ /* Disable hardware debugging while we are in kgdb */
+ asm volatile("movq %0,%%db7": /* no output */ : "r"(0UL));
+}
+
+void kgdb_post_master_code(struct pt_regs *regs, int eVector, int err_code)
+{
+ /* Master processor is completely in the debugger */
+ gdb_x86_64vector = eVector;
+ gdb_x86_64errcode = err_code;
+}
+
+int kgdb_arch_handle_exception(int exceptionVector, int signo, int err_code,
+ char *remcomInBuffer, char *remcomOutBuffer,
+ struct pt_regs *linux_regs)
+{
+ unsigned long addr, length;
+ unsigned long breakno, breaktype;
+ char *ptr;
+ int newPC;
+ unsigned long dr6;
+
+ switch (remcomInBuffer[0]) {
+ case 'c':
+ case 's':
+ if (kgdb_contthread && kgdb_contthread != current) {
+ strcpy(remcomOutBuffer, "E00");
+ break;
+ }
+
+ kgdb_contthread = NULL;
+
+ /* try to read optional parameter, pc unchanged if no parm */
+ ptr = &remcomInBuffer[1];
+ if (kgdb_hexToLong(&ptr, &addr)) {
+ linux_regs->rip = addr;
+ }
+ newPC = linux_regs->rip;
+
+ /* clear the trace bit */
+ linux_regs->eflags &= 0xfffffeff;
+
+ /* set the trace bit if we're stepping */
+ if (remcomInBuffer[0] == 's') {
+ linux_regs->eflags |= 0x100;
+ debugger_step = 1;
+ }
+
+ asm volatile ("movq %%db6, %0\n" : "=r" (dr6));
+ if (!(dr6 & 0x4000)) {
+ for (breakno = 0; breakno < 4; ++breakno) {
+ if (dr6 & (1 << breakno)) {
+ if (breakinfo[breakno].type == 0) {
+ /* Set restore flag */
+ linux_regs->eflags |= 0x10000;
+ break;
+ }
+ }
+ }
+ }
+ kgdb_correct_hw_break();
+ asm volatile ("movq %0, %%db6\n"::"r" (0UL));
+
+ return (0);
+
+ case 'Y':
+ ptr = &remcomInBuffer[1];
+ kgdb_hexToLong(&ptr, &breakno);
+ ptr++;
+ kgdb_hexToLong(&ptr, &breaktype);
+ ptr++;
+ kgdb_hexToLong(&ptr, &length);
+ ptr++;
+ kgdb_hexToLong(&ptr, &addr);
+ if (set_hw_break(breakno & 0x3, breaktype & 0x3,
+ length & 0x3, addr) == 0) {
+ strcpy(remcomOutBuffer, "OK");
+ } else {
+ strcpy(remcomOutBuffer, "ERROR");
+ }
+ break;
+
+ /* Remove hardware breakpoint */
+ case 'y':
+ ptr = &remcomInBuffer[1];
+ kgdb_hexToLong(&ptr, &breakno);
+ if (remove_hw_break(breakno & 0x3) == 0) {
+ strcpy(remcomOutBuffer, "OK");
+ } else {
+ strcpy(remcomOutBuffer, "ERROR");
+ }
+ break;
+
+ } /* switch */
+ return -1; /* this means that we do not want to exit from the handler */
+}
+
+static struct pt_regs *in_interrupt_stack(unsigned long rsp, int cpu)
+{
+ struct pt_regs *regs;
+ unsigned long end = (unsigned long) cpu_pda[cpu].irqstackptr;
+ if (rsp <= end &&
+ rsp >= end - IRQSTACKSIZE + 8) {
+ regs = *(((struct pt_regs **)end) -1);
+ return regs;
+ }
+ return NULL;
+}
+
+static struct pt_regs *in_exception_stack(unsigned long rsp, int cpu)
+{
+ int i;
+ for (i = 0; i < N_EXCEPTION_STACKS; i++)
+ if (rsp >= init_tss[cpu].ist[i] &&
+ rsp <= init_tss[cpu].ist[i] + EXCEPTION_STKSZ) {
+ struct pt_regs *r = (void *)init_tss[cpu].ist[i] + EXCEPTION_STKSZ;
+ return r-1;
+ }
+ return NULL;
+}
+
+static void kgdb_shadowinfo(struct pt_regs *regs, char *buffer,
+ unsigned threadid)
+{
+ static char intr_desc[] = "Stack at interrupt entrypoint";
+ static char exc_desc[] = "Stack at exception entrypoint";
+ struct pt_regs *stregs;
+ int cpu = hard_smp_processor_id();
+
+ if ((stregs = in_interrupt_stack(regs->rsp, cpu))) {
+ kgdb_mem2hex(intr_desc, buffer, strlen(intr_desc), 0);
+ } else if ((stregs = in_exception_stack(regs->rsp, cpu))) {
+ kgdb_mem2hex(exc_desc, buffer, strlen(exc_desc), 0);
+ }
+}
+
+static struct task_struct *kgdb_get_shadow_thread(struct pt_regs *regs,
+ int threadid)
+{
+ struct pt_regs *stregs;
+ int cpu = hard_smp_processor_id();
+
+ if ((stregs = in_interrupt_stack(regs->rsp, cpu))) {
+ return current;
+ } else if ((stregs = in_exception_stack(regs->rsp, cpu))) {
+ return current;
+ }
+ return NULL;
+}
+
+static struct pt_regs *kgdb_shadow_regs(struct pt_regs *regs, int threadid)
+{
+ struct pt_regs *stregs;
+ int cpu = hard_smp_processor_id();
+
+ if ((stregs = in_interrupt_stack(regs->rsp, cpu))) {
+ return stregs;
+ } else if ((stregs = in_exception_stack(regs->rsp, cpu))) {
+ return stregs;
+ }
+ return NULL;
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+ .gdb_bpt_instr = {0xcc},
+ .flags = KGDB_HW_BREAKPOINT,
+ .shadowth = 1,
+};
--- a/arch/x86_64/mm/fault.c Wed Feb 11 15:42:06 2004
+++ b/arch/x86_64/mm/fault.c Wed Feb 11 15:42:06 2004
@@ -23,6 +23,7 @@
 #include <linux/vt_kern.h> /* For unblank_screen() */
 #include <linux/compiler.h>
 #include <linux/module.h>
+#include <linux/debugger.h>
 
 #include <asm/system.h>
 #include <asm/uaccess.h>
@@ -290,6 +291,11 @@
                 return;
 
  again:
+ if (debugger_memerr_expected) {
+ /* This fault was caused by memory access through a debugger.
+ * Don't handle it like user accesses */
+ goto no_context;
+ }
         down_read(&mm->mmap_sem);
 
         vma = find_vma(mm, address);
@@ -410,6 +416,8 @@
 
         if (is_errata93(regs, address))
                 return;
+
+ CHK_DEBUGGER(14, SIGSEGV,error_code, regs,)
 
 /*
  * Oops. The kernel tried to access some bad page. We'll have to
--- a/include/asm-x86_64/dwarf2.h Wed Feb 11 15:42:06 2004
+++ b/include/asm-x86_64/dwarf2.h Wed Feb 11 15:42:06 2004
@@ -12,6 +12,8 @@
    See "as.info" for details on these pseudo ops. Unfortunately
    they are only supported in very new binutils, so define them
    away for older version.
+
+ If you want to build a KGDB kernel install the new assembler.
  */
 
 #ifdef CONFIG_DEBUG_INFO
--- /dev/null Wed Dec 31 16:00:00 1969
+++ b/include/asm-x86_64/kgdb.h Wed Feb 11 15:42:06 2004
@@ -0,0 +1,57 @@
+#ifndef _ASM_KGDB_H_
+#define _ASM_KGDB_H_
+
+/*
+ * Copyright (C) 2001-2004 Amit S. Kale
+ */
+
+#include <linux/ptrace.h>
+
+/* gdb locks */
+#define KGDB_MAX_NO_CPUS 8
+
+/************************************************************************/
+/* BUFMAX defines the maximum number of characters in inbound/outbound buffers*/
+/* at least NUMREGBYTES*2 are needed for register packets */
+/* Longer buffer is needed to list all threads */
+#define BUFMAX 1024
+
+/*
+ * Note that this register image is in a different order than
+ * the register image that Linux produces at interrupt time.
+ *
+ * Linux's register image is defined by struct pt_regs in ptrace.h.
+ * Just why GDB uses a different order is a historical mystery.
+ */
+
+enum regnames {_RAX,
+ _RDX,
+ _RCX,
+ _RBX,
+ _RSI,
+ _RDI,
+ _RBP,
+ _RSP,
+ _R8,
+ _R9,
+ _R10,
+ _R11,
+ _R12,
+ _R13,
+ _R14,
+ _R15,
+ _PC,
+ _PS,
+ _LASTREG=_PS };
+
+#define PC_REGNUM _PC /* Program Counter */
+#define SP_REGNUM _RSP /* Stack Pointer */
+#define PTRACE_PC rip /* Program Counter, in ptrace regs. */
+
+/* Number of bytes of registers. */
+#define NUMREGBYTES (_LASTREG*8)
+
+#define BREAKPOINT() asm(" int $3");
+#define BREAK_INSTR_SIZE 1
+
+#endif /* _ASM_KGDB_H_ */
--- a/include/asm-x86_64/processor.h Wed Feb 11 15:42:06 2004
+++ b/include/asm-x86_64/processor.h Wed Feb 11 15:42:06 2004
@@ -252,6 +252,7 @@
         unsigned long *io_bitmap_ptr;
 /* cached TLS descriptors. */
         u64 tls_array[GDT_ENTRY_TLS_ENTRIES];
+ void *debuggerinfo;
 };
 
 #define INIT_THREAD {}
--- a/include/asm-x86_64/system.h Wed Feb 11 15:42:06 2004
+++ b/include/asm-x86_64/system.h Wed Feb 11 15:42:06 2004
@@ -19,6 +19,56 @@
 #define __SAVE(reg,offset) "movq %%" #reg ",(14-" #offset ")*8(%%rsp)\n\t"
 #define __RESTORE(reg,offset) "movq (14-" #offset ")*8(%%rsp),%%" #reg "\n\t"
 
+/* #ifdef CONFIG_KGDB */
+
+/* full frame for the debug stub */
+/* Should be replaced with a dwarf2 cie/fde description, then gdb could
+ figure it out all by itself. */
+struct save_context_frame {
+ unsigned long rbp;
+ unsigned long rbx;
+ unsigned long r11;
+ unsigned long r10;
+ unsigned long r9;
+ unsigned long r8;
+ unsigned long rcx;
+ unsigned long rdx;
+ unsigned long r15;
+ unsigned long r14;
+ unsigned long r13;
+ unsigned long r12;
+ unsigned long rdi;
+ unsigned long rsi;
+ unsigned long flags;
+};
+
+#if 0
+#define SAVE_CONTEXT \
+ "pushfq\n\t" \
+ "subq $14*8,%%rsp\n\t" \
+ __SAVE(rbx, 12) __SAVE(rdi, 1) \
+ __SAVE(rdx, 6) __SAVE(rcx, 7) \
+ __SAVE(r8, 8) __SAVE(r9, 9) \
+ __SAVE(r12, 2) __SAVE(r13, 3) \
+ __SAVE(r14, 4) __SAVE(r15, 5) \
+ __SAVE(r10, 10) __SAVE(r11, 11) \
+ __SAVE(rsi, 0) __SAVE(rbp, 13) \
+
+
+#define RESTORE_CONTEXT \
+ __RESTORE(rbx, 12) __RESTORE(rdi, 1) \
+ __RESTORE(rdx, 6) __RESTORE(rcx, 7) \
+ __RESTORE(r12, 2) __RESTORE(r13, 3) \
+ __RESTORE(r14, 4) __RESTORE(r15, 5) \
+ __RESTORE(r10, 10) __RESTORE(r11, 11) \
+ __RESTORE(r8, 8) __RESTORE(r9, 9) \
+ __RESTORE(rbp, 13) __RESTORE(rsi, 0) \
+ "addq $14*8,%%rsp\n\t" \
+ "popfq\n\t"
+
+#define __EXTRA_CLOBBER
+
+#else
 /* frame pointer must be last for get_wchan */
 #define SAVE_CONTEXT "pushfq ; pushq %%rbp ; movq %%rsi,%%rbp\n\t"
 #define RESTORE_CONTEXT "movq %%rbp,%%rsi ; popq %%rbp ; popfq\n\t"

-- 
Tom Rini
http://gate.crashing.org/~trini/
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