[patch 2/8] KGDB support for i386

From: Tom Rini
Date: Fri Oct 29 2004 - 13:57:44 EST


This adds support for KGDB on the i386 architecture. The only slightly
related change is to make i386 parse early_params now as KGDB registers as
one. We also add an early_trap_init() call which does the parts of
trap_init() which need to be done for KGDB to be entered, and can be done
safely this early.

As an aside, I believe the hunk to arch/i386/kernel/signal.c can be dropped in
a post 2.6.10-rc1 tree as something similar using unlikey() has been put in.

---

linux-2.6.10-rc1-trini/arch/i386/kernel/Makefile | 1
linux-2.6.10-rc1-trini/arch/i386/kernel/irq.c | 3
linux-2.6.10-rc1-trini/arch/i386/kernel/kgdb.c | 300 +++++++++++++++++++++++
linux-2.6.10-rc1-trini/arch/i386/kernel/nmi.c | 11
linux-2.6.10-rc1-trini/arch/i386/kernel/setup.c | 3
linux-2.6.10-rc1-trini/arch/i386/kernel/signal.c | 3
linux-2.6.10-rc1-trini/arch/i386/kernel/traps.c | 31 +-
linux-2.6.10-rc1-trini/arch/i386/mm/fault.c | 10
linux-2.6.10-rc1-trini/include/asm-i386/kgdb.h | 48 +++
linux-2.6.10-rc1-trini/include/asm-i386/system.h | 10
linux-2.6.10-rc1-trini/lib/Kconfig.debug | 2
11 files changed, 405 insertions(+), 17 deletions(-)

diff -puN arch/i386/kernel/Makefile~i386-lite arch/i386/kernel/Makefile
--- linux-2.6.10-rc1/arch/i386/kernel/Makefile~i386-lite 2004-10-29 11:26:44.461448834 -0700
+++ linux-2.6.10-rc1-trini/arch/i386/kernel/Makefile 2004-10-29 11:26:44.481444139 -0700
@@ -32,6 +32,7 @@ obj-$(CONFIG_ACPI_SRAT) += srat.o
obj-$(CONFIG_HPET_TIMER) += time_hpet.o
obj-$(CONFIG_EFI) += efi.o efi_stub.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
+obj-$(CONFIG_KGDB) += kgdb.o

EXTRA_AFLAGS := -traditional

diff -puN arch/i386/kernel/irq.c~i386-lite arch/i386/kernel/irq.c
--- linux-2.6.10-rc1/arch/i386/kernel/irq.c~i386-lite 2004-10-29 11:26:44.463448364 -0700
+++ linux-2.6.10-rc1-trini/arch/i386/kernel/irq.c 2004-10-29 11:26:44.482443904 -0700
@@ -15,6 +15,7 @@
#include <linux/seq_file.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
+#include <linux/kgdb.h>

#ifndef CONFIG_X86_LOCAL_APIC
/*
@@ -103,6 +104,8 @@ asmlinkage unsigned int do_IRQ(struct pt

irq_exit();

+ kgdb_process_breakpoint();
+
return 1;
}

diff -puN /dev/null arch/i386/kernel/kgdb.c
--- /dev/null 2004-10-25 00:35:20.587727328 -0700
+++ linux-2.6.10-rc1-trini/arch/i386/kernel/kgdb.c 2004-10-29 11:26:44.482443904 -0700
@@ -0,0 +1,300 @@
+/*
+ *
+ * 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) 2000-2001 VERITAS Software Corporation.
+ */
+/*
+ * Contributor: Lake Stevens Instrument Division$
+ * Written by: Glenn Engel $
+ * Updated by: Amit Kale<akale@xxxxxxxxxxx>
+ * Modified for 386 by Jim Kingdon, Cygnus Support.
+ * Origianl kgdb, compatibility with 2.1.xx kernel by David Grothe <dave@xxxxxxxx>
+ */
+
+#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/vm86.h>
+#include <asm/system.h>
+#include <asm/ptrace.h> /* for linux pt_regs struct */
+#include <linux/kgdb.h>
+#include <linux/init.h>
+#include <linux/debugger.h>
+#include <asm/desc.h>
+#include <asm/kdebug.h>
+
+/* Put the error code here just in case the user cares. */
+int gdb_i386errcode;
+/* Likewise, the vector number here (since GDB only gets the signal
+ number through the usual means, and that's not very specific). */
+int gdb_i386vector = -1;
+
+extern atomic_t cpu_doing_single_step;
+
+void regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ gdb_regs[_EAX] = regs->eax;
+ gdb_regs[_EBX] = regs->ebx;
+ gdb_regs[_ECX] = regs->ecx;
+ gdb_regs[_EDX] = regs->edx;
+ gdb_regs[_ESI] = regs->esi;
+ gdb_regs[_EDI] = regs->edi;
+ gdb_regs[_EBP] = regs->ebp;
+ gdb_regs[_DS] = regs->xds;
+ gdb_regs[_ES] = regs->xes;
+ gdb_regs[_PS] = regs->eflags;
+ gdb_regs[_CS] = regs->xcs;
+ gdb_regs[_PC] = regs->eip;
+ gdb_regs[_ESP] = (int)(&regs->esp);
+ gdb_regs[_SS] = __KERNEL_DS;
+ gdb_regs[_FS] = 0xFFFF;
+ gdb_regs[_GS] = 0xFFFF;
+}
+
+/*
+ * Extracts ebp, esp and eip values understandable by gdb from the values
+ * saved by switch_to.
+ * thread.esp points to ebp. flags and ebp are pushed in switch_to hence esp
+ * prior to entering switch_to is 8 greater then the value that is saved.
+ * If switch_to changes, change following code appropriately.
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+ gdb_regs[_EAX] = 0;
+ gdb_regs[_EBX] = 0;
+ gdb_regs[_ECX] = 0;
+ gdb_regs[_EDX] = 0;
+ gdb_regs[_ESI] = 0;
+ gdb_regs[_EDI] = 0;
+ gdb_regs[_EBP] = *(unsigned long *)p->thread.esp;
+ gdb_regs[_DS] = __KERNEL_DS;
+ gdb_regs[_ES] = __KERNEL_DS;
+ gdb_regs[_PS] = *(unsigned long *)(p->thread.esp + 4);
+ gdb_regs[_CS] = __KERNEL_CS;
+ gdb_regs[_PC] = p->thread.eip;
+ gdb_regs[_ESP] = p->thread.esp;
+ gdb_regs[_SS] = __KERNEL_DS;
+ gdb_regs[_FS] = 0xFFFF;
+ gdb_regs[_GS] = 0xFFFF;
+}
+
+void gdb_regs_to_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ regs->eax = gdb_regs[_EAX];
+ regs->ebx = gdb_regs[_EBX];
+ regs->ecx = gdb_regs[_ECX];
+ regs->edx = gdb_regs[_EDX];
+ regs->esi = gdb_regs[_ESI];
+ regs->edi = gdb_regs[_EDI];
+ regs->ebp = gdb_regs[_EBP];
+ regs->xds = gdb_regs[_DS];
+ regs->xes = gdb_regs[_ES];
+ regs->eflags = gdb_regs[_PS];
+ regs->xcs = gdb_regs[_CS];
+ regs->eip = gdb_regs[_PC];
+#if 0 /* can't change these */
+ regs->esp = gdb_regs[_ESP];
+ regs->xss = gdb_regs[_SS];
+ regs->fs = gdb_regs[_FS];
+ regs->gs = gdb_regs[_GS];
+#endif
+
+}
+
+struct hw_breakpoint {
+ unsigned enabled;
+ unsigned type;
+ unsigned len;
+ unsigned addr;
+} breakinfo[4] = {
+ { .enabled = 0 },
+ { .enabled = 0 },
+ { .enabled = 0 },
+ { .enabled = 0 },
+};
+
+void kgdb_correct_hw_break(void)
+{
+ int breakno;
+ int correctit;
+ int breakbit;
+ unsigned dr7;
+
+ asm volatile ("movl %%db7, %0\n":"=r" (dr7)
+ :);
+ do {
+ unsigned addr0, addr1, addr2, addr3;
+ asm volatile ("movl %%db0, %0\n"
+ "movl %%db1, %1\n"
+ "movl %%db2, %2\n"
+ "movl %%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 ("movl %0, %%dr0\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 1:
+ asm volatile ("movl %0, %%dr1\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 2:
+ asm volatile ("movl %0, %%dr2\n"::"r"
+ (breakinfo[breakno].addr));
+ break;
+
+ case 3:
+ asm volatile ("movl %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 ("movl %0, %%db7\n"::"r" (dr7));
+ }
+}
+
+void kgdb_disable_hw_debug(struct pt_regs *regs)
+{
+ /* Disable hardware debugging while we are in kgdb */
+ asm volatile ("movl %0,%%db7": /* no output */ :"r" (0));
+}
+
+void kgdb_post_master_code(struct pt_regs *regs, int eVector, int err_code)
+{
+ /* Master processor is completely in the debugger */
+ gdb_i386vector = eVector;
+ gdb_i386errcode = err_code;
+}
+
+int kgdb_arch_handle_exception(int exceptionVector, int signo,
+ int err_code, char *remcom_in_buffer,
+ char *remcom_out_buffer,
+ struct pt_regs *linux_regs)
+{
+ long addr;
+ long breakno;
+ char *ptr;
+ int newPC;
+ int dr6;
+
+ switch (remcom_in_buffer[0]) {
+ case 'c':
+ case 's':
+ if (kgdb_contthread && kgdb_contthread != current) {
+ strcpy(remcom_out_buffer, "E00");
+ break;
+ }
+
+ /* try to read optional parameter, pc unchanged if no parm */
+ ptr = &remcom_in_buffer[1];
+ if (kgdb_hex2long(&ptr, &addr)) {
+ linux_regs->eip = addr;
+ }
+ newPC = linux_regs->eip;
+
+ /* clear the trace bit */
+ linux_regs->eflags &= ~TF_MASK;
+ atomic_set(&cpu_doing_single_step,-1);
+
+ /* set the trace bit if we're stepping */
+ if (remcom_in_buffer[0] == 's') {
+ linux_regs->eflags |= TF_MASK;
+ debugger_step = 1;
+ if (kgdb_contthread)
+ atomic_set(&cpu_doing_single_step,smp_processor_id());
+ }
+
+ asm volatile ("movl %%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 |= X86_EFLAGS_RF;
+ break;
+ }
+ }
+ }
+ }
+ kgdb_correct_hw_break();
+ asm volatile ("movl %0, %%db6\n"::"r" (0));
+
+ return (0);
+ } /* switch */
+ return -1; /* this means that we do not want to exit from the handler */
+}
+
+/* Register KGDB with the i386die_chain so that we hook into all of the right
+ * spots. */
+static int kgdb_notify(struct notifier_block *self, unsigned long cmd,
+ void *ptr)
+{
+ struct die_args *args = (struct die_args *)ptr;
+ struct pt_regs *regs = args->regs;
+
+ /* See if KGDB is interested. */
+ if (cmd == DIE_PAGE_FAULT)
+ return NOTIFY_DONE;
+ else if (user_mode(regs)) {
+ if (cmd == DIE_OOPS)
+ CHK_DEBUGGER(args->trapnr, args->signr, args->err,
+ args->regs,);
+ return NOTIFY_DONE;
+ } else if (cmd == DIE_NMI_IPI) {
+ if (atomic_read(&debugger_active)) {
+ debugger_nmihook(smp_processor_id(), ptr);
+ return NOTIFY_STOP;
+ }
+ }
+
+ CHK_DEBUGGER(args->trapnr, args->signr, args->err, args->regs,);
+
+ return NOTIFY_STOP;
+}
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_notify,
+};
+
+int kgdb_arch_init(void) {
+ notifier_chain_register(&i386die_chain, &kgdb_notifier);
+ return 0;
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+ .gdb_bpt_instr = {0xcc},
+};
diff -puN arch/i386/kernel/nmi.c~i386-lite arch/i386/kernel/nmi.c
--- linux-2.6.10-rc1/arch/i386/kernel/nmi.c~i386-lite 2004-10-29 11:26:44.465447895 -0700
+++ linux-2.6.10-rc1-trini/arch/i386/kernel/nmi.c 2004-10-29 11:26:44.483443669 -0700
@@ -26,6 +26,7 @@
#include <linux/nmi.h>
#include <linux/sysdev.h>
#include <linux/sysctl.h>
+#include <linux/debugger.h>

#include <asm/smp.h>
#include <asm/mtrr.h>
@@ -481,7 +482,15 @@ void nmi_watchdog_tick (struct pt_regs *

sum = irq_stat[cpu].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 ...
diff -puN arch/i386/kernel/setup.c~i386-lite arch/i386/kernel/setup.c
--- linux-2.6.10-rc1/arch/i386/kernel/setup.c~i386-lite 2004-10-29 11:26:44.467447425 -0700
+++ linux-2.6.10-rc1-trini/arch/i386/kernel/setup.c 2004-10-29 11:26:44.484443435 -0700
@@ -117,6 +117,7 @@ struct e820map e820;
unsigned char aux_device_present;

extern void early_cpu_init(void);
+extern void early_trap_init(void);
extern void dmi_scan_machine(void);
extern void generic_apic_probe(char *);
extern int root_mountflags;
@@ -1302,6 +1303,7 @@ void __init setup_arch(char **cmdline_p)
memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
pre_setup_arch_hook();
early_cpu_init();
+ early_trap_init();

/*
* FIXME: This isn't an official loader_type right
@@ -1358,6 +1360,7 @@ void __init setup_arch(char **cmdline_p)
data_resource.end = virt_to_phys(_edata)-1;

parse_cmdline_early(cmdline_p);
+ parse_early_param();

max_low_pfn = setup_memory();

diff -puN arch/i386/kernel/signal.c~i386-lite arch/i386/kernel/signal.c
--- linux-2.6.10-rc1/arch/i386/kernel/signal.c~i386-lite 2004-10-29 11:26:44.469446956 -0700
+++ linux-2.6.10-rc1-trini/arch/i386/kernel/signal.c 2004-10-29 11:26:44.485443200 -0700
@@ -600,7 +600,8 @@ int fastcall do_signal(struct pt_regs *r
* have been cleared if the watchpoint triggered
* inside the kernel.
*/
- __asm__("movl %0,%%db7" : : "r" (current->thread.debugreg[7]));
+ if (current->thread.debugreg[7])
+ __asm__("movl %0,%%db7" : : "r" (current->thread.debugreg[7]));

/* Whee! Actually deliver the signal. */
handle_signal(signr, &info, &ka, oldset, regs);
diff -puN arch/i386/kernel/traps.c~i386-lite arch/i386/kernel/traps.c
--- linux-2.6.10-rc1/arch/i386/kernel/traps.c~i386-lite 2004-10-29 11:26:44.471446486 -0700
+++ linux-2.6.10-rc1-trini/arch/i386/kernel/traps.c 2004-10-29 11:26:44.486442965 -0700
@@ -53,6 +53,7 @@

#include <linux/irq.h>
#include <linux/module.h>
+#include <linux/debugger.h>

#include "mach_traps.h"

@@ -332,7 +333,7 @@ void die(const char * str, struct pt_reg
#endif
if (nl)
printk("\n");
- notify_die(DIE_OOPS, (char *)str, regs, err, 255, SIGSEGV);
+ notify_die(DIE_OOPS, (char *)str, regs, err, 255, SIGSEGV);
show_registers(regs);
} else
printk(KERN_ERR "Recursive die() failure, output suppressed\n");
@@ -711,7 +712,7 @@ asmlinkage void do_debug(struct pt_regs
tsk->thread.debugreg[6] = 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
@@ -733,12 +734,14 @@ asmlinkage void do_debug(struct pt_regs
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
-
- /* If this is a kernel mode trap, save the user PC on entry to
- * the kernel, that's what the debugger can make sense of.
- */
- info.si_addr = ((regs->xcs & 3) == 0) ? (void __user *)tsk->thread.eip
- : (void __user *)regs->eip;
+
+ /* If this is a kernel mode trap, we need to reset db7 to allow us
+ * to continue sanely */
+ if ((regs->xcs & 3) == 0)
+ goto clear_dr7;
+
+ info.si_addr = (void *)regs->eip;
+
force_sig_info(SIGTRAP, &info, tsk);

/* Disable additional traps. They'll be re-enabled when
@@ -748,6 +751,7 @@ clear_dr7:
__asm__("movl %0,%%db7"
: /* no output */
: "r" (0));
+ notify_die(DIE_DEBUG, "debug", regs, condition, error_code, SIGTRAP);
return;

debug_vm86:
@@ -1005,6 +1009,12 @@ static void __init set_task_gate(unsigne
_set_gate(idt_table+n,5,0,0,(gdt_entry<<3));
}

+/* Some traps need to be set early. */
+void __init early_trap_init(void) {
+ set_intr_gate(1,&debug);
+ set_system_intr_gate(3, &int3); /* int3 can be called from all */
+ set_intr_gate(14,&page_fault);
+}

void __init trap_init(void)
{
@@ -1019,10 +1029,8 @@ void __init trap_init(void)
#endif

set_trap_gate(0,&divide_error);
- set_intr_gate(1,&debug);
set_intr_gate(2,&nmi);
- set_system_intr_gate(3, &int3); /* int3-5 can be called from all */
- set_system_gate(4,&overflow);
+ set_system_gate(4,&overflow); /* int4/5 can be called from all */
set_system_gate(5,&bounds);
set_trap_gate(6,&invalid_op);
set_trap_gate(7,&device_not_available);
@@ -1032,7 +1040,6 @@ void __init trap_init(void)
set_trap_gate(11,&segment_not_present);
set_trap_gate(12,&stack_segment);
set_trap_gate(13,&general_protection);
- set_intr_gate(14,&page_fault);
set_trap_gate(15,&spurious_interrupt_bug);
set_trap_gate(16,&coprocessor_error);
set_trap_gate(17,&alignment_check);
diff -puN arch/i386/mm/fault.c~i386-lite arch/i386/mm/fault.c
--- linux-2.6.10-rc1/arch/i386/mm/fault.c~i386-lite 2004-10-29 11:26:44.473446017 -0700
+++ linux-2.6.10-rc1-trini/arch/i386/mm/fault.c 2004-10-29 11:26:44.486442965 -0700
@@ -2,6 +2,11 @@
* linux/arch/i386/mm/fault.c
*
* Copyright (C) 1995 Linus Torvalds
+ *
+ * Change History
+ *
+ * Tigran Aivazian <tigran@xxxxxxx> Remote debugging support.
+ *
*/

#include <linux/signal.h>
@@ -21,6 +26,7 @@
#include <linux/vt_kern.h> /* For unblank_screen() */
#include <linux/highmem.h>
#include <linux/module.h>
+#include <linux/debugger.h>

#include <asm/system.h>
#include <asm/uaccess.h>
@@ -426,6 +432,10 @@ no_context:
if (is_prefetch(regs, address, error_code))
return;

+ if (notify_die(DIE_PAGE_FAULT, "page fault", regs, error_code, 14,
+ SIGSEGV) == NOTIFY_BAD)
+ return;
+
/*
* Oops. The kernel tried to access some bad page. We'll have to
* terminate things with extreme prejudice.
diff -puN /dev/null include/asm-i386/kgdb.h
--- /dev/null 2004-10-25 00:35:20.587727328 -0700
+++ linux-2.6.10-rc1-trini/include/asm-i386/kgdb.h 2004-10-29 11:26:44.487442730 -0700
@@ -0,0 +1,48 @@
+#ifndef _ASM_KGDB_H_
+#define _ASM_KGDB_H_
+
+/*
+ * Copyright (C) 2001-2004 Amit S. Kale
+ */
+
+#include <linux/ptrace.h>
+
+/************************************************************************/
+/* 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
+
+/* Number of bytes of registers. */
+#define NUMREGBYTES 64
+/*
+ * 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 { _EAX, /* 0 */
+ _ECX, /* 1 */
+ _EDX, /* 2 */
+ _EBX, /* 3 */
+ _ESP, /* 4 */
+ _EBP, /* 5 */
+ _ESI, /* 6 */
+ _EDI, /* 7 */
+ _PC, /* 8 also known as eip */
+ _PS, /* 9 also known as eflags */
+ _CS, /* 10 */
+ _SS, /* 11 */
+ _DS, /* 12 */
+ _ES, /* 13 */
+ _FS, /* 14 */
+ _GS /* 15 */
+};
+
+#define BREAKPOINT() asm(" int $3");
+#define BREAK_INSTR_SIZE 1
+
+#define CHECK_EXCEPTION_STACK() 1
+
+#endif /* _ASM_KGDB_H_ */
diff -puN include/asm-i386/system.h~i386-lite include/asm-i386/system.h
--- linux-2.6.10-rc1/include/asm-i386/system.h~i386-lite 2004-10-29 11:26:44.476445313 -0700
+++ linux-2.6.10-rc1-trini/include/asm-i386/system.h 2004-10-29 11:26:44.487442730 -0700
@@ -12,9 +12,13 @@
struct task_struct; /* one of the stranger aspects of C forward declarations.. */
extern struct task_struct * FASTCALL(__switch_to(struct task_struct *prev, struct task_struct *next));

+/* sleeping_thread_to_gdb_regs depends on this code. Correct it if you change
+ * any of the following */
#define switch_to(prev,next,last) do { \
unsigned long esi,edi; \
- asm volatile("pushfl\n\t" \
+ asm volatile(".globl __switch_to_begin\n" \
+ "__switch_to_begin:" \
+ "pushfl\n\t" \
"pushl %%ebp\n\t" \
"movl %%esp,%0\n\t" /* save ESP */ \
"movl %5,%%esp\n\t" /* restore ESP */ \
@@ -23,7 +27,9 @@ extern struct task_struct * FASTCALL(__s
"jmp __switch_to\n" \
"1:\t" \
"popl %%ebp\n\t" \
- "popfl" \
+ "popfl\n" \
+ ".globl __switch_to_end\n" \
+ "__switch_to_end:\n" \
:"=m" (prev->thread.esp),"=m" (prev->thread.eip), \
"=a" (last),"=S" (esi),"=D" (edi) \
:"m" (next->thread.esp),"m" (next->thread.eip), \
diff -puN lib/Kconfig.debug~i386-lite lib/Kconfig.debug
--- linux-2.6.10-rc1/lib/Kconfig.debug~i386-lite 2004-10-29 11:26:44.477445078 -0700
+++ linux-2.6.10-rc1-trini/lib/Kconfig.debug 2004-10-29 11:32:58.640565630 -0700
@@ -115,7 +115,7 @@ endif

config KGDB
bool "KGDB: kernel debugging with remote gdb"
- depends on DEBUG_KERNEL
+ depends on DEBUG_KERNEL && (X86)
help
If you say Y here, it will be possible to remotely debug the
kernel using gdb. This enlarges your kernel image disk size by
_
-
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