aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
Diffstat
-rw-r--r--Documentation/kernel-parameters.txt17
-rw-r--r--arch/x86/include/asm/processor.h2
-rw-r--r--arch/x86/kernel/cpu/common.c29
-rw-r--r--arch/x86/kernel/early_printk.c8
-rw-r--r--arch/x86/kernel/kgdb.c47
-rw-r--r--arch/x86/kernel/setup.c1
-rw-r--r--arch/x86/kernel/traps.c14
-rw-r--r--drivers/serial/kgdboc.c19
-rw-r--r--drivers/usb/early/ehci-dbgp.c120
-rw-r--r--include/linux/kgdb.h14
-rw-r--r--init/main.c4
-rw-r--r--kernel/debug/debug_core.c16
12 files changed, 255 insertions, 36 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index bdce359820bb..f5fce483930c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -713,6 +713,12 @@ and is between 256 and 4096 characters. It is defined in the file
The VGA output is eventually overwritten by the real
console.
+ ekgdboc= [X86,KGDB] Allow early kernel console debugging
+ ekgdboc=kbd
+
+ This is desgined to be used in conjunction with
+ the boot argument: earlyprintk=vga
+
eata= [HW,SCSI]
edd= [EDD]
@@ -1121,6 +1127,17 @@ and is between 256 and 4096 characters. It is defined in the file
use the HighMem zone if it exists, and the Normal
zone if it does not.
+ kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port.
+ Format: <Controller#>[,poll interval]
+ The controller # is the number of the ehci usb debug
+ port as it is probed via PCI. The poll interval is
+ optional and is the number seconds in between
+ each poll cycle to the debug port in case you need
+ the functionality for interrupting the kernel with
+ gdb or control-c on the dbgp connection. When
+ not using this parameter you use sysrq-g to break into
+ the kernel debugger.
+
kgdboc= [KGDB,HW] kgdb over consoles.
Requires a tty driver that supports console polling,
or a supported polling keyboard driver (non-usb).
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 5a51379dcbe4..7e5c6a60b8ee 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -789,6 +789,8 @@ static inline void wbinvd_halt(void)
extern void enable_sep_cpu(void);
extern int sysenter_setup(void);
+extern void early_trap_init(void);
+
/* Defined in head.S */
extern struct desc_ptr early_gdt_descr;
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index c1c00d0b1692..cc83a002786e 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1084,6 +1084,20 @@ static void clear_all_debug_regs(void)
}
}
+#ifdef CONFIG_KGDB
+/*
+ * Restore debug regs if using kgdbwait and you have a kernel debugger
+ * connection established.
+ */
+static void dbg_restore_debug_regs(void)
+{
+ if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break))
+ arch_kgdb_ops.correct_hw_break();
+}
+#else /* ! CONFIG_KGDB */
+#define dbg_restore_debug_regs()
+#endif /* ! CONFIG_KGDB */
+
/*
* cpu_init() initializes state that is per-CPU. Some data is already
* initialized (naturally) in the bootstrap process, such as the GDT
@@ -1174,18 +1188,8 @@ void __cpuinit cpu_init(void)
load_TR_desc();
load_LDT(&init_mm.context);
-#ifdef CONFIG_KGDB
- /*
- * If the kgdb is connected no debug regs should be altered. This
- * is only applicable when KGDB and a KGDB I/O module are built
- * into the kernel and you are using early debugging with
- * kgdbwait. KGDB will control the kernel HW breakpoint registers.
- */
- if (kgdb_connected && arch_kgdb_ops.correct_hw_break)
- arch_kgdb_ops.correct_hw_break();
- else
-#endif
- clear_all_debug_regs();
+ clear_all_debug_regs();
+ dbg_restore_debug_regs();
fpu_init();
@@ -1239,6 +1243,7 @@ void __cpuinit cpu_init(void)
#endif
clear_all_debug_regs();
+ dbg_restore_debug_regs();
/*
* Force FPU initialization:
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index b9c830c12b4a..fa99bae75ace 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -41,6 +41,14 @@ static void early_vga_write(struct console *con, const char *str, unsigned n)
writew(0x720, VGABASE + 2*(max_xpos*j + i));
current_ypos = max_ypos-1;
}
+#ifdef CONFIG_KGDB_KDB
+ if (c == '\b') {
+ if (current_xpos > 0)
+ current_xpos--;
+ } else if (c == '\r') {
+ current_xpos = 0;
+ } else
+#endif
if (c == '\n') {
current_xpos = 0;
current_ypos++;
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 95b89d4cb8f1..4f4af75b9482 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -199,6 +199,8 @@ static struct hw_breakpoint {
struct perf_event **pev;
} breakinfo[4];
+static unsigned long early_dr7;
+
static void kgdb_correct_hw_break(void)
{
int breakno;
@@ -210,6 +212,14 @@ static void kgdb_correct_hw_break(void)
int cpu = raw_smp_processor_id();
if (!breakinfo[breakno].enabled)
continue;
+ if (dbg_is_early) {
+ set_debugreg(breakinfo[breakno].addr, breakno);
+ early_dr7 |= encode_dr7(breakno,
+ breakinfo[breakno].len,
+ breakinfo[breakno].type);
+ set_debugreg(early_dr7, 7);
+ continue;
+ }
bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu);
info = counter_arch_bp(bp);
if (bp->attr.disabled != 1)
@@ -224,7 +234,8 @@ static void kgdb_correct_hw_break(void)
if (!val)
bp->attr.disabled = 0;
}
- hw_breakpoint_restore();
+ if (!dbg_is_early)
+ hw_breakpoint_restore();
}
static int hw_break_reserve_slot(int breakno)
@@ -233,6 +244,9 @@ static int hw_break_reserve_slot(int breakno)
int cnt = 0;
struct perf_event **pevent;
+ if (dbg_is_early)
+ return 0;
+
for_each_online_cpu(cpu) {
cnt++;
pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
@@ -258,6 +272,9 @@ static int hw_break_release_slot(int breakno)
struct perf_event **pevent;
int cpu;
+ if (dbg_is_early)
+ return 0;
+
for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
if (dbg_release_bp_slot(*pevent))
@@ -302,7 +319,11 @@ static void kgdb_remove_all_hw_break(void)
bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
if (bp->attr.disabled == 1)
continue;
- arch_uninstall_hw_breakpoint(bp);
+ if (dbg_is_early)
+ early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
+ breakinfo[i].type);
+ else
+ arch_uninstall_hw_breakpoint(bp);
bp->attr.disabled = 1;
}
}
@@ -379,6 +400,11 @@ void kgdb_disable_hw_debug(struct pt_regs *regs)
for (i = 0; i < 4; i++) {
if (!breakinfo[i].enabled)
continue;
+ if (dbg_is_early) {
+ early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
+ breakinfo[i].type);
+ continue;
+ }
bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
if (bp->attr.disabled == 1)
continue;
@@ -596,14 +622,15 @@ static struct notifier_block kgdb_notifier = {
*/
int kgdb_arch_init(void)
{
+ return register_die_notifier(&kgdb_notifier);
+}
+
+void kgdb_arch_late(void)
+{
int i, cpu;
- int ret;
struct perf_event_attr attr;
struct perf_event **pevent;
- ret = register_die_notifier(&kgdb_notifier);
- if (ret != 0)
- return ret;
/*
* Pre-allocate the hw breakpoint structions in the non-atomic
* portion of kgdb because this operation requires mutexs to
@@ -615,12 +642,15 @@ int kgdb_arch_init(void)
attr.bp_type = HW_BREAKPOINT_W;
attr.disabled = 1;
for (i = 0; i < 4; i++) {
+ if (breakinfo[i].pev)
+ continue;
breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL);
if (IS_ERR(breakinfo[i].pev)) {
- printk(KERN_ERR "kgdb: Could not allocate hw breakpoints\n");
+ printk(KERN_ERR "kgdb: Could not allocate hw"
+ "breakpoints\nDisabling the kernel debugger\n");
breakinfo[i].pev = NULL;
kgdb_arch_exit();
- return -1;
+ return;
}
for_each_online_cpu(cpu) {
pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
@@ -631,7 +661,6 @@ int kgdb_arch_init(void)
}
}
}
- return ret;
}
/**
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c4851eff57b3..e8029896309a 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -725,6 +725,7 @@ void __init setup_arch(char **cmdline_p)
/* VMI may relocate the fixmap; do this before touching ioremap area */
vmi_init();
+ early_trap_init();
early_cpu_init();
early_ioremap_init();
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 7eaad4c5110a..142d70c74b02 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -808,6 +808,16 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
}
#endif
+/* Set of traps needed for early debugging. */
+void __init early_trap_init(void)
+{
+ set_intr_gate_ist(1, &debug, DEBUG_STACK);
+ /* int3 can be called from all */
+ set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
+ set_intr_gate(14, &page_fault);
+ load_idt(&idt_descr);
+}
+
void __init trap_init(void)
{
int i;
@@ -821,10 +831,7 @@ void __init trap_init(void)
#endif
set_intr_gate(0, &divide_error);
- set_intr_gate_ist(1, &debug, DEBUG_STACK);
set_intr_gate_ist(2, &nmi, NMI_STACK);
- /* int3 can be called from all */
- set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
/* int4 can be called from all */
set_system_intr_gate(4, &overflow);
set_intr_gate(5, &bounds);
@@ -840,7 +847,6 @@ void __init trap_init(void)
set_intr_gate(11, &segment_not_present);
set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
set_intr_gate(13, &general_protection);
- set_intr_gate(14, &page_fault);
set_intr_gate(15, &spurious_interrupt_bug);
set_intr_gate(16, &coprocessor_error);
set_intr_gate(17, &alignment_check);
diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c
index b765ab48dfe7..a9a94ae72349 100644
--- a/drivers/serial/kgdboc.c
+++ b/drivers/serial/kgdboc.c
@@ -223,6 +223,25 @@ static struct kgdb_io kgdboc_io_ops = {
.post_exception = kgdboc_post_exp_handler,
};
+#ifdef CONFIG_KGDB_SERIAL_CONSOLE
+/* This is only available if kgdboc is a built in for early debugging */
+int __init kgdboc_early_init(char *opt)
+{
+ /* save the first character of the config string because the
+ * init routine can destroy it.
+ */
+ char save_ch;
+
+ kgdboc_option_setup(opt);
+ save_ch = config[0];
+ init_kgdboc();
+ config[0] = save_ch;
+ return 0;
+}
+
+early_param("ekgdboc", kgdboc_early_init);
+#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
+
module_init(init_kgdboc);
module_exit(cleanup_kgdboc);
module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);
diff --git a/drivers/usb/early/ehci-dbgp.c b/drivers/usb/early/ehci-dbgp.c
index 6e98a3697844..94ecdbc758ce 100644
--- a/drivers/usb/early/ehci-dbgp.c
+++ b/drivers/usb/early/ehci-dbgp.c
@@ -19,6 +19,9 @@
#include <linux/usb/ch9.h>
#include <linux/usb/ehci_def.h>
#include <linux/delay.h>
+#include <linux/serial_core.h>
+#include <linux/kgdb.h>
+#include <linux/kthread.h>
#include <asm/io.h>
#include <asm/pci-direct.h>
#include <asm/fixmap.h>
@@ -55,6 +58,7 @@ static struct ehci_regs __iomem *ehci_regs;
static struct ehci_dbg_port __iomem *ehci_debug;
static int dbgp_not_safe; /* Cannot use debug device during ehci reset */
static unsigned int dbgp_endpoint_out;
+static unsigned int dbgp_endpoint_in;
struct ehci_dev {
u32 bus;
@@ -91,6 +95,13 @@ static inline u32 dbgp_len_update(u32 x, u32 len)
return (x & ~0x0f) | (len & 0x0f);
}
+#ifdef CONFIG_KGDB
+static struct kgdb_io kgdbdbgp_io_ops;
+#define dbgp_kgdb_mode (dbg_io_ops == &kgdbdbgp_io_ops)
+#else
+#define dbgp_kgdb_mode (0)
+#endif
+
/*
* USB Packet IDs (PIDs)
*/
@@ -182,11 +193,10 @@ static void dbgp_breath(void)
/* Sleep to give the debug port a chance to breathe */
}
-static int dbgp_wait_until_done(unsigned ctrl)
+static int dbgp_wait_until_done(unsigned ctrl, int loop)
{
u32 pids, lpid;
int ret;
- int loop = DBGP_LOOPS;
retry:
writel(ctrl | DBGP_GO, &ehci_debug->control);
@@ -276,13 +286,13 @@ static int dbgp_bulk_write(unsigned devnum, unsigned endpoint,
dbgp_set_data(bytes, size);
writel(addr, &ehci_debug->address);
writel(pids, &ehci_debug->pids);
- ret = dbgp_wait_until_done(ctrl);
+ ret = dbgp_wait_until_done(ctrl, DBGP_LOOPS);
return ret;
}
static int dbgp_bulk_read(unsigned devnum, unsigned endpoint, void *data,
- int size)
+ int size, int loops)
{
u32 pids, addr, ctrl;
int ret;
@@ -302,7 +312,7 @@ static int dbgp_bulk_read(unsigned devnum, unsigned endpoint, void *data,
writel(addr, &ehci_debug->address);
writel(pids, &ehci_debug->pids);
- ret = dbgp_wait_until_done(ctrl);
+ ret = dbgp_wait_until_done(ctrl, loops);
if (ret < 0)
return ret;
@@ -343,12 +353,12 @@ static int dbgp_control_msg(unsigned devnum, int requesttype,
dbgp_set_data(&req, sizeof(req));
writel(addr, &ehci_debug->address);
writel(pids, &ehci_debug->pids);
- ret = dbgp_wait_until_done(ctrl);
+ ret = dbgp_wait_until_done(ctrl, DBGP_LOOPS);
if (ret < 0)
return ret;
/* Read the result */
- return dbgp_bulk_read(devnum, 0, data, size);
+ return dbgp_bulk_read(devnum, 0, data, size, DBGP_LOOPS);
}
/* Find a PCI capability */
@@ -559,6 +569,7 @@ try_again:
goto err;
}
dbgp_endpoint_out = dbgp_desc.bDebugOutEndpoint;
+ dbgp_endpoint_in = dbgp_desc.bDebugInEndpoint;
/* Move the device to 127 if it isn't already there */
if (devnum != USB_DEBUG_DEVNUM) {
@@ -968,8 +979,9 @@ int dbgp_reset_prep(void)
if (!ehci_debug)
return 0;
- if (early_dbgp_console.index != -1 &&
- !(early_dbgp_console.flags & CON_BOOT))
+ if ((early_dbgp_console.index != -1 &&
+ !(early_dbgp_console.flags & CON_BOOT)) ||
+ dbgp_kgdb_mode)
return 1;
/* This means the console is not initialized, or should get
* shutdown so as to allow for reuse of the usb device, which
@@ -982,3 +994,93 @@ int dbgp_reset_prep(void)
return 0;
}
EXPORT_SYMBOL_GPL(dbgp_reset_prep);
+
+#ifdef CONFIG_KGDB
+
+static char kgdbdbgp_buf[DBGP_MAX_PACKET];
+static int kgdbdbgp_buf_sz;
+static int kgdbdbgp_buf_idx;
+static int kgdbdbgp_loop_cnt = DBGP_LOOPS;
+
+static int kgdbdbgp_read_char(void)
+{
+ int ret;
+
+ if (kgdbdbgp_buf_idx < kgdbdbgp_buf_sz) {
+ char ch = kgdbdbgp_buf[kgdbdbgp_buf_idx++];
+ return ch;
+ }
+
+ ret = dbgp_bulk_read(USB_DEBUG_DEVNUM, dbgp_endpoint_in,
+ &kgdbdbgp_buf, DBGP_MAX_PACKET,
+ kgdbdbgp_loop_cnt);
+ if (ret <= 0)
+ return NO_POLL_CHAR;
+ kgdbdbgp_buf_sz = ret;
+ kgdbdbgp_buf_idx = 1;
+ return kgdbdbgp_buf[0];
+}
+
+static void kgdbdbgp_write_char(u8 chr)
+{
+ early_dbgp_write(NULL, &chr, 1);
+}
+
+static struct kgdb_io kgdbdbgp_io_ops = {
+ .name = "kgdbdbgp",
+ .read_char = kgdbdbgp_read_char,
+ .write_char = kgdbdbgp_write_char,
+};
+
+static int kgdbdbgp_wait_time;
+
+static int __init kgdbdbgp_parse_config(char *str)
+{
+ char *ptr;
+
+ if (!ehci_debug) {
+ if (early_dbgp_init(str))
+ return -1;
+ }
+ ptr = strchr(str, ',');
+ if (ptr) {
+ ptr++;
+ kgdbdbgp_wait_time = simple_strtoul(ptr, &ptr, 10);
+ }
+ kgdb_register_io_module(&kgdbdbgp_io_ops);
+ kgdbdbgp_io_ops.is_console = early_dbgp_console.index != -1;
+
+ return 0;
+}
+early_param("kgdbdbgp", kgdbdbgp_parse_config);
+
+static int kgdbdbgp_reader_thread(void *ptr)
+{
+ int ret;
+
+ while (readl(&ehci_debug->control) & DBGP_ENABLED) {
+ kgdbdbgp_loop_cnt = 1;
+ ret = kgdbdbgp_read_char();
+ kgdbdbgp_loop_cnt = DBGP_LOOPS;
+ if (ret != NO_POLL_CHAR) {
+ if (ret == 0x3 || ret == '$') {
+ if (ret == '$')
+ kgdbdbgp_buf_idx--;
+ kgdb_breakpoint();
+ }
+ continue;
+ }
+ schedule_timeout_interruptible(kgdbdbgp_wait_time * HZ);
+ }
+ return 0;
+}
+
+static int __init kgdbdbgp_start_thread(void)
+{
+ if (dbgp_kgdb_mode && kgdbdbgp_wait_time)
+ kthread_run(kgdbdbgp_reader_thread, NULL, "%s", "dbgp");
+
+ return 0;
+}
+module_init(kgdbdbgp_start_thread);
+#endif /* CONFIG_KGDB */
diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
index 6c784ab6856a..9340f34d1bb5 100644
--- a/include/linux/kgdb.h
+++ b/include/linux/kgdb.h
@@ -208,6 +208,17 @@ extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr);
extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle);
/**
+ * kgdb_arch_late - Perform any architecture specific initalization.
+ *
+ * This function will handle the late initalization of any
+ * architecture specific callbacks. This is an optional function for
+ * handling things like late initialization of hw breakpoints. The
+ * default implementation does nothing.
+ */
+extern void kgdb_arch_late(void);
+
+
+/**
* struct kgdb_arch - Describe architecture specific values.
* @gdb_bpt_instr: The instruction to trigger a breakpoint.
* @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT.
@@ -285,7 +296,10 @@ extern int kgdb_single_step;
extern atomic_t kgdb_active;
#define in_dbg_master() \
(raw_smp_processor_id() == atomic_read(&kgdb_active))
+extern bool dbg_is_early;
+extern void __init dbg_late_init(void);
#else /* ! CONFIG_KGDB */
#define in_dbg_master() (0)
+#define dbg_late_init()
#endif /* ! CONFIG_KGDB */
#endif /* _KGDB_H_ */
diff --git a/init/main.c b/init/main.c
index 372771333d98..22881b5e95e3 100644
--- a/init/main.c
+++ b/init/main.c
@@ -62,7 +62,7 @@
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/idr.h>
-#include <linux/kdb.h>
+#include <linux/kgdb.h>
#include <linux/ftrace.h>
#include <linux/async.h>
#include <linux/kmemcheck.h>
@@ -676,7 +676,7 @@ asmlinkage void __init start_kernel(void)
buffer_init();
key_init();
security_init();
- kdb_init(KDB_INIT_FULL);
+ dbg_late_init();
vfs_caches_init(totalram_pages);
signals_init();
/* rootfs populating might need page-writeback */
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 64b5588c9638..5cb7cd1de10c 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -78,6 +78,8 @@ static DEFINE_SPINLOCK(kgdb_registration_lock);
static int kgdb_con_registered;
/* determine if kgdb console output should be used */
static int kgdb_use_con;
+/* Flag for alternate operations for early debugging */
+bool dbg_is_early = true;
/* Next cpu to become the master debug core */
int dbg_switch_cpu;
@@ -777,11 +779,25 @@ static struct notifier_block kgdb_panic_event_nb = {
.priority = INT_MAX,
};
+void __weak kgdb_arch_late(void)
+{
+}
+
+void __init dbg_late_init(void)
+{
+ dbg_is_early = false;
+ if (kgdb_io_module_registered)
+ kgdb_arch_late();
+ kdb_init(KDB_INIT_FULL);
+}
+
static void kgdb_register_callbacks(void)
{
if (!kgdb_io_module_registered) {
kgdb_io_module_registered = 1;
kgdb_arch_init();
+ if (!dbg_is_early)
+ kgdb_arch_late();
atomic_notifier_chain_register(&panic_notifier_list,
&kgdb_panic_event_nb);
#ifdef CONFIG_MAGIC_SYSRQ
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.