kgdb: core

kgdb core code. Handles the protocol and the arch details.

[ mingo@elte.hu: heavily modified, simplified and cleaned up. ]
[ xemul@openvz.org: use find_task_by_pid_ns ]

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 271 insertions, 0 deletions

diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h
new file mode 100644
index 000000000000..b0985b79b638
--- /dev/null
+++ b/include/linux/kgdb.h
@@ -0,0 +1,271 @@
+/*
+ * This provides the callbacks and functions that KGDB needs to share between
+ * the core, I/O and arch-specific portions.
+ *
+ * Author: Amit Kale <amitkale@linsyssoft.com> and
+ *         Tom Rini <trini@kernel.crashing.org>
+ *
+ * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc.
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+#ifndef _KGDB_H_
+#define _KGDB_H_
+
+#include <linux/serial_8250.h>
+#include <linux/linkage.h>
+#include <linux/init.h>
+
+#include <asm/atomic.h>
+#include <asm/kgdb.h>
+
+struct pt_regs;
+
+/*
+ *      kgdb_skipexception - Bail out of KGDB when we've been triggered.
+ *      @exception: Exception vector number
+ *      @regs: Current &struct pt_regs.
+ *
+ *      On some architectures we need to skip a breakpoint exception when
+ *      it occurs after a breakpoint has been removed.
+ */
+extern int kgdb_skipexception(int exception, struct pt_regs *regs);
+
+/*
+ *      kgdb_post_primary_code - Save error vector/code numbers.
+ *      @regs: Original pt_regs.
+ *      @e_vector: Original error vector.
+ *      @err_code: Original error code.
+ *
+ *      This is needed on architectures which support SMP and KGDB.
+ *      This function is called after all the secondary cpus have been put
+ *      to a know spin state and the primary CPU has control over KGDB.
+ */
+extern void kgdb_post_primary_code(struct pt_regs *regs, int e_vector,
+                                  int err_code);
+
+/*
+ *      kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb.
+ *      @regs: Current &struct pt_regs.
+ *
+ *      This function will be called if the particular architecture must
+ *      disable hardware debugging while it is processing gdb packets or
+ *      handling exception.
+ */
+extern void kgdb_disable_hw_debug(struct pt_regs *regs);
+
+struct tasklet_struct;
+struct task_struct;
+struct uart_port;
+
+/* To enter the debugger explicitly. */
+void kgdb_breakpoint(void);
+
+extern int kgdb_connected;
+
+extern atomic_t                 kgdb_setting_breakpoint;
+extern atomic_t                 kgdb_cpu_doing_single_step;
+
+extern struct task_struct       *kgdb_usethread;
+extern struct task_struct       *kgdb_contthread;
+
+enum kgdb_bptype {
+        BP_BREAKPOINT = 0,
+        BP_HARDWARE_BREAKPOINT,
+        BP_WRITE_WATCHPOINT,
+        BP_READ_WATCHPOINT,
+        BP_ACCESS_WATCHPOINT
+};
+
+enum kgdb_bpstate {
+        BP_UNDEFINED = 0,
+        BP_REMOVED,
+        BP_SET,
+        BP_ACTIVE
+};
+
+struct kgdb_bkpt {
+        unsigned long           bpt_addr;
+        unsigned char           saved_instr[BREAK_INSTR_SIZE];
+        enum kgdb_bptype        type;
+        enum kgdb_bpstate       state;
+};
+
+#ifndef KGDB_MAX_BREAKPOINTS
+# define KGDB_MAX_BREAKPOINTS   1000
+#endif
+
+#define KGDB_HW_BREAKPOINT      1
+
+/*
+ * Functions each KGDB-supporting architecture must provide:
+ */
+
+/*
+ *      kgdb_arch_init - Perform any architecture specific initalization.
+ *
+ *      This function will handle the initalization of any architecture
+ *      specific callbacks.
+ */
+extern int kgdb_arch_init(void);
+
+/*
+ *      kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ *      This function will handle the uninitalization of any architecture
+ *      specific callbacks, for dynamic registration and unregistration.
+ */
+extern void kgdb_arch_exit(void);
+
+/*
+ *      pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
+ *      @gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *      @regs: The &struct pt_regs of the current process.
+ *
+ *      Convert the pt_regs in @regs into the format for registers that
+ *      GDB expects, stored in @gdb_regs.
+ */
+extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/*
+ *      sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs
+ *      @gdb_regs: A pointer to hold the registers in the order GDB wants.
+ *      @p: The &struct task_struct of the desired process.
+ *
+ *      Convert the register values of the sleeping process in @p to
+ *      the format that GDB expects.
+ *      This function is called when kgdb does not have access to the
+ *      &struct pt_regs and therefore it should fill the gdb registers
+ *      @gdb_regs with what has been saved in &struct thread_struct
+ *      thread field during switch_to.
+ */
+extern void
+sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p);
+
+/*
+ *      gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs.
+ *      @gdb_regs: A pointer to hold the registers we've received from GDB.
+ *      @regs: A pointer to a &struct pt_regs to hold these values in.
+ *
+ *      Convert the GDB regs in @gdb_regs into the pt_regs, and store them
+ *      in @regs.
+ */
+extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs);
+
+/*
+ *      kgdb_arch_handle_exception - Handle architecture specific GDB packets.
+ *      @vector: The error vector of the exception that happened.
+ *      @signo: The signal number of the exception that happened.
+ *      @err_code: The error code of the exception that happened.
+ *      @remcom_in_buffer: The buffer of the packet we have read.
+ *      @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into.
+ *      @regs: The &struct pt_regs of the current process.
+ *
+ *      This function MUST handle the 'c' and 's' command packets,
+ *      as well packets to set / remove a hardware breakpoint, if used.
+ *      If there are additional packets which the hardware needs to handle,
+ *      they are handled here.  The code should return -1 if it wants to
+ *      process more packets, and a %0 or %1 if it wants to exit from the
+ *      kgdb callback.
+ */
+extern int
+kgdb_arch_handle_exception(int vector, int signo, int err_code,
+                           char *remcom_in_buffer,
+                           char *remcom_out_buffer,
+                           struct pt_regs *regs);
+
+/*
+ *      kgdb_roundup_cpus - Get other CPUs into a holding pattern
+ *      @flags: Current IRQ state
+ *
+ *      On SMP systems, we need to get the attention of the other CPUs
+ *      and get them be in a known state.  This should do what is needed
+ *      to get the other CPUs to call kgdb_wait(). Note that on some arches,
+ *      the NMI approach is not used for rounding up all the CPUs. For example,
+ *      in case of MIPS, smp_call_function() is used to roundup CPUs. In
+ *      this case, we have to make sure that interrupts are enabled before
+ *      calling smp_call_function(). The argument to this function is
+ *      the flags that will be used when restoring the interrupts. There is
+ *      local_irq_save() call before kgdb_roundup_cpus().
+ *
+ *      On non-SMP systems, this is not called.
+ */
+extern void kgdb_roundup_cpus(unsigned long flags);
+
+/* Optional functions. */
+extern int kgdb_validate_break_address(unsigned long addr);
+extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr);
+extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle);
+
+/*
+ * 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.
+ * @set_breakpoint: Allow an architecture to specify how to set a software
+ * breakpoint.
+ * @remove_breakpoint: Allow an architecture to specify how to remove a
+ * software breakpoint.
+ * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware
+ * breakpoint.
+ * @remove_hw_breakpoint: Allow an architecture to specify how to remove a
+ * hardware breakpoint.
+ * @remove_all_hw_break: Allow an architecture to specify how to remove all
+ * hardware breakpoints.
+ * @correct_hw_break: Allow an architecture to specify how to correct the
+ * hardware debug registers.
+ */
+struct kgdb_arch {
+        unsigned char           gdb_bpt_instr[BREAK_INSTR_SIZE];
+        unsigned long           flags;
+
+        int     (*set_breakpoint)(unsigned long, char *);
+        int     (*remove_breakpoint)(unsigned long, char *);
+        int     (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+        int     (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype);
+        void    (*remove_all_hw_break)(void);
+        void    (*correct_hw_break)(void);
+};
+
+/*
+ * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB.
+ * @name: Name of the I/O driver.
+ * @read_char: Pointer to a function that will return one char.
+ * @write_char: Pointer to a function that will write one char.
+ * @flush: Pointer to a function that will flush any pending writes.
+ * @init: Pointer to a function that will initialize the device.
+ * @pre_exception: Pointer to a function that will do any prep work for
+ * the I/O driver.
+ * @post_exception: Pointer to a function that will do any cleanup work
+ * for the I/O driver.
+ */
+struct kgdb_io {
+        const char              *name;
+        int                     (*read_char) (void);
+        void                    (*write_char) (u8);
+        void                    (*flush) (void);
+        int                     (*init) (void);
+        void                    (*pre_exception) (void);
+        void                    (*post_exception) (void);
+};
+
+extern struct kgdb_arch         arch_kgdb_ops;
+
+extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops);
+extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops);
+
+extern int kgdb_hex2long(char **ptr, long *long_val);
+extern int kgdb_mem2hex(char *mem, char *buf, int count);
+extern int kgdb_hex2mem(char *buf, char *mem, int count);
+
+extern int kgdb_isremovedbreak(unsigned long addr);
+
+extern int
+kgdb_handle_exception(int ex_vector, int signo, int err_code,
+                      struct pt_regs *regs);
+extern int kgdb_nmicallback(int cpu, void *regs);
+
+extern int                      kgdb_single_step;
+extern atomic_t                 kgdb_active;
+
+#endif /* _KGDB_H_ */