[RFC PATCH v5 4/9] Add basic Linux kernel support

Philipp Rudo
2018-03-12T15:31:42Z

Implement the basic infrastructure and functionality to allow Linux kernel
debugging with GDB. This contains handling of kernel symbols and data
structures as well as a simple target_ops to hook into GDB. For the code
to work architectures must provide an implementation for the virtual
methods in linux_kernel_ops.

For simplicity this patch only supports static targets, i.e. core dumps.
Support for live debugging will be provided in a separate patch.

gdb/ChangeLog:

* gdbarch.sh (get_new_lk_ops): New hook.
* gdbarch.h: Regenerated.
* gdbarch.c: Regenerated.
* defs.h (gdb_osabi): Add GDB_OSABI_LINUX_KERNEL.
* osabi.c (gdb_osabi_names): Add Linux kernel entry.
* lk-low.h: New file.
* lk-low.c: New file.
* lk-list.h: New file.
* lk-bitmap.h: New file.
* Makefile.in (ALLDEPFILES): Add lk-low.c.
(HFILES_NO_SRCDIR): Add lk-low.h.
(ALL_TARGET_OBS): Add lk-low.o.
* configure.tgt (lk_tobjs): New variable with object files for Linux
kernel support.
(s390*-*-linux*): Add lk_tobjs.
---
gdb/Makefile.in | 3 +
gdb/configure.tgt | 7 +-
gdb/defs.h | 1 +
gdb/gdbarch.c | 32 ++
gdb/gdbarch.h | 9 +
gdb/gdbarch.sh | 4 +
gdb/lk-bitmap.h | 226 ++++++++++++++
gdb/lk-list.h | 201 +++++++++++++
gdb/lk-low.c | 864 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
gdb/lk-low.h | 335 +++++++++++++++++++++
gdb/osabi.c | 1 +
11 files changed, 1682 insertions(+), 1 deletion(-)
create mode 100644 gdb/lk-bitmap.h
create mode 100644 gdb/lk-list.h
create mode 100644 gdb/lk-low.c
create mode 100644 gdb/lk-low.h

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 690653ac04..056333e2cd 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -715,6 +715,7 @@ ALL_TARGET_OBS = \
iq2000-tdep.o \
linux-record.o \
linux-tdep.o \
+ lk-low.o \
lm32-tdep.o \
m32c-tdep.o \
m32r-linux-tdep.o \
@@ -1276,6 +1277,7 @@ HFILES_NO_SRCDIR = \
linux-nat.h \
linux-record.h \
linux-tdep.h \
+ lk-low.h \
location.h \
m2-lang.h \
m32r-tdep.h \
@@ -2256,6 +2258,7 @@ ALLDEPFILES = \
linux-fork.c \
linux-record.c \
linux-tdep.c \
+ lk-low.c \
lm32-tdep.c \
m32r-linux-nat.c \
m32r-linux-tdep.c \
diff --git a/gdb/configure.tgt b/gdb/configure.tgt
index ba90411782..be68ac50fc 100644
--- a/gdb/configure.tgt
+++ b/gdb/configure.tgt
@@ -40,6 +40,10 @@ esac
i386_tobjs="i386-tdep.o arch/i386.o i387-tdep.o"
amd64_tobjs="amd64-tdep.o arch/amd64.o"

+# List of objectfiles for Linux kernel support. To be included into *-linux*
+# targets wich support Linux kernel debugging.
+lk_tobjs="lk-low.o"
+
# Here are three sections to get a list of target specific object
# files according to target triplet $TARG.

@@ -516,7 +520,8 @@ powerpc*-*-*)
s390*-*-linux*)
# Target: S390 running Linux
gdb_target_obs="s390-linux-tdep.o s390-tdep.o solib-svr4.o \
- linux-tdep.o linux-record.o symfile-mem.o"
+ linux-tdep.o linux-record.o symfile-mem.o \
+ ${lk_tobjs}"
build_gdbserver=yes
;;

diff --git a/gdb/defs.h b/gdb/defs.h
index 91988758a3..692a7b8407 100644
--- a/gdb/defs.h
+++ b/gdb/defs.h
@@ -490,6 +490,7 @@ enum gdb_osabi
GDB_OSABI_HURD,
GDB_OSABI_SOLARIS,
GDB_OSABI_LINUX,
+ GDB_OSABI_LINUX_KERNEL,
GDB_OSABI_FREEBSD,
GDB_OSABI_NETBSD,
GDB_OSABI_OPENBSD,
diff --git a/gdb/gdbarch.c b/gdb/gdbarch.c
index b8703e5a55..fd37c51f6b 100644
--- a/gdb/gdbarch.c
+++ b/gdb/gdbarch.c
@@ -352,6 +352,7 @@ struct gdbarch
gdbarch_addressable_memory_unit_size_ftype *addressable_memory_unit_size;
char ** disassembler_options;
const disasm_options_t * valid_disassembler_options;
+ gdbarch_get_new_lk_ops_ftype *get_new_lk_ops;
};

/* Create a new ``struct gdbarch'' based on information provided by
@@ -713,6 +714,7 @@ verify_gdbarch (struct gdbarch *gdbarch)
/* Skip verify of addressable_memory_unit_size, invalid_p == 0 */
/* Skip verify of disassembler_options, invalid_p == 0 */
/* Skip verify of valid_disassembler_options, invalid_p == 0 */
+ /* Skip verify of get_new_lk_ops, has predicate. */
if (!log.empty ())
internal_error (__FILE__, __LINE__,
_("verify_gdbarch: the following are invalid ...%s"),
@@ -1058,6 +1060,12 @@ gdbarch_dump (struct gdbarch *gdbarch, struct ui_file *file)
"gdbarch_dump: get_longjmp_target = <%s>\n",
host_address_to_string (gdbarch->get_longjmp_target));
fprintf_unfiltered (file,
+ "gdbarch_dump: gdbarch_get_new_lk_ops_p() = %d\n",
+ gdbarch_get_new_lk_ops_p (gdbarch));
+ fprintf_unfiltered (file,
+ "gdbarch_dump: get_new_lk_ops = <%s>\n",
+ host_address_to_string (gdbarch->get_new_lk_ops));
+ fprintf_unfiltered (file,
"gdbarch_dump: gdbarch_get_siginfo_type_p() = %d\n",
gdbarch_get_siginfo_type_p (gdbarch));
fprintf_unfiltered (file,
@@ -5077,6 +5085,30 @@ set_gdbarch_valid_disassembler_options (struct gdbarch *gdbarch,
gdbarch->valid_disassembler_options = valid_disassembler_options;
}

+int
+gdbarch_get_new_lk_ops_p (struct gdbarch *gdbarch)
+{
+ gdb_assert (gdbarch != NULL);
+ return gdbarch->get_new_lk_ops != NULL;
+}
+
+linux_kernel_ops *
+gdbarch_get_new_lk_ops (struct gdbarch *gdbarch, struct target_ops *target)
+{
+ gdb_assert (gdbarch != NULL);
+ gdb_assert (gdbarch->get_new_lk_ops != NULL);
+ if (gdbarch_debug >= 2)
+ fprintf_unfiltered (gdb_stdlog, "gdbarch_get_new_lk_ops called\n");
+ return gdbarch->get_new_lk_ops (gdbarch, target);
+}
+
+void
+set_gdbarch_get_new_lk_ops (struct gdbarch *gdbarch,
+ gdbarch_get_new_lk_ops_ftype get_new_lk_ops)
+{
+ gdbarch->get_new_lk_ops = get_new_lk_ops;
+}
+

/* Keep a registry of per-architecture data-pointers required by GDB
modules. */
diff --git a/gdb/gdbarch.h b/gdb/gdbarch.h
index 5cb131de1d..d1f54c08c9 100644
--- a/gdb/gdbarch.h
+++ b/gdb/gdbarch.h
@@ -65,6 +65,7 @@ struct mem_range;
struct syscalls_info;
struct thread_info;
struct ui_out;
+class linux_kernel_ops;

#include "regcache.h"

@@ -1554,6 +1555,14 @@ extern void set_gdbarch_disassembler_options (struct gdbarch *gdbarch, char ** d
extern const disasm_options_t * gdbarch_valid_disassembler_options (struct gdbarch *gdbarch);
extern void set_gdbarch_valid_disassembler_options (struct gdbarch *gdbarch, const disasm_options_t * valid_disassembler_options);

+/* Return a new instance of a class inherited from linux_kernel_ops */
+
+extern int gdbarch_get_new_lk_ops_p (struct gdbarch *gdbarch);
+
+typedef linux_kernel_ops * (gdbarch_get_new_lk_ops_ftype) (struct gdbarch *gdbarch, struct target_ops *target);
+extern linux_kernel_ops * gdbarch_get_new_lk_ops (struct gdbarch *gdbarch, struct target_ops *target);
+extern void set_gdbarch_get_new_lk_ops (struct gdbarch *gdbarch, gdbarch_get_new_lk_ops_ftype *get_new_lk_ops);
+
/* Definition for an unknown syscall, used basically in error-cases. */
#define UNKNOWN_SYSCALL (-1)

diff --git a/gdb/gdbarch.sh b/gdb/gdbarch.sh
index 33dfa6b349..80167f2dc2 100755
--- a/gdb/gdbarch.sh
+++ b/gdb/gdbarch.sh
@@ -1160,6 +1160,9 @@ m;int;addressable_memory_unit_size;void;;;default_addressable_memory_unit_size;;
v;char **;disassembler_options;;;0;0;;0;pstring_ptr (gdbarch->disassembler_options)
v;const disasm_options_t *;valid_disassembler_options;;;0;0;;0;host_address_to_string (gdbarch->valid_disassembler_options)

+# Return a new instance of a class inherited from linux_kernel_ops
+M;linux_kernel_ops *;get_new_lk_ops;struct target_ops *target;target
+
EOF
}

@@ -1285,6 +1288,7 @@ struct mem_range;
struct syscalls_info;
struct thread_info;
struct ui_out;
+class linux_kernel_ops;

#include "regcache.h"

diff --git a/gdb/lk-bitmap.h b/gdb/lk-bitmap.h
new file mode 100644
index 0000000000..1247e7f9fb
--- /dev/null
+++ b/gdb/lk-bitmap.h
@@ -0,0 +1,226 @@
+/* Iterator for bitmaps from the Linux kernel.
+
+ Copyright (C) 2017 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 3 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, see <http://www.gnu.org/licenses/>. */
+
+#ifndef __LK_BITMAP_H__
+#define __LK_BITMAP_H__
+
+#include "defs.h"
+
+#include "lk-low.h"
+
+/* Short hand access to frequently used bitmap. */
+#define lk_cpu_online_mask lk_bitmap ("cpu_online_mask", "cpumask->bits")
+
+/* Container class to handle bitmaps declared with DECLARE_BITMAP from
+ <linux>/include/linux/types.h. */
+
+class lk_bitmap
+{
+public:
+
+ template<class T>
+ class base_iterator
+ : public std::iterator<std::bidirectional_iterator_tag, T>
+ {
+ public:
+ base_iterator (const base_iterator<T> &it) = default;
+ base_iterator (std::vector<unsigned long>::const_iterator start,
+ size_t bit, size_t size)
+ : m_start (start), m_bit (bit), m_size (size)
+ { next (); }
+
+ base_iterator<T> &operator++ ()
+ { m_bit++; return next (); }
+
+ base_iterator<T> operator++ (int)
+ { base_iterator<T> retval = *this; ++(*this); return retval; }
+
+ base_iterator<T> &operator-- ()
+ { m_bit--; return prev (); }
+
+ base_iterator<T> operator-- (int)
+ { base_iterator<T> retval = *this; --(*this); return retval; }
+
+ bool operator== (base_iterator<T> other) const
+ { return (m_start == other.m_start && m_bit == other.m_bit
+ && m_size == other.m_size); }
+
+ bool operator!= (base_iterator<T> other) const
+ { return !(*this == other); }
+
+ T operator* () const
+ { return m_bit; }
+
+ private:
+ /* Start of the vector containing the bitmap. */
+ std::vector<unsigned long>::const_iterator m_start;
+
+ /* Last set bit returned. */
+ size_t m_bit;
+
+ /* Size of the bitmap in bit. */
+ size_t m_size;
+
+ /* Get next set bit. */
+ base_iterator<T> &next ();
+
+ /* Get previous set bit. */
+ base_iterator<T> &prev ();
+ }; /* class base_iterator */
+
+ /* Constructor for bitmaps defined as variable NAME. */
+ inline lk_bitmap (const std::string &name);
+
+ /* Constructor for bitmaps defined as field in variable NAME. */
+ inline lk_bitmap (const std::string &name, const std::string &alias);
+
+ typedef base_iterator<size_t> iterator;
+ typedef base_iterator<const size_t> const_iterator;
+
+ iterator begin () { return iterator (m_bitmap.cbegin (), 0, size ()); }
+ iterator end () { return iterator (m_bitmap.cbegin (), size (), size ()); }
+
+ const_iterator cbegin () const
+ { return const_iterator (m_bitmap.cbegin (), 0, size ()); }
+ const_iterator cend () const
+ { return const_iterator (m_bitmap.cbegin (), size (), size ()); }
+
+ const_iterator begin () const
+ { return this->cbegin (); }
+ const_iterator end () const
+ { return this->cend (); }
+
+ /* Returns size of bitmap in bits. */
+ inline size_t size () const;
+
+ /* Returns Hamming weight, i.e. number of set bits, of bitmap. */
+ inline size_t hweight () const;
+
+private:
+ /* Read content of bitmap NAME. */
+ inline void read (const std::string &name);
+
+ /* Returns number of unsigned longs needed to store N bytes. */
+ inline size_t byte_to_ulong (size_t n) const;
+
+ /* Storage for content of bitmap. */
+ std::vector<unsigned long> m_bitmap;
+}; /* class bitmap */
+
+/* see declaration. */
+
+template<class T>
+lk_bitmap::base_iterator<T> &
+lk_bitmap::base_iterator<T>::next ()
+{
+ size_t ulong_bits = lk_builtin_type_size (unsigned_long) * LK_BITS_PER_BYTE;
+ auto ulong = m_start + m_bit / ulong_bits;
+ while (m_bit < m_size)
+ {
+ if (*ulong & (1 << m_bit))
+ return *this;
+
+ m_bit++;
+ if ((m_bit % ulong_bits) == 0)
+ ulong++;
+ }
+ return *this;
+}
+
+/* see declaration. */
+
+template<class T>
+lk_bitmap::base_iterator<T> &
+lk_bitmap::base_iterator<T>::prev ()
+{
+ size_t ulong_bits = lk_builtin_type_size (unsigned_long) * LK_BITS_PER_BYTE;
+ auto ulong = m_start + m_bit / ulong_bits;
+ while (m_bit > m_size)
+ {
+ if (*ulong & (1 << m_bit))
+ return *this;
+
+ m_bit--;
+ if ((m_bit % ulong_bits) == 0)
+ ulong--;
+ }
+ return *this;
+}
+
+/* see declaration. */
+
+lk_bitmap::lk_bitmap (const std::string &name)
+{
+ symbol *sym = lookup_symbol (name.c_str (), NULL, VAR_DOMAIN, NULL).symbol;
+ size_t size = TYPE_LENGTH (check_typedef (SYMBOL_TYPE (sym)));
+
+ m_bitmap.resize (byte_to_ulong (size));
+ read (name);
+}
+
+/* see declaration. */
+
+lk_bitmap::lk_bitmap (const std::string &name, const std::string &alias)
+{
+ field *field = lk_field (alias);
+ m_bitmap.resize (byte_to_ulong (FIELD_SIZE (field)));
+ read (name);
+}
+
+/* see declaration. */
+
+void
+lk_bitmap::read (const std::string &name)
+{
+ size_t ulong_size = lk_builtin_type_size (unsigned_long);
+ CORE_ADDR addr = lk_address (name);
+
+ for (size_t i = 0; i < m_bitmap.size (); i++)
+ m_bitmap[i] = lk_read_ulong (addr + i * ulong_size);
+}
+
+/* see declaration. */
+size_t
+lk_bitmap::byte_to_ulong (size_t n) const
+{
+ size_t ulong_size = lk_builtin_type_size (unsigned_long);
+ return (n + ulong_size - 1) / ulong_size;
+}
+
+/* see declaration. */
+
+size_t
+lk_bitmap::size () const
+{
+ size_t ulong_size = lk_builtin_type_size (unsigned_long);
+ return (m_bitmap.size () * ulong_size * LK_BITS_PER_BYTE);
+}
+
+/* see declaration. */
+
+size_t
+lk_bitmap::hweight () const
+{
+ size_t ret = 0;
+ for (auto bit : *this)
+ ret++;
+ return ret;
+}
+
+#endif /* __LK_BITMAP_H__ */
diff --git a/gdb/lk-list.h b/gdb/lk-list.h
new file mode 100644
index 0000000000..512a47ba08
--- /dev/null
+++ b/gdb/lk-list.h
@@ -0,0 +1,201 @@
+/* Iterators for internal data structures of the Linux kernel.
+
+ Copyright (C) 2016 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 3 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, see <http://www.gnu.org/licenses/>. */
+
+#ifndef __LK_LIST_H__
+#define __LK_LIST_H__
+
+#include "defs.h"
+
+#include "inferior.h"
+#include "lk-low.h"
+
+
+/* Container class to handle doubly linked list using struct list_head from
+ <linux>/include/linux/types.h . */
+
+class lk_list
+{
+ template<class T>
+ class base_iterator
+ : public std::iterator<std::bidirectional_iterator_tag, T>
+ {
+ public:
+ base_iterator (const base_iterator<T> &it) = default;
+ base_iterator (CORE_ADDR start, CORE_ADDR offset, bool embedded)
+ : m_current (start), m_start (start), m_offset (offset)
+ {
+ if (!embedded)
+ next ();
+ }
+
+ base_iterator<T> &operator++ ()
+ { return next (); }
+
+ base_iterator<T> operator++ (int)
+ { base_iterator<T> retval = *this; ++(*this); return retval; }
+
+ base_iterator<T> &operator-- ()
+ { return next (false); }
+
+ base_iterator<T> operator-- (int)
+ { base_iterator<T> retval = *this; --(*this); return retval; }
+
+ bool operator== (base_iterator<T> &other) const
+ { return (m_start == other.m_start && m_current == other.m_current
+ && !m_first); }
+
+ bool operator!= (base_iterator<T> &other) const
+ { return !(*this == other); }
+
+ /* Return container of the list_head. */
+ T operator* () const
+ { return m_current - m_offset; }
+
+ private:
+ /* The list_head we are currently at. */
+ CORE_ADDR m_current;
+
+ /* First element of the list. */
+ CORE_ADDR m_start;
+
+ /* Offset of the list_head in the containing struct. */
+ CORE_ADDR m_offset;
+
+ /* For doubly linked lists start == end. Use m_first to track if we
+ just started. */
+ bool m_first = true;
+
+ /* Go to the next (forward) or prev (!forward) element. */
+ base_iterator<T> &next (bool forward = true);
+
+ /* We must always assume that the data we handle is corrupted. Use
+ curr->next->prev == curr (or ->prev->next if goining back). */
+ bool is_valid_next (CORE_ADDR next, bool forward) const;
+ }; /* class base_iterator */
+
+public:
+ /* Constructor for lists starting at address START. */
+ inline lk_list (CORE_ADDR start, const std::string &alias,
+ bool embedded = true);
+
+ /* Constructor for lists starting at variable NAME. */
+ inline lk_list (const std::string &name, const std::string &alias)
+ : lk_list (lk_address (name), alias, is_embedded (name))
+ {}
+
+ typedef base_iterator<CORE_ADDR> iterator;
+ typedef base_iterator<const CORE_ADDR> const_iterator;
+
+ /* Never advance to next element for end () --> embedded = true. */
+ iterator begin () { return iterator (m_start, m_offset, m_embedded); }
+ iterator end () { return iterator (m_start, m_offset, true); }
+
+ const_iterator cbegin () const
+ { return const_iterator (m_start, m_offset, m_embedded); }
+ const_iterator cend () const
+ { return const_iterator (m_start, m_offset, true); }
+
+ const_iterator begin () const
+ { return this->cbegin (); }
+ const_iterator end () const
+ { return this->cend (); }
+
+private:
+ /* First element of the list. */
+ CORE_ADDR m_start;
+
+ /* Offset of the list_head in the containing struct. */
+ CORE_ADDR m_offset;
+
+ /* Is the first list_head embedded in the containing struct, i.e. do we
+ have to consider m_start as a full element of the list or just an entry
+ point? */
+ bool m_embedded;
+
+ /* Check whether variable name is embeded, i.e. is not a list_head. */
+ inline bool is_embedded (const std::string &name) const;
+}; /* class lk_list */
+
+/* see declaration. */
+
+lk_list::lk_list (CORE_ADDR start, const std::string &alias, bool embedded)
+ : m_offset (lk_offset (alias)), m_embedded (embedded)
+{
+ m_start = start;
+ if (m_embedded)
+ m_start += m_offset;
+}
+
+/* see declaration. */
+
+bool
+lk_list::is_embedded (const std::string &name) const
+{
+ symbol *sym = lookup_symbol (name.c_str (), NULL, VAR_DOMAIN, NULL).symbol;
+ type *type = SYMBOL_TYPE (sym);
+
+ return !(TYPE_CODE (type) == TYPE_CODE_STRUCT
+ && streq ("list_head", TYPE_TAG_NAME (type)));
+}
+
+/* see declaration. */
+
+template<class T>
+bool
+lk_list::base_iterator<T>::is_valid_next (CORE_ADDR next, bool forward) const
+{
+ if (forward)
+ next += lk_offset ("list_head->prev");
+ else
+ next += lk_offset ("list_head->next");
+
+ return m_current == lk_read_addr (next);
+}
+
+/* see declaration. */
+
+template<class T>
+lk_list::base_iterator<T> &
+lk_list::base_iterator<T>::next (bool forward)
+{
+ CORE_ADDR next;
+
+ if (m_current == m_start && !m_first)
+ return *this;
+
+ m_first = false;
+
+ if (forward)
+ next = lk_read_addr (m_current + lk_offset ("list_head->next"));
+ else
+ next = lk_read_addr (m_current + lk_offset ("list_head->prev"));
+
+ if (!is_valid_next (next, forward))
+ {
+ error (_("Memory corruption detected while iterating list_head at "
+ "0x%s: list_head->%s != list_head."),
+ phex (m_current, lk_builtin_type_size (unsigned_long)),
+ forward ? "next->prev" : "prev->next");
+ }
+
+ m_current = next;
+
+ return *this;
+}
+#endif /* __LK_LIST_H__ */
diff --git a/gdb/lk-low.c b/gdb/lk-low.c
new file mode 100644
index 0000000000..193619e6f5
--- /dev/null
+++ b/gdb/lk-low.c
@@ -0,0 +1,864 @@
+/* Basic Linux kernel support, architecture independent.
+
+ Copyright (C) 2016 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 3 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, see <http://www.gnu.org/licenses/>. */
+
+#include "defs.h"
+
+#include "block.h"
+#include "exceptions.h"
+#include "frame.h"
+#include "gdbarch.h"
+#include "gdbcore.h"
+#include "gdbthread.h"
+#include "gdbtypes.h"
+#include "inferior.h"
+#include "lk-bitmap.h"
+#include "lk-list.h"
+#include "lk-low.h"
+#include "objfiles.h"
+#include "observer.h"
+#include "solib.h"
+#include "target.h"
+#include "value.h"
+
+#include <algorithm>
+
+target_ops *lk_target_ops = NULL;
+linux_kernel_ops *lk_ops = NULL;
+
+/* Helper function for declare_address. Returns address of variable NAME on
+ success or -1 on failure. */
+
+static CORE_ADDR
+lk_find_address (const std::string &name)
+{
+ bound_minimal_symbol bmsym = lookup_minimal_symbol (name.c_str (), NULL,
+ NULL);
+ if (bmsym.minsym == NULL)
+ return -1;
+
+ return BMSYMBOL_VALUE_ADDRESS (bmsym);
+}
+
+/* See lk-low.h. */
+
+bool
+linux_kernel_ops::try_declare_address (const std::string &alias,
+ const std::string &name)
+{
+ if (has_address (alias))
+ return true;
+
+ CORE_ADDR addr = lk_find_address (name);
+ if (addr == -1)
+ return false;
+
+ m_symbols[alias].addr = addr;
+ return true;
+}
+
+/* See lk-low.h. */
+
+void
+linux_kernel_ops::declare_address (const std::string &alias,
+ const std::string &name,
+ const lk_kconfig config)
+{
+ if (!try_declare_address (alias, name))
+ {
+ m_kconfig |= config;
+ warning (_("Missing address: %s"), alias.c_str ());
+ }
+}
+
+/* See lk-low.h. */
+
+void
+linux_kernel_ops::declare_address (const std::string &alias,
+ const std::initializer_list<const std::string> names,
+ const lk_kconfig config)
+{
+ for (auto &name: names)
+ if (try_declare_address (alias, name))
+ break;
+
+ if (!has_address (alias))
+ {
+ m_kconfig |= config;
+ warning (_("Missing address: %s"), alias.c_str ());
+ }
+}
+
+/* Helper function for try_declare_type. Returns type on success or NULL on
+ failure */
+
+static struct type *
+lk_find_type (const std::string &name)
+{
+ const struct block *global;
+ const struct symbol *sym;
+
+ global = block_global_block(get_selected_block (0));
+ sym = lookup_symbol (name.c_str (), global, STRUCT_DOMAIN, NULL).symbol;
+ if (sym != NULL)
+ return SYMBOL_TYPE (sym);
+
+ /* Chek for "typedef struct { ... } name;"-like definitions. */
+ sym = lookup_symbol (name.c_str (), global, VAR_DOMAIN, NULL).symbol;
+ if (sym == NULL)
+ return NULL;
+
+ struct type *type = check_typedef (SYMBOL_TYPE (sym));
+ if (TYPE_CODE (type) != TYPE_CODE_STRUCT)
+ return NULL;
+
+ return type;
+}
+
+/* See lk-low.h. */
+
+bool
+linux_kernel_ops::try_declare_type (const std::string &alias,
+ const std::string &name)
+{
+ if (has_type (alias))
+ return true;
+
+ struct type *type = lk_find_type (name);
+
+ if (type == NULL)
+ return false;
+
+ m_symbols[unique_type_alias (alias)].type = type;
+
+ /* Also add an entry with the name actually used to m_symbol. Needed to
+ support chained field lookup. */
+ if (alias != name)
+ m_symbols[unique_type_alias (name)].type = type;
+
+ return true;
+}
+
+/* See lk-low.h. */
+
+void
+linux_kernel_ops::declare_type (const std::string &alias,
+ const std::string &name,
+ const lk_kconfig config)
+{
+ if (!try_declare_type (alias, name))
+ {
+ m_kconfig |= config;
+ warning (_("Missing type: %s"), unique_type_alias (alias).c_str ());
+ }
+}
+
+/* See lk-low.h. */
+
+void
+linux_kernel_ops::declare_type (const std::string &alias,
+ const std::initializer_list<const std::string> names,
+ const lk_kconfig config)
+{
+ for (auto &name: names)
+ if (try_declare_type (alias, name))
+ break;
+
+ if (!has_type (alias))
+ {
+ m_kconfig |= config;
+ warning (_("Missing type: %s"), unique_type_alias (alias).c_str ());
+ }
+}
+
+/* Helper function for try_declare_field. Returns lk_symbol with field
+ belonging to TYPE on success or empty on failure. */
+
+static lk_symbol
+lk_find_field (const std::string &f_name, const struct type *type)
+{
+ struct field *field = TYPE_FIELDS (type);
+ struct field *last = field + TYPE_NFIELDS (type);
+
+ while (field != last)
+ {
+ if (streq (field->name, f_name.c_str ()))
+ return lk_symbol (field, FIELD_BYTEPOS (field));
+
+ /* Check if field is defined in anonymous struct within TYPE. */
+ if (streq (field->name, ""))
+ {
+ lk_symbol sym = lk_find_field (f_name, FIELD_TYPE (*field));
+ if (sym.field != NULL)
+ return lk_symbol (sym.field, FIELD_BYTEPOS (field) + sym.offset);
+ }
+ field++;
+ }
+ return lk_symbol ();
+}
+
+/* Helper class to parse C-like field names (type->field1->field2->...) and
+ generate aliases used in lk_ops->m_symbols. */
+
+class lk_field_parser
+{
+public:
+ lk_field_parser (const std::string &alias)
+ : m_alias (alias)
+ {
+ /* The alias must begin with s_name->f_name of the first field. */
+ m_end = m_alias.find (delim);
+ gdb_assert (m_end != std::string::npos);
+ m_end = m_alias.find (delim, m_end + delim.size ());
+ }
+
+ /* Return the struct, i.e. type name of the current field. */
+ std::string s_name () const
+ {
+ if (m_last_type == NULL)
+ return m_alias.substr (0, m_alias.find (delim));
+
+ if (TYPE_CODE (m_last_type) == TYPE_CODE_TYPEDEF)
+ return TYPE_NAME (m_last_type);
+ else
+ return TYPE_TAG_NAME (m_last_type);
+ }
+
+ /* Return the field name of the current field. */
+ std::string f_name () const
+ {
+ size_t start;
+
+ if (m_last_type == NULL)
+ start = m_alias.find (delim) + delim.size ();
+ else
+ start = m_start;
+
+ return m_alias.substr (start, m_end - start);
+ }
+
+ /* Return the full name of the current field. */
+ std::string name () const
+ { return s_name () + delim + f_name (); }
+
+ /* Advance to the next field. */
+ lk_field_parser *next ()
+ {
+ gdb_assert (!empty ());
+
+ m_last_type = FIELD_TYPE (*lk_field (name ()));
+ m_start = m_end + delim.size ();
+ m_end = m_alias.find (delim, m_start);
+
+ return this;
+ }
+
+ /* True when all fiels have been parsed. */
+ bool empty () const
+ { return m_end == std::string::npos; }
+
+ /* Return the depth, i.e. number of fields, in m_alias. */
+ unsigned int depth () const
+ {
+ size_t pos = m_alias.find (delim);
+ unsigned int ret = 0;
+
+ while (pos != std::string::npos)
+ {
+ ret ++;
+ pos = m_alias.find (delim, pos + delim.size ());
+ }
+
+ return ret;
+ }
+
+private:
+ /* Alias originally passed to parser. */
+ std::string m_alias;
+
+ /* First index of current field in m_alias. */
+ size_t m_start = 0;
+
+ /* Last index of current field in m_alias. */
+ size_t m_end = 0;
+
+ /* Type of the last field found. Needed to get s_name of embedded
+ fields. */
+ struct type *m_last_type = NULL;
+
+ /* Delemiter used to separate fields. */
+ const std::string delim = "->";
+};
+
+/* See lk-low.h. */
+
+bool
+linux_kernel_ops::try_declare_field (const std::string &orig_alias,
+ const std::string &orig_name)
+{
+ if (has_field (orig_alias))
+ return true;
+
+ lk_field_parser alias (orig_alias);
+ lk_field_parser name (orig_name);
+
+ /* Only allow declaration of one field at a time. */
+ gdb_assert (alias.depth () == 1);
+ gdb_assert (name.depth () == 1);
+
+ if (!try_declare_type (alias.s_name (), name.s_name ()))
+ return false;
+
+ lk_symbol field = lk_find_field (name.f_name (), type (alias.s_name ()));
+ if (field.field == NULL)
+ return false;
+
+ m_symbols[alias.name ()] = field;
+ return true;
+}
+
+/* See lk-low.h. */
+
+void
+linux_kernel_ops::declare_field (const std::string &alias,
+ const std::string &name,
+ const lk_kconfig config)
+{
+ if (!try_declare_field (alias, name))
+ {
+ m_kconfig |= config;
+ warning (_("Missing field: %s"), alias.c_str ());
+ }
+}
+
+/* See lk-low.h. */
+
+void
+linux_kernel_ops::declare_field (const std::string &alias,
+ const std::initializer_list<const std::string> names,
+ const lk_kconfig config)
+{
+ for (auto &name: names)
+ if (try_declare_field (alias, name))
+ break;
+
+ if (!has_field (alias))
+ {
+ m_kconfig |= config;
+ warning (_("Missing field: %s"), alias.c_str ());
+ }
+}
+
+/* See lk-low.h. */
+
+void
+linux_kernel_ops::read_symbols ()
+{
+ if (!m_symbols.empty ())
+ m_symbols.clear ();
+
+ declare_field ("task_struct->tasks", LK_CONFIG_ALWAYS);
+ declare_field ("task_struct->pid", LK_CONFIG_ALWAYS);
+ declare_field ("task_struct->tgid", LK_CONFIG_ALWAYS);
+ declare_field ("task_struct->thread_group", LK_CONFIG_ALWAYS);
+ declare_field ("task_struct->comm", LK_CONFIG_ALWAYS);
+ declare_field ("task_struct->thread", LK_CONFIG_ALWAYS);
+
+ declare_field ("list_head->next", LK_CONFIG_ALWAYS);
+ declare_field ("list_head->prev", LK_CONFIG_ALWAYS);
+
+ declare_field ("rq->curr", LK_CONFIG_ALWAYS);
+
+ declare_field ("cpumask->bits", LK_CONFIG_ALWAYS);
+
+ declare_address ("init_task", LK_CONFIG_ALWAYS);
+ declare_address ("runqueues", LK_CONFIG_ALWAYS);
+ declare_address ("__per_cpu_offset", LK_CONFIG_ALWAYS);
+
+ declare_address ("cpu_online_mask", {"__cpu_online_mask", /* linux 4.5+ */
+ "cpu_online_bits"}, /* linux -4.4 */
+ LK_CONFIG_ALWAYS);
+
+ arch_read_symbols ();
+
+ if (!ifdef (LK_CONFIG_ALWAYS))
+ error (_("Could not find all symbols needed. Aborting."));
+}
+
+/* See lk-low.h. */
+
+CORE_ADDR
+linux_kernel_ops::offset (const std::string &orig_alias) const
+{
+ lk_field_parser alias (orig_alias);
+ CORE_ADDR ret = m_symbols.at (alias.name ()).offset;
+
+ while (!alias.empty ())
+ ret += m_symbols.at (alias.next ()->name ()).offset;
+
+ return ret;
+}
+
+/* Map cpu number CPU to the original PTID from target beneath. */
+
+static ptid_t
+lk_cpu_to_old_ptid (const unsigned int cpu)
+{
+ struct lk_ptid_map *ptid_map;
+
+ for (ptid_map = lk_ops->old_ptid; ptid_map;
+ ptid_map = ptid_map->next)
+ {
+ if (ptid_map->cpu == cpu)
+ return ptid_map->old_ptid;
+ }
+
+ error (_("Could not map CPU %d to original PTID. Aborting."), cpu);
+}
+
+/* Helper functions to read and return basic types at a given ADDRess. */
+
+/* Read and return the integer value at address ADDR. */
+
+int
+lk_read_int (CORE_ADDR addr)
+{
+ size_t int_size = lk_builtin_type_size (int);
+ enum bfd_endian endian = gdbarch_byte_order (current_inferior ()->gdbarch);
+ return read_memory_integer (addr, int_size, endian);
+}
+
+/* Read and return the unsigned integer value at address ADDR. */
+
+unsigned int
+lk_read_uint (CORE_ADDR addr)
+{
+ size_t uint_size = lk_builtin_type_size (unsigned_int);
+ enum bfd_endian endian = gdbarch_byte_order (current_inferior ()->gdbarch);
+ return read_memory_unsigned_integer (addr, uint_size, endian);
+}
+
+/* Read and return the long integer value at address ADDR. */
+
+LONGEST
+lk_read_long (CORE_ADDR addr)
+{
+ size_t long_size = lk_builtin_type_size (long);
+ enum bfd_endian endian = gdbarch_byte_order (current_inferior ()->gdbarch);
+ return read_memory_integer (addr, long_size, endian);
+}
+
+/* Read and return the unsigned long integer value at address ADDR. */
+
+ULONGEST
+lk_read_ulong (CORE_ADDR addr)
+{
+ size_t ulong_size = lk_builtin_type_size (unsigned_long);
+ enum bfd_endian endian = gdbarch_byte_order (current_inferior ()->gdbarch);
+ return read_memory_unsigned_integer (addr, ulong_size, endian);
+}
+
+/* Read and return the address value at address ADDR. */
+
+CORE_ADDR
+lk_read_addr (CORE_ADDR addr)
+{
+ return (CORE_ADDR) lk_read_ulong (addr);
+}
+
+/* See lk-low.h. */
+
+CORE_ADDR
+linux_kernel_ops::percpu_offset (unsigned int cpu)
+{
+ size_t ulong_size = lk_builtin_type_size (unsigned_long);
+ CORE_ADDR percpu_elt = address ("__per_cpu_offset") + (ulong_size * cpu);
+ return lk_read_addr (percpu_elt);
+}
+
+/* See lk-low.h. */
+
+unsigned int
+linux_kernel_ops::beneath_thread_to_cpu (thread_info *ti)
+{
+ for (unsigned int cpu : lk_cpu_online_mask)
+ {
+ CORE_ADDR rq = address ("runqueues") + percpu_offset (cpu);
+ CORE_ADDR curr = lk_read_addr (rq + offset ("rq->curr"));
+ int pid = lk_read_int (curr + offset ("task_struct->pid"));
+
+ if (pid == ti->ptid.lwp ())
+ return cpu;
+ }
+
+ error (_("Could not map thread with pid %d, lwp %lu to a cpu."),
+ ti->ptid.pid (), ti->ptid.lwp ());
+}
+
+/* Test if a given task TASK is running. See comment in lk-low.h for
+ details. */
+
+unsigned int
+lk_task_running (CORE_ADDR task)
+{
+ for (unsigned int cpu : lk_cpu_online_mask)
+ {
+ CORE_ADDR rq = lk_address ("runqueues") + lk_ops->percpu_offset (cpu);
+ CORE_ADDR curr = lk_read_addr (rq + lk_offset ("rq->curr"));
+
+ if (curr == task)
+ return cpu;
+ }
+
+ return LK_CPU_INVAL;
+}
+
+/* Update running tasks with information from struct rq->curr. */
+
+static void
+lk_update_running_tasks ()
+{
+ for (unsigned int cpu : lk_cpu_online_mask)
+ {
+ CORE_ADDR rq = lk_address ("runqueues") + lk_ops->percpu_offset (cpu);
+ CORE_ADDR curr = lk_read_addr (rq + lk_offset ("rq->curr"));
+ int pid = lk_read_int (curr + lk_offset ("task_struct->pid"));
+ int inf_pid = current_inferior ()->pid;
+
+ ptid_t new_ptid (inf_pid, pid, curr);
+ ptid_t old_ptid = lk_cpu_to_old_ptid (cpu); /* FIXME not suitable for
+ running targets? */
+
+ thread_info *tp = find_thread_ptid (old_ptid);
+ if (tp && tp->state != THREAD_EXITED)
+ thread_change_ptid (old_ptid, new_ptid);
+ }
+}
+
+/* Update sleeping tasks by walking the task_structs starting from
+ init_task. */
+
+static void
+lk_update_sleeping_tasks ()
+{
+ int inf_pid = current_inferior ()->pid;
+
+ for (CORE_ADDR task : lk_list ("init_task", "task_struct->tasks"))
+ {
+ for (CORE_ADDR thread : lk_list (task, "task_struct->thread_group"))
+ {
+ int pid = lk_read_int (thread + lk_offset ("task_struct->pid"));
+ ptid_t ptid (inf_pid, pid, thread);
+
+ thread_info *tp = find_thread_ptid (ptid);
+ if (tp == NULL || tp->state == THREAD_EXITED)
+ add_thread (ptid);
+ }
+ }
+}
+
+/* Function for targets to_update_thread_list hook. */
+
+static void
+lk_update_thread_list (struct target_ops *target)
+{
+ prune_threads ();
+ lk_update_running_tasks ();
+ lk_update_sleeping_tasks ();
+}
+
+/* Function for targets to_fetch_registers hook. */
+
+static void
+lk_fetch_registers (struct target_ops *target,
+ struct regcache *regcache, int regnum)
+{
+ CORE_ADDR task = (CORE_ADDR) regcache->ptid ().tid ();
+
+ /* Are we called during init? */
+ if (task == 0)
+ return target->beneath->to_fetch_registers (target, regcache, regnum);
+
+ unsigned int cpu = lk_task_running (task);
+
+ /* Let the target beneath fetch registers of running tasks. */
+ if (cpu != LK_CPU_INVAL)
+ {
+ scoped_restore_regcache_ptid restore_regcache (regcache);
+ regcache->set_ptid (lk_cpu_to_old_ptid (cpu));
+
+ lk_ops->beneath ()->to_fetch_registers (target, regcache, regnum);
+ }
+ else
+ {
+ lk_ops->get_registers (task, target, regcache, regnum);
+
+ /* Mark all registers not found as unavailable. */
+ for (int i = 0; i < gdbarch_num_regs (regcache->arch ()); i++)
+ {
+ if (regcache->get_register_status (i) != REG_VALID)
+ regcache->invalidate (i);
+ }
+ }
+}
+
+/* Function for targets to_pid_to_str hook. Marks running tasks with an
+ asterisk "*". */
+
+static const char *
+lk_pid_to_str (struct target_ops *target, ptid_t ptid)
+{
+ CORE_ADDR task = (CORE_ADDR) ptid.tid ();
+ static std::string str;
+ const char *fmt;
+
+ if (lk_task_running (task) != LK_CPU_INVAL)
+ fmt = "PID: %5li*, 0x%s";
+ else
+ fmt = "PID: %6li, 0x%s";
+
+ str = string_printf (fmt, ptid.lwp (),
+ phex (task, lk_builtin_type_size (unsigned_long)));
+
+ return str.c_str ();
+}
+
+/* Function for targets to_thread_name hook. */
+
+static const char *
+lk_thread_name (struct target_ops *target, struct thread_info *ti)
+{
+ static std::string str (LK_TASK_COMM_LEN, '\0');
+
+ size_t size = std::min ((unsigned int) LK_TASK_COMM_LEN,
+ LK_ARRAY_LEN(lk_field ("task_struct->comm")));
+
+ CORE_ADDR task = (CORE_ADDR) ti->ptid.tid ();
+ CORE_ADDR comm = task + lk_offset ("task_struct->comm");
+ read_memory (comm, (gdb_byte *) str.data (), size);
+
+ str = string_printf ("%-16s", str.c_str ());
+
+ return str.c_str ();
+}
+
+
+/* Functions to initialize and free target_ops and its private data. As well
+ as functions for targets to_open/close/detach hooks. */
+
+/* Check if OBFFILE is a Linux kernel. */
+
+static bool
+lk_is_linux_kernel (struct objfile *objfile)
+{
+ int ok = 0;
+
+ if (objfile == NULL || !(objfile->flags & OBJF_MAINLINE))
+ return false;
+
+ ok += lookup_minimal_symbol ("linux_banner", NULL, objfile).minsym != NULL;
+ ok += lookup_minimal_symbol ("_stext", NULL, objfile).minsym != NULL;
+ ok += lookup_minimal_symbol ("_etext", NULL, objfile).minsym != NULL;
+
+ return (ok > 2);
+}
+
+/* Frees the cpu to old ptid map. */
+
+static void
+lk_free_ptid_map ()
+{
+ while (lk_ops->old_ptid)
+ {
+ struct lk_ptid_map *tmp;
+
+ tmp = lk_ops->old_ptid;
+ lk_ops->old_ptid = tmp->next;
+ XDELETE (tmp);
+ }
+}
+
+/* Initialize the cpu to old ptid map. */
+
+static void
+lk_init_ptid_map ()
+{
+ struct thread_info *ti;
+
+ if (lk_ops->old_ptid != NULL)
+ lk_free_ptid_map ();
+
+ ALL_THREADS (ti)
+ {
+ struct lk_ptid_map *ptid_map = XCNEW (struct lk_ptid_map);
+
+ ptid_map->cpu = lk_ops->beneath_thread_to_cpu (ti);
+ ptid_map->old_ptid = ti->ptid;
+
+ ptid_map->next = lk_ops->old_ptid;
+ lk_ops->old_ptid = ptid_map;
+ }
+}
+
+/* Initializes all private data and pushes the linux kernel target, if not
+ already done. */
+
+static void
+lk_try_push_target ()
+{
+ struct gdbarch *gdbarch;
+
+ gdbarch = current_inferior ()->gdbarch;
+ if (!(gdbarch && gdbarch_get_new_lk_ops_p (gdbarch)))
+ error (_("Linux kernel debugging not supported on %s."),
+ gdbarch_bfd_arch_info (gdbarch)->printable_name);
+
+ lk_ops = gdbarch_get_new_lk_ops (gdbarch, lk_target_ops);
+ lk_ops->read_symbols ();
+
+ lk_init_ptid_map ();
+ lk_update_thread_list (lk_ops->target ());
+
+ if (!target_is_pushed (lk_target_ops))
+ push_target (lk_ops->target ());
+}
+
+/* Function for targets to_open hook. */
+
+static void
+lk_open (const char *args, int from_tty)
+{
+ struct objfile *objfile;
+
+ if (target_is_pushed (lk_target_ops))
+ {
+ printf_unfiltered (_("Linux kernel target already pushed. Aborting\n"));
+ return;
+ }
+
+ for (objfile = current_program_space->objfiles; objfile;
+ objfile = objfile->next)
+ {
+ if (lk_is_linux_kernel (objfile)
+ && inferior_ptid.pid () != 0)
+ {
+ lk_try_push_target ();
+ return;
+ }
+ }
+ printf_unfiltered (_("Could not find a valid Linux kernel object file. "
+ "Aborting.\n"));
+}
+
+/* Function for targets to_close hook. Deletes all private data. */
+
+static void
+lk_close (struct target_ops *ops)
+{
+ lk_free_ptid_map ();
+
+ delete (lk_ops);
+}
+
+/* Function for targets to_detach hook. */
+
+static void
+lk_detach (struct target_ops *t, inferior *inf, int from_tty)
+{
+ struct target_ops *beneath = lk_ops->beneath ();
+
+ unpush_target (lk_ops->target ());
+ reinit_frame_cache ();
+ if (from_tty)
+ printf_filtered (_("Linux kernel target detached.\n"));
+
+ beneath->to_detach (beneath, inf, from_tty);
+}
+
+/* Function for new objfile observer. */
+
+static void
+lk_observer_new_objfile (struct objfile *objfile)
+{
+ if (lk_is_linux_kernel (objfile) && inferior_ptid.pid () != 0)
+ lk_try_push_target ();
+}
+
+/* Function for inferior created observer. */
+
+static void
+lk_observer_inferior_created (struct target_ops *ops, int from_tty)
+{
+ struct objfile *objfile;
+
+ if (inferior_ptid.pid () == 0)
+ return;
+
+ for (objfile = current_inferior ()->pspace->objfiles; objfile;
+ objfile = objfile->next)
+ {
+ if (lk_is_linux_kernel (objfile))
+ {
+ lk_try_push_target ();
+ return;
+ }
+ }
+}
+
+/* Initialize linux kernel target. */
+
+static void
+init_lk_target_ops (void)
+{
+ struct target_ops *t;
+
+ if (lk_target_ops != NULL)
+ return;
+
+ t = XCNEW (struct target_ops);
+ t->to_shortname = "linux-kernel";
+ t->to_longname = "linux kernel support";
+ t->to_doc = "Adds support to debug the Linux kernel";
+
+ t->to_open = lk_open;
+ t->to_close = lk_close;
+ t->to_detach = lk_detach;
+ t->to_fetch_registers = lk_fetch_registers;
+ t->to_update_thread_list = lk_update_thread_list;
+ t->to_pid_to_str = lk_pid_to_str;
+ t->to_thread_name = lk_thread_name;
+
+ t->to_stratum = thread_stratum;
+ t->to_magic = OPS_MAGIC;
+
+ lk_target_ops = t;
+
+ add_target (t);
+}
+
+/* Provide a prototype to silence -Wmissing-prototypes. */
+extern initialize_file_ftype _initialize_linux_kernel;
+
+void
+_initialize_linux_kernel (void)
+{
+ init_lk_target_ops ();
+
+ observer_attach_new_objfile (lk_observer_new_objfile);
+ observer_attach_inferior_created (lk_observer_inferior_created);
+}
diff --git a/gdb/lk-low.h b/gdb/lk-low.h
new file mode 100644
index 0000000000..39c0d88f43
--- /dev/null
+++ b/gdb/lk-low.h
@@ -0,0 +1,335 @@
+/* Basic Linux kernel support, architecture independent.
+
+ Copyright (C) 2016 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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 3 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, see <http://www.gnu.org/licenses/>. */
+
+#ifndef __LK_LOW_H__
+#define __LK_LOW_H__
+
+#include <unordered_map>
+
+#include "gdbtypes.h"
+#include "target.h"
+
+/* Copied constants defined in Linux kernel. */
+#define LK_TASK_COMM_LEN 16
+#define LK_BITS_PER_BYTE 8
+
+/* Definitions used in linux kernel target. */
+#define LK_CPU_INVAL -1U
+
+/* Helper functions to read and return a value at a given ADDRess. */
+extern int lk_read_int (CORE_ADDR addr);
+extern unsigned int lk_read_uint (CORE_ADDR addr);
+extern LONGEST lk_read_long (CORE_ADDR addr);
+extern ULONGEST lk_read_ulong (CORE_ADDR addr);
+extern CORE_ADDR lk_read_addr (CORE_ADDR addr);
+
+/* Enum to track the config options used to build the kernel. Whenever
+ a symbol is declared (in linux_kernel_ops::{arch_}read_symbols) which
+ only exists if the kernel was built with a certain config option an entry
+ has to be added here. */
+enum lk_kconfig_values
+{
+ LK_CONFIG_ALWAYS = 1 << 0,
+ LK_CONFIG_SMT = 1 << 1,
+ LK_CONFIG_MODULES = 1 << 2,
+};
+DEF_ENUM_FLAGS_TYPE (enum lk_kconfig_values, lk_kconfig);
+
+/* We use the following convention for PTIDs:
+
+ ptid->pid = inferiors PID
+ ptid->lwp = PID from task_stuct
+ ptid->tid = address of task_struct
+
+ The task_structs address as TID has two reasons. First, we need it quite
+ often and there is no other reasonable way to pass it down. Second, it
+ helps us to distinguish swapper tasks as they all have PID = 0.
+
+ Furthermore we cannot rely on the target beneath to use the same PID as the
+ task_struct. Thus we need a mapping between our PTID and the PTID of the
+ target beneath. Otherwise it is impossible to pass jobs, e.g. fetching
+ registers of running tasks, to the target beneath. */
+
+/* Private data struct to map between our and the target beneath PTID. */
+
+struct lk_ptid_map
+{
+ struct lk_ptid_map *next;
+ unsigned int cpu;
+ ptid_t old_ptid;
+};
+
+/* Cache for the value of a symbol. Used in linux_kernel_ops->m_symbols. */
+
+union lk_symbol
+{
+ CORE_ADDR addr;
+ struct type *type;
+ struct
+ {
+ struct field *field;
+ CORE_ADDR offset;
+ };
+
+ lk_symbol () {field = NULL; offset = 0;}
+ lk_symbol (struct field *f, CORE_ADDR o) {field = f, offset = o;}
+};
+
+class linux_kernel_ops
+{
+public:
+ linux_kernel_ops (struct target_ops *ops)
+ : m_ops (ops)
+ {}
+
+ virtual ~linux_kernel_ops () = default;
+
+ /* Read registers from the target and supply their content to regcache. */
+ virtual void get_registers (CORE_ADDR task, struct target_ops *target,
+ struct regcache *regcache, int regnum) = 0;
+
+ /* Return the per_cpu_offset of cpu CPU. Default uses __per_cpu_offset
+ array to determine the offset. */
+ virtual CORE_ADDR percpu_offset (unsigned int cpu);
+
+ /* Maps thread of target beneath to a cpu id. Default assumes
+ rq->curr->pid == beneath_ptid.lwp. */
+ virtual unsigned int beneath_thread_to_cpu (thread_info *ti);
+
+ /* Return the linux-kernel target. */
+ struct target_ops *target () const
+ { return m_ops; }
+
+ /* Return the target beneath the linux-kernel target. */
+ struct target_ops *beneath () const
+ { return m_ops->beneath; }
+
+ /* Return a previously declared address with key ALIAS.
+ Throws internal_error if requested symbol was not declared first. */
+ CORE_ADDR address (const std::string &alias) const
+ {
+ gdb_assert (has_address (alias));
+ return m_symbols.at (alias).addr;
+ }
+
+ /* Same like address but for types. */
+ struct type *type (const std::string &alias) const
+ {
+ gdb_assert (has_type (alias));
+ return m_symbols.at (unique_type_alias(alias)).type;
+ }
+
+ /* Same like address but for fields. */
+ struct field *field (const std::string &alias) const
+ {
+ gdb_assert (has_field (alias));
+ return m_symbols.at (alias).field;
+ }
+
+ /* Checks whether address ALIAS exists in m_symbols. */
+ bool has_address (const std::string &alias) const
+ { return has_symbol (alias); }
+
+ /* Same like has_address but for types. */
+ bool has_type (const std::string &alias) const
+ { return has_symbol (unique_type_alias (alias)); }
+
+ /* Same like has_address but for fields. */
+ bool has_field (const std::string &alias) const
+ { return has_symbol (alias); }
+
+ /* Return offset of field ALIAS (in byte). */
+ CORE_ADDR offset (const std::string &alias) const;
+
+ /* Check whether the kernel was build using this config option. */
+ bool ifdef (lk_kconfig config) const
+ { return !(m_kconfig & config); }
+
+ /* Linked list to map between cpu number and original ptid from target
+ beneath. */
+ struct lk_ptid_map *old_ptid = NULL;
+
+ /* Declare and initialize all symbols needed. Must be called _after_
+ symbol tables were initialized. */
+ void read_symbols ();
+
+protected:
+ /* Virtual method to allow architectures to declare their own symbols.
+ Called by read_symbols. */
+ virtual void arch_read_symbols ()
+ {}
+
+ /* Helper function to declare_address. Returns true when symbol NAME
+ using key ALIAS was successfully declared, false otherwise. Try not to
+ use this function directly but use declare_address instead. */
+ bool try_declare_address (const std::string &alias,
+ const std::string &names);
+
+ /* Same like try_declare_address but for types. */
+ bool try_declare_type (const std::string &alias, const std::string &name);
+
+ /* Same like try_declare_address but for fields. */
+ bool try_declare_field (const std::string &alias, const std::string &name);
+
+ /* Same like try_declare_field but with NAME = ALIAS. */
+ bool try_declare_field (const std::string &name)
+ { return try_declare_field (name, name); }
+
+ /* Declare symbol NAME using key ALIAS. If no symbol NAME could be found
+ mark CONFIG as missing. */
+ void declare_address (const std::string &alias, const std::string &name,
+ const lk_kconfig config);
+
+ /* Same like above but with NAME = ALIAS. */
+ void declare_address (const std::string &name, const lk_kconfig config)
+ { declare_address (name, name, config); }
+
+ /* Same like above but only mark CONFIG as missing if none of the symbols
+ in NAMES could be found. */
+ void declare_address (const std::string &alias,
+ const std::initializer_list<const std::string> names,
+ const lk_kconfig config);
+
+ /* See declare_address. */
+ void declare_type (const std::string &alias, const std::string &name,
+ const lk_kconfig config);
+
+ /* See declare_address. */
+ void declare_type (const std::string &name, const lk_kconfig config)
+ { declare_type (name, name, config); }
+
+ /* See declare_address. */
+ void declare_type (const std::string &alias,
+ const std::initializer_list<const std::string> names,
+ const lk_kconfig config);
+
+ /* See declare_address. */
+ void declare_field (const std::string &alias, const std::string &name,
+ const lk_kconfig kconfig);
+
+ /* See declare_address. */
+ void declare_field (const std::string &name, const lk_kconfig kconfig)
+ { declare_field (name, name, kconfig); }
+
+ /* See declare_address. */
+ void declare_field (const std::string &alias,
+ const std::initializer_list <const std::string> names,
+ const lk_kconfig config);
+
+private:
+ /* The target_ops we are working with. */
+ struct target_ops *m_ops;
+
+ /* The configuration used to build the kernel. To make the implementation
+ easier m_kconfig is inverse, i.e. it tracks the _missing_ config options
+ not the set ones. */
+ lk_kconfig m_kconfig = 0;
+
+ /* Collection of all declared symbols (addresses, fields etc.). */
+ std::unordered_map<std::string, union lk_symbol> m_symbols;
+
+ /* Returns unique alias for struct ALIAS. */
+ const std::string unique_type_alias (const std::string &alias) const
+ {
+ std::string prefix ("struct ");
+ if (startswith (alias.c_str (), prefix.c_str ()))
+ return alias;
+ return prefix + alias;
+ }
+
+ /* Check if m_symbols contains ALIAS. */
+ bool has_symbol (const std::string &alias) const
+ { return m_symbols.count (alias) != 0; }
+};
+
+extern target_ops *lk_target_ops;
+extern linux_kernel_ops *lk_ops;
+
+/* Short hand access to frequently used lk_ops methods. */
+
+static inline CORE_ADDR
+lk_address (const std::string &alias)
+{
+ return lk_ops->address (alias);
+}
+
+static inline struct type *
+lk_type (const std::string &alias)
+{
+ return lk_ops->type (alias);
+}
+
+static inline struct field *
+lk_field (const std::string &alias)
+{
+ return lk_ops->field (alias);
+}
+
+static inline CORE_ADDR
+lk_offset (const std::string &alias)
+{
+ return lk_ops->offset (alias);
+}
+
+static inline bool
+lk_ifdef (lk_kconfig config)
+{
+ return lk_ops->ifdef (config);
+}
+
+/* Align VAL to BASE. BASE must be a power of 2. */
+#define LK_ALIGN(val, base) LK_ALIGN_MASK ((val), (typeof(val))(base) - 1)
+
+/* Same as LK_ALIGN, but aligns down. */
+#define LK_ALIGN_DOWN(val, base) ((val) & ~((typeof(val))(base) - 1))
+
+/* Helper for LK_ALIGN. */
+#define LK_ALIGN_MASK(val, mask) (((val) + (mask)) & ~(mask))
+
+/* Short hand access to current gdbarchs builtin types and their
+ size (in byte). For TYPE replace spaces " " by underscore "_", e.g.
+ "unsigned int" => "unsigned_int". */
+#define lk_builtin_type(type) \
+ (builtin_type (current_inferior ()->gdbarch)->builtin_##type)
+#define lk_builtin_type_size(type) \
+ (lk_builtin_type (type)->length)
+
+/* If field FIELD is an array returns its length (in #elements). */
+#define LK_ARRAY_LEN(field) \
+ (FIELD_SIZE (field) / FIELD_TARGET_SIZE (field))
+
+/* Additional access macros to fields in the style of gdbtypes.h */
+/* Returns the size of field FIELD (in bytes). If FIELD is an array returns
+ the size of the whole array. */
+#define FIELD_SIZE(field) \
+ TYPE_LENGTH (check_typedef (FIELD_TYPE ((*field))))
+
+/* Returns the size of the target type of field FIELD (in bytes). If FIELD is
+ an array returns the size of its elements. */
+#define FIELD_TARGET_SIZE(field) \
+ TYPE_LENGTH (check_typedef (TYPE_TARGET_TYPE (FIELD_TYPE ((*field)))))
+
+#define FIELD_BYTEPOS(field) \
+ (FIELD_BITPOS (*field) / LK_BITS_PER_BYTE)
+
+/* Tests if a given task TASK is running. Returns either the cpu-id
+ if running or LK_CPU_INVAL if not. */
+extern unsigned int lk_task_running (CORE_ADDR task);
+
+#endif /* __LK_LOW_H__ */
diff --git a/gdb/osabi.c b/gdb/osabi.c
index fd44deb9fa..14ddd414f3 100644
--- a/gdb/osabi.c
+++ b/gdb/osabi.c
@@ -64,6 +64,7 @@ static const struct osabi_names gdb_osabi_names[] =
{ "GNU/Hurd", NULL },
{ "Solaris", NULL },
{ "GNU/Linux", "linux(-gnu[^-]*)?" },
+ { "Linux kernel", NULL },
{ "FreeBSD", NULL },
{ "NetBSD", NULL },
{ "OpenBSD", NULL },
--
2.13.5