new file mode 100644
@@ -0,0 +1,96 @@
+/*
+ * Debug information support.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/lockable.h"
+
+#include <elfutils/libdwfl.h>
+
+#include "debuginfo.h"
+
+static QemuMutex lock;
+static Dwfl *dwfl;
+static const Dwfl_Callbacks dwfl_callbacks = {
+ .find_elf = NULL,
+ .find_debuginfo = dwfl_standard_find_debuginfo,
+ .section_address = NULL,
+ .debuginfo_path = NULL,
+};
+
+__attribute__((constructor))
+static void debuginfo_init(void)
+{
+ qemu_mutex_init(&lock);
+}
+
+void debuginfo_report_elf(const char *name, int fd, uint64_t bias)
+{
+ QEMU_LOCK_GUARD(&lock);
+
+ if (dwfl) {
+ dwfl_report_begin_add(dwfl);
+ } else {
+ dwfl = dwfl_begin(&dwfl_callbacks);
+ }
+
+ if (dwfl) {
+ dwfl_report_elf(dwfl, name, name, fd, bias, true);
+ dwfl_report_end(dwfl, NULL, NULL);
+ }
+}
+
+void debuginfo_lock(void)
+{
+ qemu_mutex_lock(&lock);
+}
+
+void debuginfo_query(struct debuginfo_query *q, size_t n)
+{
+ const char *symbol, *file;
+ Dwfl_Module *dwfl_module;
+ Dwfl_Line *dwfl_line;
+ GElf_Off dwfl_offset;
+ GElf_Sym dwfl_sym;
+ size_t i;
+ int line;
+
+ if (!dwfl) {
+ return;
+ }
+
+ for (i = 0; i < n; i++) {
+ dwfl_module = dwfl_addrmodule(dwfl, q[i].address);
+ if (!dwfl_module) {
+ continue;
+ }
+
+ if (q[i].flags & DEBUGINFO_SYMBOL) {
+ symbol = dwfl_module_addrinfo(dwfl_module, q[i].address,
+ &dwfl_offset, &dwfl_sym,
+ NULL, NULL, NULL);
+ if (symbol) {
+ q[i].symbol = symbol;
+ q[i].offset = dwfl_offset;
+ }
+ }
+
+ if (q[i].flags & DEBUGINFO_LINE) {
+ dwfl_line = dwfl_module_getsrc(dwfl_module, q[i].address);
+ if (dwfl_line) {
+ file = dwfl_lineinfo(dwfl_line, NULL, &line, 0, NULL, NULL);
+ if (file) {
+ q[i].file = file;
+ q[i].line = line;
+ }
+ }
+ }
+ }
+}
+
+void debuginfo_unlock(void)
+{
+ qemu_mutex_unlock(&lock);
+}
new file mode 100644
@@ -0,0 +1,77 @@
+/*
+ * Debug information support.
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef ACCEL_TCG_DEBUGINFO_H
+#define ACCEL_TCG_DEBUGINFO_H
+
+/*
+ * Debuginfo describing a certain address.
+ */
+struct debuginfo_query {
+ uint64_t address; /* Input: address. */
+ int flags; /* Input: debuginfo subset. */
+ const char *symbol; /* Symbol that the address is part of. */
+ uint64_t offset; /* Offset from the symbol. */
+ const char *file; /* Source file associated with the address. */
+ int line; /* Line number in the source file. */
+};
+
+/*
+ * Debuginfo subsets.
+ */
+#define DEBUGINFO_SYMBOL BIT(1)
+#define DEBUGINFO_LINE BIT(2)
+
+#if defined(CONFIG_TCG) && defined(CONFIG_LIBDW)
+/*
+ * Load debuginfo for the specified guest ELF image.
+ * Return true on success, false on failure.
+ */
+void debuginfo_report_elf(const char *name, int fd, uint64_t bias);
+
+/*
+ * Take the debuginfo lock.
+ */
+void debuginfo_lock(void);
+
+/*
+ * Fill each on N Qs with the debuginfo about Q->ADDRESS as specified by
+ * Q->FLAGS:
+ *
+ * - DEBUGINFO_SYMBOL: update Q->SYMBOL and Q->OFFSET. If symbol debuginfo is
+ * missing, then leave them as is.
+ * - DEBUINFO_LINE: update Q->FILE and Q->LINE. If line debuginfo is missing,
+ * then leave them as is.
+ *
+ * This function must be called under the debuginfo lock. The results can be
+ * accessed only until the debuginfo lock is released.
+ */
+void debuginfo_query(struct debuginfo_query *q, size_t n);
+
+/*
+ * Release the debuginfo lock.
+ */
+void debuginfo_unlock(void);
+#else
+static inline void debuginfo_report_elf(const char *image_name, int image_fd,
+ uint64_t load_bias)
+{
+}
+
+static inline void debuginfo_lock(void)
+{
+}
+
+static inline void debuginfo_query(struct debuginfo_query *q, size_t n)
+{
+}
+
+static inline void debuginfo_unlock(void)
+{
+}
+#endif
+
+#endif
@@ -12,6 +12,7 @@ tcg_ss.add(files(
tcg_ss.add(when: 'CONFIG_USER_ONLY', if_true: files('user-exec.c'))
tcg_ss.add(when: 'CONFIG_SOFTMMU', if_false: files('user-exec-stub.c'))
tcg_ss.add(when: 'CONFIG_PLUGIN', if_true: [files('plugin-gen.c')])
+tcg_ss.add(when: libdw, if_true: files('debuginfo.c'))
specific_ss.add_all(when: 'CONFIG_TCG', if_true: tcg_ss)
specific_ss.add(when: ['CONFIG_SOFTMMU', 'CONFIG_TCG'], if_true: files(
@@ -61,6 +61,7 @@
#include "hw/boards.h"
#include "qemu/cutils.h"
#include "sysemu/runstate.h"
+#include "accel/tcg/debuginfo.h"
#include <zlib.h>
@@ -503,6 +504,10 @@ ssize_t load_elf_ram_sym(const char *filename,
clear_lsb, data_swab, as, load_rom, sym_cb);
}
+ if (ret != ELF_LOAD_FAILED) {
+ debuginfo_report_elf(filename, fd, 0);
+ }
+
fail:
close(fd);
return ret;
@@ -19,6 +19,7 @@
#include "qemu/selfmap.h"
#include "qapi/error.h"
#include "target_signal.h"
+#include "accel/tcg/debuginfo.h"
#ifdef _ARCH_PPC64
#undef ARCH_DLINFO
@@ -3261,6 +3262,8 @@ static void load_elf_image(const char *image_name, int image_fd,
load_symbols(ehdr, image_fd, load_bias);
}
+ debuginfo_report_elf(image_name, image_fd, load_bias);
+
mmap_unlock();
close(image_fd);
@@ -22,6 +22,7 @@ linux_user_ss.add(files(
'uname.c',
))
linux_user_ss.add(rt)
+linux_user_ss.add(libdw)
linux_user_ss.add(when: 'TARGET_HAS_BFLT', if_true: files('flatload.c'))
linux_user_ss.add(when: 'TARGET_I386', if_true: files('vm86.c'))
@@ -1648,6 +1648,12 @@ if libbpf.found() and not cc.links('''
endif
endif
+# libdw
+libdw = dependency('libdw',
+ method: 'pkg-config',
+ kwargs: static_kwargs,
+ required: false)
+
#################
# config-host.h #
#################
@@ -1923,6 +1929,7 @@ config_host_data.set('CONFIG_DBUS_DISPLAY', dbus_display)
config_host_data.set('CONFIG_CFI', get_option('cfi'))
config_host_data.set('CONFIG_SELINUX', selinux.found())
config_host_data.set('CONFIG_XEN_BACKEND', xen.found())
+config_host_data.set('CONFIG_LIBDW', libdw.found())
if xen.found()
# protect from xen.version() having less than three components
xen_version = xen.version().split('.') + ['0', '0']
@@ -3981,6 +3988,7 @@ summary_info += {'libudev': libudev}
# Dummy dependency, keep .found()
summary_info += {'FUSE lseek': fuse_lseek.found()}
summary_info += {'selinux': selinux}
+summary_info += {'libdw': libdw}
summary(summary_info, bool_yn: true, section: 'Dependencies')
if not supported_cpus.contains(cpu)
Add libdw-based functions for loading and querying debuginfo. Load debuginfo from the system and the linux-user loaders. This is useful for the upcoming perf support, which can then put human-readable guest symbols instead of raw guest PCs into perfmap and jitdump files. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> --- accel/tcg/debuginfo.c | 96 ++++++++++++++++++++++++++++++++++++++++++ accel/tcg/debuginfo.h | 77 +++++++++++++++++++++++++++++++++ accel/tcg/meson.build | 1 + hw/core/loader.c | 5 +++ linux-user/elfload.c | 3 ++ linux-user/meson.build | 1 + meson.build | 8 ++++ 7 files changed, 191 insertions(+) create mode 100644 accel/tcg/debuginfo.c create mode 100644 accel/tcg/debuginfo.h