From ca210ba32ef7537b02731bfe255ed8eb1e4e2b59 Mon Sep 17 00:00:00 2001 From: Joel Colledge Date: Fri, 18 Oct 2019 20:19:26 -0700 Subject: scripts/gdb: fix lx-dmesg when CONFIG_PRINTK_CALLER is set When CONFIG_PRINTK_CALLER is set, struct printk_log contains an additional member caller_id. This affects the offset of the log text. Account for this by using the type information from gdb to determine all the offsets instead of using hardcoded values. This fixes following error: (gdb) lx-dmesg Python Exception embedded null character: Error occurred in Python command: embedded null character The read_u* utility functions now take an offset argument to make them easier to use. Link: http://lkml.kernel.org/r/20191011142500.2339-1-joel.colledge@linbit.com Signed-off-by: Joel Colledge Reviewed-by: Jan Kiszka Cc: Kieran Bingham Cc: Leonard Crestez Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/gdb/linux/dmesg.py | 16 ++++++++++++---- scripts/gdb/linux/utils.py | 25 +++++++++++++------------ 2 files changed, 25 insertions(+), 16 deletions(-) (limited to 'scripts/gdb') diff --git a/scripts/gdb/linux/dmesg.py b/scripts/gdb/linux/dmesg.py index 6d2e09a2ad2f..2fa7bb83885f 100644 --- a/scripts/gdb/linux/dmesg.py +++ b/scripts/gdb/linux/dmesg.py @@ -16,6 +16,8 @@ import sys from linux import utils +printk_log_type = utils.CachedType("struct printk_log") + class LxDmesg(gdb.Command): """Print Linux kernel log buffer.""" @@ -42,9 +44,14 @@ class LxDmesg(gdb.Command): b = utils.read_memoryview(inf, log_buf_addr, log_next_idx) log_buf = a.tobytes() + b.tobytes() + length_offset = printk_log_type.get_type()['len'].bitpos // 8 + text_len_offset = printk_log_type.get_type()['text_len'].bitpos // 8 + time_stamp_offset = printk_log_type.get_type()['ts_nsec'].bitpos // 8 + text_offset = printk_log_type.get_type().sizeof + pos = 0 while pos < log_buf.__len__(): - length = utils.read_u16(log_buf[pos + 8:pos + 10]) + length = utils.read_u16(log_buf, pos + length_offset) if length == 0: if log_buf_2nd_half == -1: gdb.write("Corrupted log buffer!\n") @@ -52,10 +59,11 @@ class LxDmesg(gdb.Command): pos = log_buf_2nd_half continue - text_len = utils.read_u16(log_buf[pos + 10:pos + 12]) - text = log_buf[pos + 16:pos + 16 + text_len].decode( + text_len = utils.read_u16(log_buf, pos + text_len_offset) + text_start = pos + text_offset + text = log_buf[text_start:text_start + text_len].decode( encoding='utf8', errors='replace') - time_stamp = utils.read_u64(log_buf[pos:pos + 8]) + time_stamp = utils.read_u64(log_buf, pos + time_stamp_offset) for line in text.splitlines(): msg = u"[{time:12.6f}] {line}\n".format( diff --git a/scripts/gdb/linux/utils.py b/scripts/gdb/linux/utils.py index bc67126118c4..ea94221dbd39 100644 --- a/scripts/gdb/linux/utils.py +++ b/scripts/gdb/linux/utils.py @@ -92,15 +92,16 @@ def read_memoryview(inf, start, length): return memoryview(inf.read_memory(start, length)) -def read_u16(buffer): +def read_u16(buffer, offset): + buffer_val = buffer[offset:offset + 2] value = [0, 0] - if type(buffer[0]) is str: - value[0] = ord(buffer[0]) - value[1] = ord(buffer[1]) + if type(buffer_val[0]) is str: + value[0] = ord(buffer_val[0]) + value[1] = ord(buffer_val[1]) else: - value[0] = buffer[0] - value[1] = buffer[1] + value[0] = buffer_val[0] + value[1] = buffer_val[1] if get_target_endianness() == LITTLE_ENDIAN: return value[0] + (value[1] << 8) @@ -108,18 +109,18 @@ def read_u16(buffer): return value[1] + (value[0] << 8) -def read_u32(buffer): +def read_u32(buffer, offset): if get_target_endianness() == LITTLE_ENDIAN: - return read_u16(buffer[0:2]) + (read_u16(buffer[2:4]) << 16) + return read_u16(buffer, offset) + (read_u16(buffer, offset + 2) << 16) else: - return read_u16(buffer[2:4]) + (read_u16(buffer[0:2]) << 16) + return read_u16(buffer, offset + 2) + (read_u16(buffer, offset) << 16) -def read_u64(buffer): +def read_u64(buffer, offset): if get_target_endianness() == LITTLE_ENDIAN: - return read_u32(buffer[0:4]) + (read_u32(buffer[4:8]) << 32) + return read_u32(buffer, offset) + (read_u32(buffer, offset + 4) << 32) else: - return read_u32(buffer[4:8]) + (read_u32(buffer[0:4]) << 32) + return read_u32(buffer, offset + 4) + (read_u32(buffer, offset) << 32) target_arch = None -- cgit v1.2.3 From 585d730d41120926e3f79a601edad3930fa28366 Mon Sep 17 00:00:00 2001 From: Ilya Leoshkevich Date: Fri, 18 Oct 2019 20:20:43 -0700 Subject: scripts/gdb: fix debugging modules on s390 Currently lx-symbols assumes that module text is always located at module->core_layout->base, but s390 uses the following layout: +------+ <- module->core_layout->base | GOT | +------+ <- module->core_layout->base + module->arch->plt_offset | PLT | +------+ <- module->core_layout->base + module->arch->plt_offset + | TEXT | module->arch->plt_size +------+ Therefore, when trying to debug modules on s390, all the symbol addresses are skewed by plt_offset + plt_size. Fix by adding plt_offset + plt_size to module_addr in load_module_symbols(). Link: http://lkml.kernel.org/r/20191017085917.81791-1-iii@linux.ibm.com Signed-off-by: Ilya Leoshkevich Reviewed-by: Jan Kiszka Cc: Kieran Bingham Cc: Heiko Carstens Cc: Vasily Gorbik Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- scripts/gdb/linux/symbols.py | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'scripts/gdb') diff --git a/scripts/gdb/linux/symbols.py b/scripts/gdb/linux/symbols.py index 34e40e96dee2..7b7c2fafbc68 100644 --- a/scripts/gdb/linux/symbols.py +++ b/scripts/gdb/linux/symbols.py @@ -15,7 +15,7 @@ import gdb import os import re -from linux import modules +from linux import modules, utils if hasattr(gdb, 'Breakpoint'): @@ -116,6 +116,12 @@ lx-symbols command.""" module_file = self._get_module_file(module_name) if module_file: + if utils.is_target_arch('s390'): + # Module text is preceded by PLT stubs on s390. + module_arch = module['arch'] + plt_offset = int(module_arch['plt_offset']) + plt_size = int(module_arch['plt_size']) + module_addr = hex(int(module_addr, 0) + plt_offset + plt_size) gdb.write("loading @{addr}: {filename}\n".format( addr=module_addr, filename=module_file)) cmdline = "add-symbol-file {filename} {addr}{sections}".format( -- cgit v1.2.3