From 91341d4b2c196c689acf90e9e96f28f8d5c6665f Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Mon, 21 Jan 2008 21:31:44 +0100 Subject: kbuild: introduce new option to enhance section mismatch analysis Setting the option DEBUG_SECTION_MISMATCH will report additional section mismatch'es but this should in the end makes it possible to get rid of all of them. See help text in lib/Kconfig.debug for details. Signed-off-by: Sam Ravnborg --- lib/Kconfig.debug | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 14fb355e3caa..748e72be6e68 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -79,6 +79,36 @@ config HEADERS_CHECK exported to $(INSTALL_HDR_PATH) (usually 'usr/include' in your build tree), to make sure they're suitable. +config DEBUG_SECTION_MISMATCH + bool "Enable full Section mismatch analysis" + default n + help + The section mismatch analysis checks if there are illegal + references from one section to another section. + Linux will during link or during runtime drop some sections + and any use of code/data previously in these sections will + most likely result in an oops. + In the code functions and variables are annotated with + __init, __devinit etc. (see full list in include/linux/init.h) + which result in the code/data being placed in specific sections. + The section mismatch anaylsis are always done after a full + kernel build but enabling this options will in addition + do the following: + - Add the option -fno-inline-functions-called-once to gcc + When inlining a function annotated __init in a non-init + function we would loose the section information and thus + the analysis would not catch the illegal reference. + This options tell gcc to inline less but will also + result in a larger kernel. + - Run the section mismatch analysis for each module/built-in.o + When we run the section mismatch analysis on vmlinux.o we + looses valueable information about where the mismatch was + introduced. + Running the analysis for each module/built-in.o file + will tell where the mismatch happens much closer to the + source. The drawback is that we will report the same + mismatch at least twice. + config DEBUG_KERNEL bool "Kernel debugging" help -- cgit v1.2.3 From 588ccd732ba2d32db8228802ef9283b583d3395f Mon Sep 17 00:00:00 2001 From: Sam Ravnborg Date: Thu, 24 Jan 2008 21:12:37 +0100 Subject: kbuild: add verbose option to Section mismatch reporting in modpost If the config option CONFIG_SECTION_MISMATCH is not set and we see a Section mismatch present the following to the user: modpost: Found 1 section mismatch(es). To see additional details select "Enable full Section mismatch analysis" in the Kernel Hacking menu (CONFIG_SECTION_MISMATCH). If the option CONFIG_SECTION_MISMATCH is selected then be verbose in the Section mismatch reporting from mdopost. Sample outputs: WARNING: o-x86_64/vmlinux.o(.text+0x7396): Section mismatch in reference from the function discover_ebda() to the variable .init.data:ebda_addr The function discover_ebda() references the variable __initdata ebda_addr. This is often because discover_ebda lacks a __initdata annotation or the annotation of ebda_addr is wrong. WARNING: o-x86_64/vmlinux.o(.data+0x74d58): Section mismatch in reference from the variable pci_serial_quirks to the function .devexit.text:pci_plx9050_exit() The variable pci_serial_quirks references the function __devexit pci_plx9050_exit() If the reference is valid then annotate the variable with __exit* (see linux/init.h) or name the variable: *driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console, WARNING: o-x86_64/vmlinux.o(__ksymtab+0x630): Section mismatch in reference from the variable __ksymtab_arch_register_cpu to the function .cpuinit.text:arch_register_cpu() The symbol arch_register_cpu is exported and annotated __cpuinit Fix this by removing the __cpuinit annotation of arch_register_cpu or drop the export. Signed-off-by: Sam Ravnborg --- lib/Kconfig.debug | 2 ++ 1 file changed, 2 insertions(+) (limited to 'lib') diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 748e72be6e68..c4ecb2994ba3 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -108,6 +108,8 @@ config DEBUG_SECTION_MISMATCH will tell where the mismatch happens much closer to the source. The drawback is that we will report the same mismatch at least twice. + - Enable verbose reporting from modpost to help solving + the section mismatches reported. config DEBUG_KERNEL bool "Kernel debugging" -- cgit v1.2.3