linux/scripts/Makefile.build, branch v2.6.28

ftrace: handle generic arch calls

2008-10-23T13:58:19Z

The recordmcount script requires that the actual arch is passed in. This works well when ARCH=i386 or ARCH=x86_64 but does not handle the case of ARCH=x86. This patch adds a parameter to the function to pass in the number of bits of the architecture. So that it can determine if x86 should be run for x86_64 or i386 archs. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar

kbuild: ftrace: don't assume that scripts/recordmcount.pl is executable

2008-10-14T08:36:16Z

CHK include/linux/version.h CHK include/linux/utsrelease.h CC scripts/mod/empty.o /bin/sh: /usr/src/25/scripts/recordmcount.pl: Permission denied We shouldn't assume that files have their `x' bits set. There are various ways in which file permissions get lost, including use of patch(1). It might not be correct to assume that perl lives in $PATH? Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar

ftrace: fix build problem with CONFIG_FTRACE

2008-10-14T08:35:53Z

I'm seeing when I use separate src/build dirs: make[3]: *** [arch/x86/kernel/time_32.o] Error 1 /bin/sh: scripts/recordmcount.pl: No such file or directory make[3]: *** [arch/x86/kernel/irq_32.o] Error 1 /bin/sh: scripts/recordmcount.pl: No such file or directory make[3]: *** [arch/x86/kernel/ldt.o] Error 1 /bin/sh: scripts/recordmcount.pl: No such file or directory make[3]: *** [arch/x86/kernel/i8259.o] Error 1 /bin/sh: scripts/recordmcount.pl: No such file or directory This fixes it. Signed-off-by: Ingo Molnar

ftrace: create __mcount_loc section

2008-10-14T08:34:40Z

This patch creates a section in the kernel called "__mcount_loc". This will hold a list of pointers to the mcount relocation for each call site of mcount. For example: objdump -dr init/main.o [...] Disassembly of section .text: 0000000000000000 : 0: 55 push %rbp [...] 000000000000017b : 17b: 55 push %rbp 17c: 48 89 e5 mov %rsp,%rbp 17f: 53 push %rbx 180: 48 83 ec 08 sub $0x8,%rsp 184: e8 00 00 00 00 callq 189 185: R_X86_64_PC32 mcount+0xfffffffffffffffc [...] We will add a section to point to each function call. .section __mcount_loc,"a",@progbits [...] .quad .text + 0x185 [...] The offset to of the mcount call site in init_post is an offset from the start of the section, and not the start of the function init_post. The mcount relocation is at the call site 0x185 from the start of the .text section. .text + 0x185 == init_post + 0xa We need a way to add this __mcount_loc section in a way that we do not lose the relocations after final link. The .text section here will be attached to all other .text sections after final link and the offsets will be meaningless. We need to keep track of where these .text sections are. To do this, we use the start of the first function in the section. do_one_initcall. We can make a tmp.s file with this function as a reference to the start of the .text section. .section __mcount_loc,"a",@progbits [...] .quad do_one_initcall + 0x185 [...] Then we can compile the tmp.s into a tmp.o gcc -c tmp.s -o tmp.o And link it into back into main.o. ld -r main.o tmp.o -o tmp_main.o mv tmp_main.o main.o But we have a problem. What happens if the first function in a section is not exported, and is a static function. The linker will not let the tmp.o use it. This case exists in main.o as well. Disassembly of section .init.text: 0000000000000000 : 0: 55 push %rbp 1: 48 89 e5 mov %rsp,%rbp 4: e8 00 00 00 00 callq 9 5: R_X86_64_PC32 mcount+0xfffffffffffffffc The first function in .init.text is a static function. 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices The lowercase 't' means that set_reset_devices is local and is not exported. If we simply try to link the tmp.o with the set_reset_devices we end up with two symbols: one local and one global. .section __mcount_loc,"a",@progbits .quad set_reset_devices + 0x10 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices U set_reset_devices We still have an undefined reference to set_reset_devices, and if we try to compile the kernel, we will end up with an undefined reference to set_reset_devices, or even worst, it could be exported someplace else, and then we will have a reference to the wrong location. To handle this case, we make an intermediate step using objcopy. We convert set_reset_devices into a global exported symbol before linking it with tmp.o and set it back afterwards. 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 T set_reset_devices 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 T set_reset_devices 00000000000000a8 t __setup_set_reset_devices 000000000000105f t __setup_str_set_reset_devices 0000000000000000 t set_reset_devices Now we have a section in main.o called __mcount_loc that we can place somewhere in the kernel using vmlinux.ld.S and access it to convert all these locations that call mcount into nops before starting SMP and thus, eliminating the need to do this with kstop_machine. Note, A well documented perl script (scripts/recordmcount.pl) is used to do all this in one location. Signed-off-by: Steven Rostedt Signed-off-by: Ingo Molnar

kbuild: fix some minor typoes

2008-04-25T18:18:48Z

Signed-off-by: Robert P. J. Day Signed-off-by: Sam Ravnborg

kbuild: introduce new option to enhance section mismatch analysis

2008-01-28T22:21:18Z

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

kbuild: implement modules.order

2008-01-28T22:14:35Z

When multiple built-in modules (especially drivers) provide the same capability, they're prioritized by link order specified by the order listed in Makefile. This implicit ordering is lost for loadable modules. When driver modules are loaded by udev, what comes first in modules.alias file is selected. However, the order in this file is indeterministic (depends on filesystem listing order of installed modules). This causes confusion. The solution is two-parted. This patch updates kbuild such that it generates and installs modules.order which contains the name of modules ordered according to Makefile. The second part is update to depmod such that it generates output files according to this file. Note that both obj-y and obj-m subdirs can contain modules and ordering information between those two are lost from beginning. Currently obj-y subdirs are put before obj-m subdirs. Sam Ravnborg cleaned up Makefile modifications and suggested using awk to remove duplicate lines from modules.order instead of using separate C program. Signed-off-by: Tejun Heo Acked-by: Greg Kroah-Hartman Cc: Bill Nottingham Cc: Rusty Russell Cc: Kay Sievers Cc: Jon Masters Signed-off-by: Sam Ravnborg

kbuild: introduce ccflags-y, asflags-y and ldflags-y

2007-10-15T20:25:06Z

Introduce ccflags-y, asflags-y and ldflags-y so we soon can deprecate use of EXTRA_CFLAGS, EXTRA_AFLAGS and EXTRA_LDFLAGS. This patch does not touch any in-tree users - thats next round. Lets get this committed first and then fix the users of the soon to be deprecated variants next. The rationale behind this change is to introduce support for makefile fragments like: ccflags-$(CONFIG_WHATEVER_DEBUG) := -DDEBUG As a replacement for the uglier: ifeq ($(CONFIG_WHATEVER_DEBUG),y) EXTRA_CFLAGS := -DDEBUG endif Signed-off-by: Sam Ravnborg

kbuild: check for wrong use of CFLAGS

2007-10-14T20:26:53Z

External modules have in a few cases modifed gcc option by modifying CFLAGS. This has never been documented and was a bad practice. With the check to use KBUILD_CFLAGS it will no longer work so we better error out and tell what was wrong as a service to the external module users. This check can be overruled if KBUILD_NOPEDANTIC is set to something. Addid this possibility may allow older external module to build without any code modifications but potentially only loosing some un-important gcc options. Signed-off-by: Sam Ravnborg

kbuild: kill backward compatibility checks

2007-10-12T19:20:32Z

These checks has been present for several kernel releases (> 5). So lets just get rid of them. With this we no longer check for use of: EXTRA_TARGETS, O_TARGET, L_TARGET, list-multi, export-objs There were three remaining in-tree users of O_TARGET in some unmaintained sh64 code - mail sent to the maintainer + list. Signed-off-by: Sam Ravnborg