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Diffstat (limited to 'Documentation/sparc/README-2.5')
| -rw-r--r-- | Documentation/sparc/README-2.5 | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/Documentation/sparc/README-2.5 b/Documentation/sparc/README-2.5 new file mode 100644 index 000000000000..806fe490a56d --- /dev/null +++ b/Documentation/sparc/README-2.5 @@ -0,0 +1,46 @@ +BTFIXUP +------- + +To build new kernels you have to issue "make image". The ready kernel +in ELF format is placed in arch/sparc/boot/image. Explanation is below. + +BTFIXUP is a unique feature of Linux/sparc among other architectures, +developed by Jakub Jelinek (I think... Obviously David S. Miller took +part, too). It allows to boot the same kernel at different +sub-architectures, such as sun4c, sun4m, sun4d, where SunOS uses +different kernels. This feature is convinient for people who you move +disks between boxes and for distrution builders. + +To function, BTFIXUP must link the kernel "in the draft" first, +analyze the result, write a special stub code based on that, and +build the final kernel with the stub (btfix.o). + +Kai Germaschewski improved the build system of the kernel in the 2.5 series +significantly. Unfortunately, the traditional way of running the draft +linking from architecture specific Makefile before the actual linking +by generic Makefile is nearly impossible to support properly in the +new build system. Therefore, the way we integrate BTFIXUP with the +build system was changed in 2.5.40. Now, generic Makefile performs +the draft linking and stores the result in file vmlinux. Architecture +specific post-processing invokes BTFIXUP machinery and final linking +in the same way as other architectures do bootstraps. + +Implications of that change are as follows. + +1. Hackers must type "make image" now, instead of just "make", in the same + way as s390 people do now. It is analogous to "make bzImage" on i386. + This does NOT affect sparc64, you continue to use "make" to build sparc64 + kernels. + +2. vmlinux is not the final kernel, so RPM builders have to adjust + their spec files (if they delivered vmlinux for debugging). + System.map generated for vmlinux is still valid. + +3. Scripts that produce a.out images have to be changed. First, if they + invoke make, they have to use "make image". Second, they have to pick up + the new kernel in arch/sparc/boot/image instead of vmlinux. + +4. Since we are compliant with Kai's build system now, make -j is permitted. + +-- Pete Zaitcev +zaitcev@yahoo.com |