2d6ffcca62
Inflate requires some dynamic memory allocation very early in the boot process and this is provided with a set of four functions: malloc/free/gzip_mark/gzip_release. The old inflate code used a mark/release strategy rather than implement free. This new version instead keeps a count on the number of outstanding allocations and when it hits zero, it resets the malloc arena. This allows removing all the mark and release implementations and unifying all the malloc/free implementations. The architecture-dependent code must define two addresses: - free_mem_ptr, the address of the beginning of the area in which allocations should be made - free_mem_end_ptr, the address of the end of the area in which allocations should be made. If set to 0, then no check is made on the number of allocations, it just grows as much as needed The architecture-dependent code can also provide an arch_decomp_wdog() function call. This function will be called several times during the decompression process, and allow to notify the watchdog that the system is still running. If an architecture provides such a call, then it must define ARCH_HAS_DECOMP_WDOG so that the generic inflate code calls arch_decomp_wdog(). Work initially done by Matt Mackall, updated to a recent version of the kernel and improved by me. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Matt Mackall <mpm@selenic.com> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Mikael Starvik <mikael.starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: David Howells <dhowells@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andi Kleen <andi@firstfloor.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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README
Creation of the self-extracting compressed kernel image (vmlinuz) ----------------------------------------------------------------- This can be slightly confusing because it's a process with many steps. The kernel object built by the arch/etrax100/Makefile, vmlinux, is split by that makefile into text and data binary files, vmlinux.text and vmlinux.data. Those files together with a ROM filesystem can be catted together and burned into a flash or executed directly at the DRAM origin. They can also be catted together and compressed with gzip, which is what happens in this makefile. Together they make up piggy.img. The decompressor is built into the file decompress.o. It is turned into the binary file decompress.bin, which is catted together with piggy.img into the file vmlinuz. It can be executed in an arbitrary place in flash. Be careful - it assumes some things about free locations in DRAM. It assumes the DRAM starts at 0x40000000 and that it is at least 8 MB, so it puts its code at 0x40700000, and initial stack at 0x40800000. -Bjorn