On Mon, Sep 10, 2012 at 04:21:02PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote: > On 13:51 Mon 10 Sep , Catalin Marinas wrote: > > On Mon, Sep 10, 2012 at 06:53:39AM +0100, Jean-Christophe PLAGNIOL-VILLARD > > wrote: > > > On 19:29 Sun 09 Sep , Nicolas Pitre wrote: > > > > On Sun, 9 Sep 2012, Jean-Christophe PLAGNIOL-VILLARD wrote: > > > > > On 17:26 Fri 07 Sep , Catalin Marinas wrote: > > > > > > +The image must be placed at the specified offset (currently > > > > > > 0x80000) > > > > > > +from the start of the system RAM and called there. The start of the > > > > > > +system RAM must be aligned to 2MB. > > > > > can we drop this > > > > > > > > Drop what? > > > > And why? > > > This contrain the must be loadable at any address > > > > You can't easily load the kernel image at any address, unless it can > > relocate itself and you have a way to specify PHYS_OFFSET. We don't want > > a compile-time PHYS_OFFSET, the kernel detects it at boot time based on > > the load address. > so NACK kexec and other boot loaders require it
Just in case it wasn't clear, the kernel can be loaded at any address in RAM (and the RAM can start at any sane address). The way the kernel calculates PHYS_OFFSET is (load address - TEXT_OFFSET) unless we pass it by other means (none currently specified). For a kdump kernel, it just assumes that its PHYS_OFFSET is higher but it can ioremap the crashed kernel memory. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/