lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Mon, 19 Jul 2021 08:59:03 +0200 From: Geert Uytterhoeven <geert@...ux-m68k.org> To: Mike Rapoport <rppt@...nel.org> Cc: Rob Herring <robh@...nel.org>, Russell King <linux@...linux.org.uk>, Nicolas Pitre <nico@...xnic.net>, Ard Biesheuvel <ardb@...nel.org>, Linus Walleij <linus.walleij@...aro.org>, Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>, Nick Kossifidis <mick@....forth.gr>, Paul Walmsley <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>, Frank Rowand <frowand.list@...il.com>, Dave Young <dyoung@...hat.com>, Baoquan He <bhe@...hat.com>, Vivek Goyal <vgoyal@...hat.com>, Andrew Morton <akpm@...ux-foundation.org>, "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" <devicetree@...r.kernel.org>, Linux ARM <linux-arm-kernel@...ts.infradead.org>, linux-riscv <linux-riscv@...ts.infradead.org>, kexec@...ts.infradead.org, Linux MM <linux-mm@...ck.org>, Linux-Renesas <linux-renesas-soc@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org> Subject: Re: [PATCH v4 02/10] memblock: Add variables for usable memory limitation Hi Mike, On Sun, Jul 18, 2021 at 11:31 AM Mike Rapoport <rppt@...nel.org> wrote: > On Wed, Jul 14, 2021 at 07:51:01AM -0600, Rob Herring wrote: > > On Wed, Jul 14, 2021 at 02:50:12PM +0200, Geert Uytterhoeven wrote: > > > Add two global variables (cap_mem_addr and cap_mem_size) for storing a > > > base address and size, describing a limited region in which memory may > > > be considered available for use by the kernel. If enabled, memory > > > outside of this range is not available for use. > > > > > > These variables can by filled by firmware-specific code, and used in > > > calls to memblock_cap_memory_range() by architecture-specific code. > > > An example user is the parser of the "linux,usable-memory-range" > > > property in the DT "/chosen" node. > > > > > > Signed-off-by: Geert Uytterhoeven <geert+renesas@...der.be> > > > --- > > > This is similar to how the initial ramdisk (phys_initrd_{start,size}) > > > and ELF core headers (elfcorehdr_{addr,size})) are handled. > > > > > > Does there exist a suitable place in the common memblock code to call > > > "memblock_cap_memory_range(cap_mem_addr, cap_mem_size)", or does this > > > have to be done in architecture-specific code? > > > > Can't you just call it from early_init_dt_scan_usablemem? If the > > property is present, you want to call it. If the property is not > > present, nothing happens. I will have a look... > For memblock_cap_memory_range() to work properly it should be called after > memory is detected and added to memblock with memblock_add[_node]() > > I'm not huge fan of adding more globals to memblock so if such ordering can > be implemented on the DT side it would be great. Me neither ;-) > I don't see a way to actually enforce this ordering, so maybe we'd want to > add warning in memblock_cap_memory_range() if memblock.memory is empty. "linux,usable-memory-range" is optional, and typically used only in crashdump kernels, so it would be a bad idea to add such a warning. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
Powered by blists - more mailing lists