From: Kees Cook <keescook@chromium.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Liam R. Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>,
Lorenzo Stoakes <lstoakes@gmail.com>,
linux-mm@kvack.org, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Peter Zijlstra <peterz@infradead.org>,
Tony Luck <tony.luck@intel.com>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
linux-hardening@vger.kernel.org,
Guenter Roeck <linux@roeck-us.net>,
Ross Zwisler <zwisler@google.com>,
wklin@google.com,
Vineeth Remanan Pillai <vineeth@bitbyteword.org>,
Joel Fernandes <joel@joelfernandes.org>,
Suleiman Souhlal <suleiman@google.com>,
Linus Torvalds <torvalds@linuxfoundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>
Subject: Re: [POC][RFC][PATCH 1/2] mm/x86: Add wildcard * option as memmap=nn*align:name
Date: Tue, 9 Apr 2024 15:23:07 -0700 [thread overview]
Message-ID: <202404091521.B63E85D@keescook> (raw)
In-Reply-To: <20240409211351.075320273@goodmis.org>
On Tue, Apr 09, 2024 at 05:02:55PM -0400, Steven Rostedt wrote:
> From: "Steven Rostedt (Google)" <rostedt@goodmis.org>
>
> In order to allow for requesting a memory region that can be used for
> things like pstore on multiple machines where the memory is not the same,
> add a new option to the memmap=nn$ kernel command line.
>
> The memmap=nn$addr will reserve nn amount of memory at the physical
> address addr. To use this, one must know the physical memory layout and
> know where usable memory exists in the physical layout.
>
> Add a '*' option that will assign memory by looking for a range that can
> fit the given size and alignment. It will start at the high addresses, and
> then work its way down.
>
> The format is: memmap=nn*align:name
>
> Where it will find nn amount of memory at the given alignment of align.
> The name field is to allow another subsystem to retrieve where the memory
> was found. For example:
>
> memmap=12M*4096:oops ramoops.mem_name=oops
>
> Where ramoops.mem_name will tell ramoops that memory was reserved for it
> via the wildcard '*' option and it can find it by calling:
>
> if (memmap_named("oops", &start, &size)) {
> // start holds the start address and size holds the size given
>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
> arch/x86/kernel/e820.c | 91 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/mm.h | 2 +
> mm/memory.c | 7 ++++
> 3 files changed, 100 insertions(+)
Do we need to involve e820 at all? I think it might be possible to just
have pstore call request_mem_region() very early? Or does KASLR make
that unstable?
--
Kees Cook
next prev parent reply other threads:[~2024-04-09 22:23 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-09 21:02 [POC][RFC][PATCH 0/2] pstore/mm/x86: Add wildcard memmap to map pstore consistently Steven Rostedt
2024-04-09 21:02 ` [POC][RFC][PATCH 1/2] mm/x86: Add wildcard * option as memmap=nn*align:name Steven Rostedt
2024-04-09 22:23 ` Kees Cook [this message]
2024-04-09 23:11 ` Steven Rostedt
2024-04-09 23:41 ` Kees Cook
2024-04-12 20:59 ` Mike Rapoport
2024-04-12 22:19 ` Steven Rostedt
2024-04-15 17:22 ` Kees Cook
2024-05-01 14:57 ` Mike Rapoport
2024-05-06 10:38 ` Ard Biesheuvel
2024-05-08 23:23 ` Steven Rostedt
2024-04-09 21:02 ` [POC][RFC][PATCH 2/2] pstore/ramoops: Add ramoops.mem_name= command line option Steven Rostedt
2024-04-09 22:18 ` Kees Cook
2024-04-09 23:14 ` Steven Rostedt
2024-04-09 21:23 ` [POC][RFC][PATCH 0/2] pstore/mm/x86: Add wildcard memmap to map pstore consistently Steven Rostedt
2024-04-09 22:19 ` Kees Cook
2024-04-09 22:25 ` Luck, Tony
2024-04-09 22:41 ` Joel Fernandes
2024-04-09 23:16 ` Steven Rostedt
2024-04-09 23:37 ` Kees Cook
2024-04-09 23:52 ` Luck, Tony
2024-04-11 19:11 ` Guilherme G. Piccoli
2024-04-11 19:40 ` Steven Rostedt
2024-04-12 12:17 ` Guilherme G. Piccoli
2024-04-12 17:22 ` Steven Rostedt
2024-05-01 14:45 ` Mike Rapoport
2024-05-01 14:54 ` Steven Rostedt
2024-05-01 15:30 ` Mike Rapoport
2024-05-01 16:09 ` Steven Rostedt
2024-05-01 16:11 ` Mike Rapoport
2024-05-09 4:00 ` Steven Rostedt
2024-05-09 17:31 ` Steven Rostedt
2024-05-09 20:24 ` Mike Rapoport
2024-05-09 20:33 ` Steven Rostedt
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