All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sami Tolvanen <samitolvanen@google.com>
To: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	 Albert Ou <aou@eecs.berkeley.edu>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Kees Cook <keescook@chromium.org>
Cc: linux-mm@kvack.org, linux-riscv@lists.infradead.org,
	llvm@lists.linux.dev,  linux-kernel@vger.kernel.org,
	Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH 2/2] riscv: mm: Update mmap_rnd_bits_max
Date: Fri, 29 Sep 2023 21:11:58 +0000	[thread overview]
Message-ID: <20230929211155.3910949-6-samitolvanen@google.com> (raw)
In-Reply-To: <20230929211155.3910949-4-samitolvanen@google.com>

ARCH_MMAP_RND_BITS_MAX is based on Sv39, which leaves a few
potential bits of mmap randomness on the table if we end up enabling
4/5-level paging. Update mmap_rnd_bits_max to take the final address
space size into account. This increases mmap_rnd_bits_max from 24 to
33 with Sv48/57.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/riscv/mm/init.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 0798bd861dcb..ff8d21a6cb2d 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -762,6 +762,11 @@ static int __init print_no5lvl(char *p)
 }
 early_param("no5lvl", print_no5lvl);
 
+static void __init set_mmap_rnd_bits_max(void)
+{
+	mmap_rnd_bits_max = MMAP_VA_BITS - PAGE_SHIFT - 3;
+}
+
 /*
  * There is a simple way to determine if 4-level is supported by the
  * underlying hardware: establish 1:1 mapping in 4-level page table mode
@@ -1071,6 +1076,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 
 #if defined(CONFIG_64BIT) && !defined(CONFIG_XIP_KERNEL)
 	set_satp_mode(dtb_pa);
+	set_mmap_rnd_bits_max();
 #endif
 
 	/*
-- 
2.42.0.582.g8ccd20d70d-goog


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

WARNING: multiple messages have this Message-ID (diff)
From: Sami Tolvanen <samitolvanen@google.com>
To: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	 Albert Ou <aou@eecs.berkeley.edu>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Kees Cook <keescook@chromium.org>
Cc: linux-mm@kvack.org, linux-riscv@lists.infradead.org,
	llvm@lists.linux.dev,  linux-kernel@vger.kernel.org,
	Sami Tolvanen <samitolvanen@google.com>
Subject: [PATCH 2/2] riscv: mm: Update mmap_rnd_bits_max
Date: Fri, 29 Sep 2023 21:11:58 +0000	[thread overview]
Message-ID: <20230929211155.3910949-6-samitolvanen@google.com> (raw)
In-Reply-To: <20230929211155.3910949-4-samitolvanen@google.com>

ARCH_MMAP_RND_BITS_MAX is based on Sv39, which leaves a few
potential bits of mmap randomness on the table if we end up enabling
4/5-level paging. Update mmap_rnd_bits_max to take the final address
space size into account. This increases mmap_rnd_bits_max from 24 to
33 with Sv48/57.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
---
 arch/riscv/mm/init.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 0798bd861dcb..ff8d21a6cb2d 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -762,6 +762,11 @@ static int __init print_no5lvl(char *p)
 }
 early_param("no5lvl", print_no5lvl);
 
+static void __init set_mmap_rnd_bits_max(void)
+{
+	mmap_rnd_bits_max = MMAP_VA_BITS - PAGE_SHIFT - 3;
+}
+
 /*
  * There is a simple way to determine if 4-level is supported by the
  * underlying hardware: establish 1:1 mapping in 4-level page table mode
@@ -1071,6 +1076,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
 
 #if defined(CONFIG_64BIT) && !defined(CONFIG_XIP_KERNEL)
 	set_satp_mode(dtb_pa);
+	set_mmap_rnd_bits_max();
 #endif
 
 	/*
-- 
2.42.0.582.g8ccd20d70d-goog


  parent reply	other threads:[~2023-09-29 21:12 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-29 21:11 [PATCH 0/2] riscv: Increase mmap_rnd_bits_max on Sv48/57 Sami Tolvanen
2023-09-29 21:11 ` Sami Tolvanen
2023-09-29 21:11 ` [PATCH 1/2] mm: Change mmap_rnd_bits_max to __ro_after_init Sami Tolvanen
2023-09-29 21:11   ` Sami Tolvanen
2023-09-29 21:55   ` Kees Cook
2023-09-29 21:55     ` Kees Cook
2023-09-29 21:11 ` Sami Tolvanen [this message]
2023-09-29 21:11   ` [PATCH 2/2] riscv: mm: Update mmap_rnd_bits_max Sami Tolvanen
2023-09-29 21:54   ` Kees Cook
2023-09-29 21:54     ` Kees Cook
2023-09-29 22:52     ` Sami Tolvanen
2023-09-29 22:52       ` Sami Tolvanen
2023-09-30  9:02       ` Conor Dooley
2023-09-30  9:02         ` Conor Dooley
2023-09-30 21:01         ` Kees Cook
2023-09-30 21:01           ` Kees Cook
2023-10-01 15:19           ` Pedro Falcato
2023-10-01 15:19             ` Pedro Falcato
2023-10-02  7:02             ` Alexandre Ghiti
2023-10-02  7:02               ` Alexandre Ghiti
2023-10-02 15:58               ` Sami Tolvanen
2023-10-02 15:58                 ` Sami Tolvanen
2023-12-06 13:14 ` [PATCH 0/2] riscv: Increase mmap_rnd_bits_max on Sv48/57 Palmer Dabbelt
2023-12-06 13:14   ` Palmer Dabbelt
2023-12-06 20:28   ` Kees Cook
2023-12-06 20:28     ` Kees Cook
2024-01-17 20:29   ` Sami Tolvanen
2024-01-17 20:29     ` Sami Tolvanen
2024-01-25 21:30 ` patchwork-bot+linux-riscv
2024-01-25 21:30   ` patchwork-bot+linux-riscv

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20230929211155.3910949-6-samitolvanen@google.com \
    --to=samitolvanen@google.com \
    --cc=akpm@linux-foundation.org \
    --cc=aou@eecs.berkeley.edu \
    --cc=keescook@chromium.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=llvm@lists.linux.dev \
    --cc=palmer@dabbelt.com \
    --cc=paul.walmsley@sifive.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.