From: "Arnd Bergmann" <arnd@arndb.de>
To: "Samuel Holland" <samuel.holland@sifive.com>,
"Palmer Dabbelt" <palmer@dabbelt.com>,
linux-riscv@lists.infradead.org
Cc: "Albert Ou" <aou@eecs.berkeley.edu>,
"Alexandre Ghiti" <alexghiti@rivosinc.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Charlie Jenkins" <charlie@rivosinc.com>,
guoren <guoren@kernel.org>, "Jisheng Zhang" <jszhang@kernel.org>,
"Kemeng Shi" <shikemeng@huaweicloud.com>,
"Matthew Wilcox" <willy@infradead.org>,
"Mike Rapoport" <rppt@kernel.org>,
"Paul Walmsley" <paul.walmsley@sifive.com>,
"Xiao W Wang" <xiao.w.wang@intel.com>,
"Yangyu Chen" <cyy@cyyself.name>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] riscv: Define TASK_SIZE_MAX for __access_ok()
Date: Mon, 25 Mar 2024 21:40:41 +0100 [thread overview]
Message-ID: <3ac65601-7102-4ad1-ad89-157f7d9cef87@app.fastmail.com> (raw)
In-Reply-To: <20240313180010.295747-1-samuel.holland@sifive.com>
On Wed, Mar 13, 2024, at 18:59, Samuel Holland wrote:
> TASK_SIZE_MAX should be set to the largest userspace address under any
> runtime configuration. This optimizes the check in __access_ok(), which
> no longer needs to compute the current value of TASK_SIZE. It is still
> safe because addresses between TASK_SIZE and TASK_SIZE_MAX are invalid
> at the hardware level.
>
> This removes about half of the references to pgtable_l[45]_enabled.
>
> Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> #ifdef CONFIG_64BIT
> #define TASK_SIZE_64 (PGDIR_SIZE * PTRS_PER_PGD / 2)
> #define TASK_SIZE_MIN (PGDIR_SIZE_L3 * PTRS_PER_PGD / 2)
> +#define TASK_SIZE_MAX (PGDIR_SIZE_L5 * PTRS_PER_PGD / 2)
I see that TASK_SIZE_MIN is unused since 085e2ff9aeb0 ("efi:
libstub: Drop randomization of runtime memory map") and could
be dropped now, but it doesn't really hurt either.
Arnd
prev parent reply other threads:[~2024-03-25 20:41 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-13 17:59 Samuel Holland
2024-03-18 20:50 ` Alexandre Ghiti
2024-03-18 21:29 ` Samuel Holland
2024-03-19 16:51 ` Alexandre Ghiti
2024-03-24 19:42 ` David Laight
2024-03-25 7:30 ` Alexandre Ghiti
2024-03-25 9:30 ` David Laight
2024-03-25 16:39 ` Mark Rutland
2024-03-25 18:02 ` Arnd Bergmann
2024-03-25 18:30 ` Mark Rutland
2024-03-25 19:20 ` Samuel Holland
2024-03-25 20:38 ` Arnd Bergmann
2024-03-26 10:19 ` David Laight
2024-03-26 14:49 ` Mark Rutland
2024-03-25 20:12 ` Alexandre Ghiti
2024-03-24 22:05 ` Arnd Bergmann
2024-03-25 7:25 ` Alexandre Ghiti
2024-03-25 11:15 ` Arnd Bergmann
2024-03-25 20:40 ` Arnd Bergmann [this message]
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