linux-kernel - [PATCH 3/3] mm, thp: make mapping address of PIC binaries THP align

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Date:   Sat,  9 Oct 2021 17:26:58 +0800
From:   Rongwei Wang <rongwei.wang@...ux.alibaba.com>
To:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        linux-fsdevel@...r.kernel.org
Cc:     akpm@...ux-foundation.org, willy@...radead.org,
        viro@...iv.linux.org.uk, song@...nel.org,
        william.kucharski@...cle.com, hughd@...gle.com,
        shy828301@...il.com, linmiaohe@...wei.com, peterx@...hat.com
Subject: [PATCH 3/3] mm, thp: make mapping address of PIC binaries THP align

For binaries that are compiled with '--pie -fPIC' and with LOAD
alignment smaller than 2M (typically 4K, 64K), the load address
is least likely to be 2M aligned.

This changes the maximum_alignment of such binaries to 2M to
facilitate file THP for .text section as far as possible.

Signed-off-by: Gang Deng <gavin.dg@...ux.alibaba.com>
Signed-off-by: Xu Yu <xuyu@...ux.alibaba.com>
Signed-off-by: Rongwei Wang <rongwei.wang@...ux.alibaba.com>
---
 fs/binfmt_elf.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index a813b70f594e..78795572d877 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -1136,6 +1136,11 @@ static int load_elf_binary(struct linux_binprm *bprm)
 				retval = -EINVAL;
 				goto out_free_dentry;
 			}
+#ifdef CONFIG_HUGETEXT
+			if (hugetext_enabled() && interpreter &&
+					total_size >= HPAGE_PMD_SIZE)
+				load_bias &= HPAGE_PMD_MASK;
+#endif
 		}
 
 		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
-- 
2.27.0