LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: [PATCH v2 4/5] powerpc/uaccess: Add unsafe_clear_user()
Date: Mon, 23 Aug 2021 15:35:54 +0000 (UTC) [thread overview]
Message-ID: <ba0ea6e1fdb49d241a8be7d14fd5c13f76e2b7c8.1629732940.git.christophe.leroy@csgroup.eu> (raw)
In-Reply-To: <fd7938d94008711d441551c06b25a033669a0618.1629732940.git.christophe.leroy@csgroup.eu>
Implement unsafe_clear_user() for powerpc.
It's a copy/paste of unsafe_copy_to_user() with value 0 as source.
It may be improved in a later patch by using 'dcbz' instruction
to zeroize full cache lines at once.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
arch/powerpc/include/asm/uaccess.h | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index 22c79ab40006..962b675485ff 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -467,6 +467,26 @@ do { \
unsafe_put_user(*(u8*)(_src + _i), (u8 __user *)(_dst + _i), e); \
} while (0)
+#define unsafe_clear_user(d, l, e) \
+do { \
+ u8 __user *_dst = (u8 __user *)(d); \
+ size_t _len = (l); \
+ int _i; \
+ \
+ for (_i = 0; _i < (_len & ~(sizeof(u64) - 1)); _i += sizeof(u64)) \
+ unsafe_put_user(0, (u64 __user *)(_dst + _i), e); \
+ if (_len & 4) { \
+ unsafe_put_user(0, (u32 __user *)(_dst + _i), e); \
+ _i += 4; \
+ } \
+ if (_len & 2) { \
+ unsafe_put_user(0, (u16 __user *)(_dst + _i), e); \
+ _i += 2; \
+ } \
+ if (_len & 1) \
+ unsafe_put_user(0, (u8 __user *)(_dst + _i), e); \
+} while (0)
+
#define HAVE_GET_KERNEL_NOFAULT
#define __get_kernel_nofault(dst, src, type, err_label) \
--
2.25.0
next prev parent reply other threads:[~2021-08-23 15:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-23 15:35 [PATCH v2 1/5] powerpc/signal64: Access function descriptor with user access block Christophe Leroy
2021-08-23 15:35 ` [PATCH v2 2/5] powerpc/signal: Include the new stack frame inside the " Christophe Leroy
2021-08-23 15:35 ` [PATCH v2 3/5] signal: Add unsafe_copy_siginfo_to_user() Christophe Leroy
2021-09-02 6:54 ` Christoph Hellwig
2021-09-02 16:05 ` Linus Torvalds
2021-09-13 12:59 ` Christophe Leroy
2021-09-02 18:43 ` Eric W. Biederman
2021-09-03 8:56 ` Christophe Leroy
2021-09-08 18:17 ` Eric W. Biederman
2021-09-10 10:27 ` Christophe Leroy
2021-09-11 15:58 ` Eric W. Biederman
2021-09-13 12:56 ` Christophe Leroy
2021-08-23 15:35 ` Christophe Leroy [this message]
2021-08-23 15:35 ` [PATCH v2 5/5] powerpc/signal: Use unsafe_copy_siginfo_to_user() Christophe Leroy
2021-09-02 18:38 ` Eric W. Biederman
2021-09-03 8:53 ` Christophe Leroy
2021-09-02 6:49 ` [PATCH v2 1/5] powerpc/signal64: Access function descriptor with user access block Christoph Hellwig
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=ba0ea6e1fdb49d241a8be7d14fd5c13f76e2b7c8.1629732940.git.christophe.leroy@csgroup.eu \
--to=christophe.leroy@csgroup.eu \
--cc=benh@kernel.crashing.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mpe@ellerman.id.au \
--cc=paulus@samba.org \
--subject='Re: [PATCH v2 4/5] powerpc/uaccess: Add unsafe_clear_user()' \
/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
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).