From: Christoph Hellwig <hch@lst.de>
To: x86@kernel.org, Jan Kara <jack@suse.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, linux-arch@vger.kernel.org
Subject: [PATCH 3/4] compat: add a compat_need_64bit_alignment_fixup() helper
Date: Sun, 26 Jul 2020 18:04:00 +0200 [thread overview]
Message-ID: <20200726160401.311569-4-hch@lst.de> (raw)
In-Reply-To: <20200726160401.311569-1-hch@lst.de>
Add a helper to check if the calling syscall needs a fixup for
non-natural 64-bit type alignment in the compat ABI. This will only
return true for i386 syscalls on x86_64.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/x86/include/asm/compat.h | 1 +
include/linux/compat.h | 9 +++++++++
2 files changed, 10 insertions(+)
diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h
index bf547701f41f87..0e327a01f50fbb 100644
--- a/arch/x86/include/asm/compat.h
+++ b/arch/x86/include/asm/compat.h
@@ -209,6 +209,7 @@ static inline bool in_compat_syscall(void)
return in_32bit_syscall();
}
#define in_compat_syscall in_compat_syscall /* override the generic impl */
+#define compat_need_64bit_alignment_fixup in_ia32_syscall
#endif
struct compat_siginfo;
diff --git a/include/linux/compat.h b/include/linux/compat.h
index c22a7f1d253b87..afdd44ba3a8869 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -945,6 +945,15 @@ static inline bool in_compat_syscall(void) { return false; }
#endif /* CONFIG_COMPAT */
+/*
+ * Some legacy ABIs like the i386 one use less than natural alignment for 64-bit
+ * types, and will need special compat treatment for that. Most architectures
+ * don't need that special handling even for compat syscalls.
+ */
+#ifndef compat_need_64bit_alignment_fixup
+#define compat_need_64bit_alignment_fixup() false
+#endif
+
/*
* A pointer passed in from user mode. This should not
* be used for syscall parameters, just declare them
--
2.27.0
next prev parent reply other threads:[~2020-07-26 16:04 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-26 16:03 improve compat handling for the i386 u64 alignment quirk Christoph Hellwig
2020-07-26 16:03 ` [PATCH 1/4] arm64: stop using <asm/compat.h> directly Christoph Hellwig
2020-07-30 17:34 ` Nathan Chancellor
2020-07-31 8:41 ` Naresh Kamboju
2020-07-26 16:03 ` [PATCH 2/4] compat: lift compat_s64 and compat_u64 to <linux/compat.h> Christoph Hellwig
2020-07-29 6:08 ` [PATCH 2/4 v2] " Christoph Hellwig
2020-07-26 16:04 ` Christoph Hellwig [this message]
2020-07-26 16:04 ` [PATCH 4/4] quota: simplify the quotactl compat handling Christoph Hellwig
2020-07-26 16:32 ` Al Viro
2020-07-26 16:34 ` Christoph Hellwig
2020-07-26 16:37 ` Al Viro
2020-07-27 12:41 ` Jan Kara
2020-07-27 15:56 ` Al Viro
2020-07-27 21:31 ` Jan Kara
2020-07-28 1:49 ` Al Viro
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