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From: Dan Williams <dan.j.williams@intel.com>
To: linux-nvdimm@lists.01.org
Cc: x86@kernel.org, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, Al Viro <viro@zeniv.linux.org.uk>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andy Lutomirski <luto@amacapital.net>,
	Peter Zijlstra <peterz@infradead.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Tony Luck <tony.luck@intel.com>,
	hch@lst.de, linux-kernel@vger.kernel.org, tony.luck@intel.com,
	linux-fsdevel@vger.kernel.org
Subject: [PATCH v3 2/9] x86, memcpy_mcsafe: add labels for write fault handling
Date: Thu, 03 May 2018 17:06:16 -0700	[thread overview]
Message-ID: <152539237606.31796.6719743548991782264.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <152539236455.31796.7516599166555186700.stgit@dwillia2-desk3.amr.corp.intel.com>

The memcpy_mcsafe() implementation handles CPU exceptions when reading
from the source address. Before it can be used for user copies it needs
to grow support for handling write faults. In preparation for adding
that exception handling update the labels for the read cache word X case
(.L_cache_rX) and write cache word X case (.L_cache_wX).

Cc: <x86@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reported-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
 arch/x86/lib/memcpy_64.S |   21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S
index 54c971892db5..5709f3ec22a4 100644
--- a/arch/x86/lib/memcpy_64.S
+++ b/arch/x86/lib/memcpy_64.S
@@ -204,13 +204,14 @@ ENTRY(__memcpy_mcsafe)
 	subl $8, %ecx
 	negl %ecx
 	subl %ecx, %edx
-.L_copy_leading_bytes:
+.L_read_leading_bytes:
 	movb (%rsi), %al
+.L_write_leading_bytes:
 	movb %al, (%rdi)
 	incq %rsi
 	incq %rdi
 	decl %ecx
-	jnz .L_copy_leading_bytes
+	jnz .L_read_leading_bytes
 
 .L_8byte_aligned:
 	movl %edx, %ecx
@@ -218,13 +219,14 @@ ENTRY(__memcpy_mcsafe)
 	shrl $3, %ecx
 	jz .L_no_whole_words
 
-.L_copy_words:
+.L_read_words:
 	movq (%rsi), %r8
+.L_write_words:
 	movq %r8, (%rdi)
 	addq $8, %rsi
 	addq $8, %rdi
 	decl %ecx
-	jnz .L_copy_words
+	jnz .L_read_words
 
 	/* Any trailing bytes? */
 .L_no_whole_words:
@@ -233,13 +235,14 @@ ENTRY(__memcpy_mcsafe)
 
 	/* Copy trailing bytes */
 	movl %edx, %ecx
-.L_copy_trailing_bytes:
+.L_read_trailing_bytes:
 	movb (%rsi), %al
+.L_write_trailing_bytes:
 	movb %al, (%rdi)
 	incq %rsi
 	incq %rdi
 	decl %ecx
-	jnz .L_copy_trailing_bytes
+	jnz .L_read_trailing_bytes
 
 	/* Copy successful. Return zero */
 .L_done_memcpy_trap:
@@ -256,7 +259,7 @@ EXPORT_SYMBOL_GPL(__memcpy_mcsafe)
 
 	.previous
 
-	_ASM_EXTABLE_FAULT(.L_copy_leading_bytes, .L_memcpy_mcsafe_fail)
-	_ASM_EXTABLE_FAULT(.L_copy_words, .L_memcpy_mcsafe_fail)
-	_ASM_EXTABLE_FAULT(.L_copy_trailing_bytes, .L_memcpy_mcsafe_fail)
+	_ASM_EXTABLE_FAULT(.L_read_leading_bytes, .L_memcpy_mcsafe_fail)
+	_ASM_EXTABLE_FAULT(.L_read_words, .L_memcpy_mcsafe_fail)
+	_ASM_EXTABLE_FAULT(.L_read_trailing_bytes, .L_memcpy_mcsafe_fail)
 #endif

  parent reply	other threads:[~2018-05-04  0:16 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-05-04  0:06 [PATCH v3 0/9] Series short description Dan Williams
2018-05-04  0:06 ` [PATCH v3 1/9] x86, memcpy_mcsafe: remove loop unrolling Dan Williams
2018-05-04  0:06 ` Dan Williams [this message]
2018-05-04  0:06 ` [PATCH v3 3/9] x86, memcpy_mcsafe: return bytes remaining Dan Williams
2018-05-04  0:06 ` [PATCH v3 4/9] x86, memcpy_mcsafe: add write-protection-fault handling Dan Williams
2018-05-04  0:06 ` [PATCH v3 5/9] x86, memcpy_mcsafe: define copy_to_iter_mcsafe() Dan Williams
2018-05-04  0:06 ` [PATCH v3 6/9] dax: introduce a ->copy_to_iter dax operation Dan Williams
2018-05-23 16:13   ` Ross Zwisler
2018-05-04  0:06 ` [PATCH v3 7/9] dax: report bytes remaining in dax_iomap_actor() Dan Williams
2018-05-23 16:34   ` Ross Zwisler
2018-05-23 16:39     ` Dan Williams
2018-05-23 16:47       ` Ross Zwisler
2018-05-23 16:53         ` Dan Williams
2018-05-23 17:04           ` Ross Zwisler
2018-05-04  0:06 ` [PATCH v3 8/9] pmem: switch to copy_to_iter_mcsafe() Dan Williams
2018-05-23 16:35   ` Ross Zwisler
2018-05-04  0:06 ` [PATCH v3 9/9] x86, nfit_test: unit test for memcpy_mcsafe() Dan Williams

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