Commit 861574d51bbd ("powerpc/uaccess: Implement masked user access")
provides optimised user access by avoiding the cost of access_ok().
Convert csum_and_copy_to_user() and csum_and_copy_from_user() to
scoped user access to benefit from masked user access.
csum_and_copy_to_user() and csum_and_copy_from_user() are only
called respectively by csum_and_copy_to_iter() and
csum_and_copy_from_iter_full() and they are only called twice.
Those functions used to be large but they were first reduced by
commit c693cc4676a0 ("saner calling conventions for
csum_and_copy_..._user()") then commit 70d65cd555c5 ("ppc: propagate
the calling conventions change down to csum_partial_copy_generic()").
With the additional size reduction provided by conversion to scoped
user access they are not worth being kept out of line.
$ ./scripts/bloat-o-meter vmlinux.0 vmlinux.1
add/remove: 0/2 grow/shrink: 2/0 up/down: 136/-176 (-40)
Function old new delta
csum_and_copy_to_iter 2416 2488 +72
csum_and_copy_from_iter_full 2272 2336 +64
csum_and_copy_to_user 88 - -88
csum_and_copy_from_user 88 - -88
Total: Before=11514471, After=11514431, chg -0.00%
Signed-off-by: Christophe Leroy (CS GROUP) <[email protected]>
---
This patch applies on top of v7.0-rc3, it requires commit af4e9ef3d784
("uaccess: Fix scoped_user_read_access() for 'pointer to const'")
---
arch/powerpc/include/asm/checksum.h | 22 +++++++++++++---
arch/powerpc/lib/Makefile | 3 +--
arch/powerpc/lib/checksum_wrappers.c | 39 ----------------------------
3 files changed, 19 insertions(+), 45 deletions(-)
delete mode 100644 arch/powerpc/lib/checksum_wrappers.c
diff --git a/arch/powerpc/include/asm/checksum.h
b/arch/powerpc/include/asm/checksum.h
index 4b573a3b7e17..52921ea2494a 100644
--- a/arch/powerpc/include/asm/checksum.h
+++ b/arch/powerpc/include/asm/checksum.h
@@ -8,6 +8,7 @@
#include <linux/bitops.h>
#include <linux/in6.h>
+#include <linux/uaccess.h>
/*
* Computes the checksum of a memory block at src, length len,
* and adds in "sum" (32-bit), while copying the block to dst.
@@ -21,11 +22,24 @@
extern __wsum csum_partial_copy_generic(const void *src, void *dst, int len);
#define _HAVE_ARCH_COPY_AND_CSUM_FROM_USER
-extern __wsum csum_and_copy_from_user(const void __user *src, void *dst,
- int len);
+static inline __wsum csum_and_copy_from_user(const void __user *src, void
*dst, int len)
+{
+ scoped_user_read_access_size(src, len, efault)
+ return csum_partial_copy_generic((void __force *)src, dst, len);
+
+efault:
+ return 0;
+}
+
#define HAVE_CSUM_COPY_USER
-extern __wsum csum_and_copy_to_user(const void *src, void __user *dst,
- int len);
+static inline __wsum csum_and_copy_to_user(const void *src, void __user *dst,
int len)
+{
+ scoped_user_write_access_size(dst, len, efault)
+ return csum_partial_copy_generic(src, (void __force *)dst, len);
+
+efault:
+ return 0;
+}
#define _HAVE_ARCH_CSUM_AND_COPY
#define csum_partial_copy_nocheck(src, dst, len) \
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index f14ecab674a3..bcdf387f3998 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -62,8 +62,7 @@ obj64-$(CONFIG_ALTIVEC) += vmx-helper.o
obj64-$(CONFIG_KPROBES_SANITY_TEST) += test_emulate_step.o \
test_emulate_step_exec_instr.o
-obj-y += checksum_$(BITS).o checksum_wrappers.o \
- string_$(BITS).o
+obj-y += checksum_$(BITS).o string_$(BITS).o
obj-y += sstep.o
obj-$(CONFIG_PPC_FPU) += ldstfp.o
diff --git a/arch/powerpc/lib/checksum_wrappers.c
b/arch/powerpc/lib/checksum_wrappers.c
deleted file mode 100644
index 1a14c8780278..000000000000
--- a/arch/powerpc/lib/checksum_wrappers.c
+++ /dev/null
@@ -1,39 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- *
- * Copyright (C) IBM Corporation, 2010
- *
- * Author: Anton Blanchard <[email protected]>
- */
-#include <linux/export.h>
-#include <linux/compiler.h>
-#include <linux/types.h>
-#include <asm/checksum.h>
-#include <linux/uaccess.h>
-
-__wsum csum_and_copy_from_user(const void __user *src, void *dst,
- int len)
-{
- __wsum csum;
-
- if (unlikely(!user_read_access_begin(src, len)))
- return 0;
-
- csum = csum_partial_copy_generic((void __force *)src, dst, len);
-
- user_read_access_end();
- return csum;
-}
-
-__wsum csum_and_copy_to_user(const void *src, void __user *dst, int len)
-{
- __wsum csum;
-
- if (unlikely(!user_write_access_begin(dst, len)))
- return 0;
-
- csum = csum_partial_copy_generic(src, (void __force *)dst, len);
-
- user_write_access_end();
- return csum;
-}
--
2.49.0
