[PATCH 4.9 24/31] ARM: 8805/2: remove unneeded naked function usage

Greg Kroah-Hartman
2021-12-20T14:39:04Z

From: Nicolas Pitre <nicolas.pitre@linaro.org>

commit b99afae1390140f5b0039e6b37a7380de31ae874 upstream.

The naked attribute is known to confuse some old gcc versions when
function arguments aren't explicitly listed as inline assembly operands
despite the gcc documentation. That resulted in commit 9a40ac86152c
("ARM: 6164/1: Add kto and kfrom to input operands list.").

Yet that commit has problems of its own by having assembly operand
constraints completely wrong. If the generated code has been OK since
then, it is due to luck rather than correctness. So this patch also
provides proper assembly operand constraints, and removes two instances
of redundant register usages in the implementation while at it.

Inspection of the generated code with this patch doesn't show any
obvious quality degradation either, so not relying on __naked at all
will make the code less fragile, and avoid some issues with clang.

The only remaining __naked instances (excluding the kprobes test cases)
are exynos_pm_power_up_setup(), tc2_pm_power_up_setup() and

cci_enable_port_for_self(. But in the first two cases, only the function
address is used by the compiler with no chance of inlining it by
mistake, and the third case is called from assembly code only. And the
fact that no stack is available when the corresponding code is executed
does warrant the __naked usage in those cases.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Reviewed-by: Stefan Agner <stefan@agner.ch>
Tested-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Anders Roxell <anders.roxell@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm/mm/copypage-fa.c | 35 ++++++--------
arch/arm/mm/copypage-feroceon.c | 98 +++++++++++++++++++---------------------
arch/arm/mm/copypage-v4mc.c | 19 +++----
arch/arm/mm/copypage-v4wb.c | 41 ++++++++--------
arch/arm/mm/copypage-v4wt.c | 37 +++++++--------
arch/arm/mm/copypage-xsc3.c | 71 ++++++++++++----------------
arch/arm/mm/copypage-xscale.c | 71 ++++++++++++++--------------
7 files changed, 178 insertions(+), 194 deletions(-)

--- a/arch/arm/mm/copypage-fa.c
+++ b/arch/arm/mm/copypage-fa.c
@@ -17,26 +17,25 @@
/*
* Faraday optimised copy_user_page
*/
-static void __naked
-fa_copy_user_page(void *kto, const void *kfrom)
+static void fa_copy_user_page(void *kto, const void *kfrom)
{
- asm("\
- stmfd sp!, {r4, lr} @ 2\n\
- mov r2, %0 @ 1\n\
-1: ldmia r1!, {r3, r4, ip, lr} @ 4\n\
- stmia r0, {r3, r4, ip, lr} @ 4\n\
- mcr p15, 0, r0, c7, c14, 1 @ 1 clean and invalidate D line\n\
- add r0, r0, #16 @ 1\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4\n\
- stmia r0, {r3, r4, ip, lr} @ 4\n\
- mcr p15, 0, r0, c7, c14, 1 @ 1 clean and invalidate D line\n\
- add r0, r0, #16 @ 1\n\
- subs r2, r2, #1 @ 1\n\
+ int tmp;
+
+ asm volatile ("\
+1: ldmia %1!, {r3, r4, ip, lr} @ 4\n\
+ stmia %0, {r3, r4, ip, lr} @ 4\n\
+ mcr p15, 0, %0, c7, c14, 1 @ 1 clean and invalidate D line\n\
+ add %0, %0, #16 @ 1\n\
+ ldmia %1!, {r3, r4, ip, lr} @ 4\n\
+ stmia %0, {r3, r4, ip, lr} @ 4\n\
+ mcr p15, 0, %0, c7, c14, 1 @ 1 clean and invalidate D line\n\
+ add %0, %0, #16 @ 1\n\
+ subs %2, %2, #1 @ 1\n\
bne 1b @ 1\n\
- mcr p15, 0, r2, c7, c10, 4 @ 1 drain WB\n\
- ldmfd sp!, {r4, pc} @ 3"
- :
- : "I" (PAGE_SIZE / 32));
+ mcr p15, 0, %2, c7, c10, 4 @ 1 drain WB"
+ : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
+ : "2" (PAGE_SIZE / 32)
+ : "r3", "r4", "ip", "lr");
}

void fa_copy_user_highpage(struct page *to, struct page *from,
--- a/arch/arm/mm/copypage-feroceon.c
+++ b/arch/arm/mm/copypage-feroceon.c
@@ -13,58 +13,56 @@
#include <linux/init.h>
#include <linux/highmem.h>

-static void __naked
-feroceon_copy_user_page(void *kto, const void *kfrom)
+static void feroceon_copy_user_page(void *kto, const void *kfrom)
{
- asm("\
- stmfd sp!, {r4-r9, lr} \n\
- mov ip, %2 \n\
-1: mov lr, r1 \n\
- ldmia r1!, {r2 - r9} \n\
- pld [lr, #32] \n\
- pld [lr, #64] \n\
- pld [lr, #96] \n\
- pld [lr, #128] \n\
- pld [lr, #160] \n\
- pld [lr, #192] \n\
- pld [lr, #224] \n\
- stmia r0, {r2 - r9} \n\
- ldmia r1!, {r2 - r9} \n\
- mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D line\n\
- add r0, r0, #32 \n\
- stmia r0, {r2 - r9} \n\
- ldmia r1!, {r2 - r9} \n\
- mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D line\n\
- add r0, r0, #32 \n\
- stmia r0, {r2 - r9} \n\
- ldmia r1!, {r2 - r9} \n\
- mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D line\n\
- add r0, r0, #32 \n\
- stmia r0, {r2 - r9} \n\
- ldmia r1!, {r2 - r9} \n\
- mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D line\n\
- add r0, r0, #32 \n\
- stmia r0, {r2 - r9} \n\
- ldmia r1!, {r2 - r9} \n\
- mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D line\n\
- add r0, r0, #32 \n\
- stmia r0, {r2 - r9} \n\
- ldmia r1!, {r2 - r9} \n\
- mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D line\n\
- add r0, r0, #32 \n\
- stmia r0, {r2 - r9} \n\
- ldmia r1!, {r2 - r9} \n\
- mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D line\n\
- add r0, r0, #32 \n\
- stmia r0, {r2 - r9} \n\
- subs ip, ip, #(32 * 8) \n\
- mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D line\n\
- add r0, r0, #32 \n\
+ int tmp;
+
+ asm volatile ("\
+1: ldmia %1!, {r2 - r7, ip, lr} \n\
+ pld [%1, #0] \n\
+ pld [%1, #32] \n\
+ pld [%1, #64] \n\
+ pld [%1, #96] \n\
+ pld [%1, #128] \n\
+ pld [%1, #160] \n\
+ pld [%1, #192] \n\
+ stmia %0, {r2 - r7, ip, lr} \n\
+ ldmia %1!, {r2 - r7, ip, lr} \n\
+ mcr p15, 0, %0, c7, c14, 1 @ clean and invalidate D line\n\
+ add %0, %0, #32 \n\
+ stmia %0, {r2 - r7, ip, lr} \n\
+ ldmia %1!, {r2 - r7, ip, lr} \n\
+ mcr p15, 0, %0, c7, c14, 1 @ clean and invalidate D line\n\
+ add %0, %0, #32 \n\
+ stmia %0, {r2 - r7, ip, lr} \n\
+ ldmia %1!, {r2 - r7, ip, lr} \n\
+ mcr p15, 0, %0, c7, c14, 1 @ clean and invalidate D line\n\
+ add %0, %0, #32 \n\
+ stmia %0, {r2 - r7, ip, lr} \n\
+ ldmia %1!, {r2 - r7, ip, lr} \n\
+ mcr p15, 0, %0, c7, c14, 1 @ clean and invalidate D line\n\
+ add %0, %0, #32 \n\
+ stmia %0, {r2 - r7, ip, lr} \n\
+ ldmia %1!, {r2 - r7, ip, lr} \n\
+ mcr p15, 0, %0, c7, c14, 1 @ clean and invalidate D line\n\
+ add %0, %0, #32 \n\
+ stmia %0, {r2 - r7, ip, lr} \n\
+ ldmia %1!, {r2 - r7, ip, lr} \n\
+ mcr p15, 0, %0, c7, c14, 1 @ clean and invalidate D line\n\
+ add %0, %0, #32 \n\
+ stmia %0, {r2 - r7, ip, lr} \n\
+ ldmia %1!, {r2 - r7, ip, lr} \n\
+ mcr p15, 0, %0, c7, c14, 1 @ clean and invalidate D line\n\
+ add %0, %0, #32 \n\
+ stmia %0, {r2 - r7, ip, lr} \n\
+ subs %2, %2, #(32 * 8) \n\
+ mcr p15, 0, %0, c7, c14, 1 @ clean and invalidate D line\n\
+ add %0, %0, #32 \n\
bne 1b \n\
- mcr p15, 0, ip, c7, c10, 4 @ drain WB\n\
- ldmfd sp!, {r4-r9, pc}"
- :
- : "r" (kto), "r" (kfrom), "I" (PAGE_SIZE));
+ mcr p15, 0, %2, c7, c10, 4 @ drain WB"
+ : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
+ : "2" (PAGE_SIZE)
+ : "r2", "r3", "r4", "r5", "r6", "r7", "ip", "lr");
}

void feroceon_copy_user_highpage(struct page *to, struct page *from,
--- a/arch/arm/mm/copypage-v4mc.c
+++ b/arch/arm/mm/copypage-v4mc.c
@@ -40,12 +40,11 @@ static DEFINE_RAW_SPINLOCK(minicache_loc
* instruction. If your processor does not supply this, you have to write your
* own copy_user_highpage that does the right thing.
*/
-static void __naked
-mc_copy_user_page(void *from, void *to)
+static void mc_copy_user_page(void *from, void *to)
{
- asm volatile(
- "stmfd sp!, {r4, lr} @ 2\n\
- mov r4, %2 @ 1\n\
+ int tmp;
+
+ asm volatile ("\
ldmia %0!, {r2, r3, ip, lr} @ 4\n\
1: mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\
stmia %1!, {r2, r3, ip, lr} @ 4\n\
@@ -55,13 +54,13 @@ mc_copy_user_page(void *from, void *to)
mcr p15, 0, %1, c7, c6, 1 @ 1 invalidate D line\n\
stmia %1!, {r2, r3, ip, lr} @ 4\n\
ldmia %0!, {r2, r3, ip, lr} @ 4\n\
- subs r4, r4, #1 @ 1\n\
+ subs %2, %2, #1 @ 1\n\
stmia %1!, {r2, r3, ip, lr} @ 4\n\
ldmneia %0!, {r2, r3, ip, lr} @ 4\n\
- bne 1b @ 1\n\
- ldmfd sp!, {r4, pc} @ 3"
- :
- : "r" (from), "r" (to), "I" (PAGE_SIZE / 64));
+ bne 1b @ "
+ : "+&r" (from), "+&r" (to), "=&r" (tmp)
+ : "2" (PAGE_SIZE / 64)
+ : "r2", "r3", "ip", "lr");
}

void v4_mc_copy_user_highpage(struct page *to, struct page *from,
--- a/arch/arm/mm/copypage-v4wb.c
+++ b/arch/arm/mm/copypage-v4wb.c
@@ -22,29 +22,28 @@
* instruction. If your processor does not supply this, you have to write your
* own copy_user_highpage that does the right thing.
*/
-static void __naked
-v4wb_copy_user_page(void *kto, const void *kfrom)
+static void v4wb_copy_user_page(void *kto, const void *kfrom)
{
- asm("\
- stmfd sp!, {r4, lr} @ 2\n\
- mov r2, %2 @ 1\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4\n\
-1: mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line\n\
- stmia r0!, {r3, r4, ip, lr} @ 4\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4+1\n\
- stmia r0!, {r3, r4, ip, lr} @ 4\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4\n\
- mcr p15, 0, r0, c7, c6, 1 @ 1 invalidate D line\n\
- stmia r0!, {r3, r4, ip, lr} @ 4\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4\n\
- subs r2, r2, #1 @ 1\n\
- stmia r0!, {r3, r4, ip, lr} @ 4\n\
- ldmneia r1!, {r3, r4, ip, lr} @ 4\n\
+ int tmp;
+
+ asm volatile ("\
+ ldmia %1!, {r3, r4, ip, lr} @ 4\n\
+1: mcr p15, 0, %0, c7, c6, 1 @ 1 invalidate D line\n\
+ stmia %0!, {r3, r4, ip, lr} @ 4\n\
+ ldmia %1!, {r3, r4, ip, lr} @ 4+1\n\
+ stmia %0!, {r3, r4, ip, lr} @ 4\n\
+ ldmia %1!, {r3, r4, ip, lr} @ 4\n\
+ mcr p15, 0, %0, c7, c6, 1 @ 1 invalidate D line\n\
+ stmia %0!, {r3, r4, ip, lr} @ 4\n\
+ ldmia %1!, {r3, r4, ip, lr} @ 4\n\
+ subs %2, %2, #1 @ 1\n\
+ stmia %0!, {r3, r4, ip, lr} @ 4\n\
+ ldmneia %1!, {r3, r4, ip, lr} @ 4\n\
bne 1b @ 1\n\
- mcr p15, 0, r1, c7, c10, 4 @ 1 drain WB\n\
- ldmfd sp!, {r4, pc} @ 3"
- :
- : "r" (kto), "r" (kfrom), "I" (PAGE_SIZE / 64));
+ mcr p15, 0, %1, c7, c10, 4 @ 1 drain WB"
+ : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
+ : "2" (PAGE_SIZE / 64)
+ : "r3", "r4", "ip", "lr");
}

void v4wb_copy_user_highpage(struct page *to, struct page *from,
--- a/arch/arm/mm/copypage-v4wt.c
+++ b/arch/arm/mm/copypage-v4wt.c
@@ -20,27 +20,26 @@
* dirty data in the cache. However, we do have to ensure that
* subsequent reads are up to date.
*/
-static void __naked
-v4wt_copy_user_page(void *kto, const void *kfrom)
+static void v4wt_copy_user_page(void *kto, const void *kfrom)
{
- asm("\
- stmfd sp!, {r4, lr} @ 2\n\
- mov r2, %2 @ 1\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4\n\
-1: stmia r0!, {r3, r4, ip, lr} @ 4\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4+1\n\
- stmia r0!, {r3, r4, ip, lr} @ 4\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4\n\
- stmia r0!, {r3, r4, ip, lr} @ 4\n\
- ldmia r1!, {r3, r4, ip, lr} @ 4\n\
- subs r2, r2, #1 @ 1\n\
- stmia r0!, {r3, r4, ip, lr} @ 4\n\
- ldmneia r1!, {r3, r4, ip, lr} @ 4\n\
+ int tmp;
+
+ asm volatile ("\
+ ldmia %1!, {r3, r4, ip, lr} @ 4\n\
+1: stmia %0!, {r3, r4, ip, lr} @ 4\n\
+ ldmia %1!, {r3, r4, ip, lr} @ 4+1\n\
+ stmia %0!, {r3, r4, ip, lr} @ 4\n\
+ ldmia %1!, {r3, r4, ip, lr} @ 4\n\
+ stmia %0!, {r3, r4, ip, lr} @ 4\n\
+ ldmia %1!, {r3, r4, ip, lr} @ 4\n\
+ subs %2, %2, #1 @ 1\n\
+ stmia %0!, {r3, r4, ip, lr} @ 4\n\
+ ldmneia %1!, {r3, r4, ip, lr} @ 4\n\
bne 1b @ 1\n\
- mcr p15, 0, r2, c7, c7, 0 @ flush ID cache\n\
- ldmfd sp!, {r4, pc} @ 3"
- :
- : "r" (kto), "r" (kfrom), "I" (PAGE_SIZE / 64));
+ mcr p15, 0, %2, c7, c7, 0 @ flush ID cache"
+ : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
+ : "2" (PAGE_SIZE / 64)
+ : "r3", "r4", "ip", "lr");
}

void v4wt_copy_user_highpage(struct page *to, struct page *from,
--- a/arch/arm/mm/copypage-xsc3.c
+++ b/arch/arm/mm/copypage-xsc3.c
@@ -21,53 +21,46 @@

/*
* XSC3 optimised copy_user_highpage
- * r0 = destination
- * r1 = source
*
* The source page may have some clean entries in the cache already, but we
* can safely ignore them - break_cow() will flush them out of the cache
* if we eventually end up using our copied page.
*
*/
-static void __naked
-xsc3_mc_copy_user_page(void *kto, const void *kfrom)
+static void xsc3_mc_copy_user_page(void *kto, const void *kfrom)
{
- asm("\
- stmfd sp!, {r4, r5, lr} \n\
- mov lr, %2 \n\
- \n\
- pld [r1, #0] \n\
- pld [r1, #32] \n\
-1: pld [r1, #64] \n\
- pld [r1, #96] \n\
+ int tmp;
+
+ asm volatile ("\
+ pld [%1, #0] \n\
+ pld [%1, #32] \n\
+1: pld [%1, #64] \n\
+ pld [%1, #96] \n\
\n\
-2: ldrd r2, [r1], #8 \n\
- mov ip, r0 \n\
- ldrd r4, [r1], #8 \n\
- mcr p15, 0, ip, c7, c6, 1 @ invalidate\n\
- strd r2, [r0], #8 \n\
- ldrd r2, [r1], #8 \n\
- strd r4, [r0], #8 \n\
- ldrd r4, [r1], #8 \n\
- strd r2, [r0], #8 \n\
- strd r4, [r0], #8 \n\
- ldrd r2, [r1], #8 \n\
- mov ip, r0 \n\
- ldrd r4, [r1], #8 \n\
- mcr p15, 0, ip, c7, c6, 1 @ invalidate\n\
- strd r2, [r0], #8 \n\
- ldrd r2, [r1], #8 \n\
- subs lr, lr, #1 \n\
- strd r4, [r0], #8 \n\
- ldrd r4, [r1], #8 \n\
- strd r2, [r0], #8 \n\
- strd r4, [r0], #8 \n\
+2: ldrd r2, [%1], #8 \n\
+ ldrd r4, [%1], #8 \n\
+ mcr p15, 0, %0, c7, c6, 1 @ invalidate\n\
+ strd r2, [%0], #8 \n\
+ ldrd r2, [%1], #8 \n\
+ strd r4, [%0], #8 \n\
+ ldrd r4, [%1], #8 \n\
+ strd r2, [%0], #8 \n\
+ strd r4, [%0], #8 \n\
+ ldrd r2, [%1], #8 \n\
+ ldrd r4, [%1], #8 \n\
+ mcr p15, 0, %0, c7, c6, 1 @ invalidate\n\
+ strd r2, [%0], #8 \n\
+ ldrd r2, [%1], #8 \n\
+ subs %2, %2, #1 \n\
+ strd r4, [%0], #8 \n\
+ ldrd r4, [%1], #8 \n\
+ strd r2, [%0], #8 \n\
+ strd r4, [%0], #8 \n\
bgt 1b \n\
- beq 2b \n\
- \n\
- ldmfd sp!, {r4, r5, pc}"
- :
- : "r" (kto), "r" (kfrom), "I" (PAGE_SIZE / 64 - 1));
+ beq 2b "
+ : "+&r" (kto), "+&r" (kfrom), "=&r" (tmp)
+ : "2" (PAGE_SIZE / 64 - 1)
+ : "r2", "r3", "r4", "r5");
}

void xsc3_mc_copy_user_highpage(struct page *to, struct page *from,
@@ -85,8 +78,6 @@ void xsc3_mc_copy_user_highpage(struct p

/*
* XScale optimised clear_user_page
- * r0 = destination
- * r1 = virtual user address of ultimate destination page
*/
void xsc3_mc_clear_user_highpage(struct page *page, unsigned long vaddr)
{
--- a/arch/arm/mm/copypage-xscale.c
+++ b/arch/arm/mm/copypage-xscale.c
@@ -36,52 +36,51 @@ static DEFINE_RAW_SPINLOCK(minicache_loc
* Dcache aliasing issue. The writes will be forwarded to the write buffer,
* and merged as appropriate.
*/
-static void __naked
-mc_copy_user_page(void *from, void *to)
+static void mc_copy_user_page(void *from, void *to)
{
+ int tmp;
+
/*
* Strangely enough, best performance is achieved
* when prefetching destination as well. (NP)
*/
- asm volatile(
- "stmfd sp!, {r4, r5, lr} \n\
- mov lr, %2 \n\
- pld [r0, #0] \n\
- pld [r0, #32] \n\
- pld [r1, #0] \n\
- pld [r1, #32] \n\
-1: pld [r0, #64] \n\
- pld [r0, #96] \n\
- pld [r1, #64] \n\
- pld [r1, #96] \n\
-2: ldrd r2, [r0], #8 \n\
- ldrd r4, [r0], #8 \n\
- mov ip, r1 \n\
- strd r2, [r1], #8 \n\
- ldrd r2, [r0], #8 \n\
- strd r4, [r1], #8 \n\
- ldrd r4, [r0], #8 \n\
- strd r2, [r1], #8 \n\
- strd r4, [r1], #8 \n\
+ asm volatile ("\
+ pld [%0, #0] \n\
+ pld [%0, #32] \n\
+ pld [%1, #0] \n\
+ pld [%1, #32] \n\
+1: pld [%0, #64] \n\
+ pld [%0, #96] \n\
+ pld [%1, #64] \n\
+ pld [%1, #96] \n\
+2: ldrd r2, [%0], #8 \n\
+ ldrd r4, [%0], #8 \n\
+ mov ip, %1 \n\
+ strd r2, [%1], #8 \n\
+ ldrd r2, [%0], #8 \n\
+ strd r4, [%1], #8 \n\
+ ldrd r4, [%0], #8 \n\
+ strd r2, [%1], #8 \n\
+ strd r4, [%1], #8 \n\
mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\
- ldrd r2, [r0], #8 \n\
+ ldrd r2, [%0], #8 \n\
mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\
- ldrd r4, [r0], #8 \n\
- mov ip, r1 \n\
- strd r2, [r1], #8 \n\
- ldrd r2, [r0], #8 \n\
- strd r4, [r1], #8 \n\
- ldrd r4, [r0], #8 \n\
- strd r2, [r1], #8 \n\
- strd r4, [r1], #8 \n\
+ ldrd r4, [%0], #8 \n\
+ mov ip, %1 \n\
+ strd r2, [%1], #8 \n\
+ ldrd r2, [%0], #8 \n\
+ strd r4, [%1], #8 \n\
+ ldrd r4, [%0], #8 \n\
+ strd r2, [%1], #8 \n\
+ strd r4, [%1], #8 \n\
mcr p15, 0, ip, c7, c10, 1 @ clean D line\n\
- subs lr, lr, #1 \n\
+ subs %2, %2, #1 \n\
mcr p15, 0, ip, c7, c6, 1 @ invalidate D line\n\
bgt 1b \n\
- beq 2b \n\
- ldmfd sp!, {r4, r5, pc} "
- :
- : "r" (from), "r" (to), "I" (PAGE_SIZE / 64 - 1));
+ beq 2b "
+ : "+&r" (from), "+&r" (to), "=&r" (tmp)
+ : "2" (PAGE_SIZE / 64 - 1)
+ : "r2", "r3", "r4", "r5", "ip");
}

void xscale_mc_copy_user_highpage(struct page *to, struct page *from,