Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc

Pull sparc updates from David Miller:
 "Mostly VDSO cleanups and optimizations"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sparc: Several small VDSO vclock_gettime.c improvements.
  sparc: Validate VDSO for undefined symbols.
  sparc: Really use linker with LDFLAGS.
  sparc: Improve VDSO CFLAGS.
  sparc: Set DISABLE_BRANCH_PROFILING in VDSO CFLAGS.
  sparc: Don't bother masking out TICK_PRIV_BIT in VDSO code.
  sparc: Inline VDSO gettime code aggressively.
  sparc: Improve VDSO instruction patching.
  sparc: Fix parport build warnings.

11 files changed, 123 insertions, 107 deletions

diff --git a/arch/sparc/include/asm/parport.h b/arch/sparc/include/asm/parport.h
index 05df5f043053..3c5a1c620f0f 100644
--- a/arch/sparc/include/asm/parport.h
+++ b/arch/sparc/include/asm/parport.h
@@ -21,6 +21,7 @@
  */
 #define HAS_DMA
 
+#ifdef CONFIG_PARPORT_PC_FIFO
 static DEFINE_SPINLOCK(dma_spin_lock);
 
 #define claim_dma_lock() \
@@ -31,6 +32,7 @@ static DEFINE_SPINLOCK(dma_spin_lock);
 
 #define release_dma_lock(__flags) \
 	spin_unlock_irqrestore(&dma_spin_lock, __flags);
+#endif
 
 static struct sparc_ebus_info {
 	struct ebus_dma_info info;
diff --git a/arch/sparc/include/asm/thread_info_64.h b/arch/sparc/include/asm/thread_info_64.h
index 7fb676360928..20255471e653 100644
--- a/arch/sparc/include/asm/thread_info_64.h
+++ b/arch/sparc/include/asm/thread_info_64.h
@@ -121,8 +121,12 @@ struct thread_info {
 }
 
 /* how to get the thread information struct from C */
+#ifndef BUILD_VDSO
 register struct thread_info *current_thread_info_reg asm("g6");
 #define current_thread_info()	(current_thread_info_reg)
+#else
+extern struct thread_info *current_thread_info(void);
+#endif
 
 /* thread information allocation */
 #if PAGE_SHIFT == 13
diff --git a/arch/sparc/include/asm/vdso.h b/arch/sparc/include/asm/vdso.h
index 93b628731a5e..56836eb01787 100644
--- a/arch/sparc/include/asm/vdso.h
+++ b/arch/sparc/include/asm/vdso.h
@@ -8,10 +8,10 @@
 struct vdso_image {
 	void *data;
 	unsigned long size;   /* Always a multiple of PAGE_SIZE */
+
+	unsigned long tick_patch, tick_patch_len;
+
 	long sym_vvar_start;  /* Negative offset to the vvar area */
-	long sym_vread_tick; /* Start of vread_tick section */
-	long sym_vread_tick_patch_start; /* Start of tick read */
-	long sym_vread_tick_patch_end;   /* End of tick read */
 };
 
 #ifdef CONFIG_SPARC64
diff --git a/arch/sparc/kernel/time_64.c b/arch/sparc/kernel/time_64.c
index f0eba72aa1ad..5f356dc8e178 100644
--- a/arch/sparc/kernel/time_64.c
+++ b/arch/sparc/kernel/time_64.c
@@ -53,8 +53,6 @@
 
 DEFINE_SPINLOCK(rtc_lock);
 
-unsigned int __read_mostly vdso_fix_stick;
-
 #ifdef CONFIG_SMP
 unsigned long profile_pc(struct pt_regs *regs)
 {
@@ -838,7 +836,6 @@ void __init time_init_early(void)
 		} else {
 			init_tick_ops(&tick_operations);
 			clocksource_tick.archdata.vclock_mode = VCLOCK_TICK;
-			vdso_fix_stick = 1;
 		}
 	} else {
 		init_tick_ops(&stick_operations);
diff --git a/arch/sparc/vdso/Makefile b/arch/sparc/vdso/Makefile
index dc85570d8839..a6e18ca4cc18 100644
--- a/arch/sparc/vdso/Makefile
+++ b/arch/sparc/vdso/Makefile
@@ -33,10 +33,8 @@ targets += $(vdso_img_sodbg) $(vdso_img-y:%=vdso%.so)
 
 CPPFLAGS_vdso.lds += -P -C
 
-VDSO_LDFLAGS_vdso.lds = -m64 -Wl,-soname=linux-vdso.so.1 \
-			-Wl,--no-undefined \
-			-Wl,-z,max-page-size=8192 -Wl,-z,common-page-size=8192 \
-			$(DISABLE_LTO)
+VDSO_LDFLAGS_vdso.lds = -m elf64_sparc -soname linux-vdso.so.1 --no-undefined \
+			-z max-page-size=8192 -z common-page-size=8192
 
 $(obj)/vdso64.so.dbg: $(obj)/vdso.lds $(vobjs) FORCE
 	$(call if_changed,vdso)
@@ -54,13 +52,14 @@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE
 # Don't omit frame pointers for ease of userspace debugging, but do
 # optimize sibling calls.
 #
-CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables \
-       -m64 -ffixed-g2 -ffixed-g3 -fcall-used-g4 -fcall-used-g5 -ffixed-g6 \
-       -ffixed-g7 $(filter -g%,$(KBUILD_CFLAGS)) \
-       $(call cc-option, -fno-stack-protector) -fno-omit-frame-pointer \
-       -foptimize-sibling-calls -DBUILD_VDSO
+CFL := $(PROFILING) -mcmodel=medlow -fPIC -O2 -fasynchronous-unwind-tables -m64 \
+       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \
+       -fno-omit-frame-pointer -foptimize-sibling-calls \
+       -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO
 
-$(vobjs): KBUILD_CFLAGS += $(CFL)
+SPARC_REG_CFLAGS = -ffixed-g4 -ffixed-g5 -fcall-used-g5 -fcall-used-g7
+
+$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
 
 #
 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.
@@ -73,7 +72,7 @@ $(obj)/%.so: $(obj)/%.so.dbg
 	$(call if_changed,objcopy)
 
 CPPFLAGS_vdso32.lds = $(CPPFLAGS_vdso.lds)
-VDSO_LDFLAGS_vdso32.lds = -m32 -Wl,-m,elf32_sparc,-soname=linux-gate.so.1
+VDSO_LDFLAGS_vdso32.lds = -m elf32_sparc -soname linux-gate.so.1
 
 #This makes sure the $(obj) subdirectory exists even though vdso32/
 #is not a kbuild sub-make subdirectory
@@ -91,7 +90,8 @@ KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
 KBUILD_CFLAGS_32 := $(filter-out -mcmodel=medlow,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
 KBUILD_CFLAGS_32 := $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS_32))
-KBUILD_CFLAGS_32 += -m32 -msoft-float -fpic -mno-app-regs -ffixed-g7
+KBUILD_CFLAGS_32 := $(filter-out $(SPARC_REG_CFLAGS),$(KBUILD_CFLAGS_32))
+KBUILD_CFLAGS_32 += -m32 -msoft-float -fpic
 KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector)
 KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)
 KBUILD_CFLAGS_32 += -fno-omit-frame-pointer
@@ -109,12 +109,13 @@ $(obj)/vdso32.so.dbg: FORCE \
 # The DSO images are built using a special linker script.
 #
 quiet_cmd_vdso = VDSO    $@
-      cmd_vdso = $(CC) -nostdlib -o $@ \
+      cmd_vdso = $(LD) -nostdlib -o $@ \
 		       $(VDSO_LDFLAGS) $(VDSO_LDFLAGS_$(filter %.lds,$(^F))) \
-		       -Wl,-T,$(filter %.lds,$^) $(filter %.o,$^)
+		       -T $(filter %.lds,$^) $(filter %.o,$^) && \
+		sh $(srctree)/$(src)/checkundef.sh '$(OBJDUMP)' '$@'
 
-VDSO_LDFLAGS = -fPIC -shared $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) \
-	$(call cc-ldoption, -Wl$(comma)--build-id) -Wl,-Bsymbolic
+VDSO_LDFLAGS = -shared $(call ld-option, --hash-style=both) \
+	$(call ld-option, --build-id) -Bsymbolic
 GCOV_PROFILE := n
 
 #
diff --git a/arch/sparc/vdso/checkundef.sh b/arch/sparc/vdso/checkundef.sh
new file mode 100644
index 000000000000..2d85876ffc32
--- /dev/null
+++ b/arch/sparc/vdso/checkundef.sh
@@ -0,0 +1,10 @@
+#!/bin/sh
+objdump="$1"
+file="$2"
+$objdump -t "$file" | grep '*UUND*' | grep -v '#scratch' > /dev/null 2>&1
+if [ $? -eq 1 ]; then
+    exit 0
+else
+    echo "$file: undefined symbols found" >&2
+    exit 1
+fi
diff --git a/arch/sparc/vdso/vclock_gettime.c b/arch/sparc/vdso/vclock_gettime.c
index 75dca9aab737..7b539ceebe13 100644
--- a/arch/sparc/vdso/vclock_gettime.c
+++ b/arch/sparc/vdso/vclock_gettime.c
@@ -12,11 +12,6 @@
  * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
  */
 
-/* Disable profiling for userspace code: */
-#ifndef	DISABLE_BRANCH_PROFILING
-#define	DISABLE_BRANCH_PROFILING
-#endif
-
 #include <linux/kernel.h>
 #include <linux/time.h>
 #include <linux/string.h>
@@ -26,13 +21,6 @@
 #include <asm/clocksource.h>
 #include <asm/vvar.h>
 
-#undef	TICK_PRIV_BIT
-#ifdef	CONFIG_SPARC64
-#define	TICK_PRIV_BIT	(1UL << 63)
-#else
-#define	TICK_PRIV_BIT	(1ULL << 63)
-#endif
-
 #ifdef	CONFIG_SPARC64
 #define SYSCALL_STRING							\
 	"ta	0x6d;"							\
@@ -60,24 +48,22 @@
  * Compute the vvar page's address in the process address space, and return it
  * as a pointer to the vvar_data.
  */
-static notrace noinline struct vvar_data *
-get_vvar_data(void)
+notrace static __always_inline struct vvar_data *get_vvar_data(void)
 {
 	unsigned long ret;
 
 	/*
-	 * vdso data page is the first vDSO page so grab the return address
+	 * vdso data page is the first vDSO page so grab the PC
 	 * and move up a page to get to the data page.
 	 */
-	ret = (unsigned long)__builtin_return_address(0);
+	__asm__("rd %%pc, %0" : "=r" (ret));
 	ret &= ~(8192 - 1);
 	ret -= 8192;
 
 	return (struct vvar_data *) ret;
 }
 
-static notrace long
-vdso_fallback_gettime(long clock, struct timespec *ts)
+notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
 {
 	register long num __asm__("g1") = __NR_clock_gettime;
 	register long o0 __asm__("o0") = clock;
@@ -88,8 +74,7 @@ vdso_fallback_gettime(long clock, struct timespec *ts)
 	return o0;
 }
 
-static notrace __always_inline long
-vdso_fallback_gettimeofday(struct timeval *tv, struct timezone *tz)
+notrace static long vdso_fallback_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
 	register long num __asm__("g1") = __NR_gettimeofday;
 	register long o0 __asm__("o0") = (long) tv;
@@ -101,38 +86,43 @@ vdso_fallback_gettimeofday(struct timeval *tv, struct timezone *tz)
 }
 
 #ifdef	CONFIG_SPARC64
-static notrace noinline u64
-vread_tick(void) {
+notrace static __always_inline u64 vread_tick(void)
+{
 	u64	ret;
 
-	__asm__ __volatile__("rd	%%asr24, %0 \n"
-			     ".section	.vread_tick_patch, \"ax\" \n"
-			     "rd	%%tick, %0 \n"
-			     ".previous \n"
-			     : "=&r" (ret));
-	return ret & ~TICK_PRIV_BIT;
+	__asm__ __volatile__("1:\n\t"
+			     "rd		%%tick, %0\n\t"
+			     ".pushsection	.tick_patch, \"a\"\n\t"
+			     ".word		1b - ., 1f - .\n\t"
+			     ".popsection\n\t"
+			     ".pushsection	.tick_patch_replacement, \"ax\"\n\t"
+			     "1:\n\t"
+			     "rd		%%asr24, %0\n\t"
+			     ".popsection\n"
+			     : "=r" (ret));
+	return ret;
 }
 #else
-static notrace noinline u64
-vread_tick(void)
+notrace static __always_inline u64 vread_tick(void)
 {
-	unsigned int lo, hi;
-
-	__asm__ __volatile__("rd	%%asr24, %%g1\n\t"
-			     "srlx	%%g1, 32, %1\n\t"
-			     "srl	%%g1, 0, %0\n"
-			     ".section	.vread_tick_patch, \"ax\" \n"
-			     "rd	%%tick, %%g1\n"
-			     ".previous \n"
-			     : "=&r" (lo), "=&r" (hi)
-			     :
-			     : "g1");
-	return lo | ((u64)hi << 32);
+	register unsigned long long ret asm("o4");
+
+	__asm__ __volatile__("1:\n\t"
+			     "rd		%%tick, %L0\n\t"
+			     "srlx		%L0, 32, %H0\n\t"
+			     ".pushsection	.tick_patch, \"a\"\n\t"
+			     ".word		1b - ., 1f - .\n\t"
+			     ".popsection\n\t"
+			     ".pushsection	.tick_patch_replacement, \"ax\"\n\t"
+			     "1:\n\t"
+			     "rd		%%asr24, %L0\n\t"
+			     ".popsection\n"
+			     : "=r" (ret));
+	return ret;
 }
 #endif
 
-static notrace inline u64
-vgetsns(struct vvar_data *vvar)
+notrace static __always_inline u64 vgetsns(struct vvar_data *vvar)
 {
 	u64 v;
 	u64 cycles;
@@ -142,13 +132,12 @@ vgetsns(struct vvar_data *vvar)
 	return v * vvar->clock.mult;
 }
 
-static notrace noinline int
-do_realtime(struct vvar_data *vvar, struct timespec *ts)
+notrace static __always_inline int do_realtime(struct vvar_data *vvar,
+					       struct timespec *ts)
 {
 	unsigned long seq;
 	u64 ns;
 
-	ts->tv_nsec = 0;
 	do {
 		seq = vvar_read_begin(vvar);
 		ts->tv_sec = vvar->wall_time_sec;
@@ -157,18 +146,18 @@ do_realtime(struct vvar_data *vvar, struct timespec *ts)
 		ns >>= vvar->clock.shift;
 	} while (unlikely(vvar_read_retry(vvar, seq)));
 
-	timespec_add_ns(ts, ns);
+	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
 
 	return 0;
 }
 
-static notrace noinline int
-do_monotonic(struct vvar_data *vvar, struct timespec *ts)
+notrace static __always_inline int do_monotonic(struct vvar_data *vvar,
+						struct timespec *ts)
 {
 	unsigned long seq;
 	u64 ns;
 
-	ts->tv_nsec = 0;
 	do {
 		seq = vvar_read_begin(vvar);
 		ts->tv_sec = vvar->monotonic_time_sec;
@@ -177,13 +166,14 @@ do_monotonic(struct vvar_data *vvar, struct timespec *ts)
 		ns >>= vvar->clock.shift;
 	} while (unlikely(vvar_read_retry(vvar, seq)));
 
-	timespec_add_ns(ts, ns);
+	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
+	ts->tv_nsec = ns;
 
 	return 0;
 }
 
-static notrace noinline int
-do_realtime_coarse(struct vvar_data *vvar, struct timespec *ts)
+notrace static int do_realtime_coarse(struct vvar_data *vvar,
+				      struct timespec *ts)
 {
 	unsigned long seq;
 
@@ -195,8 +185,8 @@ do_realtime_coarse(struct vvar_data *vvar, struct timespec *ts)
 	return 0;
 }
 
-static notrace noinline int
-do_monotonic_coarse(struct vvar_data *vvar, struct timespec *ts)
+notrace static int do_monotonic_coarse(struct vvar_data *vvar,
+				       struct timespec *ts)
 {
 	unsigned long seq;
 
diff --git a/arch/sparc/vdso/vdso-layout.lds.S b/arch/sparc/vdso/vdso-layout.lds.S
index f2c83abaca12..ed36d49e1617 100644
--- a/arch/sparc/vdso/vdso-layout.lds.S
+++ b/arch/sparc/vdso/vdso-layout.lds.S
@@ -73,11 +73,8 @@ SECTIONS
 
 	.text		: { *(.text*) }			:text	=0x90909090,
 
-	.vread_tick_patch : {
-		vread_tick_patch_start = .;
-		*(.vread_tick_patch)
-		vread_tick_patch_end = .;
-	}
+	.tick_patch 	  : { *(.tick_patch) }		:text
+	.tick_patch_insns : { *(.tick_patch_insns) }	:text
 
 	/DISCARD/ : {
 		*(.discard)
diff --git a/arch/sparc/vdso/vdso2c.c b/arch/sparc/vdso/vdso2c.c
index 9f5b1cd6d51d..ab7504176a7f 100644
--- a/arch/sparc/vdso/vdso2c.c
+++ b/arch/sparc/vdso/vdso2c.c
@@ -63,9 +63,6 @@ enum {
 	sym_vvar_start,
 	sym_VDSO_FAKE_SECTION_TABLE_START,
 	sym_VDSO_FAKE_SECTION_TABLE_END,
-	sym_vread_tick,
-	sym_vread_tick_patch_start,
-	sym_vread_tick_patch_end
 };
 
 struct vdso_sym {
@@ -81,9 +78,6 @@ struct vdso_sym required_syms[] = {
 	[sym_VDSO_FAKE_SECTION_TABLE_END] = {
 		"VDSO_FAKE_SECTION_TABLE_END", 0
 	},
-	[sym_vread_tick] = {"vread_tick", 1},
-	[sym_vread_tick_patch_start] = {"vread_tick_patch_start", 1},
-	[sym_vread_tick_patch_end] = {"vread_tick_patch_end", 1}
 };
 
 __attribute__((format(printf, 1, 2))) __attribute__((noreturn))
diff --git a/arch/sparc/vdso/vdso2c.h b/arch/sparc/vdso/vdso2c.h
index 808decb0f7be..4df005cf98c0 100644
--- a/arch/sparc/vdso/vdso2c.h
+++ b/arch/sparc/vdso/vdso2c.h
@@ -17,10 +17,11 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 	unsigned long mapping_size;
 	int i;
 	unsigned long j;
-
-	ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr;
+	ELF(Shdr) *symtab_hdr = NULL, *strtab_hdr, *secstrings_hdr,
+		*patch_sec = NULL;
 	ELF(Ehdr) *hdr = (ELF(Ehdr) *)raw_addr;
 	ELF(Dyn) *dyn = 0, *dyn_end = 0;
+	const char *secstrings;
 	INT_BITS syms[NSYMS] = {};
 
 	ELF(Phdr) *pt = (ELF(Phdr) *)(raw_addr + GET_BE(&hdr->e_phoff));
@@ -63,11 +64,18 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 	}
 
 	/* Walk the section table */
+	secstrings_hdr = raw_addr + GET_BE(&hdr->e_shoff) +
+		GET_BE(&hdr->e_shentsize)*GET_BE(&hdr->e_shstrndx);
+	secstrings = raw_addr + GET_BE(&secstrings_hdr->sh_offset);
 	for (i = 0; i < GET_BE(&hdr->e_shnum); i++) {
 		ELF(Shdr) *sh = raw_addr + GET_BE(&hdr->e_shoff) +
 			GET_BE(&hdr->e_shentsize) * i;
 		if (GET_BE(&sh->sh_type) == SHT_SYMTAB)
 			symtab_hdr = sh;
+
+		if (!strcmp(secstrings + GET_BE(&sh->sh_name),
+			    ".tick_patch"))
+			patch_sec = sh;
 	}
 
 	if (!symtab_hdr)
@@ -134,6 +142,12 @@ static void BITSFUNC(go)(void *raw_addr, size_t raw_len,
 	fprintf(outfile, "const struct vdso_image %s_builtin = {\n", name);
 	fprintf(outfile, "\t.data = raw_data,\n");
 	fprintf(outfile, "\t.size = %lu,\n", mapping_size);
+	if (patch_sec) {
+		fprintf(outfile, "\t.tick_patch = %lu,\n",
+			(unsigned long)GET_BE(&patch_sec->sh_offset));
+		fprintf(outfile, "\t.tick_patch_len = %lu,\n",
+			(unsigned long)GET_BE(&patch_sec->sh_size));
+	}
 	for (i = 0; i < NSYMS; i++) {
 		if (required_syms[i].export && syms[i])
 			fprintf(outfile, "\t.sym_%s = %" PRIi64 ",\n",
diff --git a/arch/sparc/vdso/vma.c b/arch/sparc/vdso/vma.c
index 5eaff3c1aa0c..8874a27d8adc 100644
--- a/arch/sparc/vdso/vma.c
+++ b/arch/sparc/vdso/vma.c
@@ -16,6 +16,8 @@
 #include <linux/linkage.h>
 #include <linux/random.h>
 #include <linux/elf.h>
+#include <asm/cacheflush.h>
+#include <asm/spitfire.h>
 #include <asm/vdso.h>
 #include <asm/vvar.h>
 #include <asm/page.h>
@@ -40,7 +42,25 @@ static struct vm_special_mapping vdso_mapping32 = {
 
 struct vvar_data *vvar_data;
 
-#define	SAVE_INSTR_SIZE	4
+struct tick_patch_entry {
+	s32 orig, repl;
+};
+
+static void stick_patch(const struct vdso_image *image)
+{
+	struct tick_patch_entry *p, *p_end;
+
+	p = image->data + image->tick_patch;
+	p_end = (void *)p + image->tick_patch_len;
+	while (p < p_end) {
+		u32 *instr = (void *)&p->orig + p->orig;
+		u32 *repl = (void *)&p->repl + p->repl;
+
+		*instr = *repl;
+		flushi(instr);
+		p++;
+	}
+}
 
 /*
  * Allocate pages for the vdso and vvar, and copy in the vdso text from the
@@ -68,21 +88,8 @@ int __init init_vdso_image(const struct vdso_image *image,
 	if (!cpp)
 		goto oom;
 
-	if (vdso_fix_stick) {
-		/*
-		 * If the system uses %tick instead of %stick, patch the VDSO
-		 * with instruction reading %tick instead of %stick.
-		 */
-		unsigned int j, k = SAVE_INSTR_SIZE;
-		unsigned char *data = image->data;
-
-		for (j = image->sym_vread_tick_patch_start;
-		     j < image->sym_vread_tick_patch_end; j++) {
-
-			data[image->sym_vread_tick + k] = data[j];
-			k++;
-		}
-	}
+	if (tlb_type != spitfire)
+		stick_patch(image);
 
 	for (i = 0; i < cnpages; i++) {
 		cp = alloc_page(GFP_KERNEL);