s390/bpf,jit: BPF Just In Time compiler for s390

The s390 implementation of the JIT compiler for packet filter speedup.
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kbuild

@@ -5,3 +5,4 @@ obj-$(CONFIG_CRYPTO_HW)		+= crypto/
 obj-$(CONFIG_S390_HYPFS_FS)	+= hypfs/
 obj-$(CONFIG_APPLDATA_BASE)	+= appldata/
 obj-$(CONFIG_MATHEMU)		+= math-emu/
+obj-y				+= net/

arch/s390/Kconfig

@@ -84,6 +84,7 @@ config S390
 	select HAVE_KERNEL_XZ
 	select HAVE_ARCH_MUTEX_CPU_RELAX
 	select HAVE_ARCH_JUMP_LABEL if !MARCH_G5
+	select HAVE_BPF_JIT if 64BIT && PACK_STACK
 	select ARCH_SAVE_PAGE_KEYS if HIBERNATION
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select HAVE_MEMBLOCK

arch/s390/include/asm/processor.h

@@ -140,6 +140,7 @@ extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 extern unsigned long thread_saved_pc(struct task_struct *t);
 
 extern void show_code(struct pt_regs *regs);
+extern void print_fn_code(unsigned char *code, unsigned long len);
 
 unsigned long get_wchan(struct task_struct *p);
 #define task_pt_regs(tsk) ((struct pt_regs *) \

arch/s390/kernel/dis.c

@@ -1601,3 +1601,26 @@ void show_code(struct pt_regs *regs)
 	}
 	printk("\n");
 }
+
+void print_fn_code(unsigned char *code, unsigned long len)
+{
+	char buffer[64], *ptr;
+	int opsize, i;
+
+	while (len) {
+		ptr = buffer;
+		opsize = insn_length(*code);
+		ptr += sprintf(ptr, "%p: ", code);
+		for (i = 0; i < opsize; i++)
+			ptr += sprintf(ptr, "%02x", code[i]);
+		*ptr++ = '\t';
+		if (i < 4)
+			*ptr++ = '\t';
+		ptr += print_insn(ptr, code, (unsigned long) code);
+		*ptr++ = '\n';
+		*ptr++ = 0;
+		printk(buffer);
+		code += opsize;
+		len -= opsize;
+	}
+}

arch/s390/net/Makefile

+#
+# Arch-specific network modules
+#
+obj-$(CONFIG_BPF_JIT) += bpf_jit.o bpf_jit_comp.o

arch/s390/net/bpf_jit.S

+/*
+ * BPF Jit compiler for s390, help functions.
+ *
+ * Copyright IBM Corp. 2012
+ *
+ * Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
+ */
+#include <linux/linkage.h>
+
+/*
+ * Calling convention:
+ * registers %r2, %r6-%r8, %r10-%r11, %r13, %r15 are call saved
+ *   %r2: skb pointer
+ *   %r3: offset parameter
+ *   %r5: BPF A accumulator
+ *   %r8: return address
+ *   %r9: save register for skb pointer
+ *   %r10: skb->data
+ *   %r11: skb->len - skb->data_len (headlen)
+ *   %r12: BPF X accumulator
+ *
+ * skb_copy_bits takes 4 parameters:
+ *   %r2 = skb pointer
+ *   %r3 = offset into skb data
+ *   %r4 = length to copy
+ *   %r5 = pointer to temp buffer
+ */
+#define SKBDATA	%r8
+
+	/* A = *(u32 *) (skb->data+K+X) */
+ENTRY(sk_load_word_ind)
+	ar	%r3,%r12		# offset += X
+	bmr	%r8			# < 0 -> return with cc
+
+	/* A = *(u32 *) (skb->data+K) */
+ENTRY(sk_load_word)
+	llgfr	%r1,%r3			# extend offset
+	ahi	%r3,4			# offset + 4
+	clr	%r11,%r3		# hlen <= offset + 4 ?
+	jl	sk_load_word_slow
+	l	%r5,0(%r1,%r10)		# get word from skb
+	xr	%r1,%r1			# set cc to zero
+	br	%r8
+
+sk_load_word_slow:
+	lgr	%r9,%r2			# save %r2
+	lhi	%r4,4			# 4 bytes
+	la	%r5,160(%r15)		# pointer to temp buffer
+	brasl	%r14,skb_copy_bits	# get data from skb
+	l	%r5,160(%r15)		# load result from temp buffer
+	ltgr	%r2,%r2			# set cc to (%r2 != 0)
+	lgr	%r2,%r9			# restore %r2
+	br	%r8
+
+	/* A = *(u16 *) (skb->data+K+X) */
+ENTRY(sk_load_half_ind)
+	ar	%r3,%r12		# offset += X
+	bmr	%r8			# < 0 -> return with cc
+
+	/* A = *(u16 *) (skb->data+K) */
+ENTRY(sk_load_half)
+	llgfr	%r1,%r3			# extend offset
+	ahi	%r3,2			# offset + 2
+	clr	%r11,%r3		# hlen <= offset + 2 ?
+	jl	sk_load_half_slow
+	llgh	%r5,0(%r1,%r10)		# get half from skb
+	xr	%r1,%r1			# set cc to zero
+	br	%r8
+
+sk_load_half_slow:
+	lgr	%r9,%r2			# save %r2
+	lhi	%r4,2			# 2 bytes
+	la	%r5,162(%r15)		# pointer to temp buffer
+	brasl	%r14,skb_copy_bits	# get data from skb
+	xc	160(2,%r15),160(%r15)
+	l	%r5,160(%r15)		# load result from temp buffer
+	ltgr	%r2,%r2			# set cc to (%r2 != 0)
+	lgr	%r2,%r9			# restore %r2
+	br	%r8
+
+	/* A = *(u8 *) (skb->data+K+X) */
+ENTRY(sk_load_byte_ind)
+	ar	%r3,%r12		# offset += X
+	bmr	%r8			# < 0 -> return with cc
+
+	/* A = *(u8 *) (skb->data+K) */
+ENTRY(sk_load_byte)
+	llgfr	%r1,%r3			# extend offset
+	clr	%r11,%r3		# hlen < offset ?
+	jle	sk_load_byte_slow
+	lhi	%r5,0
+	ic	%r5,0(%r1,%r10)		# get byte from skb
+	xr	%r1,%r1			# set cc to zero
+	br	%r8
+
+sk_load_byte_slow:
+	lgr	%r9,%r2			# save %r2
+	lhi	%r4,1			# 1 bytes
+	la	%r5,163(%r15)		# pointer to temp buffer
+	brasl	%r14,skb_copy_bits	# get data from skb
+	xc	160(3,%r15),160(%r15)
+	l	%r5,160(%r15)		# load result from temp buffer
+	ltgr	%r2,%r2			# set cc to (%r2 != 0)
+	lgr	%r2,%r9			# restore %r2
+	br	%r8
+
+	/* A = (*(u8 *)(skb->data+K) & 0xf) << 2 */
+ENTRY(sk_load_byte_msh)
+	llgfr	%r1,%r3			# extend offset
+	clr	%r11,%r3		# hlen < offset ?
+	jle	sk_load_byte_slow
+	lhi	%r12,0
+	ic	%r12,0(%r1,%r10)	# get byte from skb
+	nill	%r12,0x0f
+	sll	%r12,2
+	xr	%r1,%r1			# set cc to zero
+	br	%r8
+
+sk_load_byte_msh_slow:
+	lgr	%r9,%r2			# save %r2
+	lhi	%r4,2			# 2 bytes
+	la	%r5,162(%r15)		# pointer to temp buffer
+	brasl	%r14,skb_copy_bits	# get data from skb
+	xc	160(3,%r15),160(%r15)
+	l	%r12,160(%r15)		# load result from temp buffer
+	nill	%r12,0x0f
+	sll	%r12,2
+	ltgr	%r2,%r2			# set cc to (%r2 != 0)
+	lgr	%r2,%r9			# restore %r2
+	br	%r8