Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 285 insertions, 0 deletions

diff --git a/arch/mips/net/bpf_jit_asm.S b/arch/mips/net/bpf_jit_asm.S
new file mode 100644
index 000000000..57154c588
--- /dev/null
+++ b/arch/mips/net/bpf_jit_asm.S
@@ -0,0 +1,285 @@
+/*
+ * bpf_jib_asm.S: Packet/header access helper functions for MIPS/MIPS64 BPF
+ * compiler.
+ *
+ * Copyright (C) 2015 Imagination Technologies Ltd.
+ * Author: Markos Chandras <markos.chandras@imgtec.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; version 2 of the License.
+ */
+
+#include <asm/asm.h>
+#include <asm/isa-rev.h>
+#include <asm/regdef.h>
+#include "bpf_jit.h"
+
+/* ABI
+ *
+ * r_skb_hl	skb header length
+ * r_skb_data	skb data
+ * r_off(a1)	offset register
+ * r_A		BPF register A
+ * r_X		PF register X
+ * r_skb(a0)	*skb
+ * r_M		*scratch memory
+ * r_skb_le	skb length
+ * r_s0		Scratch register 0
+ * r_s1		Scratch register 1
+ *
+ * On entry:
+ * a0: *skb
+ * a1: offset (imm or imm + X)
+ *
+ * All non-BPF-ABI registers are free for use. On return, we only
+ * care about r_ret. The BPF-ABI registers are assumed to remain
+ * unmodified during the entire filter operation.
+ */
+
+#define skb	a0
+#define offset	a1
+#define SKF_LL_OFF  (-0x200000) /* Can't include linux/filter.h in assembly */
+
+	/* We know better :) so prevent assembler reordering etc */
+	.set 	noreorder
+
+#define is_offset_negative(TYPE)				\
+	/* If offset is negative we have more work to do */	\
+	slti	t0, offset, 0;					\
+	bgtz	t0, bpf_slow_path_##TYPE##_neg;			\
+	/* Be careful what follows in DS. */
+
+#define is_offset_in_header(SIZE, TYPE)				\
+	/* Reading from header? */				\
+	addiu	$r_s0, $r_skb_hl, -SIZE;			\
+	slt	t0, $r_s0, offset;				\
+	bgtz	t0, bpf_slow_path_##TYPE;			\
+
+LEAF(sk_load_word)
+	is_offset_negative(word)
+FEXPORT(sk_load_word_positive)
+	is_offset_in_header(4, word)
+	/* Offset within header boundaries */
+	PTR_ADDU t1, $r_skb_data, offset
+	.set	reorder
+	lw	$r_A, 0(t1)
+	.set	noreorder
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+# if MIPS_ISA_REV >= 2
+	wsbh	t0, $r_A
+	rotr	$r_A, t0, 16
+# else
+	sll	t0, $r_A, 24
+	srl	t1, $r_A, 24
+	srl	t2, $r_A, 8
+	or	t0, t0, t1
+	andi	t2, t2, 0xff00
+	andi	t1, $r_A, 0xff00
+	or	t0, t0, t2
+	sll	t1, t1, 8
+	or	$r_A, t0, t1
+# endif
+#endif
+	jr	$r_ra
+	 move	$r_ret, zero
+	END(sk_load_word)
+
+LEAF(sk_load_half)
+	is_offset_negative(half)
+FEXPORT(sk_load_half_positive)
+	is_offset_in_header(2, half)
+	/* Offset within header boundaries */
+	PTR_ADDU t1, $r_skb_data, offset
+	lhu	$r_A, 0(t1)
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+# if MIPS_ISA_REV >= 2
+	wsbh	$r_A, $r_A
+# else
+	sll	t0, $r_A, 8
+	srl	t1, $r_A, 8
+	andi	t0, t0, 0xff00
+	or	$r_A, t0, t1
+# endif
+#endif
+	jr	$r_ra
+	 move	$r_ret, zero
+	END(sk_load_half)
+
+LEAF(sk_load_byte)
+	is_offset_negative(byte)
+FEXPORT(sk_load_byte_positive)
+	is_offset_in_header(1, byte)
+	/* Offset within header boundaries */
+	PTR_ADDU t1, $r_skb_data, offset
+	lbu	$r_A, 0(t1)
+	jr	$r_ra
+	 move	$r_ret, zero
+	END(sk_load_byte)
+
+/*
+ * call skb_copy_bits:
+ * (prototype in linux/skbuff.h)
+ *
+ * int skb_copy_bits(sk_buff *skb, int offset, void *to, int len)
+ *
+ * o32 mandates we leave 4 spaces for argument registers in case
+ * the callee needs to use them. Even though we don't care about
+ * the argument registers ourselves, we need to allocate that space
+ * to remain ABI compliant since the callee may want to use that space.
+ * We also allocate 2 more spaces for $r_ra and our return register (*to).
+ *
+ * n64 is a bit different. The *caller* will allocate the space to preserve
+ * the arguments. So in 64-bit kernels, we allocate the 4-arg space for no
+ * good reason but it does not matter that much really.
+ *
+ * (void *to) is returned in r_s0
+ *
+ */
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+#define DS_OFFSET(SIZE) (4 * SZREG)
+#else
+#define DS_OFFSET(SIZE) ((4 * SZREG) + (4 - SIZE))
+#endif
+#define bpf_slow_path_common(SIZE)				\
+	/* Quick check. Are we within reasonable boundaries? */ \
+	LONG_ADDIU	$r_s1, $r_skb_len, -SIZE;		\
+	sltu		$r_s0, offset, $r_s1;			\
+	beqz		$r_s0, fault;				\
+	/* Load 4th argument in DS */				\
+	 LONG_ADDIU	a3, zero, SIZE;				\
+	PTR_ADDIU	$r_sp, $r_sp, -(6 * SZREG);		\
+	PTR_LA		t0, skb_copy_bits;			\
+	PTR_S		$r_ra, (5 * SZREG)($r_sp);		\
+	/* Assign low slot to a2 */				\
+	PTR_ADDIU	a2, $r_sp, DS_OFFSET(SIZE);		\
+	jalr		t0;					\
+	/* Reset our destination slot (DS but it's ok) */	\
+	 INT_S		zero, (4 * SZREG)($r_sp);		\
+	/*							\
+	 * skb_copy_bits returns 0 on success and -EFAULT	\
+	 * on error. Our data live in a2. Do not bother with	\
+	 * our data if an error has been returned.		\
+	 */							\
+	/* Restore our frame */					\
+	PTR_L		$r_ra, (5 * SZREG)($r_sp);		\
+	INT_L		$r_s0, (4 * SZREG)($r_sp);		\
+	bltz		v0, fault;				\
+	 PTR_ADDIU	$r_sp, $r_sp, 6 * SZREG;		\
+	move		$r_ret, zero;				\
+
+NESTED(bpf_slow_path_word, (6 * SZREG), $r_sp)
+	bpf_slow_path_common(4)
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+# if MIPS_ISA_REV >= 2
+	wsbh	t0, $r_s0
+	jr	$r_ra
+	 rotr	$r_A, t0, 16
+# else
+	sll	t0, $r_s0, 24
+	srl	t1, $r_s0, 24
+	srl	t2, $r_s0, 8
+	or	t0, t0, t1
+	andi	t2, t2, 0xff00
+	andi	t1, $r_s0, 0xff00
+	or	t0, t0, t2
+	sll	t1, t1, 8
+	jr	$r_ra
+	 or	$r_A, t0, t1
+# endif
+#else
+	jr	$r_ra
+	 move	$r_A, $r_s0
+#endif
+
+	END(bpf_slow_path_word)
+
+NESTED(bpf_slow_path_half, (6 * SZREG), $r_sp)
+	bpf_slow_path_common(2)
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+# if MIPS_ISA_REV >= 2
+	jr	$r_ra
+	 wsbh	$r_A, $r_s0
+# else
+	sll	t0, $r_s0, 8
+	andi	t1, $r_s0, 0xff00
+	andi	t0, t0, 0xff00
+	srl	t1, t1, 8
+	jr	$r_ra
+	 or	$r_A, t0, t1
+# endif
+#else
+	jr	$r_ra
+	 move	$r_A, $r_s0
+#endif
+
+	END(bpf_slow_path_half)
+
+NESTED(bpf_slow_path_byte, (6 * SZREG), $r_sp)
+	bpf_slow_path_common(1)
+	jr	$r_ra
+	 move	$r_A, $r_s0
+
+	END(bpf_slow_path_byte)
+
+/*
+ * Negative entry points
+ */
+	.macro bpf_is_end_of_data
+	li	t0, SKF_LL_OFF
+	/* Reading link layer data? */
+	slt	t1, offset, t0
+	bgtz	t1, fault
+	/* Be careful what follows in DS. */
+	.endm
+/*
+ * call skb_copy_bits:
+ * (prototype in linux/filter.h)
+ *
+ * void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
+ *                                            int k, unsigned int size)
+ *
+ * see above (bpf_slow_path_common) for ABI restrictions
+ */
+#define bpf_negative_common(SIZE)					\
+	PTR_ADDIU	$r_sp, $r_sp, -(6 * SZREG);			\
+	PTR_LA		t0, bpf_internal_load_pointer_neg_helper;	\
+	PTR_S		$r_ra, (5 * SZREG)($r_sp);			\
+	jalr		t0;						\
+	 li		a2, SIZE;					\
+	PTR_L		$r_ra, (5 * SZREG)($r_sp);			\
+	/* Check return pointer */					\
+	beqz		v0, fault;					\
+	 PTR_ADDIU	$r_sp, $r_sp, 6 * SZREG;			\
+	/* Preserve our pointer */					\
+	move		$r_s0, v0;					\
+	/* Set return value */						\
+	move		$r_ret, zero;					\
+
+bpf_slow_path_word_neg:
+	bpf_is_end_of_data
+NESTED(sk_load_word_negative, (6 * SZREG), $r_sp)
+	bpf_negative_common(4)
+	jr	$r_ra
+	 lw	$r_A, 0($r_s0)
+	END(sk_load_word_negative)
+
+bpf_slow_path_half_neg:
+	bpf_is_end_of_data
+NESTED(sk_load_half_negative, (6 * SZREG), $r_sp)
+	bpf_negative_common(2)
+	jr	$r_ra
+	 lhu	$r_A, 0($r_s0)
+	END(sk_load_half_negative)
+
+bpf_slow_path_byte_neg:
+	bpf_is_end_of_data
+NESTED(sk_load_byte_negative, (6 * SZREG), $r_sp)
+	bpf_negative_common(1)
+	jr	$r_ra
+	 lbu	$r_A, 0($r_s0)
+	END(sk_load_byte_negative)
+
+fault:
+	jr	$r_ra
+	 addiu $r_ret, zero, 1