Orange Pi5 kernel

 /*
 * 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

	/*
	* 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