mirror of
https://github.com/torvalds/linux.git
synced 2024-11-25 13:41:51 +00:00
a81507c79f
o Socket data is unsigned, so use unsigned accessors instructions. o Fix path result pointer generation arithmetic. o Fix half-word byte swapping code for unsigned semantics. Signed-off-by: David Daney <david.daney@cavium.com> Cc: James Hogan <james.hogan@imgtec.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Steven J. Hill <steven.hill@cavium.com> Cc: linux-mips@linux-mips.org Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/15747/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
285 lines
6.9 KiB
ArmAsm
285 lines
6.9 KiB
ArmAsm
/*
|
|
* 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/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 defined(__mips_isa_rev) && (__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 defined(__mips_isa_rev) && (__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 defined(__mips_isa_rev) && (__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 defined(__mips_isa_rev) && (__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
|