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/*
* bpf_jit64.h: BPF JIT compiler for PPC64
*
* Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
* IBM Corporation
*
* 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.
*/
#ifndef _BPF_JIT64_H
#define _BPF_JIT64_H
#include "bpf_jit.h"
/*
* Stack layout:
* Ensure the top half (upto local_tmp_var) stays consistent
* with our redzone usage.
*
* [ prev sp ] <-------------
* [ nv gpr save area ] 8*8 |
* [ tail_call_cnt ] 8 |
* [ local_tmp_var ] 8 |
* fp (r31) --> [ ebpf stack space ] 512 |
* [ frame header ] 32/112 |
* sp (r1) ---> [ stack pointer ] --------------
*/
/* for gpr non volatile registers BPG_REG_6 to 10, plus skb cache registers */
#define BPF_PPC_STACK_SAVE (8*8)
/* for bpf JIT code internal usage */
#define BPF_PPC_STACK_LOCALS 16
/* Ensure this is quadword aligned */
#define BPF_PPC_STACKFRAME (STACK_FRAME_MIN_SIZE + MAX_BPF_STACK + \
BPF_PPC_STACK_LOCALS + BPF_PPC_STACK_SAVE)
#ifndef __ASSEMBLY__
/* BPF register usage */
#define SKB_HLEN_REG (MAX_BPF_JIT_REG + 0)
#define SKB_DATA_REG (MAX_BPF_JIT_REG + 1)
#define TMP_REG_1 (MAX_BPF_JIT_REG + 2)
#define TMP_REG_2 (MAX_BPF_JIT_REG + 3)
/* BPF to ppc register mappings */
static const int b2p[] = {
/* function return value */
[BPF_REG_0] = 8,
/* function arguments */
[BPF_REG_1] = 3,
[BPF_REG_2] = 4,
[BPF_REG_3] = 5,
[BPF_REG_4] = 6,
[BPF_REG_5] = 7,
/* non volatile registers */
[BPF_REG_6] = 27,
[BPF_REG_7] = 28,
[BPF_REG_8] = 29,
[BPF_REG_9] = 30,
/* frame pointer aka BPF_REG_10 */
[BPF_REG_FP] = 31,
/* eBPF jit internal registers */
[BPF_REG_AX] = 2,
[SKB_HLEN_REG] = 25,
[SKB_DATA_REG] = 26,
[TMP_REG_1] = 9,
[TMP_REG_2] = 10
};
/* PPC NVR range -- update this if we ever use NVRs below r24 */
#define BPF_PPC_NVR_MIN 24
/* Assembly helpers */
#define DECLARE_LOAD_FUNC(func) u64 func(u64 r3, u64 r4); \
u64 func##_negative_offset(u64 r3, u64 r4); \
u64 func##_positive_offset(u64 r3, u64 r4);
DECLARE_LOAD_FUNC(sk_load_word);
DECLARE_LOAD_FUNC(sk_load_half);
DECLARE_LOAD_FUNC(sk_load_byte);
#define CHOOSE_LOAD_FUNC(imm, func) \
(imm < 0 ? \
(imm >= SKF_LL_OFF ? func##_negative_offset : func) : \
func##_positive_offset)
/*
* WARNING: These can use TMP_REG_2 if the offset is not at word boundary,
* so ensure that it isn't in use already.
*/
#define PPC_BPF_LL(r, base, i) do { \
if ((i) % 4) { \
PPC_LI(b2p[TMP_REG_2], (i)); \
PPC_LDX(r, base, b2p[TMP_REG_2]); \
} else \
PPC_LD(r, base, i); \
} while(0)
#define PPC_BPF_STL(r, base, i) do { \
if ((i) % 4) { \
PPC_LI(b2p[TMP_REG_2], (i)); \
PPC_STDX(r, base, b2p[TMP_REG_2]); \
} else \
PPC_STD(r, base, i); \
} while(0)
#define PPC_BPF_STLU(r, base, i) do { PPC_STDU(r, base, i); } while(0)
#define SEEN_FUNC 0x1000 /* might call external helpers */
#define SEEN_STACK 0x2000 /* uses BPF stack */
#define SEEN_SKB 0x4000 /* uses sk_buff */
#define SEEN_TAILCALL 0x8000 /* uses tail calls */
struct codegen_context {
/*
* This is used to track register usage as well
* as calls to external helpers.
* - register usage is tracked with corresponding
* bits (r3-r10 and r25-r31)
* - rest of the bits can be used to track other
* things -- for now, we use bits 16 to 23
* encoded in SEEN_* macros above
*/
unsigned int seen;
unsigned int idx;
};
#endif /* !__ASSEMBLY__ */
#endif
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