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ac0761ebcb
Take advantage of stack_depth tracking, originally introduced for x64, in powerpc JIT as well. Round up allocated stack by 16 bytes to make sure it stays aligned for functions called from JITed bpf program. Signed-off-by: Sandipan Das <sandipan@linux.vnet.ibm.com> Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
112 lines
3.0 KiB
C
112 lines
3.0 KiB
C
/*
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* bpf_jit64.h: BPF JIT compiler for PPC64
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*
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* Copyright 2016 Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
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* IBM Corporation
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*/
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#ifndef _BPF_JIT64_H
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#define _BPF_JIT64_H
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#include "bpf_jit.h"
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/*
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* Stack layout:
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* Ensure the top half (upto local_tmp_var) stays consistent
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* with our redzone usage.
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*
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* [ prev sp ] <-------------
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* [ nv gpr save area ] 8*8 |
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* [ tail_call_cnt ] 8 |
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* [ local_tmp_var ] 8 |
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* fp (r31) --> [ ebpf stack space ] upto 512 |
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* [ frame header ] 32/112 |
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* sp (r1) ---> [ stack pointer ] --------------
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*/
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/* for gpr non volatile registers BPG_REG_6 to 10, plus skb cache registers */
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#define BPF_PPC_STACK_SAVE (8*8)
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/* for bpf JIT code internal usage */
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#define BPF_PPC_STACK_LOCALS 16
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/* stack frame excluding BPF stack, ensure this is quadword aligned */
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#define BPF_PPC_STACKFRAME (STACK_FRAME_MIN_SIZE + \
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BPF_PPC_STACK_LOCALS + BPF_PPC_STACK_SAVE)
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#ifndef __ASSEMBLY__
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/* BPF register usage */
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#define SKB_HLEN_REG (MAX_BPF_JIT_REG + 0)
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#define SKB_DATA_REG (MAX_BPF_JIT_REG + 1)
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#define TMP_REG_1 (MAX_BPF_JIT_REG + 2)
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#define TMP_REG_2 (MAX_BPF_JIT_REG + 3)
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/* BPF to ppc register mappings */
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static const int b2p[] = {
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/* function return value */
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[BPF_REG_0] = 8,
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/* function arguments */
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[BPF_REG_1] = 3,
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[BPF_REG_2] = 4,
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[BPF_REG_3] = 5,
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[BPF_REG_4] = 6,
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[BPF_REG_5] = 7,
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/* non volatile registers */
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[BPF_REG_6] = 27,
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[BPF_REG_7] = 28,
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[BPF_REG_8] = 29,
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[BPF_REG_9] = 30,
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/* frame pointer aka BPF_REG_10 */
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[BPF_REG_FP] = 31,
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/* eBPF jit internal registers */
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[BPF_REG_AX] = 2,
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[SKB_HLEN_REG] = 25,
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[SKB_DATA_REG] = 26,
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[TMP_REG_1] = 9,
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[TMP_REG_2] = 10
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};
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/* PPC NVR range -- update this if we ever use NVRs below r24 */
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#define BPF_PPC_NVR_MIN 24
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/* Assembly helpers */
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#define DECLARE_LOAD_FUNC(func) u64 func(u64 r3, u64 r4); \
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u64 func##_negative_offset(u64 r3, u64 r4); \
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u64 func##_positive_offset(u64 r3, u64 r4);
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DECLARE_LOAD_FUNC(sk_load_word);
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DECLARE_LOAD_FUNC(sk_load_half);
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DECLARE_LOAD_FUNC(sk_load_byte);
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#define CHOOSE_LOAD_FUNC(imm, func) \
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(imm < 0 ? \
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(imm >= SKF_LL_OFF ? func##_negative_offset : func) : \
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func##_positive_offset)
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#define SEEN_FUNC 0x1000 /* might call external helpers */
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#define SEEN_STACK 0x2000 /* uses BPF stack */
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#define SEEN_SKB 0x4000 /* uses sk_buff */
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#define SEEN_TAILCALL 0x8000 /* uses tail calls */
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struct codegen_context {
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/*
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* This is used to track register usage as well
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* as calls to external helpers.
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* - register usage is tracked with corresponding
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* bits (r3-r10 and r25-r31)
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* - rest of the bits can be used to track other
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* things -- for now, we use bits 16 to 23
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* encoded in SEEN_* macros above
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*/
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unsigned int seen;
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unsigned int idx;
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unsigned int stack_size;
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};
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#endif /* !__ASSEMBLY__ */
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#endif
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