linux/arch/arc/net/bpf_jit.h
Shahab Vahedi dd6a403795 ARC, bpf: Fix issues reported by the static analyzers
Also updated couple of comments along the way.

One of the issues reported was indeed a bug in the code:

  memset(ctx, 0, sizeof(ctx))      // original line
  memset(ctx, 0, sizeof(*ctx))     // fixed line

That was a nice catch.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202405222314.UG5F2NHn-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202405232036.Xqoc3b0J-lkp@intel.com/
Signed-off-by: Shahab Vahedi <shahab@synopsys.com>
Link: https://lore.kernel.org/r/20240525035628.1026-1-list+bpf@vahedi.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2024-05-25 10:47:21 -07:00

165 lines
5.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* The interface that a back-end should provide to bpf_jit_core.c.
*
* Copyright (c) 2024 Synopsys Inc.
* Author: Shahab Vahedi <shahab@synopsys.com>
*/
#ifndef _ARC_BPF_JIT_H
#define _ARC_BPF_JIT_H
#include <linux/bpf.h>
#include <linux/filter.h>
/* Print debug info and assert. */
//#define ARC_BPF_JIT_DEBUG
/* Determine the address type of the target. */
#ifdef CONFIG_ISA_ARCV2
#define ARC_ADDR u32
#endif
/*
* For the translation of some BPF instructions, a temporary register
* might be needed for some interim data.
*/
#define JIT_REG_TMP MAX_BPF_JIT_REG
/*
* Buffer access: If buffer "b" is not NULL, advance by "n" bytes.
*
* This macro must be used in any place that potentially requires a
* "buf + len". This way, we make sure that the "buf" argument for
* the underlying "arc_*(buf, ...)" ends up as NULL instead of something
* like "0+4" or "0+8", etc. Those "arc_*()" functions check their "buf"
* value to decide if instructions should be emitted or not.
*/
#define BUF(b, n) (((b) != NULL) ? ((b) + (n)) : (b))
/************** Functions that the back-end must provide **************/
/* Extension for 32-bit operations. */
u8 zext(u8 *buf, u8 rd);
/***** Moves *****/
u8 mov_r32(u8 *buf, u8 rd, u8 rs, u8 sign_ext);
u8 mov_r32_i32(u8 *buf, u8 reg, s32 imm);
u8 mov_r64(u8 *buf, u8 rd, u8 rs, u8 sign_ext);
u8 mov_r64_i32(u8 *buf, u8 reg, s32 imm);
u8 mov_r64_i64(u8 *buf, u8 reg, u32 lo, u32 hi);
/***** Loads and stores *****/
u8 load_r(u8 *buf, u8 rd, u8 rs, s16 off, u8 size, bool sign_ext);
u8 store_r(u8 *buf, u8 rd, u8 rs, s16 off, u8 size);
u8 store_i(u8 *buf, s32 imm, u8 rd, s16 off, u8 size);
/***** Addition *****/
u8 add_r32(u8 *buf, u8 rd, u8 rs);
u8 add_r32_i32(u8 *buf, u8 rd, s32 imm);
u8 add_r64(u8 *buf, u8 rd, u8 rs);
u8 add_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Subtraction *****/
u8 sub_r32(u8 *buf, u8 rd, u8 rs);
u8 sub_r32_i32(u8 *buf, u8 rd, s32 imm);
u8 sub_r64(u8 *buf, u8 rd, u8 rs);
u8 sub_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Multiplication *****/
u8 mul_r32(u8 *buf, u8 rd, u8 rs);
u8 mul_r32_i32(u8 *buf, u8 rd, s32 imm);
u8 mul_r64(u8 *buf, u8 rd, u8 rs);
u8 mul_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Division *****/
u8 div_r32(u8 *buf, u8 rd, u8 rs, bool sign_ext);
u8 div_r32_i32(u8 *buf, u8 rd, s32 imm, bool sign_ext);
/***** Remainder *****/
u8 mod_r32(u8 *buf, u8 rd, u8 rs, bool sign_ext);
u8 mod_r32_i32(u8 *buf, u8 rd, s32 imm, bool sign_ext);
/***** Bitwise AND *****/
u8 and_r32(u8 *buf, u8 rd, u8 rs);
u8 and_r32_i32(u8 *buf, u8 rd, s32 imm);
u8 and_r64(u8 *buf, u8 rd, u8 rs);
u8 and_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Bitwise OR *****/
u8 or_r32(u8 *buf, u8 rd, u8 rs);
u8 or_r32_i32(u8 *buf, u8 rd, s32 imm);
u8 or_r64(u8 *buf, u8 rd, u8 rs);
u8 or_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Bitwise XOR *****/
u8 xor_r32(u8 *buf, u8 rd, u8 rs);
u8 xor_r32_i32(u8 *buf, u8 rd, s32 imm);
u8 xor_r64(u8 *buf, u8 rd, u8 rs);
u8 xor_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Bitwise Negate *****/
u8 neg_r32(u8 *buf, u8 r);
u8 neg_r64(u8 *buf, u8 r);
/***** Bitwise left shift *****/
u8 lsh_r32(u8 *buf, u8 rd, u8 rs);
u8 lsh_r32_i32(u8 *buf, u8 rd, u8 imm);
u8 lsh_r64(u8 *buf, u8 rd, u8 rs);
u8 lsh_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Bitwise right shift (logical) *****/
u8 rsh_r32(u8 *buf, u8 rd, u8 rs);
u8 rsh_r32_i32(u8 *buf, u8 rd, u8 imm);
u8 rsh_r64(u8 *buf, u8 rd, u8 rs);
u8 rsh_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Bitwise right shift (arithmetic) *****/
u8 arsh_r32(u8 *buf, u8 rd, u8 rs);
u8 arsh_r32_i32(u8 *buf, u8 rd, u8 imm);
u8 arsh_r64(u8 *buf, u8 rd, u8 rs);
u8 arsh_r64_i32(u8 *buf, u8 rd, s32 imm);
/***** Frame related *****/
u32 mask_for_used_regs(u8 bpf_reg, bool is_call);
u8 arc_prologue(u8 *buf, u32 usage, u16 frame_size);
u8 arc_epilogue(u8 *buf, u32 usage, u16 frame_size);
/***** Jumps *****/
/*
* Different sorts of conditions (ARC enum as opposed to BPF_*).
*
* Do not change the order of enums here. ARC_CC_SLE+1 is used
* to determine the number of JCCs.
*/
enum ARC_CC {
ARC_CC_UGT = 0, /* unsigned > */
ARC_CC_UGE, /* unsigned >= */
ARC_CC_ULT, /* unsigned < */
ARC_CC_ULE, /* unsigned <= */
ARC_CC_SGT, /* signed > */
ARC_CC_SGE, /* signed >= */
ARC_CC_SLT, /* signed < */
ARC_CC_SLE, /* signed <= */
ARC_CC_AL, /* always */
ARC_CC_EQ, /* == */
ARC_CC_NE, /* != */
ARC_CC_SET, /* test */
ARC_CC_LAST
};
/*
* A few notes:
*
* - check_jmp_*() are prerequisites before calling the gen_jmp_*().
* They return "true" if the jump is possible and "false" otherwise.
*
* - The notion of "*_off" is to emphasize that these parameters are
* merely offsets in the JIT stream and not absolute addresses. One
* can look at them as addresses if the JIT code would start from
* address 0x0000_0000. Nonetheless, since the buffer address for the
* JIT is on a word-aligned address, this works and actually makes
* things simpler (offsets are in the range of u32 which is more than
* enough).
*/
bool check_jmp_32(u32 curr_off, u32 targ_off, u8 cond);
bool check_jmp_64(u32 curr_off, u32 targ_off, u8 cond);
u8 gen_jmp_32(u8 *buf, u8 rd, u8 rs, u8 cond, u32 c_off, u32 t_off);
u8 gen_jmp_64(u8 *buf, u8 rd, u8 rs, u8 cond, u32 c_off, u32 t_off);
/***** Miscellaneous *****/
u8 gen_func_call(u8 *buf, ARC_ADDR func_addr, bool external_func);
u8 arc_to_bpf_return(u8 *buf);
/*
* - Perform byte swaps on "rd" based on the "size".
* - If "force" is set, do it unconditionally. Otherwise, consider the
* desired "endian"ness and the host endianness.
* - For data "size"s up to 32 bits, perform a zero-extension if asked
* by the "do_zext" boolean.
*/
u8 gen_swap(u8 *buf, u8 rd, u8 size, u8 endian, bool force, bool do_zext);
#endif /* _ARC_BPF_JIT_H */