/* SPDX-License-Identifier: GPL-2.0-only */
/*
* bpf_jit.h: BPF JIT compiler for PPC
*
* Copyright 2011 Matt Evans <[email protected]>, IBM Corporation
* 2016 Naveen N. Rao <[email protected]>
*/
#ifndef _BPF_JIT_H
#define _BPF_JIT_H
#ifndef __ASSEMBLY__
#include <asm/types.h>
#include <asm/ppc-opcode.h>
#ifdef CONFIG_PPC64_ELF_ABI_V1
#define FUNCTION_DESCR_SIZE 24
#else
#define FUNCTION_DESCR_SIZE 0
#endif
#define CTX_NIA(ctx) ((unsigned long)ctx->idx * 4)
#define PLANT_INSTR(d, idx, instr) \
do { if (d) { (d)[idx] = instr; } idx++; } while (0)
#define EMIT(instr) PLANT_INSTR(image, ctx->idx, instr)
/* Long jump; (unconditional 'branch') */
#define PPC_JMP(dest) \
do { \
long offset = (long)(dest) - CTX_NIA(ctx); \
if ((dest) != 0 && !is_offset_in_branch_range(offset)) { \
pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \
return -ERANGE; \
} \
EMIT(PPC_RAW_BRANCH(offset)); \
} while (0)
/* "cond" here covers BO:BI fields. */
#define PPC_BCC_SHORT(cond, dest) \
do { \
long offset = (long)(dest) - CTX_NIA(ctx); \
if ((dest) != 0 && !is_offset_in_cond_branch_range(offset)) { \
pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \
return -ERANGE; \
} \
EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc)); \
} while (0)
/* Sign-extended 32-bit immediate load */
#define PPC_LI32(d, i) do { \
if ((int)(uintptr_t)(i) >= -32768 && \
(int)(uintptr_t)(i) < 32768) \
EMIT(PPC_RAW_LI(d, i)); \
else { \
EMIT(PPC_RAW_LIS(d, IMM_H(i))); \
if (IMM_L(i)) \
EMIT(PPC_RAW_ORI(d, d, IMM_L(i))); \
} } while(0)
#ifdef CONFIG_PPC64
#define PPC_LI64(d, i) do { \
if ((long)(i) >= -2147483648 && \
(long)(i) < 2147483648) \
PPC_LI32(d, i); \
else { \
if (!((uintptr_t)(i) & 0xffff800000000000ULL)) \
EMIT(PPC_RAW_LI(d, ((uintptr_t)(i) >> 32) & \
0xffff)); \
else { \
EMIT(PPC_RAW_LIS(d, ((uintptr_t)(i) >> 48))); \
if ((uintptr_t)(i) & 0x0000ffff00000000ULL) \
EMIT(PPC_RAW_ORI(d, d, \
((uintptr_t)(i) >> 32) & 0xffff)); \
} \
EMIT(PPC_RAW_SLDI(d, d, 32)); \
if ((uintptr_t)(i) & 0x00000000ffff0000ULL) \
EMIT(PPC_RAW_ORIS(d, d, \
((uintptr_t)(i) >> 16) & 0xffff)); \
if ((uintptr_t)(i) & 0x000000000000ffffULL) \
EMIT(PPC_RAW_ORI(d, d, (uintptr_t)(i) & \
0xffff)); \
} } while (0)
#endif
/*
* The fly in the ointment of code size changing from pass to pass is
* avoided by padding the short branch case with a NOP. If code size differs
* with different branch reaches we will have the issue of code moving from
* one pass to the next and will need a few passes to converge on a stable
* state.
*/
#define PPC_BCC(cond, dest) do { \
if (is_offset_in_cond_branch_range((long)(dest) - CTX_NIA(ctx))) { \
PPC_BCC_SHORT(cond, dest); \
EMIT(PPC_RAW_NOP()); \
} else { \
/* Flip the 'T or F' bit to invert comparison */ \
PPC_BCC_SHORT(cond ^ COND_CMP_TRUE, CTX_NIA(ctx) + 2*4); \
PPC_JMP(dest); \
} } while(0)
/* To create a branch condition, select a bit of cr0... */
#define CR0_LT 0
#define CR0_GT 1
#define CR0_EQ 2
/* ...and modify BO[3] */
#define COND_CMP_TRUE 0x100
#define COND_CMP_FALSE 0x000
/* Together, they make all required comparisons: */
#define COND_GT (CR0_GT | COND_CMP_TRUE)
#define COND_GE (CR0_LT | COND_CMP_FALSE)
#define COND_EQ (CR0_EQ | COND_CMP_TRUE)
#define COND_NE (CR0_EQ | COND_CMP_FALSE)
#define COND_LT (CR0_LT | COND_CMP_TRUE)
#define COND_LE (CR0_GT | COND_CMP_FALSE)
#define SEEN_FUNC 0x20000000 /* might call external helpers */
#define SEEN_TAILCALL 0x40000000 /* 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-r31)
* - rest of the bits can be used to track other
* things -- for now, we use bits 0 to 2
* encoded in SEEN_* macros above
*/
unsigned int seen;
unsigned int idx;
unsigned int stack_size;
int b2p[MAX_BPF_JIT_REG + 2];
unsigned int exentry_idx;
unsigned int alt_exit_addr;
};
#define bpf_to_ppc(r) (ctx->b2p[r])
#ifdef CONFIG_PPC32
#define BPF_FIXUP_LEN 3 /* Three instructions => 12 bytes */
#else
#define BPF_FIXUP_LEN 2 /* Two instructions => 8 bytes */
#endif
static inline bool bpf_is_seen_register(struct codegen_context *ctx, int i)
{
return ctx->seen & (1 << (31 - i));
}
static inline void bpf_set_seen_register(struct codegen_context *ctx, int i)
{
ctx->seen |= 1 << (31 - i);
}
static inline void bpf_clear_seen_register(struct codegen_context *ctx, int i)
{
ctx->seen &= ~(1 << (31 - i));
}
void bpf_jit_init_reg_mapping(struct codegen_context *ctx);
int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func);
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct codegen_context *ctx,
u32 *addrs, int pass, bool extra_pass);
void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx);
void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx);
void bpf_jit_realloc_regs(struct codegen_context *ctx);
int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr);
int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, u32 *fimage, int pass,
struct codegen_context *ctx, int insn_idx,
int jmp_off, int dst_reg);
#endif
#endif
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