diff options
Diffstat (limited to 'arch/loongarch')
| -rw-r--r-- | arch/loongarch/include/asm/asm-extable.h | 1 | ||||
| -rw-r--r-- | arch/loongarch/include/asm/extable.h | 10 | ||||
| -rw-r--r-- | arch/loongarch/mm/extable.c | 2 | ||||
| -rw-r--r-- | arch/loongarch/net/bpf_jit.c | 86 | ||||
| -rw-r--r-- | arch/loongarch/net/bpf_jit.h | 2 |
5 files changed, 96 insertions, 5 deletions
diff --git a/arch/loongarch/include/asm/asm-extable.h b/arch/loongarch/include/asm/asm-extable.h index f5502cb50c6e..df05005f2b80 100644 --- a/arch/loongarch/include/asm/asm-extable.h +++ b/arch/loongarch/include/asm/asm-extable.h @@ -5,6 +5,7 @@ #define EX_TYPE_NONE 0 #define EX_TYPE_FIXUP 1 #define EX_TYPE_UACCESS_ERR_ZERO 2 +#define EX_TYPE_BPF 3 #ifdef __ASSEMBLY__ diff --git a/arch/loongarch/include/asm/extable.h b/arch/loongarch/include/asm/extable.h index 92612b4364a1..5abf29f1bc91 100644 --- a/arch/loongarch/include/asm/extable.h +++ b/arch/loongarch/include/asm/extable.h @@ -32,6 +32,16 @@ do { \ (b)->data = (tmp).data; \ } while (0) +#ifdef CONFIG_BPF_JIT +bool ex_handler_bpf(const struct exception_table_entry *ex, struct pt_regs *regs); +#else +static inline +bool ex_handler_bpf(const struct exception_table_entry *ex, struct pt_regs *regs) +{ + return false; +} +#endif /* !CONFIG_BPF_JIT */ + bool fixup_exception(struct pt_regs *regs); #endif diff --git a/arch/loongarch/mm/extable.c b/arch/loongarch/mm/extable.c index 9b0cfd898940..9ab69872dcff 100644 --- a/arch/loongarch/mm/extable.c +++ b/arch/loongarch/mm/extable.c @@ -55,6 +55,8 @@ bool fixup_exception(struct pt_regs *regs) return ex_handler_fixup(ex, regs); case EX_TYPE_UACCESS_ERR_ZERO: return ex_handler_uaccess_err_zero(ex, regs); + case EX_TYPE_BPF: + return ex_handler_bpf(ex, regs); } BUG(); diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index bdcd0c7719a9..c4b1947ebf76 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -387,6 +387,65 @@ static bool is_signed_bpf_cond(u8 cond) cond == BPF_JSGE || cond == BPF_JSLE; } +#define BPF_FIXUP_REG_MASK GENMASK(31, 27) +#define BPF_FIXUP_OFFSET_MASK GENMASK(26, 0) + +bool ex_handler_bpf(const struct exception_table_entry *ex, + struct pt_regs *regs) +{ + int dst_reg = FIELD_GET(BPF_FIXUP_REG_MASK, ex->fixup); + off_t offset = FIELD_GET(BPF_FIXUP_OFFSET_MASK, ex->fixup); + + regs->regs[dst_reg] = 0; + regs->csr_era = (unsigned long)&ex->fixup - offset; + + return true; +} + +/* For accesses to BTF pointers, add an entry to the exception table */ +static int add_exception_handler(const struct bpf_insn *insn, + struct jit_ctx *ctx, + int dst_reg) +{ + unsigned long pc; + off_t offset; + struct exception_table_entry *ex; + + if (!ctx->image || !ctx->prog->aux->extable || BPF_MODE(insn->code) != BPF_PROBE_MEM) + return 0; + + if (WARN_ON_ONCE(ctx->num_exentries >= ctx->prog->aux->num_exentries)) + return -EINVAL; + + ex = &ctx->prog->aux->extable[ctx->num_exentries]; + pc = (unsigned long)&ctx->image[ctx->idx - 1]; + + offset = pc - (long)&ex->insn; + if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN)) + return -ERANGE; + + ex->insn = offset; + + /* + * Since the extable follows the program, the fixup offset is always + * negative and limited to BPF_JIT_REGION_SIZE. Store a positive value + * to keep things simple, and put the destination register in the upper + * bits. We don't need to worry about buildtime or runtime sort + * modifying the upper bits because the table is already sorted, and + * isn't part of the main exception table. + */ + offset = (long)&ex->fixup - (pc + LOONGARCH_INSN_SIZE); + if (!FIELD_FIT(BPF_FIXUP_OFFSET_MASK, offset)) + return -ERANGE; + + ex->type = EX_TYPE_BPF; + ex->fixup = FIELD_PREP(BPF_FIXUP_OFFSET_MASK, offset) | FIELD_PREP(BPF_FIXUP_REG_MASK, dst_reg); + + ctx->num_exentries++; + + return 0; +} + static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool extra_pass) { u8 tm = -1; @@ -816,6 +875,10 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext case BPF_LDX | BPF_MEM | BPF_H: case BPF_LDX | BPF_MEM | BPF_W: case BPF_LDX | BPF_MEM | BPF_DW: + case BPF_LDX | BPF_PROBE_MEM | BPF_DW: + case BPF_LDX | BPF_PROBE_MEM | BPF_W: + case BPF_LDX | BPF_PROBE_MEM | BPF_H: + case BPF_LDX | BPF_PROBE_MEM | BPF_B: switch (BPF_SIZE(code)) { case BPF_B: if (is_signed_imm12(off)) { @@ -854,6 +917,10 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, bool ext } break; } + + ret = add_exception_handler(insn, ctx, dst); + if (ret) + return ret; break; /* *(size *)(dst + off) = imm */ @@ -1018,6 +1085,9 @@ static int validate_code(struct jit_ctx *ctx) return -1; } + if (WARN_ON_ONCE(ctx->num_exentries != ctx->prog->aux->num_exentries)) + return -1; + return 0; } @@ -1025,7 +1095,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) { bool tmp_blinded = false, extra_pass = false; u8 *image_ptr; - int image_size; + int image_size, prog_size, extable_size; struct jit_ctx ctx; struct jit_data *jit_data; struct bpf_binary_header *header; @@ -1066,7 +1136,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) image_ptr = jit_data->image; header = jit_data->header; extra_pass = true; - image_size = sizeof(u32) * ctx.idx; + prog_size = sizeof(u32) * ctx.idx; goto skip_init_ctx; } @@ -1088,12 +1158,15 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) ctx.epilogue_offset = ctx.idx; build_epilogue(&ctx); + extable_size = prog->aux->num_exentries * sizeof(struct exception_table_entry); + /* Now we know the actual image size. * As each LoongArch instruction is of length 32bit, * we are translating number of JITed intructions into * the size required to store these JITed code. */ - image_size = sizeof(u32) * ctx.idx; + prog_size = sizeof(u32) * ctx.idx; + image_size = prog_size + extable_size; /* Now we know the size of the structure to make */ header = bpf_jit_binary_alloc(image_size, &image_ptr, sizeof(u32), jit_fill_hole); @@ -1104,9 +1177,12 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) /* 2. Now, the actual pass to generate final JIT code */ ctx.image = (union loongarch_instruction *)image_ptr; + if (extable_size) + prog->aux->extable = (void *)image_ptr + prog_size; skip_init_ctx: ctx.idx = 0; + ctx.num_exentries = 0; build_prologue(&ctx); if (build_body(&ctx, extra_pass)) { @@ -1125,7 +1201,7 @@ skip_init_ctx: /* And we're done */ if (bpf_jit_enable > 1) - bpf_jit_dump(prog->len, image_size, 2, ctx.image); + bpf_jit_dump(prog->len, prog_size, 2, ctx.image); /* Update the icache */ flush_icache_range((unsigned long)header, (unsigned long)(ctx.image + ctx.idx)); @@ -1147,7 +1223,7 @@ skip_init_ctx: jit_data->header = header; } prog->jited = 1; - prog->jited_len = image_size; + prog->jited_len = prog_size; prog->bpf_func = (void *)ctx.image; if (!prog->is_func || extra_pass) { diff --git a/arch/loongarch/net/bpf_jit.h b/arch/loongarch/net/bpf_jit.h index e665ddb0aeb8..ca708024fdd3 100644 --- a/arch/loongarch/net/bpf_jit.h +++ b/arch/loongarch/net/bpf_jit.h @@ -4,6 +4,7 @@ * * Copyright (C) 2022 Loongson Technology Corporation Limited */ +#include <linux/bitfield.h> #include <linux/bpf.h> #include <linux/filter.h> #include <asm/cacheflush.h> @@ -15,6 +16,7 @@ struct jit_ctx { unsigned int flags; unsigned int epilogue_offset; u32 *offset; + int num_exentries; union loongarch_instruction *image; u32 stack_size; }; |