Commit f9320c49 authored by Naveen N. Rao's avatar Naveen N. Rao Committed by Michael Ellerman
Browse files

powerpc/bpf: Update ldimm64 instructions during extra pass 



These instructions are updated after the initial JIT, so redo codegen
during the extra pass. Rename bpf_jit_fixup_subprog_calls() to clarify
that this is more than just subprog calls.

Fixes: 69c087ba ("bpf: Add bpf_for_each_map_elem() helper")
Cc: stable@vger.kernel.org # v5.15
Signed-off-by: default avatarNaveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: default avatarJiri Olsa <jolsa@redhat.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/7cc162af77ba918eb3ecd26ec9e7824bc44b1fae.1641468127.git.naveen.n.rao@linux.vnet.ibm.com
parent fab07611

arch/powerpc/net/bpf_jit_comp.c

+23 −6
Original line number Diff line number Diff line
@@ -23,15 +23,15 @@ static void bpf_jit_fill_ill_insns(void *area, unsigned int size) 
	memset32(area, BREAKPOINT_INSTRUCTION, size / 4);

}



/* Fix the branch target addresses for subprog calls */

static int bpf_jit_fixup_subprog_calls(struct bpf_prog *fp, u32 *image,

/* Fix updated addresses (for subprog calls, ldimm64, et al) during extra pass */

static int bpf_jit_fixup_addresses(struct bpf_prog *fp, u32 *image,

				   struct codegen_context *ctx, u32 *addrs)

{

	const struct bpf_insn *insn = fp->insnsi;

	bool func_addr_fixed;

	u64 func_addr;

	u32 tmp_idx;

	int i, ret;

	int i, j, ret;



	for (i = 0; i < fp->len; i++) {

		/*
@@ -66,6 +66,23 @@ static int bpf_jit_fixup_subprog_calls(struct bpf_prog *fp, u32 *image, 
			 * of the JITed sequence remains unchanged.

			 */

			ctx->idx = tmp_idx;

		} else if (insn[i].code == (BPF_LD | BPF_IMM | BPF_DW)) {

			tmp_idx = ctx->idx;

			ctx->idx = addrs[i] / 4;

#ifdef CONFIG_PPC32

			PPC_LI32(ctx->b2p[insn[i].dst_reg] - 1, (u32)insn[i + 1].imm);

			PPC_LI32(ctx->b2p[insn[i].dst_reg], (u32)insn[i].imm);

			for (j = ctx->idx - addrs[i] / 4; j < 4; j++)

				EMIT(PPC_RAW_NOP());

#else

			func_addr = ((u64)(u32)insn[i].imm) | (((u64)(u32)insn[i + 1].imm) << 32);

			PPC_LI64(b2p[insn[i].dst_reg], func_addr);

			/* overwrite rest with nops */

			for (j = ctx->idx - addrs[i] / 4; j < 5; j++)

				EMIT(PPC_RAW_NOP());

#endif

			ctx->idx = tmp_idx;

			i++;

		}

	}
@@ -200,13 +217,13 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp) 
		/*

		 * Do not touch the prologue and epilogue as they will remain

		 * unchanged. Only fix the branch target address for subprog

		 * calls in the body.

		 * calls in the body, and ldimm64 instructions.

		 *

		 * This does not change the offsets and lengths of the subprog

		 * call instruction sequences and hence, the size of the JITed

		 * image as well.

		 */

		bpf_jit_fixup_subprog_calls(fp, code_base, &cgctx, addrs);

		bpf_jit_fixup_addresses(fp, code_base, &cgctx, addrs);



		/* There is no need to perform the usual passes. */

		goto skip_codegen_passes;

arch/powerpc/net/bpf_jit_comp32.c

+6 −0
Original line number Diff line number Diff line
@@ -293,6 +293,8 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * 
		bool func_addr_fixed;

		u64 func_addr;

		u32 true_cond;

		u32 tmp_idx;

		int j;



		/*

		 * addrs[] maps a BPF bytecode address into a real offset from
@@ -908,8 +910,12 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * 
		 * 16 byte instruction that uses two 'struct bpf_insn'

		 */

		case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */

			tmp_idx = ctx->idx;

			PPC_LI32(dst_reg_h, (u32)insn[i + 1].imm);

			PPC_LI32(dst_reg, (u32)insn[i].imm);

			/* padding to allow full 4 instructions for later patching */

			for (j = ctx->idx - tmp_idx; j < 4; j++)

				EMIT(PPC_RAW_NOP());

			/* Adjust for two bpf instructions */

			addrs[++i] = ctx->idx * 4;

			break;

arch/powerpc/net/bpf_jit_comp64.c

+6 −1
Original line number Diff line number Diff line
@@ -319,6 +319,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * 
		u64 imm64;

		u32 true_cond;

		u32 tmp_idx;

		int j;



		/*

		 * addrs[] maps a BPF bytecode address into a real offset from
@@ -848,9 +849,13 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context * 
		case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */

			imm64 = ((u64)(u32) insn[i].imm) |

				    (((u64)(u32) insn[i+1].imm) << 32);

			tmp_idx = ctx->idx;

			PPC_LI64(dst_reg, imm64);

			/* padding to allow full 5 instructions for later patching */

			for (j = ctx->idx - tmp_idx; j < 5; j++)

				EMIT(PPC_RAW_NOP());

			/* Adjust for two bpf instructions */

			addrs[++i] = ctx->idx * 4;

			PPC_LI64(dst_reg, imm64);

			break;



		/*