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Commit 8d8d18c3 authored by David Daney's avatar David Daney Committed by David S. Miller
Browse files

MIPS,bpf: Fix using smp_processor_id() in preemptible splat. 



If the kernel is configured with preemption enabled we were getting
warning stack traces for use of current_cpu_type().

Fix by moving the test between preempt_disable()/preempt_enable() and
caching the results of the CPU type tests for use during code
generation.

Signed-off-by: default avatarDavid Daney <david.daney@cavium.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent da6817eb

arch/mips/net/ebpf_jit.c

+14 −14
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ struct jit_ctx { 
	u64 *reg_val_types;

	unsigned int long_b_conversion:1;

	unsigned int gen_b_offsets:1;

	unsigned int use_bbit_insns:1;

};



static void set_reg_val_type(u64 *rvt, int reg, enum reg_val_type type)
@@ -655,19 +656,6 @@ static int emit_bpf_tail_call(struct jit_ctx *ctx, int this_idx) 
	return build_int_epilogue(ctx, MIPS_R_T9);

}



static bool use_bbit_insns(void)

{

	switch (current_cpu_type()) {

	case CPU_CAVIUM_OCTEON:

	case CPU_CAVIUM_OCTEON_PLUS:

	case CPU_CAVIUM_OCTEON2:

	case CPU_CAVIUM_OCTEON3:

		return true;

	default:

		return false;

	}

}



static bool is_bad_offset(int b_off)

{

	return b_off > 0x1ffff || b_off < -0x20000;
@@ -1198,7 +1186,7 @@ static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, 
		if (dst < 0)

			return dst;



		if (use_bbit_insns() && hweight32((u32)insn->imm) == 1) {

		if (ctx->use_bbit_insns && hweight32((u32)insn->imm) == 1) {

			if ((insn + 1)->code == (BPF_JMP | BPF_EXIT) && insn->off == 1) {

				b_off = b_imm(exit_idx, ctx);

				if (is_bad_offset(b_off))
@@ -1853,6 +1841,18 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) 


	memset(&ctx, 0, sizeof(ctx));



	preempt_disable();

	switch (current_cpu_type()) {

	case CPU_CAVIUM_OCTEON:

	case CPU_CAVIUM_OCTEON_PLUS:

	case CPU_CAVIUM_OCTEON2:

	case CPU_CAVIUM_OCTEON3:

		ctx.use_bbit_insns = 1;

	default:

		ctx.use_bbit_insns = 0;

	}

	preempt_enable();



	ctx.offsets = kcalloc(prog->len + 1, sizeof(*ctx.offsets), GFP_KERNEL);

	if (ctx.offsets == NULL)

		goto out_err;