From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f43.google.com (mail-pj1-f43.google.com [209.85.216.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6AB471E376C for ; Sun, 12 Apr 2026 01:19:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775956744; cv=none; b=H2COm7/fffR3PgUX/YZsSJ/+TYlPnOId+BV5kcBK/i55PsioUaWuxj+xg8x0bkB6m6G9KaQaQCK7JTPwyj0cDzM2nt3+jM1jcM6SinP7eG7yFKYzC6vvHN1IYZppJ4NduOKksQAnXLJxi5KYPpccL0gkDKvmdxs+VM8vcCu0RIo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775956744; c=relaxed/simple; bh=6FQmlQCDaw5G/b7s9wJcOxLrOo2RvH/fvTmkPB1qLlA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qVh1pv8gRaQiisfaRE2NMQO1zoXw25052FySIOqIX5ZpK4cf0R//Kz+Jxnqz9jzUBa01Bz8157/WXwAo5l3FnIIJh7kJZzcp4QJ18tQYlP+d2z/wP1pRLVHtJtA/f6+3RqLMBdAD3diTKvF58k4rXWHDya9DCbwBZuXIum3s7OE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=etsalapatis.com; spf=pass smtp.mailfrom=etsalapatis.com; dkim=pass (2048-bit key) header.d=etsalapatis-com.20251104.gappssmtp.com header.i=@etsalapatis-com.20251104.gappssmtp.com header.b=A0jeyE24; arc=none smtp.client-ip=209.85.216.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=etsalapatis.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=etsalapatis.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=etsalapatis-com.20251104.gappssmtp.com header.i=@etsalapatis-com.20251104.gappssmtp.com header.b="A0jeyE24" Received: by mail-pj1-f43.google.com with SMTP id 98e67ed59e1d1-35f9ab079bdso60524a91.2 for ; Sat, 11 Apr 2026 18:19:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=etsalapatis-com.20251104.gappssmtp.com; s=20251104; t=1775956743; x=1776561543; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=IY6kyTbszWVS4VGgGorOA/XgXWWD/B5lBcXctB5E5wQ=; b=A0jeyE24utCmi7GMYsRP+e3Gzz6KzeA/yAk2W49L6kS4p8ROeYw7ttpwhX8u0AfxOj Mcc7vxMX1tgczhHzVc1dd1QfuJ7hkt4h3G/ueqFHIM2e4jibIfQgjzJiVW0EiY8fw8dL du4C0+b3XvWEo1nQqztSAQrWkG7NmymdcLxPnWRzFNwmIUlLDt5lDv5dep0Dg6LRPI6D YU+itra84SscuIqNjCXjr1dSHZnBSops14+AJCmSKOnelICjNg7eoHHcjbw+C/nLKiHO R9xXhlPB9aSCYDRk8TmXef05SUU8GyvzleiBspbWtIiLy/jn2lsCqQszHEN3Yk6xZX1y T0OQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775956743; x=1776561543; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=IY6kyTbszWVS4VGgGorOA/XgXWWD/B5lBcXctB5E5wQ=; b=PLFJKMUJK99tFUBj3usWcLcZmGBRA1Q3BAXpq65GPRArZ0ieu0fQYRdup3Nk5rXgVT l6Rvyw+o7FJocuLN5H8rKcDUf1yRZCnbAMNx/j566s89hDR1kef1G8ceO/2DvnpcNLpy wzzhUS52cviDckTbL5KV1JLVyCeMkT9IeBmUKZ9coJsrmctv7BhySjGjC/BuvS78rkq6 WV1qDQSeElQyA/wckrl+NL8lCS+IgYn+vo87DZlugt4m0qORibcRU51Ab/5GNEd60Fn1 RCIP37QDBGjTYo9sg3WR5RbhSeN70BTwlpi9v7RyqLtCIR/29EE6HZVzB2xXj31syHon csHQ== X-Gm-Message-State: AOJu0YzVT14odyuMKbOdt4vBn7qLRtorLesYaYRKgbGEvmZv2+Bk22vJ POhsAGdUzso5lWpIqjZy1yussSHKd2A8ulh4DQpm6s/zYle+MQ1an83Ue8GyyqoHyoXqtxeEIYh R7Z0R/70= X-Gm-Gg: AeBDies5h4wngUQArxrI5Ms+GpXaOH7LE9EDrHbkeUCX0+ZGkjIVVZqCtYFS2rzLO2e tnysAgJ7cHYir8HFleR/2WbnqkxjTBpvHMJeAvzBE2sOyyqCxWP6L3oP2dsrZU0fPZ//73R1V6z y4wnsseryeXYlXrWYK4vz+Z+YlG1T6kY2ajwo+R7K/gnTHx73Z1W0Z0MZbFiY2SgyBa4tadfrAP sko2+c7wZyyIgatFWk2tPGo0595cqVaGcAJ4H3kEe4uO4n/a3CcsVWxq6jsSeLVCb0XaxhWOQ/g 5dgkh8sYWoKymNbKrhTW8ChIe7deXvcMy0cknf4HvDb4at2Uw5OuZpoWyJF98NxL1mZ/Um9csIz Z6OfYG0h268wpG+ycCjtkHkyOcznJ4jMExqLU6uNDiT3ShB0vLqlhZhViQgA9lWiTQ5Op0+mU9D bj5w== X-Received: by 2002:a05:6a21:6d83:b0:398:a934:9be6 with SMTP id adf61e73a8af0-39fe3ffd282mr8766324637.43.1775956742679; Sat, 11 Apr 2026 18:19:02 -0700 (PDT) Received: from krios ([2604:3d08:487d:cd00::5517]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c79216ffa72sm6569310a12.6.2026.04.11.18.19.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 11 Apr 2026 18:19:02 -0700 (PDT) From: Emil Tsalapatis To: bpf@vger.kernel.org Cc: ast@kernel.org, andrii@kernel.org, memxor@gmail.com, daniel@iogearbox.net, eddyz87@gmail.com, song@kernel.org, Emil Tsalapatis Subject: [PATCH bpf-next v6 2/9] selftests/bpf: Add test for scalar/arena pointer addition Date: Sat, 11 Apr 2026 21:18:50 -0400 Message-ID: <20260412011857.3387-3-emil@etsalapatis.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260412011857.3387-1-emil@etsalapatis.com> References: <20260412011857.3387-1-emil@etsalapatis.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Add a selftest that ensures scalar += ptr_to_arena instructions are accepted by the verifier. Signed-off-by: Emil Tsalapatis Acked-by: Song Liu --- .../selftests/bpf/progs/verifier_arena.c | 127 ++++++++++++++++++ 1 file changed, 127 insertions(+) diff --git a/tools/testing/selftests/bpf/progs/verifier_arena.c b/tools/testing/selftests/bpf/progs/verifier_arena.c index c4b8daac4388..614e61166f2d 100644 --- a/tools/testing/selftests/bpf/progs/verifier_arena.c +++ b/tools/testing/selftests/bpf/progs/verifier_arena.c @@ -477,4 +477,131 @@ int arena_kfuncs_under_bpf_lock(void *ctx) return 0; } + +#if defined(__BPF_FEATURE_ADDR_SPACE_CAST) + +/* + * Test that scalar += PTR_TO_ARENA correctly upgrades the + * destination register to a PTR_TO_ARENA. + */ +SEC("syscall") +__success __retval(0) +int scalar_add_arena_ptr(void *ctx) +{ + int __arena *scalar, *arena_ptr; + + volatile char __arena *base = arena_base(&arena); + + asm volatile ( + "%[arena_ptr] = 8192;" + "%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);" + "%[scalar] = 12;" + "%[scalar] += %[arena_ptr];" + : [scalar] "=r"(scalar), + [arena_ptr] "=&r"(arena_ptr) + : "r"(base) + : + ); + return 0; +} + +/* + * Test that PTR_TO_ARENA + PTR_TO_ARENA is allowed. + */ +SEC("syscall") +__success __retval(0) +int arena_ptr_add_arena_ptr(void *ctx) +{ + int __arena *arena_ptr2, *arena_ptr1; + + /* Needed for the verifier to link the arena to the subprog. */ + volatile char __arena *base = arena_base(&arena); + + asm volatile ( + "%[arena_ptr1] = 8192;" + "%[arena_ptr1] = addr_space_cast(%[arena_ptr1], 0x0, 0x1);" + "%[arena_ptr2] = 4096;" + "%[arena_ptr2] = addr_space_cast(%[arena_ptr2], 0x0, 0x1);" + "%[arena_ptr2] += %[arena_ptr1];" + : [arena_ptr2] "=r"(arena_ptr2), + [arena_ptr1] "=&r"(arena_ptr1) + : "r"(base) + : + ); + return 0; +} + +SEC("syscall") +__success __retval(0) +int scalar_xor_arena_ptr(void *ctx) +{ + int __arena *scalar, *arena_ptr; + + volatile char __arena *base = arena_base(&arena); + + asm volatile ( + "%[arena_ptr] = 8192;" + "%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);" + "%[scalar] = 12;" + "%[scalar] ^= %[arena_ptr];" + : [scalar] "=r"(scalar), + [arena_ptr] "=&r"(arena_ptr) + : "r"(base) + : + ); + return 0; +} + +SEC("syscall") +__failure __msg("R4 += R3: Invalid operation between bpf_reg_state types") +int arena_ptr_add_to_non_arena_ptr(void *ctx) +{ + register int __arena *arena_ptr asm("r3"); + register void *dst asm("r4"); + + volatile char __arena *base = arena_base(&arena); + + asm volatile ( + "%[arena_ptr] = 8192;" + "%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);" + "%[dst] = %[ctx];" + "%[dst] += %[arena_ptr];" + : [arena_ptr] "=&r"(arena_ptr), + [dst] "=&r"(dst) + : [ctx] "r"(ctx), "r"(base) + : + ); + + (void)ctx; + + return 0; +} + +SEC("syscall") +__failure __msg("R3 += R4: Invalid operation between bpf_reg_state types") +int non_arena_ptr_add_to_arena_ptr(void *ctx) +{ + register int __arena *arena_ptr asm("r3"); + register void *src asm("r4"); + + volatile char __arena *base = arena_base(&arena); + + asm volatile ( + "%[arena_ptr] = 8192;" + "%[arena_ptr] = addr_space_cast(%[arena_ptr], 0x0, 0x1);" + "%[src] = %[ctx];" + "%[arena_ptr] += %[src];" + : [arena_ptr] "=&r"(arena_ptr), + [src] "=&r"(src) + : [ctx] "r"(ctx), "r"(base) + : + ); + + (void)ctx; + + return 0; +} + +#endif + char _license[] SEC("license") = "GPL"; -- 2.53.0