From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0316439337; Thu, 9 Jul 2026 12:47:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783601272; cv=none; b=X4JUyKjil6Xygnidp/j6DoRc6A97Pt8QX3g3QYXYw3wy+ydZAUHBulfDSJofh0Z5WL/CW9qbK9RsHPvymJ5ZAh4NFJKQE/t1i3v8p4Tc3Nz9+U2z8qfCRkJPfn3ivsUeGBfaTHh3qNw3hrRFnhSt2XK3spt78oKIVbZhs/1TCOk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783601272; c=relaxed/simple; bh=oGFZSDzfT8inmFJ2z03dxCAa4YK4yHbZnQRFMeNIiDw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=iAYVeDnoVlZu9HT/PZfMj7dKVVhkOdQem14eO1a3jHP31TK4VNGI8z2dOwDKYTVBQiGto55VazxyVWl0t7sz0izgp6M5cKMxYEfmkK3xcfWSwtAv1M37jjyYch9Y+SyvcBxE1d9nAcOAyQ5BC9G1Z9H8A2cb7rCAxnKybTP3AoY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HUDpIf3q; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HUDpIf3q" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EC8541F00AC4; Thu, 9 Jul 2026 12:47:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783601270; bh=Bvu1pVARNrRdquNNzMQzZTMsYi1sl740x7KIfOlZMPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HUDpIf3qCXq3WSEtooxlezUa9eLVN2OpDT01n+fXcBENyBczngHIaOrch3bkt3OXi ViOvnSWudvA+bY1wIz5UbQ+PLi6iKYqqznpts3Gk79IrtvrETQSNuxzCuANIvu8Bg/ iO1HSABhD2f8QLqO0E6guaqQ6lQCoRFbsaH2fkDf6U0dYB44G1aVXPPntnXiN6pSI7 2rc0Lpi4l8+cxTirMcPzAKetVZq1xfSIwrHIWsBV/DYQEhLjsdbzuTUDSGHMTa6wkr TYzsVFHAtqAbT2pxC5As02f1s5XHaHPoeibXhAQFISD8f8RoJoYV2khdZS3yeCLlzf cwrZxoCCw7MtA== From: "Rafael J. Wysocki" To: Linux PM Cc: Linux ACPI , Sudeep Holla Subject: [PATCH v1 04/17] ACPI: processor: idle: Rearrange acpi_processor_evaluate_lpi() Date: Thu, 09 Jul 2026 14:33:41 +0200 Message-ID: <3426078.44csPzL39Z@rafael.j.wysocki> Organization: Linux Kernel Development - Intel In-Reply-To: <4746278.LvFx2qVVIh@rafael.j.wysocki> References: <4746278.LvFx2qVVIh@rafael.j.wysocki> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="UTF-8" From: "Rafael J. Wysocki" Rearrange acpi_processor_evaluate_lpi() to make it somewhat easier to follow and diagnose (if need be). In particular: * Rename some local variables and reorder their definitions. * Change the type of local variables used for storing firmware-provided values to unsigned int (they cannot be negative). * Eliminate local variable "loop" that is redundant. * Avoid explicit pointer arithmetic. * Print the correct number of _LPI state packages in the final debug message. No intentional functional impact beyond debug output. Signed-off-by: Rafael J. Wysocki --- drivers/acpi/processor_idle.c | 64 +++++++++++++++++++---------------- 1 file changed, 34 insertions(+), 30 deletions(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index e8682f779249..cd506e9e5a84 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -872,12 +872,12 @@ static int obj_get_integer(union acpi_object *obj, u32 *value) static int acpi_processor_evaluate_lpi(acpi_handle handle, struct acpi_lpi_states_array *info) { - acpi_status status; - int ret = 0; - int pkg_count, state_idx = 1, loop; struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; - union acpi_object *lpi_data; + union acpi_object *lpi_data, *lpi_pkg; + unsigned int lpi_pkg_count, state_idx; struct acpi_lpi_state *lpi_state; + acpi_status status; + int ret = 0; status = acpi_evaluate_object(handle, "_LPI", NULL, &buffer); if (ACPI_FAILURE(status)) { @@ -895,41 +895,46 @@ static int acpi_processor_evaluate_lpi(acpi_handle handle, goto end; } - pkg_count = lpi_data->package.elements[2].integer.value; + lpi_pkg_count = lpi_data->package.elements[2].integer.value; /* Validate number of power states. */ - if (pkg_count < 1 || pkg_count != lpi_data->package.count - 3) { + if (!lpi_pkg_count || lpi_pkg_count != lpi_data->package.count - 3) { acpi_handle_debug(handle, "Invalid _LPI state count\n"); ret = -ENODATA; goto end; } - lpi_state = kzalloc_objs(*lpi_state, pkg_count); + lpi_state = kzalloc_objs(*lpi_state, lpi_pkg_count); if (!lpi_state) { ret = -ENOMEM; goto end; } - info->size = pkg_count; + info->size = lpi_pkg_count; info->entries = lpi_state; - /* LPI States start at index 3 */ - for (loop = 3; state_idx <= pkg_count; loop++, state_idx++, lpi_state++) { - union acpi_object *element, *pkg_elem, *obj; + /* _LPI State packages start at index 3. */ + lpi_pkg = &lpi_data->package.elements[3]; - element = &lpi_data->package.elements[loop]; - if (element->type != ACPI_TYPE_PACKAGE || element->package.count < 7) + for (state_idx = 1; state_idx <= lpi_pkg_count; + state_idx++, lpi_state++, lpi_pkg++) { + union acpi_object *lpi_pkg_elem, *obj; + + lpi_state->index = state_idx; + + if (lpi_pkg->type != ACPI_TYPE_PACKAGE || lpi_pkg->package.count < 7) continue; - pkg_elem = element->package.elements; + lpi_pkg_elem = lpi_pkg->package.elements; - obj = pkg_elem + 6; + /* Get the entry method first and skip the state if that fails. */ + obj = &lpi_pkg_elem[6]; if (obj->type == ACPI_TYPE_BUFFER) { struct acpi_power_register *reg; if (obj->buffer.length < sizeof(*reg)) { acpi_handle_debug(handle, - "Invalid register data for _LPI state %d\n", + "Invalid register data for _LPI state %u\n", state_idx); continue; } @@ -937,7 +942,7 @@ static int acpi_processor_evaluate_lpi(acpi_handle handle, reg = (struct acpi_power_register *)obj->buffer.pointer; if (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE) { acpi_handle_debug(handle, - "Unsupported entry method for _LPI state %d\n", + "Unsupported entry method for _LPI state %u\n", state_idx); continue; } @@ -949,36 +954,35 @@ static int acpi_processor_evaluate_lpi(acpi_handle handle, lpi_state->address = obj->integer.value; } else { acpi_handle_debug(handle, - "Invalid entry method for _LPI state %d\n", + "Invalid entry method for _LPI state %u\n", state_idx); continue; } - lpi_state->index = state_idx; - if (obj_get_integer(pkg_elem + 0, &lpi_state->min_residency)) { + if (obj_get_integer(&lpi_pkg_elem[0], &lpi_state->min_residency)) { acpi_handle_debug(handle, - "Assuming 10 us min. residency for _LPI state %d\n", + "Assuming 10 us min. residency for _LPI state %u\n", state_idx); lpi_state->min_residency = 10; } - if (obj_get_integer(pkg_elem + 1, &lpi_state->wake_latency)) { + if (obj_get_integer(&lpi_pkg_elem[1], &lpi_state->wake_latency)) { acpi_handle_debug(handle, - "Assuming 10 us wake latency for _LPI state %d\n", + "Assuming 10 us wake latency for _LPI state %u\n", state_idx); lpi_state->wake_latency = 10; } - if (obj_get_integer(pkg_elem + 2, &lpi_state->flags)) + if (obj_get_integer(&lpi_pkg_elem[2], &lpi_state->flags)) lpi_state->flags = 0; - if (obj_get_integer(pkg_elem + 3, &lpi_state->arch_flags)) + if (obj_get_integer(&lpi_pkg_elem[3], &lpi_state->arch_flags)) lpi_state->arch_flags = 0; - if (obj_get_integer(pkg_elem + 4, &lpi_state->res_cnt_freq)) + if (obj_get_integer(&lpi_pkg_elem[4], &lpi_state->res_cnt_freq)) lpi_state->res_cnt_freq = 1; - if (obj_get_integer(pkg_elem + 5, &lpi_state->enable_parent_state)) + if (obj_get_integer(&lpi_pkg_elem[5], &lpi_state->enable_parent_state)) lpi_state->enable_parent_state = 0; /* Skip elements [7-8] i.e. Residency/Usage counters. */ @@ -987,16 +991,16 @@ static int acpi_processor_evaluate_lpi(acpi_handle handle, * Avoid out-of-bounds access if the size of the package is less * than expected. */ - if (element->package.count < 10) + if (lpi_pkg->package.count < 10) continue; - obj = pkg_elem + 9; + obj = &lpi_pkg_elem[9]; if (obj->type == ACPI_TYPE_STRING) strscpy(lpi_state->desc, obj->string.pointer, ACPI_CX_DESC_LEN); } - acpi_handle_debug(handle, "Found %d power states\n", state_idx); + acpi_handle_debug(handle, "Found %u power states\n", lpi_pkg_count); end: kfree(buffer.pointer); return ret; -- 2.51.0