From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 D7D481B26B for ; Mon, 23 Oct 2023 14:03:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=none Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A42C010C1 for ; Mon, 23 Oct 2023 07:03:13 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.206]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4SDcJ74pK2z67DRW; Mon, 23 Oct 2023 21:59:35 +0800 (CST) Received: from SecurePC-101-06.china.huawei.com (10.122.247.231) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Mon, 23 Oct 2023 15:03:11 +0100 From: Jonathan Cameron To: , , Michael Tsirkin , Michael Tokarev CC: , Fan Ni , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Subject: [PATCH v5 2/5] hw/cxl: Use switch statements for read and write of cachemem registers Date: Mon, 23 Oct 2023 15:02:07 +0100 Message-ID: <20231023140210.3089-3-Jonathan.Cameron@huawei.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20231023140210.3089-1-Jonathan.Cameron@huawei.com> References: <20231023140210.3089-1-Jonathan.Cameron@huawei.com> Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [10.122.247.231] X-ClientProxiedBy: lhrpeml500005.china.huawei.com (7.191.163.240) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Establishing that only register accesses of size 4 and 8 can occur using these functions requires looking at their callers. Make it easier to see that by using switch statements. Assertions are used to enforce that the register storage is of the matching size, allowing fixed values to be used for divisors of the array indices. Suggested-by: Michael Tokarev Signed-off-by: Jonathan Cameron Reviewed-by: Fan Ni --- v5: _Static_assert() is a declaration in C, so may not follow a label. Hence wrap it in {} to ensure it doesn't. Issue seen with clang builds (and in some cases at least older GCC). We can't wrap it in {} in the QEMU_BUILD_BUG_ON() define as that is used in a few places outside of functions. hw/cxl/cxl-component-utils.c | 66 +++++++++++++++++++++++------------- 1 file changed, 43 insertions(+), 23 deletions(-) diff --git a/hw/cxl/cxl-component-utils.c b/hw/cxl/cxl-component-utils.c index f3bbf0fd13..9d4f4bc8d4 100644 --- a/hw/cxl/cxl-component-utils.c +++ b/hw/cxl/cxl-component-utils.c @@ -67,16 +67,24 @@ static uint64_t cxl_cache_mem_read_reg(void *opaque, hwaddr offset, CXLComponentState *cxl_cstate = opaque; ComponentRegisters *cregs = &cxl_cstate->crb; - if (size == 8) { + switch (size) { + case 4: + if (cregs->special_ops && cregs->special_ops->read) { + return cregs->special_ops->read(cxl_cstate, offset, 4); + } else { + QEMU_BUILD_BUG_ON(sizeof(*cregs->cache_mem_registers) != 4); + return cregs->cache_mem_registers[offset / 4]; + } + case 8: qemu_log_mask(LOG_UNIMP, "CXL 8 byte cache mem registers not implemented\n"); return 0; - } - - if (cregs->special_ops && cregs->special_ops->read) { - return cregs->special_ops->read(cxl_cstate, offset, size); - } else { - return cregs->cache_mem_registers[offset / sizeof(*cregs->cache_mem_registers)]; + default: + /* + * In line with specifiction limitaions on access sizes, this + * routine is not called with other sizes. + */ + g_assert_not_reached(); } } @@ -117,25 +125,37 @@ static void cxl_cache_mem_write_reg(void *opaque, hwaddr offset, uint64_t value, ComponentRegisters *cregs = &cxl_cstate->crb; uint32_t mask; - if (size == 8) { - qemu_log_mask(LOG_UNIMP, - "CXL 8 byte cache mem registers not implemented\n"); + switch (size) { + case 4: { + QEMU_BUILD_BUG_ON(sizeof(*cregs->cache_mem_regs_write_mask) != 4); + QEMU_BUILD_BUG_ON(sizeof(*cregs->cache_mem_registers) != 4); + mask = cregs->cache_mem_regs_write_mask[offset / 4]; + value &= mask; + /* RO bits should remain constant. Done by reading existing value */ + value |= ~mask & cregs->cache_mem_registers[offset / 4]; + if (cregs->special_ops && cregs->special_ops->write) { + cregs->special_ops->write(cxl_cstate, offset, value, size); + return; + } + + if (offset >= A_CXL_HDM_DECODER_CAPABILITY && + offset <= A_CXL_HDM_DECODER3_TARGET_LIST_HI) { + dumb_hdm_handler(cxl_cstate, offset, value); + } else { + cregs->cache_mem_registers[offset / 4] = value; + } return; } - mask = cregs->cache_mem_regs_write_mask[offset / sizeof(*cregs->cache_mem_regs_write_mask)]; - value &= mask; - /* RO bits should remain constant. Done by reading existing value */ - value |= ~mask & cregs->cache_mem_registers[offset / sizeof(*cregs->cache_mem_registers)]; - if (cregs->special_ops && cregs->special_ops->write) { - cregs->special_ops->write(cxl_cstate, offset, value, size); + case 8: + qemu_log_mask(LOG_UNIMP, + "CXL 8 byte cache mem registers not implemented\n"); return; - } - - if (offset >= A_CXL_HDM_DECODER_CAPABILITY && - offset <= A_CXL_HDM_DECODER3_TARGET_LIST_HI) { - dumb_hdm_handler(cxl_cstate, offset, value); - } else { - cregs->cache_mem_registers[offset / sizeof(*cregs->cache_mem_registers)] = value; + default: + /* + * In line with specifiction limitaions on access sizes, this + * routine is not called with other sizes. + */ + g_assert_not_reached(); } } -- 2.39.2