From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752560AbbCYNqD (ORCPT ); Wed, 25 Mar 2015 09:46:03 -0400 Received: from szxga03-in.huawei.com ([119.145.14.66]:29358 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752177AbbCYNqB (ORCPT ); Wed, 25 Mar 2015 09:46:01 -0400 Message-ID: <5512BBFD.6040504@huawei.com> Date: Wed, 25 Mar 2015 21:45:33 +0800 From: Hanjun Guo User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Lorenzo Pieralisi , , , CC: Will Deacon , Hanjun Guo , Catalin Marinas , "Rafael J. Wysocki" Subject: Re: [PATCH 4/5] ARM64: kernel: acpi: refactor ACPI tables init and checks References: <1427219940-27201-1-git-send-email-lorenzo.pieralisi@arm.com> <1427219940-27201-5-git-send-email-lorenzo.pieralisi@arm.com> In-Reply-To: <1427219940-27201-5-git-send-email-lorenzo.pieralisi@arm.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.17.188] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.5512BC09.01C6,ss=1,re=0.001,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: 154e1d174d3775b6864e965c9c225d09 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/3/25 1:58, Lorenzo Pieralisi wrote: > Current ACPI init code on ARM64 relies on acpi_table_parse() API to > check if the FADT is present and to carry out sanity checks on that. > > The handler passed to the acpi_table_parse() function and used to > carry out the parsing on the requested table returns a value that is > ignored by the acpi_table_parse() function, so it is not possible > to propagate errors back to the acpi_table_parse() caller through > the handler. > > This forces ARM64 ACPI init code to have disable_acpi() calls scattered > all over the place that makes code unwieldy and not easy to follow. > > This patch refactors the ARM64 ACPI init code, by creating a > self-contained function (ie acpi_fadt_sanity_check()) that carries > out the required checks on FADT and returns an adequate return value > to the caller. This allows creating a common error path that disables > ACPI and makes code more readable and easy to parse and change were > further checks FADT to be added in the future. > > Signed-off-by: Lorenzo Pieralisi > Cc: Will Deacon > Cc: Hanjun Guo > Cc: Catalin Marinas > Cc: Rafael J. Wysocki > --- I already reviewed this patch set, and it is fine to me Reviewed-by: Hanjun Guo Thanks Hanjun > arch/arm64/kernel/acpi.c | 104 +++++++++++++++++++++++++++++++---------------- > 1 file changed, 70 insertions(+), 34 deletions(-) > > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > index a70f714..542f045 100644 > --- a/arch/arm64/kernel/acpi.c > +++ b/arch/arm64/kernel/acpi.c > @@ -218,43 +218,60 @@ void __init acpi_init_cpus(void) > pr_info("%d CPUs enabled, %d CPUs total\n", enabled_cpus, total_cpus); > } > > -static int __init acpi_parse_fadt(struct acpi_table_header *table) > +/* > + * acpi_fadt_sanity_check() - Check FADT presence and carry out sanity > + * checks on it > + * > + * Return 0 on success, <0 on failure > + */ > +static int __init acpi_fadt_sanity_check(void) > { > - struct acpi_table_fadt *fadt = (struct acpi_table_fadt *)table; > + struct acpi_table_header *table; > + struct acpi_table_fadt *fadt; > + acpi_status status; > + acpi_size tbl_size; > + int ret = 0; > + > + /* > + * FADT is required on arm64; retrieve it to check its presence > + * and carry out revision and ACPI HW reduced compliancy tests > + */ > + status = acpi_get_table_with_size(ACPI_SIG_FADT, 0, &table, &tbl_size); > + if (ACPI_FAILURE(status)) { > + const char *msg = acpi_format_exception(status); > + > + pr_err("Failed to get FADT table, %s\n", msg); > + return -ENODEV; > + } > + > + fadt = (struct acpi_table_fadt *)table; > > /* > * Revision in table header is the FADT Major revision, and there > * is a minor revision of FADT which was introduced by ACPI 5.1, > * we only deal with ACPI 5.1 or newer revision to get GIC and SMP > - * boot protocol configuration data, or we will disable ACPI. > + * boot protocol configuration data. > */ > - if (table->revision > 5 || > - (table->revision == 5 && fadt->minor_revision >= 1)) { > - if (!acpi_gbl_reduced_hardware) { > - pr_err("Not hardware reduced ACPI mode, will not be supported\n"); > - goto disable_acpi; > - } > - > - /* > - * ACPI 5.1 only has two explicit methods to boot up SMP, > - * PSCI and Parking protocol, but the Parking protocol is > - * only specified for ARMv7 now, so make PSCI as the only > - * way for the SMP boot protocol before some updates for > - * the Parking protocol spec. > - */ > - if (acpi_psci_present()) > - return 0; > - > - pr_warn("No PSCI support, will not bring up secondary CPUs\n"); > - return -EOPNOTSUPP; > + if (table->revision < 5 || > + (table->revision == 5 && fadt->minor_revision < 1)) { > + pr_err("Unsupported FADT revision %d.%d, should be 5.1+\n", > + table->revision, fadt->minor_revision); > + ret = -EINVAL; > + goto out; > } > > - pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable ACPI\n", > - table->revision, fadt->minor_revision); > + if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) { > + pr_err("FADT not ACPI hardware reduced compliant\n"); > + ret = -EINVAL; > + } > > -disable_acpi: > - disable_acpi(); > - return -EINVAL; > +out: > + /* > + * acpi_get_table_with_size() creates FADT table mapping that > + * should be released after parsing and before resuming boot > + */ > + early_acpi_os_unmap_memory(table, tbl_size); > + return ret; > } > > /* > @@ -262,12 +279,18 @@ disable_acpi: > * 1. find RSDP and get its address, and then find XSDT > * 2. extract all tables and checksums them all > * 3. check ACPI FADT revision > + * 4. check ACPI FADT HW reduced flag > * > * We can parse ACPI boot-time tables such as MADT after > * this function is called. > + * > + * ACPI is enabled on return if ACPI tables initialized and sanity checks > + * passed, disabled otherwise > */ > void __init acpi_boot_table_init(void) > { > + int err; > + > /* > * Enable ACPI instead of device tree unless > * - ACPI has been disabled explicitly (acpi=off), or > @@ -278,19 +301,32 @@ void __init acpi_boot_table_init(void) > (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL))) > return; > > + /* > + * ACPI is disabled at this point. Enable it in order to parse > + * the ACPI tables and carry out sanity checks > + */ > enable_acpi(); > > /* Initialize the ACPI boot-time table parser. */ > - if (acpi_table_init()) { > - disable_acpi(); > - return; > + err = acpi_table_init(); > + if (err) { > + pr_err("Failed to init ACPI tables\n"); > + goto out; > } > > - if (acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt)) { > - /* disable ACPI if no FADT is found */ > + /* > + * Check FADT presence and carry out FADT sanity checks > + */ > + err = acpi_fadt_sanity_check(); > + > +out: > + /* > + * If ACPI tables are initialized and FADT sanity checks passed, > + * leave ACPI enabled and carry on booting; otherwise disable ACPI > + * on initialization error. > + */ > + if (err) > disable_acpi(); > - pr_err("Can't find FADT\n"); > - } > } > > void __init acpi_gic_init(void)