From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hanjun Guo Subject: Re: [PATCH v8 09/21] ARM64 / ACPI: Disable ACPI if FADT revision is less than 5.1 Date: Wed, 04 Feb 2015 17:38:25 +0800 Message-ID: <54D1E891.80405@linaro.org> References: <1422881149-8177-1-git-send-email-hanjun.guo@linaro.org> <1422881149-8177-10-git-send-email-hanjun.guo@linaro.org> <20150203172047.GA13339@e104818-lin.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150203172047.GA13339@e104818-lin.cambridge.arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Catalin Marinas , "Rafael J. Wysocki" Cc: Olof Johansson , Arnd Bergmann , Mark Rutland , "grant.likely@linaro.org" , Will Deacon , Lorenzo Pieralisi , "graeme.gregory@linaro.org" , Sudeep Holla , "jcm@redhat.com" , Jason Cooper , Marc Zyngier , Bjorn Helgaas , Daniel Lezcano , Mark Brown , Rob Herring , Robert Richter , Randy Dunlap , Charles Garcia-Tobin , "phoenix.liyi@huawei.com" , Timur Tabi , Ashwin Chaugule , "suravee.suthikulpanit@amd.com" List-Id: linux-acpi@vger.kernel.org On 2015=E5=B9=B402=E6=9C=8804=E6=97=A5 01:20, Catalin Marinas wrote: > On Mon, Feb 02, 2015 at 12:45:37PM +0000, Hanjun Guo wrote: >> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c >> index afe10b4..b9f64ec 100644 >> --- a/arch/arm64/kernel/acpi.c >> +++ b/arch/arm64/kernel/acpi.c >> @@ -13,6 +13,8 @@ >> * published by the Free Software Foundation. >> */ >> >> +#define pr_fmt(fmt) "ACPI: " fmt >> + >> #include >> #include >> #include >> @@ -49,10 +51,32 @@ void __init __acpi_unmap_table(char *map, unsign= ed long size) >> early_memunmap(map, size); >> } >> >> +static int __init acpi_parse_fadt(struct acpi_table_header *table) >> +{ >> + struct acpi_table_fadt *fadt =3D (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. >> + */ >> + if (table->revision > 5 || >> + (table->revision =3D=3D 5 && fadt->minor_revision >=3D 1)) >> + return 0; >> + >> + pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will dis= able ACPI\n", >> + table->revision, fadt->minor_revision); >> + disable_acpi(); >> + >> + return -EINVAL; >> +} >> + >> /* >> * acpi_boot_table_init() called from setup_arch(), always. >> * 1. find RSDP and get its address, and then find XSDT >> * 2. extract all tables and checksums them all >> + * 3. check ACPI FADT revision >> * >> * We can parse ACPI boot-time tables such as MADT after >> * this function is called. >> @@ -64,8 +88,16 @@ void __init acpi_boot_table_init(void) >> return; >> >> /* Initialize the ACPI boot-time table parser. */ >> - if (acpi_table_init()) >> + if (acpi_table_init()) { >> + disable_acpi(); >> + return; >> + } >> + >> + if (acpi_table_parse(ACPI_SIG_FADT, acpi_parse_fadt)) { >> + /* disable ACPI if no FADT is found */ >> disable_acpi(); >> + pr_err("Can't find FADT\n"); >> + } >> } > > It looks fine to call disable_acpi() here but a bit weird to call it > again in acpi_parse_fadt(). I guess that's because acpi_table_parse() > ignores the return value of the handler() call. I think it's better t= o > fix the core code (can be an additional patch on top of this series). I checked all the code calling acpi_table_parse() and I found that it will be no functional change if we return the value of handler(), but I need Rafael's confirm on it. Thanks Hanjun