From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH 2/2] arm64: acpi: Prepare for longer MADTs Date: Tue, 27 Nov 2018 15:01:50 +0000 Message-ID: <20181127150150.GA25270@e107981-ln.cambridge.arm.com> References: <20181012192937.3819951-1-jeremy.linton@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20181012192937.3819951-1-jeremy.linton@arm.com> Sender: linux-kernel-owner@vger.kernel.org To: Jeremy Linton Cc: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, ard.biesheuvel@linaro.org, james.morse@arm.com, rafael.j.wysocki@intel.com, takahiro.akashi@linaro.org, sudeep.holla@arm.com, ahs3@redhat.com, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-acpi@vger.kernel.org On Fri, Oct 12, 2018 at 02:29:37PM -0500, Jeremy Linton wrote: > The BAD_MADT_GICC_ENTRY check is a little too strict because > it rejects MADT entries that don't match the currently known > lengths. We should remove this restriction to avoid problems > if the table length changes. Future code which might depend on > additional fields should be written to validate those fields > before using them, rather than trying to globally check > known MADT version lengths. > > Signed-off-by: Jeremy Linton > --- > arch/arm64/include/asm/acpi.h | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) Hi Jeremy, as mentioned, I added a comment to the macro so that in the future we will be able to remember the logic behind it. I pushed the commit out: git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/linux.git acpi/madt Please have a look, if I hear no objections I shall be sending it to Will and Catalin to queue it for v4.21. Thanks, Lorenzo > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 709208dfdc8b..4d0946bd485a 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -22,12 +22,12 @@ > #include > > /* Macros for consistency checks of the GICC subtable of MADT */ > -#define ACPI_MADT_GICC_LENGTH \ > - (acpi_gbl_FADT.header.revision < 6 ? 76 : 80) > +#define ACPI_MADT_GICC_MIN_LENGTH ACPI_OFFSET( \ > + struct acpi_madt_generic_interrupt, efficiency_class) > > #define BAD_MADT_GICC_ENTRY(entry, end) \ > - (!(entry) || (entry)->header.length != ACPI_MADT_GICC_LENGTH || \ > - (unsigned long)(entry) + ACPI_MADT_GICC_LENGTH > (end)) > + (!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \ > + (unsigned long)(entry) + (entry)->header.length > (end)) > > /* Basic configuration for ACPI */ > #ifdef CONFIG_ACPI > -- > 2.14.3 > From mboxrd@z Thu Jan 1 00:00:00 1970 From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi) Date: Tue, 27 Nov 2018 15:01:50 +0000 Subject: [PATCH 2/2] arm64: acpi: Prepare for longer MADTs In-Reply-To: <20181012192937.3819951-1-jeremy.linton@arm.com> References: <20181012192937.3819951-1-jeremy.linton@arm.com> Message-ID: <20181127150150.GA25270@e107981-ln.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Oct 12, 2018 at 02:29:37PM -0500, Jeremy Linton wrote: > The BAD_MADT_GICC_ENTRY check is a little too strict because > it rejects MADT entries that don't match the currently known > lengths. We should remove this restriction to avoid problems > if the table length changes. Future code which might depend on > additional fields should be written to validate those fields > before using them, rather than trying to globally check > known MADT version lengths. > > Signed-off-by: Jeremy Linton > --- > arch/arm64/include/asm/acpi.h | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) Hi Jeremy, as mentioned, I added a comment to the macro so that in the future we will be able to remember the logic behind it. I pushed the commit out: git://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/linux.git acpi/madt Please have a look, if I hear no objections I shall be sending it to Will and Catalin to queue it for v4.21. Thanks, Lorenzo > diff --git a/arch/arm64/include/asm/acpi.h b/arch/arm64/include/asm/acpi.h > index 709208dfdc8b..4d0946bd485a 100644 > --- a/arch/arm64/include/asm/acpi.h > +++ b/arch/arm64/include/asm/acpi.h > @@ -22,12 +22,12 @@ > #include > > /* Macros for consistency checks of the GICC subtable of MADT */ > -#define ACPI_MADT_GICC_LENGTH \ > - (acpi_gbl_FADT.header.revision < 6 ? 76 : 80) > +#define ACPI_MADT_GICC_MIN_LENGTH ACPI_OFFSET( \ > + struct acpi_madt_generic_interrupt, efficiency_class) > > #define BAD_MADT_GICC_ENTRY(entry, end) \ > - (!(entry) || (entry)->header.length != ACPI_MADT_GICC_LENGTH || \ > - (unsigned long)(entry) + ACPI_MADT_GICC_LENGTH > (end)) > + (!(entry) || (entry)->header.length < ACPI_MADT_GICC_MIN_LENGTH || \ > + (unsigned long)(entry) + (entry)->header.length > (end)) > > /* Basic configuration for ACPI */ > #ifdef CONFIG_ACPI > -- > 2.14.3 >