On Wed, Jan 14, 2015 at 03:04:55PM +0000, Hanjun Guo wrote: > FADT Major.Minor version was introduced in ACPI 5.1, it is the same > as ACPI version. > > In ACPI 5.1, some major gaps are fixed for ARM, such as updates in > MADT table for GIC and SMP init, without those updates, we can not > get the MPIDR for SMP init, and GICv2/3 related init information, so > we can't boot arm64 ACPI properly with table versions predating 5.1. > > If firmware provides ACPI tables with ACPI version less than 5.1, > OS will be messed up with those information and have no way to init
Nit: "that information" or "...OS has no way to retrieve the configuration data that is necessary to init SMP boot protocol and the GIC properly, so.." > smp and GIC, so disable ACPI if we get an FADT table with version > less that 5.1. > Patch should be reordered in the series and must be sequenced before patch 5 for bisectability (that patch implements DT unflattening if ACPI is disabled), or squashed with previous patches. Lorenzo > Tested-by: Suravee Suthikulpanit <[email protected]> > Tested-by: Yijing Wang <[email protected]> > Signed-off-by: Hanjun Guo <[email protected]> > --- > arch/arm64/kernel/acpi.c | 31 ++++++++++++++++++++++++++++++- > 1 file changed, 30 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c > index 39a1655..4177758 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 <linux/init.h> > #include <linux/acpi.h> > #include <linux/cpumask.h> > @@ -49,10 +51,32 @@ void __init __acpi_unmap_table(char *map, unsigned long > size) > early_memunmap(map, size); > } > > +static int __init acpi_parse_fadt(struct acpi_table_header *table) > +{ > + struct acpi_table_fadt *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 arm boot flags, or we will disable ACPI. > + */ > + if (table->revision > 5 || > + (table->revision == 5 && fadt->minor_revision >= 1)) > + return 0; > + > + pr_warn("Unsupported FADT revision %d.%d, should be 5.1+, will disable > 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 +88,13 @@ 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)) > + pr_err("Can't find FADT or error happened during parsing > FADT\n"); > } > > static int __init parse_acpi(char *arg) > -- > 1.9.1 > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
