| Message ID | 20190626213718.39423-1-jeremy.linton@arm.com |
|---|---|
| Headers | show |
| Series | arm64: SPE ACPI enablement | expand |
On Wed, Jun 26, 2019 at 11:37 PM Jeremy Linton <jeremy.linton@arm.com> wrote: > > The ACPI specification implies that the IDENTICAL flag should be > set on all non leaf nodes where the children are identical. > This means that we need to be searching for the last node with > the identical flag set rather than the first one. > > Since this flag is also dependent on the table revision, we > need to add a bit of extra code to verify the table revision, > and the next node's state in the traversal. Since we want to > avoid function pointers here, lets just special case > the IDENTICAL flag. > > Tested-by: Hanjun Gou <gouhanjun@huawei.com> > Reviewed-by: Sudeep Holla <sudeep.holla@arm.com> > Signed-off-by: Jeremy Linton <jeremy.linton@arm.com> Assuming that the Tested-by tag will be fixed: Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/acpi/pptt.c | 35 +++++++++++++++++++++++++++++------ > 1 file changed, 29 insertions(+), 6 deletions(-) > > diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c > index b72e6afaa8fb..05344413f199 100644 > --- a/drivers/acpi/pptt.c > +++ b/drivers/acpi/pptt.c > @@ -432,17 +432,40 @@ static void cache_setup_acpi_cpu(struct acpi_table_header *table, > } > } > > +static bool flag_identical(struct acpi_table_header *table_hdr, > + struct acpi_pptt_processor *cpu) > +{ > + struct acpi_pptt_processor *next; > + > + /* heterogeneous machines must use PPTT revision > 1 */ > + if (table_hdr->revision < 2) > + return false; > + > + /* Locate the last node in the tree with IDENTICAL set */ > + if (cpu->flags & ACPI_PPTT_ACPI_IDENTICAL) { > + next = fetch_pptt_node(table_hdr, cpu->parent); > + if (!(next && next->flags & ACPI_PPTT_ACPI_IDENTICAL)) > + return true; > + } > + > + return false; > +} > + > /* Passing level values greater than this will result in search termination */ > #define PPTT_ABORT_PACKAGE 0xFF > > -static struct acpi_pptt_processor *acpi_find_processor_package_id(struct acpi_table_header *table_hdr, > - struct acpi_pptt_processor *cpu, > - int level, int flag) > +static struct acpi_pptt_processor *acpi_find_processor_tag(struct acpi_table_header *table_hdr, > + struct acpi_pptt_processor *cpu, > + int level, int flag) > { > struct acpi_pptt_processor *prev_node; > > while (cpu && level) { > - if (cpu->flags & flag) > + /* special case the identical flag to find last identical */ > + if (flag == ACPI_PPTT_ACPI_IDENTICAL) { > + if (flag_identical(table_hdr, cpu)) > + break; > + } else if (cpu->flags & flag) > break; > pr_debug("level %d\n", level); > prev_node = fetch_pptt_node(table_hdr, cpu->parent); > @@ -480,8 +503,8 @@ static int topology_get_acpi_cpu_tag(struct acpi_table_header *table, > > cpu_node = acpi_find_processor_node(table, acpi_cpu_id); > if (cpu_node) { > - cpu_node = acpi_find_processor_package_id(table, cpu_node, > - level, flag); > + cpu_node = acpi_find_processor_tag(table, cpu_node, > + level, flag); > /* > * As per specification if the processor structure represents > * an actual processor, then ACPI processor ID must be valid. > -- > 2.21.0 >
On Wed, Jun 26, 2019 at 04:37:14PM -0500, Jeremy Linton wrote: > This patch series enables the Arm Statistical Profiling > Extension (SPE) on ACPI platforms. > > This is possible because ACPI 6.3 uses a previously > reserved field in the MADT to store the SPE interrupt > number, similarly to how the normal PMU is described. > If a consistent valid interrupt exists across all the > cores in the system, a platform device is registered. > That then triggers the SPE module, which runs as normal. > > We also add the ability to parse the PPTT for IDENTICAL > cores. We then use this to sanity check the single SPE > device we create. This creates a bit of a problem with > respect to the specification though. The specification > says that its legal for multiple tree's to exist in the > PPTT. We handle this fine, but what happens in the > case of multiple tree's is that the lack of a common > node with IDENTICAL set forces us to assume that there > are multiple non-IDENTICAL cores in the machine. > > v4->v5: Remove error returns from arm_spe_acpi_register_device() > Add some review/test tags Cheers, I've pushed this out with the acks and typo fixes. https://git.kernel.org/pub/scm/linux/kernel/git/will/linux.git/log/?h=for-next/perf Please let me know if you spot any problems. Will