diff mbox

[RFC,v2,2/5] acpi: HMAT support in acpi_parse_entries_array()

Message ID 20170706215233.11329-3-ross.zwisler@linux.intel.com (mailing list archive)
State RFC, archived
Headers show

Commit Message

Ross Zwisler July 6, 2017, 9:52 p.m. UTC
The current implementation of acpi_parse_entries_array() assumes that each
subtable has a standard ACPI subtable entry of type struct
acpi_sutbable_header.  This standard subtable header has a one byte length
followed by a one byte type.

The HMAT subtables have to allow for a longer length so they have subtable
headers of type struct acpi_hmat_structure which has a 2 byte type and a 4
byte length.

Enhance the subtable parsing in acpi_parse_entries_array() so that it can
handle these new HMAT subtables.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
 drivers/acpi/numa.c   |  2 +-
 drivers/acpi/tables.c | 52 ++++++++++++++++++++++++++++++++++++++++-----------
 2 files changed, 42 insertions(+), 12 deletions(-)

Comments

Rafael J. Wysocki July 6, 2017, 10:13 p.m. UTC | #1
On Thu, Jul 6, 2017 at 11:52 PM, Ross Zwisler
<ross.zwisler@linux.intel.com> wrote:
> The current implementation of acpi_parse_entries_array() assumes that each
> subtable has a standard ACPI subtable entry of type struct
> acpi_sutbable_header.  This standard subtable header has a one byte length
> followed by a one byte type.
>
> The HMAT subtables have to allow for a longer length so they have subtable
> headers of type struct acpi_hmat_structure which has a 2 byte type and a 4
> byte length.
>
> Enhance the subtable parsing in acpi_parse_entries_array() so that it can
> handle these new HMAT subtables.
>
> Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> ---
>  drivers/acpi/numa.c   |  2 +-
>  drivers/acpi/tables.c | 52 ++++++++++++++++++++++++++++++++++++++++-----------
>  2 files changed, 42 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
> index edb0c79..917f1cc 100644
> --- a/drivers/acpi/numa.c
> +++ b/drivers/acpi/numa.c
> @@ -443,7 +443,7 @@ int __init acpi_numa_init(void)
>          * So go over all cpu entries in SRAT to get apicid to node mapping.
>          */
>
> -       /* SRAT: Static Resource Affinity Table */
> +       /* SRAT: System Resource Affinity Table */
>         if (!acpi_table_parse(ACPI_SIG_SRAT, acpi_parse_srat)) {
>                 struct acpi_subtable_proc srat_proc[3];
>

This change is unrelated to the rest of the patch.

Maybe send it separately?

> diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> index ff42539..7979171 100644
> --- a/drivers/acpi/tables.c
> +++ b/drivers/acpi/tables.c
> @@ -218,6 +218,33 @@ void acpi_table_print_madt_entry(struct acpi_subtable_header *header)
>         }
>  }
>
> +static unsigned long __init
> +acpi_get_entry_type(char *id, void *entry)
> +{
> +       if (!strncmp(id, ACPI_SIG_HMAT, 4))
> +               return ((struct acpi_hmat_structure *)entry)->type;
> +       else
> +               return ((struct acpi_subtable_header *)entry)->type;
> +}

I slightly prefer to use ? : in similar situations.

> +
> +static unsigned long __init
> +acpi_get_entry_length(char *id, void *entry)
> +{
> +       if (!strncmp(id, ACPI_SIG_HMAT, 4))
> +               return ((struct acpi_hmat_structure *)entry)->length;
> +       else
> +               return ((struct acpi_subtable_header *)entry)->length;
> +}
> +
> +static unsigned long __init
> +acpi_get_subtable_header_length(char *id)
> +{
> +       if (!strncmp(id, ACPI_SIG_HMAT, 4))
> +               return sizeof(struct acpi_hmat_structure);
> +       else
> +               return sizeof(struct acpi_subtable_header);
> +}
> +
>  /**
>   * acpi_parse_entries_array - for each proc_num find a suitable subtable
>   *
> @@ -242,10 +269,10 @@ acpi_parse_entries_array(char *id, unsigned long table_size,
>                 struct acpi_subtable_proc *proc, int proc_num,
>                 unsigned int max_entries)
>  {
> -       struct acpi_subtable_header *entry;
> -       unsigned long table_end;
> +       unsigned long table_end, subtable_header_length;
>         int count = 0;
>         int errs = 0;
> +       void *entry;
>         int i;
>
>         if (acpi_disabled)
> @@ -263,19 +290,23 @@ acpi_parse_entries_array(char *id, unsigned long table_size,
>         }
>
>         table_end = (unsigned long)table_header + table_header->length;
> +       subtable_header_length = acpi_get_subtable_header_length(id);
>
>         /* Parse all entries looking for a match. */
>
> -       entry = (struct acpi_subtable_header *)
> -           ((unsigned long)table_header + table_size);
> +       entry = (void *)table_header + table_size;
> +
> +       while (((unsigned long)entry) + subtable_header_length  < table_end) {
> +               unsigned long entry_type, entry_length;
>
> -       while (((unsigned long)entry) + sizeof(struct acpi_subtable_header) <
> -              table_end) {
>                 if (max_entries && count >= max_entries)
>                         break;
>
> +               entry_type = acpi_get_entry_type(id, entry);
> +               entry_length = acpi_get_entry_length(id, entry);
> +
>                 for (i = 0; i < proc_num; i++) {
> -                       if (entry->type != proc[i].id)
> +                       if (entry_type != proc[i].id)
>                                 continue;
>                         if (!proc[i].handler ||
>                              (!errs && proc[i].handler(entry, table_end))) {
> @@ -290,16 +321,15 @@ acpi_parse_entries_array(char *id, unsigned long table_size,
>                         count++;
>
>                 /*
> -                * If entry->length is 0, break from this loop to avoid
> +                * If entry_length is 0, break from this loop to avoid
>                  * infinite loop.
>                  */
> -               if (entry->length == 0) {
> +               if (entry_length == 0) {
>                         pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, proc->id);
>                         return -EINVAL;
>                 }
>
> -               entry = (struct acpi_subtable_header *)
> -                   ((unsigned long)entry + entry->length);
> +               entry += entry_length;
>         }
>
>         if (max_entries && count > max_entries) {
> --

The rest is fine by me.

Thanks,
Rafael
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Ross Zwisler July 6, 2017, 10:22 p.m. UTC | #2
On Fri, Jul 07, 2017 at 12:13:54AM +0200, Rafael J. Wysocki wrote:
> On Thu, Jul 6, 2017 at 11:52 PM, Ross Zwisler
> <ross.zwisler@linux.intel.com> wrote:
> > The current implementation of acpi_parse_entries_array() assumes that each
> > subtable has a standard ACPI subtable entry of type struct
> > acpi_sutbable_header.  This standard subtable header has a one byte length
> > followed by a one byte type.
> >
> > The HMAT subtables have to allow for a longer length so they have subtable
> > headers of type struct acpi_hmat_structure which has a 2 byte type and a 4
> > byte length.
> >
> > Enhance the subtable parsing in acpi_parse_entries_array() so that it can
> > handle these new HMAT subtables.
> >
> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
> > ---
> >  drivers/acpi/numa.c   |  2 +-
> >  drivers/acpi/tables.c | 52 ++++++++++++++++++++++++++++++++++++++++-----------
> >  2 files changed, 42 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
> > index edb0c79..917f1cc 100644
> > --- a/drivers/acpi/numa.c
> > +++ b/drivers/acpi/numa.c
> > @@ -443,7 +443,7 @@ int __init acpi_numa_init(void)
> >          * So go over all cpu entries in SRAT to get apicid to node mapping.
> >          */
> >
> > -       /* SRAT: Static Resource Affinity Table */
> > +       /* SRAT: System Resource Affinity Table */
> >         if (!acpi_table_parse(ACPI_SIG_SRAT, acpi_parse_srat)) {
> >                 struct acpi_subtable_proc srat_proc[3];
> >
> 
> This change is unrelated to the rest of the patch.
> 
> Maybe send it separately?

Sure, will do.

> > diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
> > index ff42539..7979171 100644
> > --- a/drivers/acpi/tables.c
> > +++ b/drivers/acpi/tables.c
> > @@ -218,6 +218,33 @@ void acpi_table_print_madt_entry(struct acpi_subtable_header *header)
> >         }
> >  }
> >
> > +static unsigned long __init
> > +acpi_get_entry_type(char *id, void *entry)
> > +{
> > +       if (!strncmp(id, ACPI_SIG_HMAT, 4))
> > +               return ((struct acpi_hmat_structure *)entry)->type;
> > +       else
> > +               return ((struct acpi_subtable_header *)entry)->type;
> > +}
> 
> I slightly prefer to use ? : in similar situations.

Hmm..that becomes rather long, and seems complex for the already hard to read
?: operator?  Let's see, this:

	if (!strncmp(id, ACPI_SIG_HMAT, 4))
		return ((struct acpi_hmat_structure *)entry)->type;
	else
		return ((struct acpi_subtable_header *)entry)->type;

becomes

	return strncmp(id, ACPI_SIG_HMAT, 4)) ?
		((struct acpi_subtable_header *)entry)->type :
		((struct acpi_hmat_structure *)entry)->type;

Hmm...we only save one line, and I personally find that a lot harder to read,
but that being said if you feel strongly about it I'll make the change.
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Rafael J. Wysocki July 6, 2017, 10:36 p.m. UTC | #3
On Fri, Jul 7, 2017 at 12:22 AM, Ross Zwisler
<ross.zwisler@linux.intel.com> wrote:
> On Fri, Jul 07, 2017 at 12:13:54AM +0200, Rafael J. Wysocki wrote:
>> On Thu, Jul 6, 2017 at 11:52 PM, Ross Zwisler
>> <ross.zwisler@linux.intel.com> wrote:
>> > The current implementation of acpi_parse_entries_array() assumes that each
>> > subtable has a standard ACPI subtable entry of type struct
>> > acpi_sutbable_header.  This standard subtable header has a one byte length
>> > followed by a one byte type.
>> >
>> > The HMAT subtables have to allow for a longer length so they have subtable
>> > headers of type struct acpi_hmat_structure which has a 2 byte type and a 4
>> > byte length.
>> >
>> > Enhance the subtable parsing in acpi_parse_entries_array() so that it can
>> > handle these new HMAT subtables.
>> >
>> > Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
>> > ---
>> >  drivers/acpi/numa.c   |  2 +-
>> >  drivers/acpi/tables.c | 52 ++++++++++++++++++++++++++++++++++++++++-----------
>> >  2 files changed, 42 insertions(+), 12 deletions(-)

[cut]

>> > diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
>> > index ff42539..7979171 100644
>> > --- a/drivers/acpi/tables.c
>> > +++ b/drivers/acpi/tables.c
>> > @@ -218,6 +218,33 @@ void acpi_table_print_madt_entry(struct acpi_subtable_header *header)
>> >         }
>> >  }
>> >
>> > +static unsigned long __init
>> > +acpi_get_entry_type(char *id, void *entry)
>> > +{
>> > +       if (!strncmp(id, ACPI_SIG_HMAT, 4))
>> > +               return ((struct acpi_hmat_structure *)entry)->type;
>> > +       else
>> > +               return ((struct acpi_subtable_header *)entry)->type;
>> > +}
>>
>> I slightly prefer to use ? : in similar situations.
>
> Hmm..that becomes rather long, and seems complex for the already hard to read
> ?: operator?  Let's see, this:
>
>         if (!strncmp(id, ACPI_SIG_HMAT, 4))
>                 return ((struct acpi_hmat_structure *)entry)->type;
>         else
>                 return ((struct acpi_subtable_header *)entry)->type;
>
> becomes
>
>         return strncmp(id, ACPI_SIG_HMAT, 4)) ?
>                 ((struct acpi_subtable_header *)entry)->type :
>                 ((struct acpi_hmat_structure *)entry)->type;
>
> Hmm...we only save one line, and I personally find that a lot harder to read,
> but that being said if you feel strongly about it I'll make the change.

Well, I said "slightly". :-)

Thanks,
Rafael
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diff mbox

Patch

diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index edb0c79..917f1cc 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -443,7 +443,7 @@  int __init acpi_numa_init(void)
 	 * So go over all cpu entries in SRAT to get apicid to node mapping.
 	 */
 
-	/* SRAT: Static Resource Affinity Table */
+	/* SRAT: System Resource Affinity Table */
 	if (!acpi_table_parse(ACPI_SIG_SRAT, acpi_parse_srat)) {
 		struct acpi_subtable_proc srat_proc[3];
 
diff --git a/drivers/acpi/tables.c b/drivers/acpi/tables.c
index ff42539..7979171 100644
--- a/drivers/acpi/tables.c
+++ b/drivers/acpi/tables.c
@@ -218,6 +218,33 @@  void acpi_table_print_madt_entry(struct acpi_subtable_header *header)
 	}
 }
 
+static unsigned long __init
+acpi_get_entry_type(char *id, void *entry)
+{
+	if (!strncmp(id, ACPI_SIG_HMAT, 4))
+		return ((struct acpi_hmat_structure *)entry)->type;
+	else
+		return ((struct acpi_subtable_header *)entry)->type;
+}
+
+static unsigned long __init
+acpi_get_entry_length(char *id, void *entry)
+{
+	if (!strncmp(id, ACPI_SIG_HMAT, 4))
+		return ((struct acpi_hmat_structure *)entry)->length;
+	else
+		return ((struct acpi_subtable_header *)entry)->length;
+}
+
+static unsigned long __init
+acpi_get_subtable_header_length(char *id)
+{
+	if (!strncmp(id, ACPI_SIG_HMAT, 4))
+		return sizeof(struct acpi_hmat_structure);
+	else
+		return sizeof(struct acpi_subtable_header);
+}
+
 /**
  * acpi_parse_entries_array - for each proc_num find a suitable subtable
  *
@@ -242,10 +269,10 @@  acpi_parse_entries_array(char *id, unsigned long table_size,
 		struct acpi_subtable_proc *proc, int proc_num,
 		unsigned int max_entries)
 {
-	struct acpi_subtable_header *entry;
-	unsigned long table_end;
+	unsigned long table_end, subtable_header_length;
 	int count = 0;
 	int errs = 0;
+	void *entry;
 	int i;
 
 	if (acpi_disabled)
@@ -263,19 +290,23 @@  acpi_parse_entries_array(char *id, unsigned long table_size,
 	}
 
 	table_end = (unsigned long)table_header + table_header->length;
+	subtable_header_length = acpi_get_subtable_header_length(id);
 
 	/* Parse all entries looking for a match. */
 
-	entry = (struct acpi_subtable_header *)
-	    ((unsigned long)table_header + table_size);
+	entry = (void *)table_header + table_size;
+
+	while (((unsigned long)entry) + subtable_header_length  < table_end) {
+		unsigned long entry_type, entry_length;
 
-	while (((unsigned long)entry) + sizeof(struct acpi_subtable_header) <
-	       table_end) {
 		if (max_entries && count >= max_entries)
 			break;
 
+		entry_type = acpi_get_entry_type(id, entry);
+		entry_length = acpi_get_entry_length(id, entry);
+
 		for (i = 0; i < proc_num; i++) {
-			if (entry->type != proc[i].id)
+			if (entry_type != proc[i].id)
 				continue;
 			if (!proc[i].handler ||
 			     (!errs && proc[i].handler(entry, table_end))) {
@@ -290,16 +321,15 @@  acpi_parse_entries_array(char *id, unsigned long table_size,
 			count++;
 
 		/*
-		 * If entry->length is 0, break from this loop to avoid
+		 * If entry_length is 0, break from this loop to avoid
 		 * infinite loop.
 		 */
-		if (entry->length == 0) {
+		if (entry_length == 0) {
 			pr_err("[%4.4s:0x%02x] Invalid zero length\n", id, proc->id);
 			return -EINVAL;
 		}
 
-		entry = (struct acpi_subtable_header *)
-		    ((unsigned long)entry + entry->length);
+		entry += entry_length;
 	}
 
 	if (max_entries && count > max_entries) {