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Re: [ACPI] [PATCH] Large /proc/acpi/dsdt fails
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From: KOCHI, T. <t-k...@mv...> - 2002-09-12 00:27:46
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On Wed, 11 Sep 2002 13:50:35 -0700
"Grover, Andrew" <and...@in...> wrote:
> > From: KOCHI, Takayoshi [mailto:t-k...@mv...]
> > The current /proc/acpi/dsdt reader function uses acpi_get_table() API
> > to get DSDT. The API uses acpi_os_malloc (that is, kmalloc) to
> > allocate a buffer to copy the whole table.
> >
> > This is not so good because:
> > 1. kmalloc will fail if DSDT is larger than 128K
> > 2. the copy is redundant
> >
> > So I changed the /proc/acpi/{dsdt,fadt} functions from two-copy
> > to single-copy so that you can avoid extra kmalloc.
>
> It avoids the extra kmalloc but uses a variable that is not part of the
> external interpreter interface - it is "private". C lets us down here
> because it does not have "module-level" globals, only per-file and global.
Okay.
> So I don't think the extra copy is a big deal, but maybe we want to figure
> out a way to allow larger than 128K DSDTs through this interface.
> acpi_system_read_dsdt could allocate a suitable sized buffer via vmalloc and
> pass that to acpi_get_table, possibly?
I'd think that is a hack and not a clean solution if we consider
future maintenanceability (some people may wonder and say "why use
vmalloc? use ACPI_ALLOCATE_BUFFER!").
How about this patch?
I made a new API, acpi_get_table_pointer().
Though there's a similar API (acpi_get_firmware_table() ),
it seems not to handle DSDT correctly... (returns AE_NO_EXIST)
Index: acpi-2419/drivers/acpi/acpi_ksyms.c
===================================================================
RCS file: /data/cvsroot/lia64-2.4/drivers/acpi/acpi_ksyms.c,v
retrieving revision 1.1.1.7.6.1
diff -u -r1.1.1.7.6.1 acpi_ksyms.c
--- acpi-2419/drivers/acpi/acpi_ksyms.c 25 Aug 2002 01:34:14 -0000 1.1.1.7.6.1
+++ acpi-2419/drivers/acpi/acpi_ksyms.c 12 Sep 2002 00:25:05 -0000
@@ -62,6 +62,7 @@
EXPORT_SYMBOL(acpi_get_next_object);
EXPORT_SYMBOL(acpi_evaluate_object);
EXPORT_SYMBOL(acpi_get_table);
+EXPORT_SYMBOL(acpi_get_table_pointer);
EXPORT_SYMBOL(acpi_get_firmware_table);
EXPORT_SYMBOL(acpi_install_notify_handler);
EXPORT_SYMBOL(acpi_remove_notify_handler);
Index: acpi-2419/drivers/acpi/system.c
===================================================================
RCS file: /data/cvsroot/lia64-2.4/drivers/acpi/system.c,v
retrieving revision 1.1.1.1.8.2
diff -u -r1.1.1.1.8.2 system.c
--- acpi-2419/drivers/acpi/system.c 31 Aug 2002 22:48:33 -0000 1.1.1.1.8.2
+++ acpi-2419/drivers/acpi/system.c 12 Sep 2002 00:25:05 -0000
@@ -293,30 +293,27 @@
size_t count,
loff_t *ppos)
{
- acpi_status status = AE_OK;
- acpi_buffer dsdt = {ACPI_ALLOCATE_BUFFER, NULL};
+ acpi_status status;
void *data = 0;
size_t size = 0;
+ acpi_table_header *dsdt;
ACPI_FUNCTION_TRACE("acpi_system_read_dsdt");
- status = acpi_get_table(ACPI_TABLE_DSDT, 1, &dsdt);
+ status = acpi_get_table_pointer(ACPI_TABLE_DSDT, 1, &dsdt);
if (ACPI_FAILURE(status))
return_VALUE(-ENODEV);
- if (*ppos < dsdt.length) {
- data = dsdt.pointer + file->f_pos;
- size = dsdt.length - file->f_pos;
+ if (*ppos < dsdt->length) {
+ data = (char *) acpi_gbl_DSDT + file->f_pos;
+ size = acpi_gbl_DSDT->length - file->f_pos;
if (size > count)
size = count;
if (copy_to_user(buffer, data, size)) {
- acpi_os_free(dsdt.pointer);
return_VALUE(-EFAULT);
}
}
- acpi_os_free(dsdt.pointer);
-
*ppos += size;
return_VALUE(size);
@@ -336,29 +333,28 @@
size_t count,
loff_t *ppos)
{
- acpi_status status = AE_OK;
- acpi_buffer fadt = {ACPI_ALLOCATE_BUFFER, NULL};
+ acpi_status status;
void *data = 0;
size_t size = 0;
+ acpi_table_header *fadt;
ACPI_FUNCTION_TRACE("acpi_system_read_fadt");
- status = acpi_get_table(ACPI_TABLE_FADT, 1, &fadt);
+ status = acpi_get_table_pointer(ACPI_TABLE_FADT, 1, &fadt);
if (ACPI_FAILURE(status))
return_VALUE(-ENODEV);
- if (*ppos < fadt.length) {
- data = fadt.pointer + file->f_pos;
- size = fadt.length - file->f_pos;
+ /* non-null fadt is guaranteed in acpi_get_table_pointer */
+
+ if (*ppos < fadt->length) {
+ data = (char *) fadt + file->f_pos;
+ size = fadt->length - file->f_pos;
if (size > count)
size = count;
if (copy_to_user(buffer, data, size)) {
- acpi_os_free(fadt.pointer);
return_VALUE(-EFAULT);
}
}
-
- acpi_os_free(fadt.pointer);
*ppos += size;
Index: acpi-2419/drivers/acpi/include/acpixf.h
===================================================================
RCS file: /data/cvsroot/lia64-2.4/drivers/acpi/include/acpixf.h,v
retrieving revision 1.1.1.7.8.1
diff -u -r1.1.1.7.8.1 acpixf.h
--- acpi-2419/drivers/acpi/include/acpixf.h 25 Aug 2002 01:34:15 -0000 1.1.1.7.8.1
+++ acpi-2419/drivers/acpi/include/acpixf.h 12 Sep 2002 00:25:05 -0000
@@ -131,6 +131,12 @@
acpi_buffer *ret_buffer);
acpi_status
+acpi_get_table_pointer (
+ acpi_table_type table_type,
+ u32 instance,
+ acpi_table_header **out_table_pointer);
+
+acpi_status
acpi_get_firmware_table (
acpi_string signature,
u32 instance,
Index: acpi-2419/drivers/acpi/tables/tbxface.c
===================================================================
RCS file: /data/cvsroot/lia64-2.4/drivers/acpi/tables/tbxface.c,v
retrieving revision 1.1.1.7.8.1
diff -u -r1.1.1.7.8.1 tbxface.c
--- acpi-2419/drivers/acpi/tables/tbxface.c 25 Aug 2002 01:34:16 -0000 1.1.1.7.8.1
+++ acpi-2419/drivers/acpi/tables/tbxface.c 12 Sep 2002 00:25:05 -0000
@@ -423,3 +423,65 @@
}
+/*******************************************************************************
+ *
+ * FUNCTION: Acpi_get_table_pointer
+ *
+ * PARAMETERS: Table_type - one of the defined table types
+ * Instance - the non zero instance of the table, allows
+ * support for multiple tables of the same type
+ * see Acpi_gbl_Acpi_table_flag
+ * Out_table_pointer - pointer to the table if successful
+ *
+ * DESCRIPTION: This function is called to get a pointer of an ACPI table.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_get_table_pointer (
+ acpi_table_type table_type,
+ u32 instance,
+ acpi_table_header **out_table_pointer)
+{
+ acpi_table_header *tbl_ptr;
+ acpi_status status;
+
+
+ ACPI_FUNCTION_TRACE ("Acpi_get_table_pointer");
+
+
+ if ((instance == 0) ||
+ (!out_table_pointer)) {
+ return_ACPI_STATUS (AE_BAD_PARAMETER);
+ }
+
+ /* Check the table type and instance */
+
+ if ((table_type > ACPI_TABLE_MAX) ||
+ (ACPI_IS_SINGLE_TABLE (acpi_gbl_acpi_table_data[table_type].flags) &&
+ instance > 1)) {
+ return_ACPI_STATUS (AE_BAD_PARAMETER);
+ }
+
+
+ /* Get a pointer to the entire table */
+
+ status = acpi_tb_get_table_ptr (table_type, instance, &tbl_ptr);
+ if (ACPI_FAILURE (status)) {
+ return_ACPI_STATUS (status);
+ }
+
+ /*
+ * The function will return a NULL pointer if the table is not loaded
+ */
+ if (tbl_ptr == NULL) {
+ return_ACPI_STATUS (AE_NOT_EXIST);
+ }
+
+ /*
+ * Copy the pointer to caller's variable
+ */
+ *out_table_pointer = tbl_ptr;
+
+ return_ACPI_STATUS (status);
+}
Thanks,
--
KOCHI, Takayoshi <t-k...@cq.../t-k...@mv...>
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