x86/numa: add 'nohmat' option

Disable parsing of the HMAT for debug, to workaround broken platform
instances, or cases where it is otherwise not wanted.

[[email protected]: fix build when CONFIG_ACPI is not set]
  Link: https://lkml.kernel.org/r/[email protected]

Signed-off-by: Dan Williams <[email protected]>
Signed-off-by: Randy Dunlap <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: "H. Peter Anvin" <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Benjamin Herrenschmidt <[email protected]>
Cc: Ben Skeggs <[email protected]>
Cc: Brice Goglin <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Dave Jiang <[email protected]>
Cc: David Airlie <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Ira Weiny <[email protected]>
Cc: Jason Gunthorpe <[email protected]>
Cc: Jeff Moyer <[email protected]>
Cc: Jia He <[email protected]>
Cc: Joao Martins <[email protected]>
Cc: Jonathan Cameron <[email protected]>
Cc: Michael Ellerman <[email protected]>
Cc: Mike Rapoport <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Pavel Tatashin <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Tom Lendacky <[email protected]>
Cc: Vishal Verma <[email protected]>
Cc: Wei Yang <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Boris Ostrovsky <[email protected]>
Cc: Hulk Robot <[email protected]>
Cc: Jason Yan <[email protected]>
Cc: "Jérôme Glisse" <[email protected]>
Cc: Juergen Gross <[email protected]>
Cc: kernel test robot <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Stefano Stabellini <[email protected]>
Cc: Vivek Goyal <[email protected]>
Link: https://lkml.kernel.org/r/159643095540.4062302.732962081968036212.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Linus Torvalds <[email protected]>

Author: djbw

Documentation/x86/x86_64/boot-options.rst

@@ -173,6 +173,10 @@ NUMA
   numa=noacpi
     Don't parse the SRAT table for NUMA setup
 
+  numa=nohmat
+    Don't parse the HMAT table for NUMA setup, or soft-reserved memory
+    partitioning.
+
   numa=fake=<size>[MG]
     If given as a memory unit, fills all system RAM with nodes of
     size interleaved over physical nodes.

arch/x86/mm/numa.c

@@ -41,6 +41,8 @@ static __init int numa_setup(char *opt)
 		return numa_emu_cmdline(opt + 5);
 	if (!strncmp(opt, "noacpi", 6))
 		disable_srat();
+	if (!strncmp(opt, "nohmat", 6))
+		disable_hmat();
 	return 0;
 }
 early_param("numa", numa_setup);

drivers/acpi/numa/hmat.c

@@ -26,6 +26,12 @@
 #include <linux/sysfs.h>
 
 static u8 hmat_revision;
+static int hmat_disable __initdata;
+
+void __init disable_hmat(void)
+{
+	hmat_disable = 1;
+}
 
 static LIST_HEAD(targets);
 static LIST_HEAD(initiators);
@@ -814,7 +820,7 @@ static __init int hmat_init(void)
 	enum acpi_hmat_type i;
 	acpi_status status;
 
-	if (srat_disabled())
+	if (srat_disabled() || hmat_disable)
 		return 0;
 
 	status = acpi_get_table(ACPI_SIG_SRAT, 0, &tbl);

include/acpi/acpi_numa.h

@@ -27,4 +27,12 @@ static inline void disable_srat(void)
 {
 }
 #endif				/* CONFIG_ACPI_NUMA */
+
+#ifdef CONFIG_ACPI_HMAT
+extern void disable_hmat(void);
+#else				/* CONFIG_ACPI_HMAT */
+static inline void disable_hmat(void)
+{
+}
+#endif				/* CONFIG_ACPI_HMAT */
 #endif				/* __ACP_NUMA_H */

include/linux/acpi.h

@@ -709,6 +709,8 @@ static inline u64 acpi_arch_get_root_pointer(void)
 #define ACPI_HANDLE_FWNODE(fwnode)	(NULL)
 #define ACPI_DEVICE_CLASS(_cls, _msk)	.cls = (0), .cls_msk = (0),
 
+#include <acpi/acpi_numa.h>
+
 struct fwnode_handle;
 
 static inline bool acpi_dev_found(const char *hid)