arch/tile: Allow tilegx to build with either 16K or 64K page size
This change introduces new flags for the hv_install_context()
API that passes a page table pointer to the hypervisor. Clients
can explicitly request 4K, 16K, or 64K small pages when they
install a new context. In practice, the page size is fixed at
kernel compile time and the same size is always requested every
time a new page table is installed.
The <hv/hypervisor.h> header changes so that it provides more abstract
macros for managing "page" things like PFNs and page tables. For
example there is now a HV_DEFAULT_PAGE_SIZE_SMALL instead of the old
HV_PAGE_SIZE_SMALL. The various PFN routines have been eliminated and
only PA- or PTFN-based ones remain (since PTFNs are always expressed
in fixed 2KB "page" size). The page-table management macros are
renamed with a leading underscore and take page-size arguments with
the presumption that clients will use those macros in some single
place to provide the "real" macros they will use themselves.
I happened to notice the old hv_set_caching() API was totally broken
(it assumed 4KB pages) so I changed it so it would nominally work
correctly with other page sizes.
Tag modules with the page size so you can't load a module built with
a conflicting page size. (And add a test for SMP while we're at it.)
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 74239dd..38c3957 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -139,6 +139,31 @@
smaller kernel memory footprint results from using a smaller
value on chips with fewer tiles.
+if TILEGX
+
+choice
+ prompt "Kernel page size"
+ default PAGE_SIZE_64KB
+ help
+ This lets you select the page size of the kernel. For best
+ performance on memory-intensive applications, a page size of 64KB
+ is recommended. For workloads involving many small files, many
+ connections, etc., it may be better to select 16KB, which uses
+ memory more efficiently at some cost in TLB performance.
+
+ Note that this option is TILE-Gx specific; currently
+ TILEPro page size is set by rebuilding the hypervisor.
+
+config PAGE_SIZE_16KB
+ bool "16KB"
+
+config PAGE_SIZE_64KB
+ bool "64KB"
+
+endchoice
+
+endif
+
source "kernel/time/Kconfig"
source "kernel/Kconfig.hz"