MIPS: Initialise MAARs on secondary CPUs
MAARs should be initialised on each CPU (or rather, core) in the system
in order to achieve consistent behaviour & performance. Previously they
have only been initialised on the boot CPU which leads to performance
problems if tasks are later scheduled on a secondary CPU, particularly
if those tasks make use of unaligned vector accesses where some CPUs
don't handle any cases in hardware for non-speculative memory regions.
Fix this by recording the MAAR configuration from the boot CPU and
applying it to secondary CPUs as part of their bringup.
Reported-by: Doug Gilmore <doug.gilmore@imgtec.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven J. Hill <Steven.Hill@imgtec.com>
Cc: Andrew Bresticker <abrestic@chromium.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Hemmo Nieminen <hemmo.nieminen@iki.fi>
Cc: Alex Smith <alex.smith@imgtec.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Patchwork: https://patchwork.linux-mips.org/patch/11239/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 023c164..8770e61 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -44,6 +44,7 @@
#include <asm/pgalloc.h>
#include <asm/tlb.h>
#include <asm/fixmap.h>
+#include <asm/maar.h>
/*
* We have up to 8 empty zeroed pages so we can map one of the right colour
@@ -288,10 +289,14 @@
return num_configured;
}
-static void maar_init(void)
+void maar_init(void)
{
unsigned num_maars, used, i;
phys_addr_t lower, upper, attr;
+ static struct {
+ struct maar_config cfgs[3];
+ unsigned used;
+ } recorded = { { { 0 } }, 0 };
if (!cpu_has_maar)
return;
@@ -304,8 +309,14 @@
/* MAARs should be in pairs */
WARN_ON(num_maars % 2);
- /* Configure the required MAARs */
- used = platform_maar_init(num_maars / 2);
+ /* Set MAARs using values we recorded already */
+ if (recorded.used) {
+ used = maar_config(recorded.cfgs, recorded.used, num_maars / 2);
+ BUG_ON(used != recorded.used);
+ } else {
+ /* Configure the required MAARs */
+ used = platform_maar_init(num_maars / 2);
+ }
/* Disable any further MAARs */
for (i = (used * 2); i < num_maars; i++) {
@@ -315,6 +326,9 @@
back_to_back_c0_hazard();
}
+ if (recorded.used)
+ return;
+
pr_info("MAAR configuration:\n");
for (i = 0; i < num_maars; i += 2) {
write_c0_maari(i);
@@ -341,6 +355,14 @@
pr_cont(" speculate");
pr_cont("\n");
+
+ /* Record the setup for use on secondary CPUs */
+ if (used <= ARRAY_SIZE(recorded.cfgs)) {
+ recorded.cfgs[recorded.used].lower = lower;
+ recorded.cfgs[recorded.used].upper = upper;
+ recorded.cfgs[recorded.used].attrs = attr;
+ recorded.used++;
+ }
}
}