MIPS: Support extended ASIDs

Add support for extended ASIDs as determined by the Config4.AE bit.
Since the only supported CPUs known to implement this are Netlogic XLP
and MIPS I6400, select this variable ASID support based upon
CONFIG_CPU_XLP and CONFIG_CPU_MIPSR6.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Jayachandran C. <jchandra@broadcom.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/13211/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 064ab389e964..5ca4fefb1344 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -732,6 +732,7 @@ static inline unsigned int decode_config4(struct cpuinfo_mips *c)
 	unsigned int newcf4;
 	unsigned int mmuextdef;
 	unsigned int ftlb_page = MIPS_CONF4_FTLBPAGESIZE;
+	unsigned long asid_mask;
 
 	config4 = read_c0_config4();
 
@@ -792,6 +793,18 @@ static inline unsigned int decode_config4(struct cpuinfo_mips *c)
 
 	c->kscratch_mask = (config4 >> 16) & 0xff;
 
+	asid_mask = MIPS_ENTRYHI_ASID;
+	if (config4 & MIPS_CONF4_AE)
+		asid_mask |= MIPS_ENTRYHI_ASIDX;
+	set_cpu_asid_mask(c, asid_mask);
+
+	/*
+	 * Warn if the computed ASID mask doesn't match the mask the kernel
+	 * is built for. This may indicate either a serious problem or an
+	 * easy optimisation opportunity, but either way should be addressed.
+	 */
+	WARN_ON(asid_mask != cpu_asid_mask(c));
+
 	return config4 & MIPS_CONF_M;
 }