MIPS: kernel: cpu-probe: Detect unique RI/XI exceptions
Detect if the core supports unique exception codes for the
Read-Inhibit and Execute-Inhibit exceptions and set the
option accordingly. The RI/XI exception support is detected
by setting the 27th bit (IEC) of the PageGrain C0 register
and reading back the value of that register to verify the
bit is enabled.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7340/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index 4171255..9775c1a 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -265,6 +265,7 @@
#define PG_XIE (_ULCAST_(1) << 30)
#define PG_ELPA (_ULCAST_(1) << 29)
#define PG_ESP (_ULCAST_(1) << 28)
+#define PG_IEC (_ULCAST_(1) << 27)
/*
* R4x00 interrupt enable / cause bits