MIPS: Save/restore MSA context around signals

This patch extends sigcontext in order to hold the most significant 64
bits of each vector register in addition to the MSA control & status
register. The least significant 64 bits are already saved as the scalar
FP context. This makes things a little awkward since the least & most
significant 64 bits of each vector register are not contiguous in
memory. Thus the copy_u & insert instructions are used to transfer the
values of the most significant 64 bits via GP registers.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6533/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 213 insertions, 0 deletions

diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 253b2fb52026..752b50a69264 100644
--- a/arch/mips/kernel/r4k_fpu.S
+++ b/arch/mips/kernel/r4k_fpu.S
@@ -13,6 +13,7 @@
  * Copyright (C) 1999, 2001 Silicon Graphics, Inc.
  */
 #include <asm/asm.h>
+#include <asm/asmmacro.h>
 #include <asm/errno.h>
 #include <asm/fpregdef.h>
 #include <asm/mipsregs.h>
@@ -245,6 +246,218 @@ LEAF(_restore_fp_context32)
 	END(_restore_fp_context32)
 #endif
 
+#ifdef CONFIG_CPU_HAS_MSA
+
+	.macro	save_sc_msareg	wr, off, sc, tmp
+#ifdef CONFIG_64BIT
+	copy_u_d \tmp, \wr, 1
+	EX sd	\tmp, (\off+(\wr*8))(\sc)
+#elif defined(CONFIG_CPU_LITTLE_ENDIAN)
+	copy_u_w \tmp, \wr, 2
+	EX sw	\tmp, (\off+(\wr*8)+0)(\sc)
+	copy_u_w \tmp, \wr, 3
+	EX sw	\tmp, (\off+(\wr*8)+4)(\sc)
+#else /* CONFIG_CPU_BIG_ENDIAN */
+	copy_u_w \tmp, \wr, 2
+	EX sw	\tmp, (\off+(\wr*8)+4)(\sc)
+	copy_u_w \tmp, \wr, 3
+	EX sw	\tmp, (\off+(\wr*8)+0)(\sc)
+#endif
+	.endm
+
+/*
+ * int _save_msa_context(struct sigcontext *sc)
+ *
+ * Save the upper 64 bits of each vector register along with the MSA_CSR
+ * register into sc. Returns zero on success, else non-zero.
+ */
+LEAF(_save_msa_context)
+	save_sc_msareg	0, SC_MSAREGS, a0, t0
+	save_sc_msareg	1, SC_MSAREGS, a0, t0
+	save_sc_msareg	2, SC_MSAREGS, a0, t0
+	save_sc_msareg	3, SC_MSAREGS, a0, t0
+	save_sc_msareg	4, SC_MSAREGS, a0, t0
+	save_sc_msareg	5, SC_MSAREGS, a0, t0
+	save_sc_msareg	6, SC_MSAREGS, a0, t0
+	save_sc_msareg	7, SC_MSAREGS, a0, t0
+	save_sc_msareg	8, SC_MSAREGS, a0, t0
+	save_sc_msareg	9, SC_MSAREGS, a0, t0
+	save_sc_msareg	10, SC_MSAREGS, a0, t0
+	save_sc_msareg	11, SC_MSAREGS, a0, t0
+	save_sc_msareg	12, SC_MSAREGS, a0, t0
+	save_sc_msareg	13, SC_MSAREGS, a0, t0
+	save_sc_msareg	14, SC_MSAREGS, a0, t0
+	save_sc_msareg	15, SC_MSAREGS, a0, t0
+	save_sc_msareg	16, SC_MSAREGS, a0, t0
+	save_sc_msareg	17, SC_MSAREGS, a0, t0
+	save_sc_msareg	18, SC_MSAREGS, a0, t0
+	save_sc_msareg	19, SC_MSAREGS, a0, t0
+	save_sc_msareg	20, SC_MSAREGS, a0, t0
+	save_sc_msareg	21, SC_MSAREGS, a0, t0
+	save_sc_msareg	22, SC_MSAREGS, a0, t0
+	save_sc_msareg	23, SC_MSAREGS, a0, t0
+	save_sc_msareg	24, SC_MSAREGS, a0, t0
+	save_sc_msareg	25, SC_MSAREGS, a0, t0
+	save_sc_msareg	26, SC_MSAREGS, a0, t0
+	save_sc_msareg	27, SC_MSAREGS, a0, t0
+	save_sc_msareg	28, SC_MSAREGS, a0, t0
+	save_sc_msareg	29, SC_MSAREGS, a0, t0
+	save_sc_msareg	30, SC_MSAREGS, a0, t0
+	save_sc_msareg	31, SC_MSAREGS, a0, t0
+	jr	ra
+	 li	v0, 0
+	END(_save_msa_context)
+
+#ifdef CONFIG_MIPS32_COMPAT
+
+/*
+ * int _save_msa_context32(struct sigcontext32 *sc)
+ *
+ * Save the upper 64 bits of each vector register along with the MSA_CSR
+ * register into sc. Returns zero on success, else non-zero.
+ */
+LEAF(_save_msa_context32)
+	save_sc_msareg	0, SC32_MSAREGS, a0, t0
+	save_sc_msareg	1, SC32_MSAREGS, a0, t0
+	save_sc_msareg	2, SC32_MSAREGS, a0, t0
+	save_sc_msareg	3, SC32_MSAREGS, a0, t0
+	save_sc_msareg	4, SC32_MSAREGS, a0, t0
+	save_sc_msareg	5, SC32_MSAREGS, a0, t0
+	save_sc_msareg	6, SC32_MSAREGS, a0, t0
+	save_sc_msareg	7, SC32_MSAREGS, a0, t0
+	save_sc_msareg	8, SC32_MSAREGS, a0, t0
+	save_sc_msareg	9, SC32_MSAREGS, a0, t0
+	save_sc_msareg	10, SC32_MSAREGS, a0, t0
+	save_sc_msareg	11, SC32_MSAREGS, a0, t0
+	save_sc_msareg	12, SC32_MSAREGS, a0, t0
+	save_sc_msareg	13, SC32_MSAREGS, a0, t0
+	save_sc_msareg	14, SC32_MSAREGS, a0, t0
+	save_sc_msareg	15, SC32_MSAREGS, a0, t0
+	save_sc_msareg	16, SC32_MSAREGS, a0, t0
+	save_sc_msareg	17, SC32_MSAREGS, a0, t0
+	save_sc_msareg	18, SC32_MSAREGS, a0, t0
+	save_sc_msareg	19, SC32_MSAREGS, a0, t0
+	save_sc_msareg	20, SC32_MSAREGS, a0, t0
+	save_sc_msareg	21, SC32_MSAREGS, a0, t0
+	save_sc_msareg	22, SC32_MSAREGS, a0, t0
+	save_sc_msareg	23, SC32_MSAREGS, a0, t0
+	save_sc_msareg	24, SC32_MSAREGS, a0, t0
+	save_sc_msareg	25, SC32_MSAREGS, a0, t0
+	save_sc_msareg	26, SC32_MSAREGS, a0, t0
+	save_sc_msareg	27, SC32_MSAREGS, a0, t0
+	save_sc_msareg	28, SC32_MSAREGS, a0, t0
+	save_sc_msareg	29, SC32_MSAREGS, a0, t0
+	save_sc_msareg	30, SC32_MSAREGS, a0, t0
+	save_sc_msareg	31, SC32_MSAREGS, a0, t0
+	jr	ra
+	 li	v0, 0
+	END(_save_msa_context32)
+
+#endif /* CONFIG_MIPS32_COMPAT */
+
+	.macro restore_sc_msareg	wr, off, sc, tmp
+#ifdef CONFIG_64BIT
+	EX ld	\tmp, (\off+(\wr*8))(\sc)
+	insert_d \wr, 1, \tmp
+#elif defined(CONFIG_CPU_LITTLE_ENDIAN)
+	EX lw	\tmp, (\off+(\wr*8)+0)(\sc)
+	insert_w \wr, 2, \tmp
+	EX lw	\tmp, (\off+(\wr*8)+4)(\sc)
+	insert_w \wr, 3, \tmp
+#else /* CONFIG_CPU_BIG_ENDIAN */
+	EX lw	\tmp, (\off+(\wr*8)+4)(\sc)
+	insert_w \wr, 2, \tmp
+	EX lw	\tmp, (\off+(\wr*8)+0)(\sc)
+	insert_w \wr, 3, \tmp
+#endif
+	.endm
+
+/*
+ * int _restore_msa_context(struct sigcontext *sc)
+ */
+LEAF(_restore_msa_context)
+	restore_sc_msareg	0, SC_MSAREGS, a0, t0
+	restore_sc_msareg	1, SC_MSAREGS, a0, t0
+	restore_sc_msareg	2, SC_MSAREGS, a0, t0
+	restore_sc_msareg	3, SC_MSAREGS, a0, t0
+	restore_sc_msareg	4, SC_MSAREGS, a0, t0
+	restore_sc_msareg	5, SC_MSAREGS, a0, t0
+	restore_sc_msareg	6, SC_MSAREGS, a0, t0
+	restore_sc_msareg	7, SC_MSAREGS, a0, t0
+	restore_sc_msareg	8, SC_MSAREGS, a0, t0
+	restore_sc_msareg	9, SC_MSAREGS, a0, t0
+	restore_sc_msareg	10, SC_MSAREGS, a0, t0
+	restore_sc_msareg	11, SC_MSAREGS, a0, t0
+	restore_sc_msareg	12, SC_MSAREGS, a0, t0
+	restore_sc_msareg	13, SC_MSAREGS, a0, t0
+	restore_sc_msareg	14, SC_MSAREGS, a0, t0
+	restore_sc_msareg	15, SC_MSAREGS, a0, t0
+	restore_sc_msareg	16, SC_MSAREGS, a0, t0
+	restore_sc_msareg	17, SC_MSAREGS, a0, t0
+	restore_sc_msareg	18, SC_MSAREGS, a0, t0
+	restore_sc_msareg	19, SC_MSAREGS, a0, t0
+	restore_sc_msareg	20, SC_MSAREGS, a0, t0
+	restore_sc_msareg	21, SC_MSAREGS, a0, t0
+	restore_sc_msareg	22, SC_MSAREGS, a0, t0
+	restore_sc_msareg	23, SC_MSAREGS, a0, t0
+	restore_sc_msareg	24, SC_MSAREGS, a0, t0
+	restore_sc_msareg	25, SC_MSAREGS, a0, t0
+	restore_sc_msareg	26, SC_MSAREGS, a0, t0
+	restore_sc_msareg	27, SC_MSAREGS, a0, t0
+	restore_sc_msareg	28, SC_MSAREGS, a0, t0
+	restore_sc_msareg	29, SC_MSAREGS, a0, t0
+	restore_sc_msareg	30, SC_MSAREGS, a0, t0
+	restore_sc_msareg	31, SC_MSAREGS, a0, t0
+	jr	ra
+	 li	v0, 0
+	END(_restore_msa_context)
+
+#ifdef CONFIG_MIPS32_COMPAT
+
+/*
+ * int _restore_msa_context32(struct sigcontext32 *sc)
+ */
+LEAF(_restore_msa_context32)
+	restore_sc_msareg	0, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	1, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	2, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	3, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	4, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	5, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	6, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	7, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	8, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	9, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	10, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	11, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	12, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	13, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	14, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	15, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	16, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	17, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	18, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	19, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	20, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	21, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	22, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	23, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	24, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	25, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	26, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	27, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	28, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	29, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	30, SC32_MSAREGS, a0, t0
+	restore_sc_msareg	31, SC32_MSAREGS, a0, t0
+	jr	ra
+	 li	v0, 0
+	END(_restore_msa_context32)
+
+#endif /* CONFIG_MIPS32_COMPAT */
+
+#endif /* CONFIG_CPU_HAS_MSA */
+
 	.set	reorder
 
 	.type	fault@function