Revert "MIPS: Save/restore MSA context around signals"

This reverts commit eec43a224cf1 "MIPS: Save/restore MSA context around
signals" and the MSA parts of ca750649e08c "MIPS: kernel: signal:
Prevent save/restore FPU context in user memory" (the restore path of
which appears incorrect anyway...).

The reverted patch took care not to break compatibility with userland
users of struct sigcontext, but inadvertantly changed the offset of the
uc_sigmask field of struct ucontext. Thus Linux v3.15 breaks the
userland ABI. The MSA context will need to be saved via some other
opt-in mechanism, but for now revert the change to reduce the fallout.

This will have minimal impact upon use of MSA since the only supported
CPU which includes it (the P5600) is 32-bit and therefore requires that
the experimental CONFIG_MIPS_O32_FP64_SUPPORT Kconfig option be selected
before the kernel will set FR=1 for a task, a requirement for MSA use.
Thus the users of MSA are limited to known small groups of people & this
patch won't be breaking any previously working MSA-using userland
outside of experimental settings.

[ralf@linux-mips.org: Fixed rejects.]

Cc: stable@vger.kernel.org
Reported-by: Joseph S. Myers <joseph@codesourcery.com>
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: stable@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/7107/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 0 insertions, 213 deletions

diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 71814272d14..8352523568e 100644
--- a/arch/mips/kernel/r4k_fpu.S
+++ b/arch/mips/kernel/r4k_fpu.S
@@ -13,7 +13,6 @@
  * 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>
@@ -246,218 +245,6 @@ 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