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>

4 files changed, 16 insertions, 353 deletions

diff --git a/arch/mips/kernel/asm-offsets.c b/arch/mips/kernel/asm-offsets.c
index 02f075df8f2e..4bb5107511e2 100644
--- a/arch/mips/kernel/asm-offsets.c
+++ b/arch/mips/kernel/asm-offsets.c
@@ -293,7 +293,6 @@ void output_sc_defines(void)
         OFFSET(SC_LO2, sigcontext, sc_lo2);
         OFFSET(SC_HI3, sigcontext, sc_hi3);
         OFFSET(SC_LO3, sigcontext, sc_lo3);
-        OFFSET(SC_MSAREGS, sigcontext, sc_msaregs);
         BLANK();
 }
 #endif
@@ -308,7 +307,6 @@ void output_sc_defines(void)
         OFFSET(SC_MDLO, sigcontext, sc_mdlo);
         OFFSET(SC_PC, sigcontext, sc_pc);
         OFFSET(SC_FPC_CSR, sigcontext, sc_fpc_csr);
-        OFFSET(SC_MSAREGS, sigcontext, sc_msaregs);
         BLANK();
 }
 #endif
@@ -320,7 +318,6 @@ void output_sc32_defines(void)
         OFFSET(SC32_FPREGS, sigcontext32, sc_fpregs);
         OFFSET(SC32_FPC_CSR, sigcontext32, sc_fpc_csr);
         OFFSET(SC32_FPC_EIR, sigcontext32, sc_fpc_eir);
-        OFFSET(SC32_MSAREGS, sigcontext32, sc_msaregs);
         BLANK();
 }
 #endif
diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 71814272d148..8352523568e6 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
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index 33133d3df3e5..9e60d117e41e 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -31,7 +31,6 @@
 #include <linux/bitops.h>
 #include <asm/cacheflush.h>
 #include <asm/fpu.h>
-#include <asm/msa.h>
 #include <asm/sim.h>
 #include <asm/ucontext.h>
 #include <asm/cpu-features.h>
@@ -48,9 +47,6 @@ static int (*restore_fp_context)(struct sigcontext __user *sc);
 extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
 extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
 
-extern asmlinkage int _save_msa_context(struct sigcontext __user *sc);
-extern asmlinkage int _restore_msa_context(struct sigcontext __user *sc);
-
 struct sigframe {
         u32 sf_ass[4];          /* argument save space for o32 */
         u32 sf_pad[2];          /* Was: signal trampoline */
@@ -100,60 +96,20 @@ static int copy_fp_from_sigcontext(struct sigcontext __user *sc)
 }
 
 /*
- * These functions will save only the upper 64 bits of the vector registers,
- * since the lower 64 bits have already been saved as the scalar FP context.
- */
-static int copy_msa_to_sigcontext(struct sigcontext __user *sc)
-{
-        int i;
-        int err = 0;
-
-        for (i = 0; i < NUM_FPU_REGS; i++) {
-                err |=
-                    __put_user(get_fpr64(&current->thread.fpu.fpr[i], 1),
-                               &sc->sc_msaregs[i]);
-        }
-        err |= __put_user(current->thread.fpu.msacsr, &sc->sc_msa_csr);
-
-        return err;
-}
-
-static int copy_msa_from_sigcontext(struct sigcontext __user *sc)
-{
-        int i;
-        int err = 0;
-        u64 val;
-
-        for (i = 0; i < NUM_FPU_REGS; i++) {
-                err |= __get_user(val, &sc->sc_msaregs[i]);
-                set_fpr64(&current->thread.fpu.fpr[i], 1, val);
-        }
-        err |= __get_user(current->thread.fpu.msacsr, &sc->sc_msa_csr);
-
-        return err;
-}
-
-/*
  * Helper routines
  */
-static int protected_save_fp_context(struct sigcontext __user *sc,
-                                     unsigned used_math)
+static int protected_save_fp_context(struct sigcontext __user *sc)
 {
         int err;
-        bool save_msa = cpu_has_msa && (used_math & USEDMATH_MSA);
 #ifndef CONFIG_EVA
         while (1) {
                 lock_fpu_owner();
                 if (is_fpu_owner()) {
                         err = save_fp_context(sc);
-                        if (save_msa && !err)
-                                err = _save_msa_context(sc);
                         unlock_fpu_owner();
                 } else {
                         unlock_fpu_owner();
                         err = copy_fp_to_sigcontext(sc);
-                        if (save_msa && !err)
-                                err = copy_msa_to_sigcontext(sc);
                 }
                 if (likely(!err))
                         break;
@@ -169,38 +125,24 @@ static int protected_save_fp_context(struct sigcontext __user *sc,
          * EVA does not have FPU EVA instructions so saving fpu context directly
          * does not work.
          */
-        disable_msa();
         lose_fpu(1);
         err = save_fp_context(sc); /* this might fail */
-        if (save_msa && !err)
-                err = copy_msa_to_sigcontext(sc);
 #endif
         return err;
 }
 
-static int protected_restore_fp_context(struct sigcontext __user *sc,
-                                        unsigned used_math)
+static int protected_restore_fp_context(struct sigcontext __user *sc)
 {
         int err, tmp __maybe_unused;
-        bool restore_msa = cpu_has_msa && (used_math & USEDMATH_MSA);
 #ifndef CONFIG_EVA
         while (1) {
                 lock_fpu_owner();
                 if (is_fpu_owner()) {
                         err = restore_fp_context(sc);
-                        if (restore_msa && !err) {
-                                enable_msa();
-                                err = _restore_msa_context(sc);
-                        } else {
-                                /* signal handler may have used MSA */
-                                disable_msa();
-                        }
                         unlock_fpu_owner();
                 } else {
                         unlock_fpu_owner();
                         err = copy_fp_from_sigcontext(sc);
-                        if (!err && (used_math & USEDMATH_MSA))
-                                err = copy_msa_from_sigcontext(sc);
                 }
                 if (likely(!err))
                         break;
@@ -216,11 +158,8 @@ static int protected_restore_fp_context(struct sigcontext __user *sc,
          * EVA does not have FPU EVA instructions so restoring fpu context
          * directly does not work.
          */
-        enable_msa();
         lose_fpu(0);
         err = restore_fp_context(sc); /* this might fail */
-        if (restore_msa && !err)
-                err = copy_msa_from_sigcontext(sc);
 #endif
         return err;
 }
@@ -252,8 +191,7 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
                 err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
         }
 
-        used_math = used_math() ? USEDMATH_FP : 0;
-        used_math |= thread_msa_context_live() ? USEDMATH_MSA : 0;
+        used_math = !!used_math();
         err |= __put_user(used_math, &sc->sc_used_math);
 
         if (used_math) {
@@ -261,7 +199,7 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
                  * Save FPU state to signal context. Signal handler
                  * will "inherit" current FPU state.
                  */
-                err |= protected_save_fp_context(sc, used_math);
+                err |= protected_save_fp_context(sc);
         }
         return err;
 }
@@ -286,14 +224,14 @@ int fpcsr_pending(unsigned int __user *fpcsr)
 }
 
 static int
-check_and_restore_fp_context(struct sigcontext __user *sc, unsigned used_math)
+check_and_restore_fp_context(struct sigcontext __user *sc)
 {
         int err, sig;
 
         err = sig = fpcsr_pending(&sc->sc_fpc_csr);
         if (err > 0)
                 err = 0;
-        err |= protected_restore_fp_context(sc, used_math);
+        err |= protected_restore_fp_context(sc);
         return err ?: sig;
 }
 
@@ -333,10 +271,9 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
         if (used_math) {
                 /* restore fpu context if we have used it before */
                 if (!err)
-                        err = check_and_restore_fp_context(sc, used_math);
+                        err = check_and_restore_fp_context(sc);
         } else {
-                /* signal handler may have used FPU or MSA. Disable them. */
-                disable_msa();
+                /* signal handler may have used FPU.  Give it up. */
                 lose_fpu(0);
         }
 
diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c
index 299f956e4db3..bae2e6ee2109 100644
--- a/arch/mips/kernel/signal32.c
+++ b/arch/mips/kernel/signal32.c
@@ -30,7 +30,6 @@
 #include <asm/sim.h>
 #include <asm/ucontext.h>
 #include <asm/fpu.h>
-#include <asm/msa.h>
 #include <asm/war.h>
 #include <asm/vdso.h>
 #include <asm/dsp.h>
@@ -43,9 +42,6 @@ static int (*restore_fp_context32)(struct sigcontext32 __user *sc);
 extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
 extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);
 
-extern asmlinkage int _save_msa_context32(struct sigcontext32 __user *sc);
-extern asmlinkage int _restore_msa_context32(struct sigcontext32 __user *sc);
-
 /*
  * Including <asm/unistd.h> would give use the 64-bit syscall numbers ...
  */
@@ -115,59 +111,19 @@ static int copy_fp_from_sigcontext32(struct sigcontext32 __user *sc)
 }
 
 /*
- * These functions will save only the upper 64 bits of the vector registers,
- * since the lower 64 bits have already been saved as the scalar FP context.
- */
-static int copy_msa_to_sigcontext32(struct sigcontext32 __user *sc)
-{
-        int i;
-        int err = 0;
-
-        for (i = 0; i < NUM_FPU_REGS; i++) {
-                err |=
-                    __put_user(get_fpr64(&current->thread.fpu.fpr[i], 1),
-                               &sc->sc_msaregs[i]);
-        }
-        err |= __put_user(current->thread.fpu.msacsr, &sc->sc_msa_csr);
-
-        return err;
-}
-
-static int copy_msa_from_sigcontext32(struct sigcontext32 __user *sc)
-{
-        int i;
-        int err = 0;
-        u64 val;
-
-        for (i = 0; i < NUM_FPU_REGS; i++) {
-                err |= __get_user(val, &sc->sc_msaregs[i]);
-                set_fpr64(&current->thread.fpu.fpr[i], 1, val);
-        }
-        err |= __get_user(current->thread.fpu.msacsr, &sc->sc_msa_csr);
-
-        return err;
-}
-
-/*
  * sigcontext handlers
  */
-static int protected_save_fp_context32(struct sigcontext32 __user *sc,
-                                       unsigned used_math)
+static int protected_save_fp_context32(struct sigcontext32 __user *sc)
 {
         int err;
-        bool save_msa = cpu_has_msa && (used_math & USEDMATH_MSA);
         while (1) {
                 lock_fpu_owner();
                 if (is_fpu_owner()) {
                         err = save_fp_context32(sc);
-                        if (save_msa && !err)
-                                err = _save_msa_context32(sc);
                         unlock_fpu_owner();
                 } else {
                         unlock_fpu_owner();
                         err = copy_fp_to_sigcontext32(sc);
-                        if (save_msa && !err)
-                                err = copy_msa_to_sigcontext32(sc);
                 }
                 if (likely(!err))
                         break;
@@ -181,28 +137,17 @@ static int protected_save_fp_context32(struct sigcontext32 __user *sc,
         return err;
 }
 
-static int protected_restore_fp_context32(struct sigcontext32 __user *sc,
-                                          unsigned used_math)
+static int protected_restore_fp_context32(struct sigcontext32 __user *sc)
 {
         int err, tmp __maybe_unused;
-        bool restore_msa = cpu_has_msa && (used_math & USEDMATH_MSA);
         while (1) {
                 lock_fpu_owner();
                 if (is_fpu_owner()) {
                         err = restore_fp_context32(sc);
-                        if (restore_msa && !err) {
-                                enable_msa();
-                                err = _restore_msa_context32(sc);
-                        } else {
-                                /* signal handler may have used MSA */
-                                disable_msa();
-                        }
                         unlock_fpu_owner();
                 } else {
                         unlock_fpu_owner();
                         err = copy_fp_from_sigcontext32(sc);
-                        if (restore_msa && !err)
-                                err = copy_msa_from_sigcontext32(sc);
                 }
                 if (likely(!err))
                         break;
@@ -241,8 +186,7 @@ static int setup_sigcontext32(struct pt_regs *regs,
                 err |= __put_user(mflo3(), &sc->sc_lo3);
         }
 
-        used_math = used_math() ? USEDMATH_FP : 0;
-        used_math |= thread_msa_context_live() ? USEDMATH_MSA : 0;
+        used_math = !!used_math();
         err |= __put_user(used_math, &sc->sc_used_math);
 
         if (used_math) {
@@ -250,21 +194,20 @@ static int setup_sigcontext32(struct pt_regs *regs,
                  * Save FPU state to signal context.  Signal handler
                  * will "inherit" current FPU state.
                  */
-                err |= protected_save_fp_context32(sc, used_math);
+                err |= protected_save_fp_context32(sc);
         }
         return err;
 }
 
 static int
-check_and_restore_fp_context32(struct sigcontext32 __user *sc,
-                               unsigned used_math)
+check_and_restore_fp_context32(struct sigcontext32 __user *sc)
 {
         int err, sig;
 
         err = sig = fpcsr_pending(&sc->sc_fpc_csr);
         if (err > 0)
                 err = 0;
-        err |= protected_restore_fp_context32(sc, used_math);
+        err |= protected_restore_fp_context32(sc);
         return err ?: sig;
 }
 
@@ -301,10 +244,9 @@ static int restore_sigcontext32(struct pt_regs *regs,
         if (used_math) {
                 /* restore fpu context if we have used it before */
                 if (!err)
-                        err = check_and_restore_fp_context32(sc, used_math);
+                        err = check_and_restore_fp_context32(sc);
         } else {
-                /* signal handler may have used FPU or MSA. Disable them. */
-                disable_msa();
+                /* signal handler may have used FPU.  Give it up. */
                 lose_fpu(0);
         }