[PATCH v2 04/16] MIPS: use struct mips_abi offsets to save FP context

From: Paul Burton
Date: Mon Jul 27 2015 - 16:00:04 EST

When saving FP state to struct sigcontext, make use of the offsets
provided by struct mips_abi to obtain appropriate addresses for the
sc_fpregs & sc_fpc_csr fields of the sigcontext. This is done only for
the native struct sigcontext in this patch (ie. for O32 in CONFIG_32BIT
kernels or for N64 in CONFIG_64BIT kernels) but is done in preparation
for sharing this code with compat ABIs in further patches.

Signed-off-by: Paul Burton <paul.burton@xxxxxxxxxx>
---

Changes in v2: None

arch/mips/kernel/r4k_fpu.S | 151 +++++++++++++++++++++------------------
arch/mips/kernel/signal-common.h | 6 ++
arch/mips/kernel/signal.c | 85 +++++++++++++++-------
3 files changed, 145 insertions(+), 97 deletions(-)

diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 1d88af2..9e2d18d 100644
--- a/arch/mips/kernel/r4k_fpu.S
+++ b/arch/mips/kernel/r4k_fpu.S
@@ -35,6 +35,14 @@

.set noreorder

+/**
+ * _save_fp_context() - save FP context from the FPU
+ * @a0 - pointer to fpregs field of sigcontext
+ * @a1 - pointer to fpc_csr field of sigcontext
+ *
+ * Save FP context, including the 32 FP data registers and the FP
+ * control & status register, from the FPU to signal context.
+ */
LEAF(_save_fp_context)
.set push
SET_HARDFLOAT
@@ -54,45 +62,45 @@ LEAF(_save_fp_context)
nop
#endif
/* Store the 16 odd double precision registers */
- EX sdc1 $f1, SC_FPREGS+8(a0)
- EX sdc1 $f3, SC_FPREGS+24(a0)
- EX sdc1 $f5, SC_FPREGS+40(a0)
- EX sdc1 $f7, SC_FPREGS+56(a0)
- EX sdc1 $f9, SC_FPREGS+72(a0)
- EX sdc1 $f11, SC_FPREGS+88(a0)
- EX sdc1 $f13, SC_FPREGS+104(a0)
- EX sdc1 $f15, SC_FPREGS+120(a0)
- EX sdc1 $f17, SC_FPREGS+136(a0)
- EX sdc1 $f19, SC_FPREGS+152(a0)
- EX sdc1 $f21, SC_FPREGS+168(a0)
- EX sdc1 $f23, SC_FPREGS+184(a0)
- EX sdc1 $f25, SC_FPREGS+200(a0)
- EX sdc1 $f27, SC_FPREGS+216(a0)
- EX sdc1 $f29, SC_FPREGS+232(a0)
- EX sdc1 $f31, SC_FPREGS+248(a0)
+ EX sdc1 $f1, 8(a0)
+ EX sdc1 $f3, 24(a0)
+ EX sdc1 $f5, 40(a0)
+ EX sdc1 $f7, 56(a0)
+ EX sdc1 $f9, 72(a0)
+ EX sdc1 $f11, 88(a0)
+ EX sdc1 $f13, 104(a0)
+ EX sdc1 $f15, 120(a0)
+ EX sdc1 $f17, 136(a0)
+ EX sdc1 $f19, 152(a0)
+ EX sdc1 $f21, 168(a0)
+ EX sdc1 $f23, 184(a0)
+ EX sdc1 $f25, 200(a0)
+ EX sdc1 $f27, 216(a0)
+ EX sdc1 $f29, 232(a0)
+ EX sdc1 $f31, 248(a0)
1: .set pop
#endif

.set push
SET_HARDFLOAT
/* Store the 16 even double precision registers */
- EX sdc1 $f0, SC_FPREGS+0(a0)
- EX sdc1 $f2, SC_FPREGS+16(a0)
- EX sdc1 $f4, SC_FPREGS+32(a0)
- EX sdc1 $f6, SC_FPREGS+48(a0)
- EX sdc1 $f8, SC_FPREGS+64(a0)
- EX sdc1 $f10, SC_FPREGS+80(a0)
- EX sdc1 $f12, SC_FPREGS+96(a0)
- EX sdc1 $f14, SC_FPREGS+112(a0)
- EX sdc1 $f16, SC_FPREGS+128(a0)
- EX sdc1 $f18, SC_FPREGS+144(a0)
- EX sdc1 $f20, SC_FPREGS+160(a0)
- EX sdc1 $f22, SC_FPREGS+176(a0)
- EX sdc1 $f24, SC_FPREGS+192(a0)
- EX sdc1 $f26, SC_FPREGS+208(a0)
- EX sdc1 $f28, SC_FPREGS+224(a0)
- EX sdc1 $f30, SC_FPREGS+240(a0)
- EX sw t1, SC_FPC_CSR(a0)
+ EX sdc1 $f0, 0(a0)
+ EX sdc1 $f2, 16(a0)
+ EX sdc1 $f4, 32(a0)
+ EX sdc1 $f6, 48(a0)
+ EX sdc1 $f8, 64(a0)
+ EX sdc1 $f10, 80(a0)
+ EX sdc1 $f12, 96(a0)
+ EX sdc1 $f14, 112(a0)
+ EX sdc1 $f16, 128(a0)
+ EX sdc1 $f18, 144(a0)
+ EX sdc1 $f20, 160(a0)
+ EX sdc1 $f22, 176(a0)
+ EX sdc1 $f24, 192(a0)
+ EX sdc1 $f26, 208(a0)
+ EX sdc1 $f28, 224(a0)
+ EX sdc1 $f30, 240(a0)
+ EX sw t1, 0(a1)
jr ra
li v0, 0 # success
.set pop
@@ -158,13 +166,16 @@ LEAF(_save_fp_context32)
END(_save_fp_context32)
#endif

-/*
- * Restore FPU state:
- * - fp gp registers
- * - cp1 status/control register
+/**
+ * _restore_fp_context() - restore FP context to the FPU
+ * @a0 - pointer to fpregs field of sigcontext
+ * @a1 - pointer to fpc_csr field of sigcontext
+ *
+ * Restore FP context, including the 32 FP data registers and the FP
+ * control & status register, from signal context to the FPU.
*/
LEAF(_restore_fp_context)
- EX lw t1, SC_FPC_CSR(a0)
+ EX lw t1, 0(a1)

#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) || \
defined(CONFIG_CPU_MIPS32_R6)
@@ -178,42 +189,42 @@ LEAF(_restore_fp_context)
bgez t0, 1f # skip loading odd if FR=0
nop
#endif
- EX ldc1 $f1, SC_FPREGS+8(a0)
- EX ldc1 $f3, SC_FPREGS+24(a0)
- EX ldc1 $f5, SC_FPREGS+40(a0)
- EX ldc1 $f7, SC_FPREGS+56(a0)
- EX ldc1 $f9, SC_FPREGS+72(a0)
- EX ldc1 $f11, SC_FPREGS+88(a0)
- EX ldc1 $f13, SC_FPREGS+104(a0)
- EX ldc1 $f15, SC_FPREGS+120(a0)
- EX ldc1 $f17, SC_FPREGS+136(a0)
- EX ldc1 $f19, SC_FPREGS+152(a0)
- EX ldc1 $f21, SC_FPREGS+168(a0)
- EX ldc1 $f23, SC_FPREGS+184(a0)
- EX ldc1 $f25, SC_FPREGS+200(a0)
- EX ldc1 $f27, SC_FPREGS+216(a0)
- EX ldc1 $f29, SC_FPREGS+232(a0)
- EX ldc1 $f31, SC_FPREGS+248(a0)
+ EX ldc1 $f1, 8(a0)
+ EX ldc1 $f3, 24(a0)
+ EX ldc1 $f5, 40(a0)
+ EX ldc1 $f7, 56(a0)
+ EX ldc1 $f9, 72(a0)
+ EX ldc1 $f11, 88(a0)
+ EX ldc1 $f13, 104(a0)
+ EX ldc1 $f15, 120(a0)
+ EX ldc1 $f17, 136(a0)
+ EX ldc1 $f19, 152(a0)
+ EX ldc1 $f21, 168(a0)
+ EX ldc1 $f23, 184(a0)
+ EX ldc1 $f25, 200(a0)
+ EX ldc1 $f27, 216(a0)
+ EX ldc1 $f29, 232(a0)
+ EX ldc1 $f31, 248(a0)
1: .set pop
#endif
.set push
SET_HARDFLOAT
- EX ldc1 $f0, SC_FPREGS+0(a0)
- EX ldc1 $f2, SC_FPREGS+16(a0)
- EX ldc1 $f4, SC_FPREGS+32(a0)
- EX ldc1 $f6, SC_FPREGS+48(a0)
- EX ldc1 $f8, SC_FPREGS+64(a0)
- EX ldc1 $f10, SC_FPREGS+80(a0)
- EX ldc1 $f12, SC_FPREGS+96(a0)
- EX ldc1 $f14, SC_FPREGS+112(a0)
- EX ldc1 $f16, SC_FPREGS+128(a0)
- EX ldc1 $f18, SC_FPREGS+144(a0)
- EX ldc1 $f20, SC_FPREGS+160(a0)
- EX ldc1 $f22, SC_FPREGS+176(a0)
- EX ldc1 $f24, SC_FPREGS+192(a0)
- EX ldc1 $f26, SC_FPREGS+208(a0)
- EX ldc1 $f28, SC_FPREGS+224(a0)
- EX ldc1 $f30, SC_FPREGS+240(a0)
+ EX ldc1 $f0, 0(a0)
+ EX ldc1 $f2, 16(a0)
+ EX ldc1 $f4, 32(a0)
+ EX ldc1 $f6, 48(a0)
+ EX ldc1 $f8, 64(a0)
+ EX ldc1 $f10, 80(a0)
+ EX ldc1 $f12, 96(a0)
+ EX ldc1 $f14, 112(a0)
+ EX ldc1 $f16, 128(a0)
+ EX ldc1 $f18, 144(a0)
+ EX ldc1 $f20, 160(a0)
+ EX ldc1 $f22, 176(a0)
+ EX ldc1 $f24, 192(a0)
+ EX ldc1 $f26, 208(a0)
+ EX ldc1 $f28, 224(a0)
+ EX ldc1 $f30, 240(a0)
ctc1 t1, fcr31
.set pop
jr ra
diff --git a/arch/mips/kernel/signal-common.h b/arch/mips/kernel/signal-common.h
index 06805e0..d594695 100644
--- a/arch/mips/kernel/signal-common.h
+++ b/arch/mips/kernel/signal-common.h
@@ -36,4 +36,10 @@ extern int fpcsr_pending(unsigned int __user *fpcsr);
#define unlock_fpu_owner() pagefault_enable()
#endif

+/* Assembly functions to move context to/from the FPU */
+extern asmlinkage int
+_save_fp_context(void __user *fpregs, void __user *csr);
+extern asmlinkage int
+_restore_fp_context(void __user *fpregs, void __user *csr);
+
#endif /* __SIGNAL_COMMON_H */
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index ddf8318..10f7dbc 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -41,11 +41,8 @@

#include "signal-common.h"

-static int (*save_fp_context)(struct sigcontext __user *sc);
-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);
+static int (*save_fp_context)(void __user *sc);
+static int (*restore_fp_context)(void __user *sc);

struct sigframe {
u32 sf_ass[4]; /* argument save space for o32 */
@@ -65,41 +62,71 @@ struct rt_sigframe {
* Thread saved context copy to/from a signal context presumed to be on the
* user stack, and therefore accessed with appropriate macros from uaccess.h.
*/
-static int copy_fp_to_sigcontext(struct sigcontext __user *sc)
+static int copy_fp_to_sigcontext(void __user *sc)
{
+ struct mips_abi *abi = current->thread.abi;
+ uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
+ uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
int i;
int err = 0;

for (i = 0; i < NUM_FPU_REGS; i++) {
err |=
__put_user(get_fpr64(&current->thread.fpu.fpr[i], 0),
- &sc->sc_fpregs[i]);
+ &fpregs[i]);
}
- err |= __put_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr);
+ err |= __put_user(current->thread.fpu.fcr31, csr);

return err;
}

-static int copy_fp_from_sigcontext(struct sigcontext __user *sc)
+static int copy_fp_from_sigcontext(void __user *sc)
{
+ struct mips_abi *abi = current->thread.abi;
+ uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
+ uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
int i;
int err = 0;
u64 fpr_val;

for (i = 0; i < NUM_FPU_REGS; i++) {
- err |= __get_user(fpr_val, &sc->sc_fpregs[i]);
+ err |= __get_user(fpr_val, &fpregs[i]);
set_fpr64(&current->thread.fpu.fpr[i], 0, fpr_val);
}
- err |= __get_user(current->thread.fpu.fcr31, &sc->sc_fpc_csr);
+ err |= __get_user(current->thread.fpu.fcr31, csr);

return err;
}

/*
+ * Wrappers for the assembly _{save,restore}_fp_context functions.
+ */
+static int save_hw_fp_context(void __user *sc)
+{
+ struct mips_abi *abi = current->thread.abi;
+ uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
+ uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
+
+ return _save_fp_context(fpregs, csr);
+}
+
+static int restore_hw_fp_context(void __user *sc)
+{
+ struct mips_abi *abi = current->thread.abi;
+ uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
+ uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
+
+ return _restore_fp_context(fpregs, csr);
+}
+
+/*
* Helper routines
*/
-static int protected_save_fp_context(struct sigcontext __user *sc)
+static int protected_save_fp_context(void __user *sc)
{
+ struct mips_abi *abi = current->thread.abi;
+ uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
+ uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
int err;

/*
@@ -121,9 +148,9 @@ static int protected_save_fp_context(struct sigcontext __user *sc)
if (likely(!err))
break;
/* touch the sigcontext and try again */
- err = __put_user(0, &sc->sc_fpregs[0]) |
- __put_user(0, &sc->sc_fpregs[31]) |
- __put_user(0, &sc->sc_fpc_csr);
+ err = __put_user(0, &fpregs[0]) |
+ __put_user(0, &fpregs[31]) |
+ __put_user(0, csr);
if (err)
break; /* really bad sigcontext */
}
@@ -131,8 +158,11 @@ static int protected_save_fp_context(struct sigcontext __user *sc)
return err;
}

-static int protected_restore_fp_context(struct sigcontext __user *sc)
+static int protected_restore_fp_context(void __user *sc)
{
+ struct mips_abi *abi = current->thread.abi;
+ uint64_t __user *fpregs = sc + abi->off_sc_fpregs;
+ uint32_t __user *csr = sc + abi->off_sc_fpc_csr;
int err, tmp __maybe_unused;

/*
@@ -155,9 +185,9 @@ static int protected_restore_fp_context(struct sigcontext __user *sc)
if (likely(!err))
break;
/* touch the sigcontext and try again */
- err = __get_user(tmp, &sc->sc_fpregs[0]) |
- __get_user(tmp, &sc->sc_fpregs[31]) |
- __get_user(tmp, &sc->sc_fpc_csr);
+ err = __get_user(tmp, &fpregs[0]) |
+ __get_user(tmp, &fpregs[31]) |
+ __get_user(tmp, csr);
if (err)
break; /* really bad sigcontext */
}
@@ -225,11 +255,12 @@ int fpcsr_pending(unsigned int __user *fpcsr)
}

static int
-check_and_restore_fp_context(struct sigcontext __user *sc)
+check_and_restore_fp_context(void __user *sc)
{
+ struct mips_abi *abi = current->thread.abi;
int err, sig;

- err = sig = fpcsr_pending(&sc->sc_fpc_csr);
+ err = sig = fpcsr_pending(sc + abi->off_sc_fpc_csr);
if (err > 0)
err = 0;
err |= protected_restore_fp_context(sc);
@@ -634,17 +665,17 @@ asmlinkage void do_notify_resume(struct pt_regs *regs, void *unused,
}

#ifdef CONFIG_SMP
-static int smp_save_fp_context(struct sigcontext __user *sc)
+static int smp_save_fp_context(void __user *sc)
{
return raw_cpu_has_fpu
- ? _save_fp_context(sc)
+ ? save_hw_fp_context(sc)
: copy_fp_to_sigcontext(sc);
}

-static int smp_restore_fp_context(struct sigcontext __user *sc)
+static int smp_restore_fp_context(void __user *sc)
{
return raw_cpu_has_fpu
- ? _restore_fp_context(sc)
+ ? restore_hw_fp_context(sc)
: copy_fp_from_sigcontext(sc);
}
#endif
@@ -657,8 +688,8 @@ static int signal_setup(void)
restore_fp_context = smp_restore_fp_context;
#else
if (cpu_has_fpu) {
- save_fp_context = _save_fp_context;
- restore_fp_context = _restore_fp_context;
+ save_fp_context = save_hw_fp_context;
+ restore_fp_context = restore_hw_fp_context;
} else {
save_fp_context = copy_fp_to_sigcontext;
restore_fp_context = copy_fp_from_sigcontext;
--
2.4.6

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