[PATCH v2 1/4] arm64: add abstractions for FPSIMD state manipulation
Ard Biesheuvel
ard.biesheuvel at linaro.org
Wed Feb 5 12:13:35 EST 2014
This is a preparatory patch that replaces code that saves or restores the
on-CPU or preserved FPSIMD state directly with wrapper functions, resulting
in all direct manipulation of the FPSIMD state to be concentrated in fpsimd.c
Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
---
arch/arm64/include/asm/fpsimd.h | 9 ++++++---
arch/arm64/kernel/fpsimd.c | 31 +++++++++++++++++++++++++++++++
arch/arm64/kernel/process.c | 2 +-
arch/arm64/kernel/ptrace.c | 22 +++++++++++++---------
arch/arm64/kernel/signal.c | 6 +++---
arch/arm64/kernel/signal32.c | 6 +++---
6 files changed, 57 insertions(+), 19 deletions(-)
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index c43b4ac13008..7807974b49ee 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -52,12 +52,15 @@ struct fpsimd_state {
struct task_struct;
-extern void fpsimd_save_state(struct fpsimd_state *state);
-extern void fpsimd_load_state(struct fpsimd_state *state);
-
extern void fpsimd_thread_switch(struct task_struct *next);
extern void fpsimd_flush_thread(void);
+struct fpsimd_state *fpsimd_get_task_state(void);
+void fpsimd_set_task_state(struct fpsimd_state *state);
+
+struct user_fpsimd_state *fpsimd_get_user_state(struct task_struct *t);
+void fpsimd_set_user_state(struct task_struct *t, struct user_fpsimd_state *st);
+
#endif
#endif
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 4aef42a04bdc..eeb003f54ad0 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -34,6 +34,10 @@
#define FPEXC_IXF (1 << 4)
#define FPEXC_IDF (1 << 7)
+/* defined in entry-fpsimd.S but only used in this unit */
+void fpsimd_save_state(struct fpsimd_state *state);
+void fpsimd_load_state(struct fpsimd_state *state);
+
/*
* Trapped FP/ASIMD access.
*/
@@ -87,6 +91,33 @@ void fpsimd_flush_thread(void)
preempt_enable();
}
+/*
+ * Sync the saved FPSIMD context with the FPSIMD register file
+ */
+struct fpsimd_state *fpsimd_get_task_state(void)
+{
+ fpsimd_save_state(¤t->thread.fpsimd_state);
+ return ¤t->thread.fpsimd_state;
+}
+
+/*
+ * Load a new FPSIMD state into the FPSIMD register file.
+ */
+void fpsimd_set_task_state(struct fpsimd_state *state)
+{
+ fpsimd_load_state(state);
+}
+
+struct user_fpsimd_state *fpsimd_get_user_state(struct task_struct *t)
+{
+ return &t->thread.fpsimd_state.user_fpsimd;
+}
+
+void fpsimd_set_user_state(struct task_struct *t, struct user_fpsimd_state *st)
+{
+ t->thread.fpsimd_state.user_fpsimd = *st;
+}
+
#ifdef CONFIG_KERNEL_MODE_NEON
/*
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 1c0a9be2ffa8..bfa8214f92d1 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -199,7 +199,7 @@ void release_thread(struct task_struct *dead_task)
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
- fpsimd_save_state(¤t->thread.fpsimd_state);
+ fpsimd_get_task_state();
*dst = *src;
return 0;
}
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 6a8928bba03c..d0b35af14539 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -500,8 +500,7 @@ static int fpr_get(struct task_struct *target, const struct user_regset *regset,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
- struct user_fpsimd_state *uregs;
- uregs = &target->thread.fpsimd_state.user_fpsimd;
+ struct user_fpsimd_state *uregs = fpsimd_get_user_state(target);
return user_regset_copyout(&pos, &count, &kbuf, &ubuf, uregs, 0, -1);
}
@@ -516,7 +515,7 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
if (ret)
return ret;
- target->thread.fpsimd_state.user_fpsimd = newstate;
+ fpsimd_set_user_state(target, &newstate);
return ret;
}
@@ -723,7 +722,7 @@ static int compat_vfp_get(struct task_struct *target,
compat_ulong_t fpscr;
int ret;
- uregs = &target->thread.fpsimd_state.user_fpsimd;
+ uregs = fpsimd_get_user_state(target);
/*
* The VFP registers are packed into the fpsimd_state, so they all sit
@@ -746,24 +745,29 @@ static int compat_vfp_set(struct task_struct *target,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
- struct user_fpsimd_state *uregs;
+ struct user_fpsimd_state newstate;
compat_ulong_t fpscr;
int ret;
if (pos + count > VFP_STATE_SIZE)
return -EIO;
- uregs = &target->thread.fpsimd_state.user_fpsimd;
+ /*
+ * We will not overwrite the entire FPSIMD state, so we need to
+ * initialize 'newstate' with sane values.
+ */
+ newstate = *fpsimd_get_user_state(target);
- ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, uregs, 0,
+ ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &newstate, 0,
VFP_STATE_SIZE - sizeof(compat_ulong_t));
if (count && !ret) {
ret = get_user(fpscr, (compat_ulong_t *)ubuf);
- uregs->fpsr = fpscr & VFP_FPSCR_STAT_MASK;
- uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
+ newstate.fpsr = fpscr & VFP_FPSCR_STAT_MASK;
+ newstate.fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
}
+ fpsimd_set_user_state(target, &newstate);
return ret;
}
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index 890a591f75dd..54e1092c5b4c 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -47,11 +47,11 @@ struct rt_sigframe {
static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
{
- struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state;
+ struct fpsimd_state *fpsimd;
int err;
/* dump the hardware registers to the fpsimd_state structure */
- fpsimd_save_state(fpsimd);
+ fpsimd = fpsimd_get_task_state();
/* copy the FP and status/control registers */
err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
@@ -88,7 +88,7 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
/* load the hardware registers from the fpsimd_state structure */
if (!err) {
preempt_disable();
- fpsimd_load_state(&fpsimd);
+ fpsimd_set_task_state(&fpsimd);
preempt_enable();
}
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index b3fc9f5ec6d3..88e4535c3a45 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -208,7 +208,7 @@ int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
*/
static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
{
- struct fpsimd_state *fpsimd = ¤t->thread.fpsimd_state;
+ struct fpsimd_state *fpsimd;
compat_ulong_t magic = VFP_MAGIC;
compat_ulong_t size = VFP_STORAGE_SIZE;
compat_ulong_t fpscr, fpexc;
@@ -219,7 +219,7 @@ static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame)
* Note that this also saves V16-31, which aren't visible
* in AArch32.
*/
- fpsimd_save_state(fpsimd);
+ fpsimd = fpsimd_get_task_state();
/* Place structure header on the stack */
__put_user_error(magic, &frame->magic, err);
@@ -284,7 +284,7 @@ static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
*/
if (!err) {
preempt_disable();
- fpsimd_load_state(&fpsimd);
+ fpsimd_set_task_state(&fpsimd);
preempt_enable();
}
--
1.8.3.2
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