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authorMark Brown <broonie@linaro.org>2014-06-26 10:49:57 +0100
committerMark Brown <broonie@linaro.org>2014-06-26 10:49:57 +0100
commit9580f7022362bf717457b6b73de1e0ed0fede211 (patch)
tree759c4197d0bdd6ab0b0a1576e9f1085b5f950929
parentde29502181a1954f27eb774c4d22532d33fa3d04 (diff)
downloadlinux-linaro-stable-9580f7022362bf717457b6b73de1e0ed0fede211.tar.gz
Revert "Merge remote-tracking branch 'lsk/v3.10/topic/arm64-fpsimd' into linux-linaro-lsk"lsk-14.06
This reverts commit b621c22123dc6b6facafe115f6364cf80172d551, reversing changes made to d7610b8eafd543c7f75568dcaeead439f31ffa53.
-rw-r--r--arch/arm64/Kconfig3
-rw-r--r--arch/arm64/include/asm/fpsimd.h23
-rw-r--r--arch/arm64/include/asm/fpsimdmacros.h35
-rw-r--r--arch/arm64/include/asm/neon.h18
-rw-r--r--arch/arm64/include/asm/thread_info.h4
-rw-r--r--arch/arm64/kernel/entry-fpsimd.S24
-rw-r--r--arch/arm64/kernel/entry.S2
-rw-r--r--arch/arm64/kernel/fpsimd.c187
-rw-r--r--arch/arm64/kernel/process.c2
-rw-r--r--arch/arm64/kernel/ptrace.c2
-rw-r--r--arch/arm64/kernel/signal.c13
-rw-r--r--arch/arm64/kernel/signal32.c9
12 files changed, 34 insertions, 288 deletions
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 8b0c182..bb65716 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -118,9 +118,6 @@ config IOMMU_HELPER
config FIX_EARLYCON_MEM
def_bool y
-config KERNEL_MODE_NEON
- def_bool y
-
source "init/Kconfig"
source "kernel/Kconfig.freezer"
diff --git a/arch/arm64/include/asm/fpsimd.h b/arch/arm64/include/asm/fpsimd.h
index 50f559f..c43b4ac 100644
--- a/arch/arm64/include/asm/fpsimd.h
+++ b/arch/arm64/include/asm/fpsimd.h
@@ -37,21 +37,8 @@ struct fpsimd_state {
u32 fpcr;
};
};
- /* the id of the last cpu to have restored this state */
- unsigned int cpu;
};
-/*
- * Struct for stacking the bottom 'n' FP/SIMD registers.
- */
-struct fpsimd_partial_state {
- u32 fpsr;
- u32 fpcr;
- u32 num_regs;
- __uint128_t vregs[32];
-};
-
-
#if defined(__KERNEL__) && defined(CONFIG_COMPAT)
/* Masks for extracting the FPSR and FPCR from the FPSCR */
#define VFP_FPSCR_STAT_MASK 0xf800009f
@@ -71,16 +58,6 @@ extern void fpsimd_load_state(struct fpsimd_state *state);
extern void fpsimd_thread_switch(struct task_struct *next);
extern void fpsimd_flush_thread(void);
-extern void fpsimd_preserve_current_state(void);
-extern void fpsimd_restore_current_state(void);
-extern void fpsimd_update_current_state(struct fpsimd_state *state);
-
-extern void fpsimd_flush_task_state(struct task_struct *target);
-
-extern void fpsimd_save_partial_state(struct fpsimd_partial_state *state,
- u32 num_regs);
-extern void fpsimd_load_partial_state(struct fpsimd_partial_state *state);
-
#endif
#endif
diff --git a/arch/arm64/include/asm/fpsimdmacros.h b/arch/arm64/include/asm/fpsimdmacros.h
index 768414d..bbec599 100644
--- a/arch/arm64/include/asm/fpsimdmacros.h
+++ b/arch/arm64/include/asm/fpsimdmacros.h
@@ -62,38 +62,3 @@
ldr w\tmpnr, [\state, #16 * 2 + 4]
msr fpcr, x\tmpnr
.endm
-
-.altmacro
-.macro fpsimd_save_partial state, numnr, tmpnr1, tmpnr2
- mrs x\tmpnr1, fpsr
- str w\numnr, [\state, #8]
- mrs x\tmpnr2, fpcr
- stp w\tmpnr1, w\tmpnr2, [\state]
- adr x\tmpnr1, 0f
- add \state, \state, x\numnr, lsl #4
- sub x\tmpnr1, x\tmpnr1, x\numnr, lsl #1
- br x\tmpnr1
- .irp qa, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 0
- .irp qb, %(qa + 1)
- stp q\qa, q\qb, [\state, # -16 * \qa - 16]
- .endr
- .endr
-0:
-.endm
-
-.macro fpsimd_restore_partial state, tmpnr1, tmpnr2
- ldp w\tmpnr1, w\tmpnr2, [\state]
- msr fpsr, x\tmpnr1
- msr fpcr, x\tmpnr2
- adr x\tmpnr1, 0f
- ldr w\tmpnr2, [\state, #8]
- add \state, \state, x\tmpnr2, lsl #4
- sub x\tmpnr1, x\tmpnr1, x\tmpnr2, lsl #1
- br x\tmpnr1
- .irp qa, 30, 28, 26, 24, 22, 20, 18, 16, 14, 12, 10, 8, 6, 4, 2, 0
- .irp qb, %(qa + 1)
- ldp q\qa, q\qb, [\state, # -16 * \qa - 16]
- .endr
- .endr
-0:
-.endm
diff --git a/arch/arm64/include/asm/neon.h b/arch/arm64/include/asm/neon.h
deleted file mode 100644
index 13ce4cc..0000000
--- a/arch/arm64/include/asm/neon.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/*
- * linux/arch/arm64/include/asm/neon.h
- *
- * Copyright (C) 2013 Linaro Ltd <ard.biesheuvel@linaro.org>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- */
-
-#include <linux/types.h>
-
-#define cpu_has_neon() (1)
-
-#define kernel_neon_begin() kernel_neon_begin_partial(32)
-
-void kernel_neon_begin_partial(u32 num_regs);
-void kernel_neon_end(void);
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index c09cbf6..59f151f 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -109,7 +109,6 @@ static inline struct thread_info *current_thread_info(void)
#define TIF_SIGPENDING 0
#define TIF_NEED_RESCHED 1
#define TIF_NOTIFY_RESUME 2 /* callback before returning to user */
-#define TIF_FOREIGN_FPSTATE 3 /* CPU's FP state is not current's */
#define TIF_SYSCALL_TRACE 8
#define TIF_SYSCALL_AUDIT 9
#define TIF_SYSCALL_TRACEPOINT 10
@@ -125,7 +124,6 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
#define _TIF_NOTIFY_RESUME (1 << TIF_NOTIFY_RESUME)
-#define _TIF_FOREIGN_FPSTATE (1 << TIF_FOREIGN_FPSTATE)
#define _TIF_SYSCALL_TRACE (1 << TIF_SYSCALL_TRACE)
#define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT)
#define _TIF_SYSCALL_TRACEPOINT (1 << TIF_SYSCALL_TRACEPOINT)
@@ -133,7 +131,7 @@ static inline struct thread_info *current_thread_info(void)
#define _TIF_32BIT (1 << TIF_32BIT)
#define _TIF_WORK_MASK (_TIF_NEED_RESCHED | _TIF_SIGPENDING | \
- _TIF_NOTIFY_RESUME | _TIF_FOREIGN_FPSTATE)
+ _TIF_NOTIFY_RESUME)
#define _TIF_SYSCALL_WORK (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \
_TIF_SYSCALL_TRACEPOINT | _TIF_SECCOMP)
diff --git a/arch/arm64/kernel/entry-fpsimd.S b/arch/arm64/kernel/entry-fpsimd.S
index d358cca..6a27cd6 100644
--- a/arch/arm64/kernel/entry-fpsimd.S
+++ b/arch/arm64/kernel/entry-fpsimd.S
@@ -41,27 +41,3 @@ ENTRY(fpsimd_load_state)
fpsimd_restore x0, 8
ret
ENDPROC(fpsimd_load_state)
-
-#ifdef CONFIG_KERNEL_MODE_NEON
-
-/*
- * Save the bottom n FP registers.
- *
- * x0 - pointer to struct fpsimd_partial_state
- */
-ENTRY(fpsimd_save_partial_state)
- fpsimd_save_partial x0, 1, 8, 9
- ret
-ENDPROC(fpsimd_load_partial_state)
-
-/*
- * Load the bottom n FP registers.
- *
- * x0 - pointer to struct fpsimd_partial_state
- */
-ENTRY(fpsimd_load_partial_state)
- fpsimd_restore_partial x0, 8, 9
- ret
-ENDPROC(fpsimd_load_partial_state)
-
-#endif
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 1fe70fa..fa78916 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -591,7 +591,7 @@ fast_work_pending:
str x0, [sp, #S_X0] // returned x0
work_pending:
tbnz x1, #TIF_NEED_RESCHED, work_resched
- /* TIF_SIGPENDING, TIF_NOTIFY_RESUME or TIF_FOREIGN_FPSTATE case */
+ /* TIF_SIGPENDING or TIF_NOTIFY_RESUME case */
ldr x2, [sp, #S_PSTATE]
mov x0, sp // 'regs'
tst x2, #PSR_MODE_MASK // user mode regs?
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index ad8aebb..522df9c 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -22,7 +22,6 @@
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/signal.h>
-#include <linux/hardirq.h>
#include <asm/fpsimd.h>
#include <asm/cputype.h>
@@ -35,60 +34,6 @@
#define FPEXC_IDF (1 << 7)
/*
- * In order to reduce the number of times the FPSIMD state is needlessly saved
- * and restored, we need to keep track of two things:
- * (a) for each task, we need to remember which CPU was the last one to have
- * the task's FPSIMD state loaded into its FPSIMD registers;
- * (b) for each CPU, we need to remember which task's userland FPSIMD state has
- * been loaded into its FPSIMD registers most recently, or whether it has
- * been used to perform kernel mode NEON in the meantime.
- *
- * For (a), we add a 'cpu' field to struct fpsimd_state, which gets updated to
- * the id of the current CPU everytime the state is loaded onto a CPU. For (b),
- * we add the per-cpu variable 'fpsimd_last_state' (below), which contains the
- * address of the userland FPSIMD state of the task that was loaded onto the CPU
- * the most recently, or NULL if kernel mode NEON has been performed after that.
- *
- * With this in place, we no longer have to restore the next FPSIMD state right
- * when switching between tasks. Instead, we can defer this check to userland
- * resume, at which time we verify whether the CPU's fpsimd_last_state and the
- * task's fpsimd_state.cpu are still mutually in sync. If this is the case, we
- * can omit the FPSIMD restore.
- *
- * As an optimization, we use the thread_info flag TIF_FOREIGN_FPSTATE to
- * indicate whether or not the userland FPSIMD state of the current task is
- * present in the registers. The flag is set unless the FPSIMD registers of this
- * CPU currently contain the most recent userland FPSIMD state of the current
- * task.
- *
- * For a certain task, the sequence may look something like this:
- * - the task gets scheduled in; if both the task's fpsimd_state.cpu field
- * contains the id of the current CPU, and the CPU's fpsimd_last_state per-cpu
- * variable points to the task's fpsimd_state, the TIF_FOREIGN_FPSTATE flag is
- * cleared, otherwise it is set;
- *
- * - the task returns to userland; if TIF_FOREIGN_FPSTATE is set, the task's
- * userland FPSIMD state is copied from memory to the registers, the task's
- * fpsimd_state.cpu field is set to the id of the current CPU, the current
- * CPU's fpsimd_last_state pointer is set to this task's fpsimd_state and the
- * TIF_FOREIGN_FPSTATE flag is cleared;
- *
- * - the task executes an ordinary syscall; upon return to userland, the
- * TIF_FOREIGN_FPSTATE flag will still be cleared, so no FPSIMD state is
- * restored;
- *
- * - the task executes a syscall which executes some NEON instructions; this is
- * preceded by a call to kernel_neon_begin(), which copies the task's FPSIMD
- * register contents to memory, clears the fpsimd_last_state per-cpu variable
- * and sets the TIF_FOREIGN_FPSTATE flag;
- *
- * - the task gets preempted after kernel_neon_end() is called; as we have not
- * returned from the 2nd syscall yet, TIF_FOREIGN_FPSTATE is still set so
- * whatever is in the FPSIMD registers is not saved to memory, but discarded.
- */
-static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state);
-
-/*
* Trapped FP/ASIMD access.
*/
void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
@@ -126,137 +71,43 @@ void do_fpsimd_exc(unsigned int esr, struct pt_regs *regs)
void fpsimd_thread_switch(struct task_struct *next)
{
- /*
- * Save the current FPSIMD state to memory, but only if whatever is in
- * the registers is in fact the most recent userland FPSIMD state of
- * 'current'.
- */
- if (current->mm && !test_thread_flag(TIF_FOREIGN_FPSTATE))
+ /* check if not kernel threads */
+ if (current->mm)
fpsimd_save_state(&current->thread.fpsimd_state);
-
- if (next->mm) {
- /*
- * If we are switching to a task whose most recent userland
- * FPSIMD state is already in the registers of *this* cpu,
- * we can skip loading the state from memory. Otherwise, set
- * the TIF_FOREIGN_FPSTATE flag so the state will be loaded
- * upon the next return to userland.
- */
- struct fpsimd_state *st = &next->thread.fpsimd_state;
-
- if (__this_cpu_read(fpsimd_last_state) == st
- && st->cpu == smp_processor_id())
- clear_ti_thread_flag(task_thread_info(next),
- TIF_FOREIGN_FPSTATE);
- else
- set_ti_thread_flag(task_thread_info(next),
- TIF_FOREIGN_FPSTATE);
- }
+ if (next->mm)
+ fpsimd_load_state(&next->thread.fpsimd_state);
}
void fpsimd_flush_thread(void)
{
- memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
- set_thread_flag(TIF_FOREIGN_FPSTATE);
-}
-
-/*
- * Save the userland FPSIMD state of 'current' to memory, but only if the state
- * currently held in the registers does in fact belong to 'current'
- */
-void fpsimd_preserve_current_state(void)
-{
- preempt_disable();
- if (!test_thread_flag(TIF_FOREIGN_FPSTATE))
- fpsimd_save_state(&current->thread.fpsimd_state);
- preempt_enable();
-}
-
-/*
- * Load the userland FPSIMD state of 'current' from memory, but only if the
- * FPSIMD state already held in the registers is /not/ the most recent FPSIMD
- * state of 'current'
- */
-void fpsimd_restore_current_state(void)
-{
- preempt_disable();
- if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
- struct fpsimd_state *st = &current->thread.fpsimd_state;
-
- fpsimd_load_state(st);
- this_cpu_write(fpsimd_last_state, st);
- st->cpu = smp_processor_id();
- }
- preempt_enable();
-}
-
-/*
- * Load an updated userland FPSIMD state for 'current' from memory and set the
- * flag that indicates that the FPSIMD register contents are the most recent
- * FPSIMD state of 'current'
- */
-void fpsimd_update_current_state(struct fpsimd_state *state)
-{
preempt_disable();
- fpsimd_load_state(state);
- if (test_and_clear_thread_flag(TIF_FOREIGN_FPSTATE)) {
- struct fpsimd_state *st = &current->thread.fpsimd_state;
-
- this_cpu_write(fpsimd_last_state, st);
- st->cpu = smp_processor_id();
- }
+ memset(&current->thread.fpsimd_state, 0, sizeof(struct fpsimd_state));
+ fpsimd_load_state(&current->thread.fpsimd_state);
preempt_enable();
}
-/*
- * Invalidate live CPU copies of task t's FPSIMD state
- */
-void fpsimd_flush_task_state(struct task_struct *t)
-{
- t->thread.fpsimd_state.cpu = NR_CPUS;
-}
-
#ifdef CONFIG_KERNEL_MODE_NEON
-static DEFINE_PER_CPU(struct fpsimd_partial_state, hardirq_fpsimdstate);
-static DEFINE_PER_CPU(struct fpsimd_partial_state, softirq_fpsimdstate);
-
/*
* Kernel-side NEON support functions
*/
-void kernel_neon_begin_partial(u32 num_regs)
+void kernel_neon_begin(void)
{
- if (in_interrupt()) {
- struct fpsimd_partial_state *s = this_cpu_ptr(
- in_irq() ? &hardirq_fpsimdstate : &softirq_fpsimdstate);
+ /* Avoid using the NEON in interrupt context */
+ BUG_ON(in_interrupt());
+ preempt_disable();
- BUG_ON(num_regs > 32);
- fpsimd_save_partial_state(s, roundup(num_regs, 2));
- } else {
- /*
- * Save the userland FPSIMD state if we have one and if we
- * haven't done so already. Clear fpsimd_last_state to indicate
- * that there is no longer userland FPSIMD state in the
- * registers.
- */
- preempt_disable();
- if (current->mm &&
- !test_and_set_thread_flag(TIF_FOREIGN_FPSTATE))
- fpsimd_save_state(&current->thread.fpsimd_state);
- this_cpu_write(fpsimd_last_state, NULL);
- }
+ if (current->mm)
+ fpsimd_save_state(&current->thread.fpsimd_state);
}
-EXPORT_SYMBOL(kernel_neon_begin_partial);
+EXPORT_SYMBOL(kernel_neon_begin);
void kernel_neon_end(void)
{
- if (in_interrupt()) {
- struct fpsimd_partial_state *s = this_cpu_ptr(
- in_irq() ? &hardirq_fpsimdstate : &softirq_fpsimdstate);
- fpsimd_load_partial_state(s);
- } else {
- preempt_enable();
- }
+ if (current->mm)
+ fpsimd_load_state(&current->thread.fpsimd_state);
+
+ preempt_enable();
}
EXPORT_SYMBOL(kernel_neon_end);
@@ -268,12 +119,12 @@ static int fpsimd_cpu_pm_notifier(struct notifier_block *self,
{
switch (cmd) {
case CPU_PM_ENTER:
- if (current->mm && !test_thread_flag(TIF_FOREIGN_FPSTATE))
+ if (current->mm)
fpsimd_save_state(&current->thread.fpsimd_state);
break;
case CPU_PM_EXIT:
if (current->mm)
- set_thread_flag(TIF_FOREIGN_FPSTATE);
+ fpsimd_load_state(&current->thread.fpsimd_state);
break;
case CPU_PM_ENTER_FAILED:
default:
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 15c91e25d..3193bf3 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -215,7 +215,7 @@ void release_thread(struct task_struct *dead_task)
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
- fpsimd_preserve_current_state();
+ fpsimd_save_state(&current->thread.fpsimd_state);
*dst = *src;
return 0;
}
diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c
index 3e926b9..0bf1955 100644
--- a/arch/arm64/kernel/ptrace.c
+++ b/arch/arm64/kernel/ptrace.c
@@ -521,7 +521,6 @@ static int fpr_set(struct task_struct *target, const struct user_regset *regset,
return ret;
target->thread.fpsimd_state.user_fpsimd = newstate;
- fpsimd_flush_task_state(target);
return ret;
}
@@ -769,7 +768,6 @@ static int compat_vfp_set(struct task_struct *target,
uregs->fpcr = fpscr & VFP_FPSCR_CTRL_MASK;
}
- fpsimd_flush_task_state(target);
return ret;
}
diff --git a/arch/arm64/kernel/signal.c b/arch/arm64/kernel/signal.c
index bbc1aad..e3cf096 100644
--- a/arch/arm64/kernel/signal.c
+++ b/arch/arm64/kernel/signal.c
@@ -51,7 +51,7 @@ static int preserve_fpsimd_context(struct fpsimd_context __user *ctx)
int err;
/* dump the hardware registers to the fpsimd_state structure */
- fpsimd_preserve_current_state();
+ fpsimd_save_state(fpsimd);
/* copy the FP and status/control registers */
err = __copy_to_user(ctx->vregs, fpsimd->vregs, sizeof(fpsimd->vregs));
@@ -86,8 +86,11 @@ static int restore_fpsimd_context(struct fpsimd_context __user *ctx)
__get_user_error(fpsimd.fpcr, &ctx->fpcr, err);
/* load the hardware registers from the fpsimd_state structure */
- if (!err)
- fpsimd_update_current_state(&fpsimd);
+ if (!err) {
+ preempt_disable();
+ fpsimd_load_state(&fpsimd);
+ preempt_enable();
+ }
return err ? -EFAULT : 0;
}
@@ -420,8 +423,4 @@ asmlinkage void do_notify_resume(struct pt_regs *regs,
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
-
- if (thread_flags & _TIF_FOREIGN_FPSTATE)
- fpsimd_restore_current_state();
-
}
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c
index 02de432..e51bbe7 100644
--- a/arch/arm64/kernel/signal32.c
+++ b/arch/arm64/kernel/signal32.c
@@ -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_preserve_current_state();
+ fpsimd_save_state(fpsimd);
/* Place structure header on the stack */
__put_user_error(magic, &frame->magic, err);
@@ -282,8 +282,11 @@ static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame)
* We don't need to touch the exception register, so
* reload the hardware state.
*/
- if (!err)
- fpsimd_update_current_state(&fpsimd);
+ if (!err) {
+ preempt_disable();
+ fpsimd_load_state(&fpsimd);
+ preempt_enable();
+ }
return err ? -EFAULT : 0;
}