mirror of
https://github.com/torvalds/linux
synced 2024-09-21 03:28:37 +00:00
ARCv2: fpu: preserve userspace fpu state
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
This commit is contained in:
Vineet Gupta
parent
f05523aa7a
commit
f45ba2bd6d
|
|
@ -351,9 +351,8 @@ config NODES_SHIFT
|
|||
Accessing memory beyond 1GB (with or w/o PAE) requires 2 memory
|
||||
zones.
|
||||
|
||||
if ISA_ARCOMPACT
|
||||
|
||||
config ARC_COMPACT_IRQ_LEVELS
|
||||
depends on ISA_ARCOMPACT
|
||||
bool "Setup Timer IRQ as high Priority"
|
||||
# if SMP, LV2 enabled ONLY if ARC implementation has LV2 re-entrancy
|
||||
depends on !SMP
|
||||
|
|
@ -361,14 +360,10 @@ config ARC_COMPACT_IRQ_LEVELS
|
|||
config ARC_FPU_SAVE_RESTORE
|
||||
bool "Enable FPU state persistence across context switch"
|
||||
help
|
||||
Double Precision Floating Point unit had dedicated regs which
|
||||
need to be saved/restored across context-switch.
|
||||
Note that ARC FPU is overly simplistic, unlike say x86, which has
|
||||
hardware pieces to allow software to conditionally save/restore,
|
||||
based on actual usage of FPU by a task. Thus our implemn does
|
||||
this for all tasks in system.
|
||||
|
||||
endif #ISA_ARCOMPACT
|
||||
ARCompact FPU has internal registers to assist with Double precision
|
||||
Floating Point operations. There are control and stauts registers
|
||||
for floating point exceptions and rounding modes. These are
|
||||
preserved across task context switch when enabled.
|
||||
|
||||
config ARC_CANT_LLSC
|
||||
def_bool n
|
||||
|
|
|
|||
|
|
@ -39,6 +39,8 @@
|
|||
#define ARC_REG_CLUSTER_BCR 0xcf
|
||||
#define ARC_REG_AUX_ICCM 0x208 /* ICCM Base Addr (ARCv2) */
|
||||
#define ARC_REG_LPB_CTRL 0x488 /* ARCv2 Loop Buffer control */
|
||||
#define ARC_REG_FPU_CTRL 0x300
|
||||
#define ARC_REG_FPU_STATUS 0x301
|
||||
|
||||
/* Common for ARCompact and ARCv2 status register */
|
||||
#define ARC_REG_STATUS32 0x0A
|
||||
|
|
|
|||
|
|
@ -11,6 +11,8 @@
|
|||
|
||||
#include <asm/ptrace.h>
|
||||
|
||||
#ifdef CONFIG_ISA_ARCOMPACT
|
||||
|
||||
/* These DPFP regs need to be saved/restored across ctx-sw */
|
||||
struct arc_fpu {
|
||||
struct {
|
||||
|
|
@ -18,11 +20,35 @@ struct arc_fpu {
|
|||
} aux_dpfp[2];
|
||||
};
|
||||
|
||||
extern void fpu_save_restore(struct task_struct *p, struct task_struct *n);
|
||||
#define fpu_init_task(regs)
|
||||
|
||||
#else
|
||||
|
||||
/*
|
||||
* ARCv2 FPU Control aux register
|
||||
* - bits to enable Traps on Exceptions
|
||||
* - Rounding mode
|
||||
*
|
||||
* ARCv2 FPU Status aux register
|
||||
* - FPU exceptions flags (Inv, Div-by-Zero, overflow, underflow, inexact)
|
||||
* - Flag Write Enable to clear flags explicitly (vs. by fpu instructions
|
||||
* only
|
||||
*/
|
||||
|
||||
struct arc_fpu {
|
||||
unsigned int ctrl, status;
|
||||
};
|
||||
|
||||
extern void fpu_init_task(struct pt_regs *regs);
|
||||
|
||||
#endif /* !CONFIG_ISA_ARCOMPACT */
|
||||
|
||||
extern void fpu_save_restore(struct task_struct *p, struct task_struct *n);
|
||||
|
||||
#else /* !CONFIG_ARC_FPU_SAVE_RESTORE */
|
||||
|
||||
#define fpu_save_restore(p, n)
|
||||
#define fpu_init_task(regs)
|
||||
|
||||
#endif /* CONFIG_ARC_FPU_SAVE_RESTORE */
|
||||
|
||||
|
|
|
|||
|
|
@ -23,7 +23,9 @@ obj-$(CONFIG_PERF_EVENTS) += perf_event.o
|
|||
obj-$(CONFIG_JUMP_LABEL) += jump_label.o
|
||||
|
||||
obj-$(CONFIG_ARC_FPU_SAVE_RESTORE) += fpu.o
|
||||
ifdef CONFIG_ISA_ARCOMPACT
|
||||
CFLAGS_fpu.o += -mdpfp
|
||||
endif
|
||||
|
||||
ifdef CONFIG_ARC_DW2_UNWIND
|
||||
CFLAGS_ctx_sw.o += -fno-omit-frame-pointer
|
||||
|
|
|
|||
|
|
@ -8,6 +8,8 @@
|
|||
#include <linux/sched.h>
|
||||
#include <asm/fpu.h>
|
||||
|
||||
#ifdef CONFIG_ISA_ARCOMPACT
|
||||
|
||||
/*
|
||||
* To save/restore FPU regs, simplest scheme would use LR/SR insns.
|
||||
* However since SR serializes the pipeline, an alternate "hack" can be used
|
||||
|
|
@ -50,3 +52,28 @@ void fpu_save_restore(struct task_struct *prev, struct task_struct *next)
|
|||
: "r" (zero), "r" (*(readfrom + 3)), "r" (*(readfrom + 2))
|
||||
);
|
||||
}
|
||||
|
||||
#else
|
||||
|
||||
void fpu_init_task(struct pt_regs *regs)
|
||||
{
|
||||
/* default rounding mode */
|
||||
write_aux_reg(ARC_REG_FPU_CTRL, 0x100);
|
||||
|
||||
/* set "Write enable" to allow explicit write to exception flags */
|
||||
write_aux_reg(ARC_REG_FPU_STATUS, 0x80000000);
|
||||
}
|
||||
|
||||
void fpu_save_restore(struct task_struct *prev, struct task_struct *next)
|
||||
{
|
||||
struct arc_fpu *save = &prev->thread.fpu;
|
||||
struct arc_fpu *restore = &next->thread.fpu;
|
||||
|
||||
save->ctrl = read_aux_reg(ARC_REG_FPU_CTRL);
|
||||
save->status = read_aux_reg(ARC_REG_FPU_STATUS);
|
||||
|
||||
write_aux_reg(ARC_REG_FPU_CTRL, restore->ctrl);
|
||||
write_aux_reg(ARC_REG_FPU_STATUS, restore->status);
|
||||
}
|
||||
|
||||
#endif
|
||||
|
|
|
|||
|
|
@ -20,6 +20,8 @@
|
|||
#include <linux/elf.h>
|
||||
#include <linux/tick.h>
|
||||
|
||||
#include <asm/fpu.h>
|
||||
|
||||
SYSCALL_DEFINE1(arc_settls, void *, user_tls_data_ptr)
|
||||
{
|
||||
task_thread_info(current)->thr_ptr = (unsigned int)user_tls_data_ptr;
|
||||
|
|
@ -263,7 +265,7 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long usp,
|
|||
/*
|
||||
* Do necessary setup to start up a new user task
|
||||
*/
|
||||
void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
|
||||
void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long usp)
|
||||
{
|
||||
regs->sp = usp;
|
||||
regs->ret = pc;
|
||||
|
|
@ -279,6 +281,8 @@ void start_thread(struct pt_regs * regs, unsigned long pc, unsigned long usp)
|
|||
regs->eflags = 0;
|
||||
#endif
|
||||
|
||||
fpu_init_task(regs);
|
||||
|
||||
/* bogus seed values for debugging */
|
||||
regs->lp_start = 0x10;
|
||||
regs->lp_end = 0x80;
|
||||
|
|
|
|||
Loading…
Reference in a new issue