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arm64: fpsimd: add support to enable/disable fpsimd_settings.

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Add support to enable/disable fpsimd_settings at runtime through
kernel command line.

fpsimd.fpsimd_settings=0 should disable it.

Change-Id: I14bf5f20e36ec4547aad45382cfffc91666a2ff4
Signed-off-by: Sanrio Alvares <salvares@codeaurora.org>
This commit is contained in:
Sanrio Alvares 2016-01-28 17:10:34 -08:00 • committed by David Keitel
parent d444053499
commit 1f7d497b0a
2 changed files with 14 additions and 3 deletions
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2
arch/arm64/include/asm/elf.h
View file

@ -180,8 +180,6 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG];
#define compat_start_thread compat_start_thread
#define COMPAT_SET_PERSONALITY(ex) \
do { \
if (current->mm) \
fpsimd_enable_trap(); \
set_thread_flag(TIF_32BIT); \
} while (0)

15
arch/arm64/kernel/fpsimd.c
View file

@ -20,6 +20,7 @@
#include <linux/cpu.h>
#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/signal.h>
@ -90,11 +91,17 @@
static DEFINE_PER_CPU(struct fpsimd_state *, fpsimd_last_state);
static DEFINE_PER_CPU(int, fpsimd_stg_enable);
static int fpsimd_settings = 0x1; /* default = 0x1 */
module_param(fpsimd_settings, int, 0644);
/*
* Trapped FP/ASIMD access.
*/
void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
{
if (!fpsimd_settings)
return;
fpsimd_disable_trap();
fpsimd_settings_disable();
this_cpu_write(fpsimd_stg_enable, 0);
@ -102,6 +109,9 @@ void do_fpsimd_acc(unsigned int esr, struct pt_regs *regs)
void do_fpsimd_acc_compat(unsigned int esr, struct pt_regs *regs)
{
if (!fpsimd_settings)
return;
fpsimd_disable_trap();
fpsimd_settings_enable();
this_cpu_write(fpsimd_stg_enable, 1);
@ -144,7 +154,7 @@ void fpsimd_thread_switch(struct task_struct *next)
if (current->mm && !test_thread_flag(TIF_FOREIGN_FPSTATE))
fpsimd_save_state(&current->thread.fpsimd_state);
if (__this_cpu_read(fpsimd_stg_enable)) {
if (fpsimd_settings && __this_cpu_read(fpsimd_stg_enable)) {
fpsimd_settings_disable();
this_cpu_write(fpsimd_stg_enable, 0);
}
@ -167,6 +177,9 @@ void fpsimd_thread_switch(struct task_struct *next)
set_ti_thread_flag(task_thread_info(next),
TIF_FOREIGN_FPSTATE);
if (!fpsimd_settings)
return;
if (test_ti_thread_flag(task_thread_info(next), TIF_32BIT))
fpsimd_enable_trap();
else