leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

x86/ioperm: Move iobitmap data into a struct

Browse Source 
No point in having all the data in thread_struct, especially as upcoming
changes add more.

Make the bitmap in the new struct accessible as array of longs and as array
of characters via a union, so both the bitmap functions and the update
logic can avoid type casts.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2019-11-11 23:03:21 +01:00
parent f5848e5fd2
commit 577d5cd7e5
5 changed files with 57 additions and 39 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
arch/x86/include/asm/io_bitmap.h Normal file
View File

@ -0,0 +1,13 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_IOBITMAP_H
#define _ASM_X86_IOBITMAP_H
#include <asm/processor.h>
struct io_bitmap {
/* The maximum number of bytes to copy so all zero bits are covered */
unsigned int max;
unsigned long bitmap[IO_BITMAP_LONGS];
};
#endif

6
arch/x86/include/asm/processor.h
View File

@ -7,6 +7,7 @@
/* Forward declaration, a strange C thing */
struct task_struct;
struct mm_struct;
struct io_bitmap;
struct vm86;
#include <asm/math_emu.h>
@ -501,10 +502,8 @@ struct thread_struct {
struct vm86 *vm86;
#endif
/* IO permissions: */
unsigned long *io_bitmap_ptr;
struct io_bitmap *io_bitmap;
unsigned long iopl;
/* Max allowed port in the bitmap, in bytes: */
unsigned io_bitmap_max;
mm_segment_t addr_limit;
@ -862,7 +861,6 @@ static inline void spin_lock_prefetch(const void *x)
#define INIT_THREAD { \
.sp0 = TOP_OF_INIT_STACK, \
.sysenter_cs = __KERNEL_CS, \
.io_bitmap_ptr = NULL, \
.addr_limit = KERNEL_DS, \
}

27
arch/x86/kernel/ioport.c
View File

@ -11,6 +11,7 @@
#include <linux/sched.h>
#include <linux/slab.h>
#include <asm/io_bitmap.h>
#include <asm/desc.h>
/*
@ -21,7 +22,7 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
unsigned int i, max_long, bytes, bytes_updated;
struct thread_struct *t = &current->thread;
struct tss_struct *tss;
unsigned long *bitmap;
struct io_bitmap *iobm;
if ((from + num <= from) || (from + num > IO_BITMAP_BITS))
return -EINVAL;
@ -34,16 +35,16 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
* IO bitmap up. ioperm() is much less timing critical than clone(),
* this is why we delay this operation until now:
*/
bitmap = t->io_bitmap_ptr;
if (!bitmap) {
iobm = t->io_bitmap;
if (!iobm) {
/* No point to allocate a bitmap just to clear permissions */
if (!turn_on)
return 0;
bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL);
if (!bitmap)
iobm = kmalloc(sizeof(*iobm), GFP_KERNEL);
if (!iobm)
return -ENOMEM;
memset(bitmap, 0xff, IO_BITMAP_BYTES);
memset(iobm->bitmap, 0xff, sizeof(iobm->bitmap));
}
/*
@ -52,9 +53,9 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
*/
preempt_disable();
if (turn_on)
bitmap_clear(bitmap, from, num);
bitmap_clear(iobm->bitmap, from, num);
else
bitmap_set(bitmap, from, num);
bitmap_set(iobm->bitmap, from, num);
/*
* Search for a (possibly new) maximum. This is simple and stupid,
@ -62,26 +63,26 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
*/
max_long = 0;
for (i = 0; i < IO_BITMAP_LONGS; i++) {
if (bitmap[i] != ~0UL)
if (iobm->bitmap[i] != ~0UL)
max_long = i;
}
bytes = (max_long + 1) * sizeof(unsigned long);
bytes_updated = max(bytes, t->io_bitmap_max);
bytes_updated = max(bytes, t->io_bitmap->max);
/* Update the thread data */
t->io_bitmap_max = bytes;
iobm->max = bytes;
/*
* Store the bitmap pointer (might be the same if the task already
* head one). Set the TIF flag, just in case this is the first
* invocation.
*/
t->io_bitmap_ptr = bitmap;
t->io_bitmap = iobm;
set_thread_flag(TIF_IO_BITMAP);
/* Update the TSS */
tss = this_cpu_ptr(&cpu_tss_rw);
memcpy(tss->io_bitmap.bitmap, t->io_bitmap_ptr, bytes_updated);
memcpy(tss->io_bitmap.bitmap, iobm->bitmap, bytes_updated);
/* Store the new end of the zero bits */
tss->io_bitmap.prev_max = bytes;
/* Make the bitmap base in the TSS valid */

38
arch/x86/kernel/process.c
View File

@ -41,6 +41,7 @@
#include <asm/desc.h>
#include <asm/prctl.h>
#include <asm/spec-ctrl.h>
#include <asm/io_bitmap.h>
#include <asm/proto.h>
#include "process.h"
@ -101,21 +102,20 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
void exit_thread(struct task_struct *tsk)
{
struct thread_struct *t = &tsk->thread;
unsigned long *bp = t->io_bitmap_ptr;
struct io_bitmap *iobm = t->io_bitmap;
struct fpu *fpu = &t->fpu;
struct tss_struct *tss;
if (bp) {
if (iobm) {
preempt_disable();
tss = this_cpu_ptr(&cpu_tss_rw);
t->io_bitmap_ptr = NULL;
t->io_bitmap_max = 0;
t->io_bitmap = NULL;
clear_thread_flag(TIF_IO_BITMAP);
/* Invalidate the io bitmap base in the TSS */
tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;
preempt_enable();
kfree(bp);
kfree(iobm);
}
free_vm86(t);
@ -135,25 +135,25 @@ static int set_new_tls(struct task_struct *p, unsigned long tls)
static inline int copy_io_bitmap(struct task_struct *tsk)
{
struct io_bitmap *iobm = current->thread.io_bitmap;
if (likely(!test_tsk_thread_flag(current, TIF_IO_BITMAP)))
return 0;
tsk->thread.io_bitmap_ptr = kmemdup(current->thread.io_bitmap_ptr,
IO_BITMAP_BYTES, GFP_KERNEL);
if (!tsk->thread.io_bitmap_ptr) {
tsk->thread.io_bitmap_max = 0;
tsk->thread.io_bitmap = kmemdup(iobm, sizeof(*iobm), GFP_KERNEL);
if (!tsk->thread.io_bitmap)
return -ENOMEM;
}
set_tsk_thread_flag(tsk, TIF_IO_BITMAP);
return 0;
}
static inline void free_io_bitmap(struct task_struct *tsk)
{
if (tsk->thread.io_bitmap_ptr) {
kfree(tsk->thread.io_bitmap_ptr);
tsk->thread.io_bitmap_ptr = NULL;
tsk->thread.io_bitmap_max = 0;
if (tsk->thread.io_bitmap) {
kfree(tsk->thread.io_bitmap);
tsk->thread.io_bitmap = NULL;
}
}
@ -172,7 +172,7 @@ int copy_thread_tls(unsigned long clone_flags, unsigned long sp,
frame->bp = 0;
frame->ret_addr = (unsigned long) ret_from_fork;
p->thread.sp = (unsigned long) fork_frame;
p->thread.io_bitmap_ptr = NULL;
p->thread.io_bitmap = NULL;
memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
#ifdef CONFIG_X86_64
@ -366,6 +366,8 @@ static inline void switch_to_bitmap(struct thread_struct *next,
struct tss_struct *tss = this_cpu_ptr(&cpu_tss_rw);
if (tifn & _TIF_IO_BITMAP) {
struct io_bitmap *iobm = next->io_bitmap;
/*
* Copy at least the size of the incoming tasks bitmap
* which covers the last permitted I/O port.
@ -374,11 +376,11 @@ static inline void switch_to_bitmap(struct thread_struct *next,
* bits permitted, then the copy needs to cover those as
* well so they get turned off.
*/
memcpy(tss->io_bitmap.bitmap, next->io_bitmap_ptr,
max(tss->io_bitmap.prev_max, next->io_bitmap_max));
memcpy(tss->io_bitmap.bitmap, next->io_bitmap->bitmap,
max(tss->io_bitmap.prev_max, next->io_bitmap->max));
/* Store the new max and set io_bitmap_base valid */
tss->io_bitmap.prev_max = next->io_bitmap_max;
tss->io_bitmap.prev_max = next->io_bitmap->max;
tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_VALID;
/*

12
arch/x86/kernel/ptrace.c
View File

@ -42,6 +42,7 @@
#include <asm/traps.h>
#include <asm/syscall.h>
#include <asm/fsgsbase.h>
#include <asm/io_bitmap.h>
#include "tls.h"
@ -697,7 +698,9 @@ static int ptrace_set_debugreg(struct task_struct *tsk, int n,
static int ioperm_active(struct task_struct *target,
const struct user_regset *regset)
{
return DIV_ROUND_UP(target->thread.io_bitmap_max, regset->size);
struct io_bitmap *iobm = target->thread.io_bitmap;
return iobm ? DIV_ROUND_UP(iobm->max, regset->size) : 0;
}
static int ioperm_get(struct task_struct *target,
@ -705,12 +708,13 @@ static int ioperm_get(struct task_struct *target,
unsigned int pos, unsigned int count,
void *kbuf, void __user *ubuf)
{
if (!target->thread.io_bitmap_ptr)
struct io_bitmap *iobm = target->thread.io_bitmap;
if (!iobm)
return -ENXIO;
return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
target->thread.io_bitmap_ptr,
0, IO_BITMAP_BYTES);
iobm->bitmap, 0, IO_BITMAP_BYTES);
}
/*