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x86/tss: Move I/O bitmap data into a seperate struct

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Move the non hardware portion of I/O bitmap data into a seperate struct for
readability sake.

Originally-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2019-11-12 18:45:29 +01:00
parent ecc7e37d4d
commit f5848e5fd2
4 changed files with 34 additions and 27 deletions
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47
arch/x86/include/asm/processor.h
View File

@ -328,11 +328,11 @@ struct x86_hw_tss {
* IO-bitmap sizes:
*/
#define IO_BITMAP_BITS 65536
#define IO_BITMAP_BYTES (IO_BITMAP_BITS/8)
#define IO_BITMAP_LONGS (IO_BITMAP_BYTES/sizeof(long))
#define IO_BITMAP_BYTES (IO_BITMAP_BITS / BITS_PER_BYTE)
#define IO_BITMAP_LONGS (IO_BITMAP_BYTES / sizeof(long))
#define IO_BITMAP_OFFSET_VALID \
(offsetof(struct tss_struct, io_bitmap) - \
#define IO_BITMAP_OFFSET_VALID \
(offsetof(struct tss_struct, io_bitmap.bitmap) - \
offsetof(struct tss_struct, x86_tss))
/*
@ -356,6 +356,28 @@ struct entry_stack_page {
struct entry_stack stack;
} __aligned(PAGE_SIZE);
/*
* All IO bitmap related data stored in the TSS:
*/
struct x86_io_bitmap {
/*
* Store the dirty size of the last io bitmap offender. The next
* one will have to do the cleanup as the switch out to a non io
* bitmap user will just set x86_tss.io_bitmap_base to a value
* outside of the TSS limit. So for sane tasks there is no need to
* actually touch the io_bitmap at all.
*/
unsigned int prev_max;
/*
* The extra 1 is there because the CPU will access an
* additional byte beyond the end of the IO permission
* bitmap. The extra byte must be all 1 bits, and must
* be within the limit.
*/
unsigned long bitmap[IO_BITMAP_LONGS + 1];
};
struct tss_struct {
/*
* The fixed hardware portion. This must not cross a page boundary
@ -364,22 +386,7 @@ struct tss_struct {
*/
struct x86_hw_tss x86_tss;
/*
* Store the dirty size of the last io bitmap offender. The next
* one will have to do the cleanup as the switch out to a non io
* bitmap user will just set x86_tss.io_bitmap_base to a value
* outside of the TSS limit. So for sane tasks there is no need to
* actually touch the io_bitmap at all.
*/
unsigned int io_bitmap_prev_max;
/*
* The extra 1 is there because the CPU will access an
* additional byte beyond the end of the IO permission
* bitmap. The extra byte must be all 1 bits, and must
* be within the limit.
*/
unsigned long io_bitmap[IO_BITMAP_LONGS + 1];
struct x86_io_bitmap io_bitmap;
} __aligned(PAGE_SIZE);
DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw);

4
arch/x86/kernel/cpu/common.c
View File

@ -1861,8 +1861,8 @@ void cpu_init(void)
/* Initialize the TSS. */
tss_setup_ist(tss);
tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;
tss->io_bitmap_prev_max = 0;
memset(tss->io_bitmap, 0xff, sizeof(tss->io_bitmap));
tss->io_bitmap.prev_max = 0;
memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap));
set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
load_TR_desc();

4
arch/x86/kernel/ioport.c
View File

@ -81,9 +81,9 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
/* Update the TSS */
tss = this_cpu_ptr(&cpu_tss_rw);
memcpy(tss->io_bitmap, t->io_bitmap_ptr, bytes_updated);
memcpy(tss->io_bitmap.bitmap, t->io_bitmap_ptr, bytes_updated);
/* Store the new end of the zero bits */
tss->io_bitmap_prev_max = bytes;
tss->io_bitmap.prev_max = bytes;
/* Make the bitmap base in the TSS valid */
tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_VALID;
/* Make sure the TSS limit covers the I/O bitmap. */

6
arch/x86/kernel/process.c
View File

@ -374,11 +374,11 @@ 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, next->io_bitmap_ptr,
max(tss->io_bitmap_prev_max, next->io_bitmap_max));
memcpy(tss->io_bitmap.bitmap, next->io_bitmap_ptr,
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;
/*