forked from Minki/linux
x86/ioperm: Extend IOPL config to control ioperm() as well
If iopl() is disabled, then providing ioperm() does not make much sense. Rename the config option and disable/enable both syscalls with it. Guard the code with #ifdefs where appropriate. Suggested-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -1254,10 +1254,13 @@ config X86_VSYSCALL_EMULATION
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Disabling this option saves about 7K of kernel size and
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possibly 4K of additional runtime pagetable memory.
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config X86_IOPL_EMULATION
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bool "IOPL Emulation"
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config X86_IOPL_IOPERM
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bool "IOPERM and IOPL Emulation"
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default y
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---help---
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This enables the ioperm() and iopl() syscalls which are necessary
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for legacy applications.
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Legacy IOPL support is an overbroad mechanism which allows user
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space aside of accessing all 65536 I/O ports also to disable
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interrupts. To gain this access the caller needs CAP_SYS_RAWIO
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@ -15,9 +15,15 @@ struct io_bitmap {
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struct task_struct;
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#ifdef CONFIG_X86_IOPL_IOPERM
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void io_bitmap_share(struct task_struct *tsk);
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void io_bitmap_exit(void);
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void tss_update_io_bitmap(void);
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#else
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static inline void io_bitmap_share(struct task_struct *tsk) { }
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static inline void io_bitmap_exit(void) { }
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static inline void tss_update_io_bitmap(void) { }
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#endif
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#endif
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@ -340,13 +340,18 @@ struct x86_hw_tss {
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(offsetof(struct tss_struct, io_bitmap.mapall) - \
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offsetof(struct tss_struct, x86_tss))
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#ifdef CONFIG_X86_IOPL_IOPERM
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/*
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* sizeof(unsigned long) coming from an extra "long" at the end of the
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* iobitmap. The limit is inclusive, i.e. the last valid byte.
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*/
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#define __KERNEL_TSS_LIMIT \
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# define __KERNEL_TSS_LIMIT \
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(IO_BITMAP_OFFSET_VALID_ALL + IO_BITMAP_BYTES + \
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sizeof(unsigned long) - 1)
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#else
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# define __KERNEL_TSS_LIMIT \
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(offsetof(struct tss_struct, x86_tss) + sizeof(struct x86_hw_tss) - 1)
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#endif
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/* Base offset outside of TSS_LIMIT so unpriviledged IO causes #GP */
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#define IO_BITMAP_OFFSET_INVALID (__KERNEL_TSS_LIMIT + 1)
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@ -398,7 +403,9 @@ struct tss_struct {
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*/
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struct x86_hw_tss x86_tss;
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#ifdef CONFIG_X86_IOPL_IOPERM
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struct x86_io_bitmap io_bitmap;
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#endif
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} __aligned(PAGE_SIZE);
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DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw);
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@ -156,8 +156,13 @@ struct thread_info {
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# define _TIF_WORK_CTXSW (_TIF_WORK_CTXSW_BASE)
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#endif
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#define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \
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#ifdef CONFIG_X86_IOPL_IOPERM
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# define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \
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_TIF_IO_BITMAP)
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#else
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# define _TIF_WORK_CTXSW_PREV (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY)
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#endif
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#define _TIF_WORK_CTXSW_NEXT (_TIF_WORK_CTXSW)
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#define STACK_WARN (THREAD_SIZE/8)
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@ -1804,6 +1804,22 @@ static inline void gdt_setup_doublefault_tss(int cpu)
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}
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#endif /* !CONFIG_X86_64 */
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static inline void tss_setup_io_bitmap(struct tss_struct *tss)
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{
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tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;
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#ifdef CONFIG_X86_IOPL_IOPERM
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tss->io_bitmap.prev_max = 0;
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tss->io_bitmap.prev_sequence = 0;
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memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap));
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/*
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* Invalidate the extra array entry past the end of the all
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* permission bitmap as required by the hardware.
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*/
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tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL;
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#endif
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}
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/*
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* cpu_init() initializes state that is per-CPU. Some data is already
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* initialized (naturally) in the bootstrap process, such as the GDT
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@ -1860,15 +1876,7 @@ void cpu_init(void)
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/* Initialize the TSS. */
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tss_setup_ist(tss);
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tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;
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tss->io_bitmap.prev_max = 0;
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tss->io_bitmap.prev_sequence = 0;
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memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap));
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/*
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* Invalidate the extra array entry past the end of the all
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* permission bitmap as required by the hardware.
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*/
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tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL;
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tss_setup_io_bitmap(tss);
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set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
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load_TR_desc();
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@ -14,6 +14,8 @@
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#include <asm/io_bitmap.h>
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#include <asm/desc.h>
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#ifdef CONFIG_X86_IOPL_IOPERM
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static atomic64_t io_bitmap_sequence;
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void io_bitmap_share(struct task_struct *tsk)
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@ -172,13 +174,6 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)
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struct thread_struct *t = ¤t->thread;
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unsigned int old;
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/*
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* Careful: the IOPL bits in regs->flags are undefined under Xen PV
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* and changing them has no effect.
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*/
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if (IS_ENABLED(CONFIG_X86_IOPL_NONE))
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return -ENOSYS;
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if (level > 3)
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return -EINVAL;
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@ -200,3 +195,20 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)
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return 0;
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}
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#else /* CONFIG_X86_IOPL_IOPERM */
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long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
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{
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return -ENOSYS;
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}
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SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on)
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{
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return -ENOSYS;
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}
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SYSCALL_DEFINE1(iopl, unsigned int, level)
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{
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return -ENOSYS;
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}
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#endif
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@ -322,6 +322,7 @@ void arch_setup_new_exec(void)
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}
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}
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#ifdef CONFIG_X86_IOPL_IOPERM
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static inline void tss_invalidate_io_bitmap(struct tss_struct *tss)
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{
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/*
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@ -409,6 +410,9 @@ void tss_update_io_bitmap(void)
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tss_invalidate_io_bitmap(tss);
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}
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}
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#else /* CONFIG_X86_IOPL_IOPERM */
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static inline void switch_to_bitmap(unsigned long tifp) { }
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#endif
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#ifdef CONFIG_SMP
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