diff options
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/Kconfig | 23 | ||||
| -rw-r--r-- | arch/x86/include/asm/paravirt.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/asm/paravirt_types.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 26 | ||||
| -rw-r--r-- | arch/x86/include/asm/xen/hypervisor.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/ioport.c | 47 | ||||
| -rw-r--r-- | arch/x86/kernel/paravirt.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/process_32.c | 9 | ||||
| -rw-r--r-- | arch/x86/kernel/process_64.c | 11 | ||||
| -rw-r--r-- | arch/x86/xen/enlighten_pv.c | 10 |
10 files changed, 17 insertions, 119 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 2aad1cd14cc5..1f926e396ec1 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1254,12 +1254,9 @@ config X86_VSYSCALL_EMULATION Disabling this option saves about 7K of kernel size and possibly 4K of additional runtime pagetable memory. -choice - prompt "IOPL" - default X86_IOPL_EMULATION - config X86_IOPL_EMULATION bool "IOPL Emulation" + default y ---help--- Legacy IOPL support is an overbroad mechanism which allows user space aside of accessing all 65536 I/O ports also to disable @@ -1269,22 +1266,8 @@ config X86_IOPL_EMULATION The emulation restricts the functionality of the syscall to only allowing the full range I/O port access, but prevents the - ability to disable interrupts from user space. - -config X86_IOPL_LEGACY - bool "IOPL Legacy" - ---help--- - Allow the full IOPL permissions, i.e. user space access to all - 65536 I/O ports and also the ability to disable interrupts, which - is overbroad and can result in system lockups. - -config X86_IOPL_NONE - bool "IOPL None" - ---help--- - Disable the IOPL permission syscall. That's the safest option as - no sane application should depend on this functionality. - -endchoice + ability to disable interrupts from user space which would be + granted if the hardware IOPL mechanism would be used. config TOSHIBA tristate "Toshiba Laptop support" diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h index 69089d46f128..86e7317eb31f 100644 --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -294,10 +294,6 @@ static inline void write_idt_entry(gate_desc *dt, int entry, const gate_desc *g) { PVOP_VCALL3(cpu.write_idt_entry, dt, entry, g); } -static inline void set_iopl_mask(unsigned mask) -{ - PVOP_VCALL1(cpu.set_iopl_mask, mask); -} static inline void paravirt_activate_mm(struct mm_struct *prev, struct mm_struct *next) diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h index 70b654f3ffe5..84812964d3dd 100644 --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -140,8 +140,6 @@ struct pv_cpu_ops { void (*load_sp0)(unsigned long sp0); - void (*set_iopl_mask)(unsigned mask); - void (*wbinvd)(void); /* cpuid emulation, mostly so that caps bits can be disabled */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index b0e02aa3f46a..1387d31c5e07 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -516,10 +516,10 @@ struct thread_struct { struct io_bitmap *io_bitmap; /* - * IOPL. Priviledge level dependent I/O permission which includes - * user space CLI/STI when granted. + * IOPL. Priviledge level dependent I/O permission which is + * emulated via the I/O bitmap to prevent user space from disabling + * interrupts. */ - unsigned long iopl; unsigned long iopl_emul; mm_segment_t addr_limit; @@ -552,25 +552,6 @@ static inline void arch_thread_struct_whitelist(unsigned long *offset, */ #define TS_COMPAT 0x0002 /* 32bit syscall active (64BIT)*/ -/* - * Set IOPL bits in EFLAGS from given mask - */ -static inline void native_set_iopl_mask(unsigned mask) -{ -#ifdef CONFIG_X86_32 - unsigned int reg; - - asm volatile ("pushfl;" - "popl %0;" - "andl %1, %0;" - "orl %2, %0;" - "pushl %0;" - "popfl" - : "=&r" (reg) - : "i" (~X86_EFLAGS_IOPL), "r" (mask)); -#endif -} - static inline void native_load_sp0(unsigned long sp0) { @@ -610,7 +591,6 @@ static inline void load_sp0(unsigned long sp0) native_load_sp0(sp0); } -#define set_iopl_mask native_set_iopl_mask #endif /* CONFIG_PARAVIRT_XXL */ /* Free all resources held by a thread. */ diff --git a/arch/x86/include/asm/xen/hypervisor.h b/arch/x86/include/asm/xen/hypervisor.h index 42e1245af0d8..ff4b52e37e60 100644 --- a/arch/x86/include/asm/xen/hypervisor.h +++ b/arch/x86/include/asm/xen/hypervisor.h @@ -62,6 +62,4 @@ void xen_arch_register_cpu(int num); void xen_arch_unregister_cpu(int num); #endif -extern void xen_set_iopl_mask(unsigned mask); - #endif /* _ASM_X86_XEN_HYPERVISOR_H */ diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c index 9ed9458e02df..d5dcde972c42 100644 --- a/arch/x86/kernel/ioport.c +++ b/arch/x86/kernel/ioport.c @@ -153,28 +153,23 @@ SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on) /* * The sys_iopl functionality depends on the level argument, which if - * granted for the task is used by the CPU to check I/O instruction and - * CLI/STI against the current priviledge level (CPL). If CPL is less than - * or equal the tasks IOPL level the instructions take effect. If not a #GP - * is raised. The default IOPL is 0, i.e. no permissions. + * granted for the task is used to enable access to all 65536 I/O ports. * - * Setting IOPL to level 0-2 is disabling the userspace access. Only level - * 3 enables it. If set it allows the user space thread: + * This does not use the IOPL mechanism provided by the CPU as that would + * also allow the user space task to use the CLI/STI instructions. * - * - Unrestricted access to all 65535 I/O ports - * - The usage of CLI/STI instructions + * Disabling interrupts in a user space task is dangerous as it might lock + * up the machine and the semantics vs. syscalls and exceptions is + * undefined. * - * The advantage over ioperm is that the context switch does not require to - * update the I/O bitmap which is especially true when a large number of - * ports is accessed. But the allowance of CLI/STI in userspace is - * considered a major problem. + * Setting IOPL to level 0-2 is disabling I/O permissions. Level 3 + * 3 enables them. * * IOPL is strictly per thread and inherited on fork. */ SYSCALL_DEFINE1(iopl, unsigned int, level) { struct thread_struct *t = ¤t->thread; - struct pt_regs *regs = current_pt_regs(); unsigned int old; /* @@ -187,10 +182,7 @@ SYSCALL_DEFINE1(iopl, unsigned int, level) if (level > 3) return -EINVAL; - if (IS_ENABLED(CONFIG_X86_IOPL_EMULATION)) - old = t->iopl_emul; - else - old = t->iopl >> X86_EFLAGS_IOPL_BIT; + old = t->iopl_emul; /* No point in going further if nothing changes */ if (level == old) @@ -203,25 +195,8 @@ SYSCALL_DEFINE1(iopl, unsigned int, level) return -EPERM; } - if (IS_ENABLED(CONFIG_X86_IOPL_EMULATION)) { - t->iopl_emul = level; - task_update_io_bitmap(); - } else { - /* - * Change the flags value on the return stack, which has - * been set up on system-call entry. See also the fork and - * signal handling code how this is handled. - */ - regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | - (level << X86_EFLAGS_IOPL_BIT); - /* Store the new level in the thread struct */ - t->iopl = level << X86_EFLAGS_IOPL_BIT; - /* - * X86_32 switches immediately and XEN handles it via - * emulation. - */ - set_iopl_mask(t->iopl); - } + t->iopl_emul = level; + task_update_io_bitmap(); return 0; } diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c index 59d3d2763a9e..789f5e4f89de 100644 --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -341,8 +341,6 @@ struct paravirt_patch_template pv_ops = { .cpu.iret = native_iret, .cpu.swapgs = native_swapgs, - .cpu.set_iopl_mask = native_set_iopl_mask, - .cpu.start_context_switch = paravirt_nop, .cpu.end_context_switch = paravirt_nop, diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 6c7d90527156..323499f48858 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -187,15 +187,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) */ load_TLS(next, cpu); - /* - * Restore IOPL if needed. In normal use, the flags restore - * in the switch assembly will handle this. But if the kernel - * is running virtualized at a non-zero CPL, the popf will - * not restore flags, so it must be done in a separate step. - */ - if (get_kernel_rpl() && unlikely(prev->iopl != next->iopl)) - set_iopl_mask(next->iopl); - switch_to_extra(prev_p, next_p); /* diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index e93a1b8fd7f9..506d66830d4d 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -497,17 +497,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) switch_to_extra(prev_p, next_p); -#ifdef CONFIG_XEN_PV - /* - * On Xen PV, IOPL bits in pt_regs->flags have no effect, and - * current_pt_regs()->flags may not match the current task's - * intended IOPL. We need to switch it manually. - */ - if (unlikely(static_cpu_has(X86_FEATURE_XENPV) && - prev->iopl != next->iopl)) - xen_set_iopl_mask(next->iopl); -#endif - if (static_cpu_has_bug(X86_BUG_SYSRET_SS_ATTRS)) { /* * AMD CPUs have a misfeature: SYSRET sets the SS selector but diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c index 5bfea374a160..ae4a41ca19f6 100644 --- a/arch/x86/xen/enlighten_pv.c +++ b/arch/x86/xen/enlighten_pv.c @@ -837,15 +837,6 @@ static void xen_load_sp0(unsigned long sp0) this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0); } -void xen_set_iopl_mask(unsigned mask) -{ - struct physdev_set_iopl set_iopl; - - /* Force the change at ring 0. */ - set_iopl.iopl = (mask == 0) ? 1 : (mask >> 12) & 3; - HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl); -} - static void xen_io_delay(void) { } @@ -1055,7 +1046,6 @@ static const struct pv_cpu_ops xen_cpu_ops __initconst = { .write_idt_entry = xen_write_idt_entry, .load_sp0 = xen_load_sp0, - .set_iopl_mask = xen_set_iopl_mask, .io_delay = xen_io_delay, /* Xen takes care of %gs when switching to usermode for us */ |
