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>

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 1f926e396ec1c90486557f4d4d7c0e57931edbe1..b162ce1482fcbe030a26c3ab7ed583ba43e47378 100644 (file)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1254,10 +1254,13 @@ config X86_VSYSCALL_EMULATION
         Disabling this option saves about 7K of kernel size and
         possibly 4K of additional runtime pagetable memory.
 
-config X86_IOPL_EMULATION
-       bool "IOPL Emulation"
+config X86_IOPL_IOPERM
+       bool "IOPERM and IOPL Emulation"
        default y
        ---help---
+         This enables the ioperm() and iopl() syscalls which are necessary
+         for legacy applications.
+
          Legacy IOPL support is an overbroad mechanism which allows user
          space aside of accessing all 65536 I/O ports also to disable
          interrupts. To gain this access the caller needs CAP_SYS_RAWIO

diff --git a/arch/x86/include/asm/io_bitmap.h b/arch/x86/include/asm/io_bitmap.h
index b664baadf736b542b58655b3b4e00dc4d5e23e80..02c6ef8f7667725b2730e049a2a51d78caec650e 100644 (file)
--- a/arch/x86/include/asm/io_bitmap.h
+++ b/arch/x86/include/asm/io_bitmap.h
@@ -15,9 +15,15 @@ struct io_bitmap {
 
 struct task_struct;
 
+#ifdef CONFIG_X86_IOPL_IOPERM
 void io_bitmap_share(struct task_struct *tsk);
 void io_bitmap_exit(void);
 
 void tss_update_io_bitmap(void);
+#else
+static inline void io_bitmap_share(struct task_struct *tsk) { }
+static inline void io_bitmap_exit(void) { }
+static inline void tss_update_io_bitmap(void) { }
+#endif
 
 #endif

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 1387d31c5e07765ae4816b34e9dcda8a877b5817..45f416a2c1f13e89cd0754b75ed4d8613289ae96 100644 (file)
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -340,13 +340,18 @@ struct x86_hw_tss {
        (offsetof(struct tss_struct, io_bitmap.mapall) -        \
         offsetof(struct tss_struct, x86_tss))
 
+#ifdef CONFIG_X86_IOPL_IOPERM
 /*
  * sizeof(unsigned long) coming from an extra "long" at the end of the
  * iobitmap. The limit is inclusive, i.e. the last valid byte.
  */
-#define __KERNEL_TSS_LIMIT     \
+# define __KERNEL_TSS_LIMIT    \
        (IO_BITMAP_OFFSET_VALID_ALL + IO_BITMAP_BYTES + \
         sizeof(unsigned long) - 1)
+#else
+# define __KERNEL_TSS_LIMIT    \
+       (offsetof(struct tss_struct, x86_tss) + sizeof(struct x86_hw_tss) - 1)
+#endif
 
 /* Base offset outside of TSS_LIMIT so unpriviledged IO causes #GP */
 #define IO_BITMAP_OFFSET_INVALID       (__KERNEL_TSS_LIMIT + 1)
@@ -398,7 +403,9 @@ struct tss_struct {
         */
        struct x86_hw_tss       x86_tss;
 
+#ifdef CONFIG_X86_IOPL_IOPERM
        struct x86_io_bitmap    io_bitmap;
+#endif
 } __aligned(PAGE_SIZE);
 
 DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw);

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 0accf44878a5b74861fcbe71248c377e442dc2f4..d779366ce3f89f161c977e7fad5389659108a1bd 100644 (file)
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -156,8 +156,13 @@ struct thread_info {
 # define _TIF_WORK_CTXSW       (_TIF_WORK_CTXSW_BASE)
 #endif
 
-#define _TIF_WORK_CTXSW_PREV   (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \
+#ifdef CONFIG_X86_IOPL_IOPERM
+# define _TIF_WORK_CTXSW_PREV  (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY | \
                                 _TIF_IO_BITMAP)
+#else
+# define _TIF_WORK_CTXSW_PREV  (_TIF_WORK_CTXSW| _TIF_USER_RETURN_NOTIFY)
+#endif
+
 #define _TIF_WORK_CTXSW_NEXT   (_TIF_WORK_CTXSW)
 
 #define STACK_WARN             (THREAD_SIZE/8)

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 7bf402be13bb18019cd78d044a15a44420407802..6f6ca6bd58d6b2ded6aa0fc5702aec231d12bde9 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1804,6 +1804,22 @@ static inline void gdt_setup_doublefault_tss(int cpu)
 }
 #endif /* !CONFIG_X86_64 */
 
+static inline void tss_setup_io_bitmap(struct tss_struct *tss)
+{
+       tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;
+
+#ifdef CONFIG_X86_IOPL_IOPERM
+       tss->io_bitmap.prev_max = 0;
+       tss->io_bitmap.prev_sequence = 0;
+       memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap));
+       /*
+        * Invalidate the extra array entry past the end of the all
+        * permission bitmap as required by the hardware.
+        */
+       tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL;
+#endif
+}
+
 /*
  * cpu_init() initializes state that is per-CPU. Some data is already
  * initialized (naturally) in the bootstrap process, such as the GDT
@@ -1860,15 +1876,7 @@ 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;
-       tss->io_bitmap.prev_sequence = 0;
-       memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap));
-       /*
-        * Invalidate the extra array entry past the end of the all
-        * permission bitmap as required by the hardware.
-        */
-       tss->io_bitmap.mapall[IO_BITMAP_LONGS] = ~0UL;
+       tss_setup_io_bitmap(tss);
        set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
 
        load_TR_desc();

diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index d5dcde972c4274163ec267a996292882a5fa8711..8abeee0dd7bfeb769621605350dd5e6992a0241f 100644 (file)
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -14,6 +14,8 @@
 #include <asm/io_bitmap.h>
 #include <asm/desc.h>
 
+#ifdef CONFIG_X86_IOPL_IOPERM
+
 static atomic64_t io_bitmap_sequence;
 
 void io_bitmap_share(struct task_struct *tsk)
@@ -172,13 +174,6 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)
        struct thread_struct *t = &current->thread;
        unsigned int old;
 
-       /*
-        * Careful: the IOPL bits in regs->flags are undefined under Xen PV
-        * and changing them has no effect.
-        */
-       if (IS_ENABLED(CONFIG_X86_IOPL_NONE))
-               return -ENOSYS;
-
        if (level > 3)
                return -EINVAL;
 
@@ -200,3 +195,20 @@ SYSCALL_DEFINE1(iopl, unsigned int, level)
 
        return 0;
 }
+
+#else /* CONFIG_X86_IOPL_IOPERM */
+
+long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
+{
+       return -ENOSYS;
+}
+SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on)
+{
+       return -ENOSYS;
+}
+
+SYSCALL_DEFINE1(iopl, unsigned int, level)
+{
+       return -ENOSYS;
+}
+#endif

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 8a844a5d5ae801da1b7350ea680363ed89e2dd8b..7964d7db936654b6981838603f955796d68998e2 100644 (file)
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -322,6 +322,7 @@ void arch_setup_new_exec(void)
        }
 }
 
+#ifdef CONFIG_X86_IOPL_IOPERM
 static inline void tss_invalidate_io_bitmap(struct tss_struct *tss)
 {
        /*
@@ -409,6 +410,9 @@ void tss_update_io_bitmap(void)
                tss_invalidate_io_bitmap(tss);
        }
 }
+#else /* CONFIG_X86_IOPL_IOPERM */
+static inline void switch_to_bitmap(unsigned long tifp) { }
+#endif
 
 #ifdef CONFIG_SMP