x86, um: ... and asm-x86 move

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 208 insertions, 0 deletions

diff --git a/arch/x86/include/asm/vm86.h b/arch/x86/include/asm/vm86.h
new file mode 100644
index 000000000000..998bd18eb737
--- /dev/null
+++ b/arch/x86/include/asm/vm86.h
@@ -0,0 +1,208 @@
+#ifndef ASM_X86__VM86_H
+#define ASM_X86__VM86_H
+
+/*
+ * I'm guessing at the VIF/VIP flag usage, but hope that this is how
+ * the Pentium uses them. Linux will return from vm86 mode when both
+ * VIF and VIP is set.
+ *
+ * On a Pentium, we could probably optimize the virtual flags directly
+ * in the eflags register instead of doing it "by hand" in vflags...
+ *
+ * Linus
+ */
+
+#include <asm/processor-flags.h>
+
+#define BIOSSEG         0x0f000
+
+#define CPU_086         0
+#define CPU_186         1
+#define CPU_286         2
+#define CPU_386         3
+#define CPU_486         4
+#define CPU_586         5
+
+/*
+ * Return values for the 'vm86()' system call
+ */
+#define VM86_TYPE(retval)       ((retval) & 0xff)
+#define VM86_ARG(retval)        ((retval) >> 8)
+
+#define VM86_SIGNAL     0       /* return due to signal */
+#define VM86_UNKNOWN    1       /* unhandled GP fault
+                                   - IO-instruction or similar */
+#define VM86_INTx       2       /* int3/int x instruction (ARG = x) */
+#define VM86_STI        3       /* sti/popf/iret instruction enabled
+                                   virtual interrupts */
+
+/*
+ * Additional return values when invoking new vm86()
+ */
+#define VM86_PICRETURN  4       /* return due to pending PIC request */
+#define VM86_TRAP       6       /* return due to DOS-debugger request */
+
+/*
+ * function codes when invoking new vm86()
+ */
+#define VM86_PLUS_INSTALL_CHECK 0
+#define VM86_ENTER              1
+#define VM86_ENTER_NO_BYPASS    2
+#define VM86_REQUEST_IRQ        3
+#define VM86_FREE_IRQ           4
+#define VM86_GET_IRQ_BITS       5
+#define VM86_GET_AND_RESET_IRQ  6
+
+/*
+ * This is the stack-layout seen by the user space program when we have
+ * done a translation of "SAVE_ALL" from vm86 mode. The real kernel layout
+ * is 'kernel_vm86_regs' (see below).
+ */
+
+struct vm86_regs {
+/*
+ * normal regs, with special meaning for the segment descriptors..
+ */
+        long ebx;
+        long ecx;
+        long edx;
+        long esi;
+        long edi;
+        long ebp;
+        long eax;
+        long __null_ds;
+        long __null_es;
+        long __null_fs;
+        long __null_gs;
+        long orig_eax;
+        long eip;
+        unsigned short cs, __csh;
+        long eflags;
+        long esp;
+        unsigned short ss, __ssh;
+/*
+ * these are specific to v86 mode:
+ */
+        unsigned short es, __esh;
+        unsigned short ds, __dsh;
+        unsigned short fs, __fsh;
+        unsigned short gs, __gsh;
+};
+
+struct revectored_struct {
+        unsigned long __map[8];                 /* 256 bits */
+};
+
+struct vm86_struct {
+        struct vm86_regs regs;
+        unsigned long flags;
+        unsigned long screen_bitmap;
+        unsigned long cpu_type;
+        struct revectored_struct int_revectored;
+        struct revectored_struct int21_revectored;
+};
+
+/*
+ * flags masks
+ */
+#define VM86_SCREEN_BITMAP      0x0001
+
+struct vm86plus_info_struct {
+        unsigned long force_return_for_pic:1;
+        unsigned long vm86dbg_active:1;       /* for debugger */
+        unsigned long vm86dbg_TFpendig:1;     /* for debugger */
+        unsigned long unused:28;
+        unsigned long is_vm86pus:1;           /* for vm86 internal use */
+        unsigned char vm86dbg_intxxtab[32];   /* for debugger */
+};
+struct vm86plus_struct {
+        struct vm86_regs regs;
+        unsigned long flags;
+        unsigned long screen_bitmap;
+        unsigned long cpu_type;
+        struct revectored_struct int_revectored;
+        struct revectored_struct int21_revectored;
+        struct vm86plus_info_struct vm86plus;
+};
+
+#ifdef __KERNEL__
+
+#include <asm/ptrace.h>
+
+/*
+ * This is the (kernel) stack-layout when we have done a "SAVE_ALL" from vm86
+ * mode - the main change is that the old segment descriptors aren't
+ * useful any more and are forced to be zero by the kernel (and the
+ * hardware when a trap occurs), and the real segment descriptors are
+ * at the end of the structure. Look at ptrace.h to see the "normal"
+ * setup. For user space layout see 'struct vm86_regs' above.
+ */
+
+struct kernel_vm86_regs {
+/*
+ * normal regs, with special meaning for the segment descriptors..
+ */
+        struct pt_regs pt;
+/*
+ * these are specific to v86 mode:
+ */
+        unsigned short es, __esh;
+        unsigned short ds, __dsh;
+        unsigned short fs, __fsh;
+        unsigned short gs, __gsh;
+};
+
+struct kernel_vm86_struct {
+        struct kernel_vm86_regs regs;
+/*
+ * the below part remains on the kernel stack while we are in VM86 mode.
+ * 'tss.esp0' then contains the address of VM86_TSS_ESP0 below, and when we
+ * get forced back from VM86, the CPU and "SAVE_ALL" will restore the above
+ * 'struct kernel_vm86_regs' with the then actual values.
+ * Therefore, pt_regs in fact points to a complete 'kernel_vm86_struct'
+ * in kernelspace, hence we need not reget the data from userspace.
+ */
+#define VM86_TSS_ESP0 flags
+        unsigned long flags;
+        unsigned long screen_bitmap;
+        unsigned long cpu_type;
+        struct revectored_struct int_revectored;
+        struct revectored_struct int21_revectored;
+        struct vm86plus_info_struct vm86plus;
+        struct pt_regs *regs32;   /* here we save the pointer to the old regs */
+/*
+ * The below is not part of the structure, but the stack layout continues
+ * this way. In front of 'return-eip' may be some data, depending on
+ * compilation, so we don't rely on this and save the pointer to 'oldregs'
+ * in 'regs32' above.
+ * However, with GCC-2.7.2 and the current CFLAGS you see exactly this:
+
+        long return-eip;        from call to vm86()
+        struct pt_regs oldregs;  user space registers as saved by syscall
+ */
+};
+
+#ifdef CONFIG_VM86
+
+void handle_vm86_fault(struct kernel_vm86_regs *, long);
+int handle_vm86_trap(struct kernel_vm86_regs *, long, int);
+struct pt_regs *save_v86_state(struct kernel_vm86_regs *);
+
+struct task_struct;
+void release_vm86_irqs(struct task_struct *);
+
+#else
+
+#define handle_vm86_fault(a, b)
+#define release_vm86_irqs(a)
+
+static inline int handle_vm86_trap(struct kernel_vm86_regs *a, long b, int c)
+{
+        return 0;
+}
+
+#endif /* CONFIG_VM86 */
+
+#endif /* __KERNEL__ */
+
+#endif /* ASM_X86__VM86_H */