uml: throw out CONFIG_MODE_TT

This patchset throws out tt mode, which has been non-functional for a while.

This is done in phases, interspersed with code cleanups on the affected files.

The removal is done as follows:
	remove all code, config options, and files which depend on
CONFIG_MODE_TT
	get rid of the CHOOSE_MODE macro, which decided whether to
call tt-mode or skas-mode code, and replace invocations with their
skas portions
	replace all now-trivial procedures with their skas equivalents

There are now a bunch of now-redundant pieces of data structures, including
mode-specific pieces of the thread structure, pt_regs, and mm_context.  These
are all replaced with their skas-specific contents.

As part of the ongoing style compliance project, I made a style pass over all
files that were changed.  There are three such patches, one for each phase,
covering the files affected by that phase but no later ones.

I noticed that we weren't freeing the LDT state associated with a process when
it exited, so that's fixed in one of the later patches.

The last patch is a tidying patch which I've had for a while, but which caused
inexplicable crashes under tt mode.  Since that is no longer a problem, this
can now go in.

This patch:

Start getting rid of tt mode support.

This patch throws out CONFIG_MODE_TT and all config options, code, and files
which depend on it.

CONFIG_MODE_SKAS is gone and everything that depends on it is included
unconditionally.

The few changed lines are in re-written Kconfig help, lines which needed
something skas-related removed from them, and a few more which weren't
strictly deletions.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

7 files changed, 2 insertions, 380 deletions

diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile
index a4618b6b85b9..94b6ede5ef6c 100644
--- a/arch/um/sys-i386/Makefile
+++ b/arch/um/sys-i386/Makefile
@@ -1,8 +1,6 @@
 obj-y = bug.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
-        ptrace_user.o setjmp.o signal.o sigcontext.o syscalls.o sysrq.o \
-        sys_call_table.o tls.o
-
-obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
+        ptrace_user.o setjmp.o signal.o sigcontext.o stub.o stub_segv.o \
+        syscalls.o sysrq.o sys_call_table.o tls.o
 
 subarch-obj-y = lib/bitops_32.o lib/semaphore_32.o lib/string_32.o
 subarch-obj-$(CONFIG_HIGHMEM) += mm/highmem_32.o
@@ -13,11 +11,7 @@ USER_OBJS := bugs.o ptrace_user.o sigcontext.o fault.o
 USER_OBJS += user-offsets.s
 extra-y += user-offsets.s
 
-extra-$(CONFIG_MODE_TT) += unmap.o
-
 UNPROFILE_OBJS := stub_segv.o
 CFLAGS_stub_segv.o := $(CFLAGS_NO_HARDENING)
 
 include arch/um/scripts/Makefile.rules
-
-$(obj)/unmap.%: _c_flags = $(call unprofile,$(CFLAGS))
diff --git a/arch/um/sys-i386/ldt.c b/arch/um/sys-i386/ldt.c
index a939a7ef0227..762a12aec757 100644
--- a/arch/um/sys-i386/ldt.c
+++ b/arch/um/sys-i386/ldt.c
@@ -19,72 +19,6 @@
 
 extern int modify_ldt(int func, void *ptr, unsigned long bytecount);
 
-#ifdef CONFIG_MODE_TT
-
-static long do_modify_ldt_tt(int func, void __user *ptr,
-                              unsigned long bytecount)
-{
-        struct user_desc info;
-        int res = 0;
-        void *buf = NULL;
-        void *p = NULL; /* What we pass to host. */
-
-        switch(func){
-        case 1:
-        case 0x11: /* write_ldt */
-                /* Do this check now to avoid overflows. */
-                if (bytecount != sizeof(struct user_desc)) {
-                        res = -EINVAL;
-                        goto out;
-                }
-
-                if(copy_from_user(&info, ptr, sizeof(info))) {
-                        res = -EFAULT;
-                        goto out;
-                }
-
-                p = &info;
-                break;
-        case 0:
-        case 2: /* read_ldt */
-
-                /* The use of info avoids kmalloc on the write case, not on the
-                 * read one. */
-                buf = kmalloc(bytecount, GFP_KERNEL);
-                if (!buf) {
-                        res = -ENOMEM;
-                        goto out;
-                }
-                p = buf;
-                break;
-        default:
-                res = -ENOSYS;
-                goto out;
-        }
-
-        res = modify_ldt(func, p, bytecount);
-        if(res < 0)
-                goto out;
-
-        switch(func){
-        case 0:
-        case 2:
-                /* Modify_ldt was for reading and returned the number of read
-                 * bytes.*/
-                if(copy_to_user(ptr, p, res))
-                        res = -EFAULT;
-                break;
-        }
-
-out:
-        kfree(buf);
-        return res;
-}
-
-#endif
-
-#ifdef CONFIG_MODE_SKAS
-
 #include "skas.h"
 #include "skas_ptrace.h"
 #include "asm/mmu_context.h"
@@ -569,7 +503,6 @@ void free_ldt(struct mmu_context_skas * mm)
         }
         mm->ldt.entry_count = 0;
 }
-#endif
 
 int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
 {
diff --git a/arch/um/sys-i386/ptrace.c b/arch/um/sys-i386/ptrace.c
index 28bf01150323..572fd504b94b 100644
--- a/arch/um/sys-i386/ptrace.c
+++ b/arch/um/sys-i386/ptrace.c
@@ -14,12 +14,6 @@
 #include "sysdep/sigcontext.h"
 #include "sysdep/sc.h"
 
-void arch_switch_to_tt(struct task_struct *from, struct task_struct *to)
-{
-        update_debugregs(to->thread.arch.debugregs_seq);
-        arch_switch_tls_tt(from, to);
-}
-
 void arch_switch_to_skas(struct task_struct *from, struct task_struct *to)
 {
         int err = arch_switch_tls_skas(from, to);
@@ -233,79 +227,12 @@ static inline unsigned long twd_fxsr_to_i387( struct i387_fxsave_struct *fxsave
         return ret;
 }
 
-/*
- * FXSR floating point environment conversions.
- */
-
-#ifdef CONFIG_MODE_TT
-static inline int convert_fxsr_to_user_tt(struct _fpstate __user *buf,
-                                          struct pt_regs *regs)
-{
-        struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
-        unsigned long env[7];
-        struct _fpreg __user *to;
-        struct _fpxreg *from;
-        int i;
-
-        env[0] = (unsigned long)fxsave->cwd | 0xffff0000;
-        env[1] = (unsigned long)fxsave->swd | 0xffff0000;
-        env[2] = twd_fxsr_to_i387(fxsave);
-        env[3] = fxsave->fip;
-        env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16);
-        env[5] = fxsave->foo;
-        env[6] = fxsave->fos;
-
-        if ( __copy_to_user( buf, env, 7 * sizeof(unsigned long) ) )
-                return 1;
-
-        to = &buf->_st[0];
-        from = (struct _fpxreg *) &fxsave->st_space[0];
-        for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
-                if ( __copy_to_user( to, from, sizeof(*to) ) )
-                        return 1;
-        }
-        return 0;
-}
-#endif
-
 static inline int convert_fxsr_to_user(struct _fpstate __user *buf,
                                        struct pt_regs *regs)
 {
         return(CHOOSE_MODE(convert_fxsr_to_user_tt(buf, regs), 0));
 }
 
-#ifdef CONFIG_MODE_TT
-static inline int convert_fxsr_from_user_tt(struct pt_regs *regs,
-                                            struct _fpstate __user *buf)
-{
-        struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
-        unsigned long env[7];
-        struct _fpxreg *to;
-        struct _fpreg __user *from;
-        int i;
-
-        if ( __copy_from_user( env, buf, 7 * sizeof(long) ) )
-                return 1;
-
-        fxsave->cwd = (unsigned short)(env[0] & 0xffff);
-        fxsave->swd = (unsigned short)(env[1] & 0xffff);
-        fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff));
-        fxsave->fip = env[3];
-        fxsave->fop = (unsigned short)((env[4] & 0xffff0000) >> 16);
-        fxsave->fcs = (env[4] & 0xffff);
-        fxsave->foo = env[5];
-        fxsave->fos = env[6];
-
-        to = (struct _fpxreg *) &fxsave->st_space[0];
-        from = &buf->_st[0];
-        for ( i = 0 ; i < 8 ; i++, to++, from++ ) {
-                if ( __copy_from_user( to, from, sizeof(*from) ) )
-                        return 1;
-        }
-        return 0;
-}
-#endif
-
 static inline int convert_fxsr_from_user(struct pt_regs *regs, 
                                          struct _fpstate __user *buf)
 {
@@ -332,39 +259,11 @@ int set_fpregs(unsigned long buf, struct task_struct *child)
         else return(0);
 }
 
-#ifdef CONFIG_MODE_TT
-int get_fpxregs_tt(unsigned long buf, struct task_struct *tsk)
-{
-        struct pt_regs *regs = &tsk->thread.regs;
-        struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
-        int err;
-
-        err = __copy_to_user((void __user *) buf, fxsave,
-                             sizeof(struct user_fxsr_struct));
-        if(err) return -EFAULT;
-        else return 0;
-}
-#endif
-
 int get_fpxregs(unsigned long buf, struct task_struct *tsk)
 {
         return(CHOOSE_MODE(get_fpxregs_tt(buf, tsk), 0));
 }
 
-#ifdef CONFIG_MODE_TT
-int set_fpxregs_tt(unsigned long buf, struct task_struct *tsk)
-{
-        struct pt_regs *regs = &tsk->thread.regs;
-        struct i387_fxsave_struct *fxsave = SC_FXSR_ENV(PT_REGS_SC(regs));
-        int err;
-
-        err = __copy_from_user(fxsave, (void __user *) buf,
-                               sizeof(struct user_fxsr_struct) );
-        if(err) return -EFAULT;
-        else return 0;
-}
-#endif
-
 int set_fpxregs(unsigned long buf, struct task_struct *tsk)
 {
         return(CHOOSE_MODE(set_fpxregs_tt(buf, tsk), 0));
@@ -387,25 +286,6 @@ int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 }
 #endif
 
-#ifdef CONFIG_MODE_TT
-static inline void copy_fpu_fxsave_tt(struct pt_regs *regs,
-                                      struct user_i387_struct *buf)
-{
-        struct i387_fxsave_struct *fpu = SC_FXSR_ENV(PT_REGS_SC(regs));
-        unsigned short *to;
-        unsigned short *from;
-        int i;
-
-        memcpy( buf, fpu, 7 * sizeof(long) );
-
-        to = (unsigned short *) &buf->st_space[0];
-        from = (unsigned short *) &fpu->st_space[0];
-        for ( i = 0 ; i < 8 ; i++, to += 5, from += 8 ) {
-                memcpy( to, from, 5 * sizeof(unsigned short) );
-        }
-}
-#endif
-
 static inline void copy_fpu_fxsave(struct pt_regs *regs,
                                    struct user_i387_struct *buf)
 {
diff --git a/arch/um/sys-i386/ptrace_user.c b/arch/um/sys-i386/ptrace_user.c
index 40ff0c831bd0..b68dd230e646 100644
--- a/arch/um/sys-i386/ptrace_user.c
+++ b/arch/um/sys-i386/ptrace_user.c
@@ -43,89 +43,3 @@ int ptrace_setfpregs(long pid, unsigned long *regs)
                 return -errno;
         return 0;
 }
-
-#ifdef UML_CONFIG_MODE_TT
-
-static void write_debugregs(int pid, unsigned long *regs)
-{
-        struct user *dummy;
-        int nregs, i;
-
-        dummy = NULL;
-        nregs = ARRAY_SIZE(dummy->u_debugreg);
-        for(i = 0; i < nregs; i++){
-                if((i == 4) || (i == 5)) continue;
-                if(ptrace(PTRACE_POKEUSR, pid, &dummy->u_debugreg[i],
-                          regs[i]) < 0)
-                        printk("write_debugregs - ptrace failed on "
-                               "register %d, value = 0x%lx, errno = %d\n", i,
-                               regs[i], errno);
-        }
-}
-
-static void read_debugregs(int pid, unsigned long *regs)
-{
-        struct user *dummy;
-        int nregs, i;
-
-        dummy = NULL;
-        nregs = ARRAY_SIZE(dummy->u_debugreg);
-        for(i = 0; i < nregs; i++){
-                regs[i] = ptrace(PTRACE_PEEKUSR, pid,
-                                 &dummy->u_debugreg[i], 0);
-        }
-}
-
-/* Accessed only by the tracing thread */
-static unsigned long kernel_debugregs[8] = { [ 0 ... 7 ] = 0 };
-
-void arch_enter_kernel(void *task, int pid)
-{
-        read_debugregs(pid, TASK_DEBUGREGS(task));
-        write_debugregs(pid, kernel_debugregs);
-}
-
-void arch_leave_kernel(void *task, int pid)
-{
-        read_debugregs(pid, kernel_debugregs);
-        write_debugregs(pid, TASK_DEBUGREGS(task));
-}
-
-#ifdef UML_CONFIG_PT_PROXY
-/* Accessed only by the tracing thread */
-static int debugregs_seq;
-
-/* Only called by the ptrace proxy */
-void ptrace_pokeuser(unsigned long addr, unsigned long data)
-{
-        if((addr < offsetof(struct user, u_debugreg[0])) ||
-           (addr > offsetof(struct user, u_debugreg[7])))
-                return;
-        addr -= offsetof(struct user, u_debugreg[0]);
-        addr = addr >> 2;
-        if(kernel_debugregs[addr] == data) return;
-
-        kernel_debugregs[addr] = data;
-        debugregs_seq++;
-}
-
-static void update_debugregs_cb(void *arg)
-{
-        int pid = *((int *) arg);
-
-        write_debugregs(pid, kernel_debugregs);
-}
-
-/* Optimized out in its header when not defined */
-void update_debugregs(int seq)
-{
-        int me;
-
-        if(seq == debugregs_seq) return;
-
-        me = os_getpid();
-        initial_thread_cb(update_debugregs_cb, &me);
-}
-#endif
-
-#endif
diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c
index 1cbf95f6858a..187ea27536bd 100644
--- a/arch/um/sys-i386/signal.c
+++ b/arch/um/sys-i386/signal.c
@@ -13,9 +13,6 @@
 #include "sigcontext.h"
 #include "registers.h"
 #include "mode.h"
-
-#ifdef CONFIG_MODE_SKAS
-
 #include "skas.h"
 
 void copy_sc(union uml_pt_regs *regs, void *from)
@@ -108,61 +105,6 @@ int copy_sc_to_user_skas(struct sigcontext __user *to, struct _fpstate __user *t
         return copy_to_user(to, &sc, sizeof(sc)) ||
                copy_to_user(to_fp, fpregs, sizeof(fpregs));
 }
-#endif
-
-#ifdef CONFIG_MODE_TT
-
-/* These copy a sigcontext to/from userspace.  They copy the fpstate pointer,
- * blowing away the old, good one.  So, that value is saved, and then restored
- * after the sigcontext copy.  In copy_from, the variable holding the saved
- * fpstate pointer, and the sigcontext that it should be restored to are both
- * in the kernel, so we can just restore using an assignment.  In copy_to, the
- * saved pointer is in the kernel, but the sigcontext is in userspace, so we
- * copy_to_user it.
- */
-int copy_sc_from_user_tt(struct sigcontext *to, struct sigcontext __user *from,
-                         int fpsize)
-{
-        struct _fpstate *to_fp;
-        struct _fpstate __user *from_fp;
-        unsigned long sigs;
-        int err;
-
-        to_fp = to->fpstate;
-        sigs = to->oldmask;
-        err = copy_from_user(to, from, sizeof(*to));
-        from_fp = to->fpstate;
-        to->oldmask = sigs;
-        to->fpstate = to_fp;
-        if(to_fp != NULL)
-                err |= copy_from_user(to_fp, from_fp, fpsize);
-        return err;
-}
-
-int copy_sc_to_user_tt(struct sigcontext __user *to, struct _fpstate __user *fp,
-                       struct sigcontext *from, int fpsize, unsigned long sp)
-{
-        struct _fpstate __user *to_fp;
-        struct _fpstate *from_fp;
-        int err;
-
-        to_fp = (fp ? fp : (struct _fpstate __user *) (to + 1));
-        from_fp = from->fpstate;
-        err = copy_to_user(to, from, sizeof(*to));
-
-        /* The SP in the sigcontext is the updated one for the signal
-         * delivery.  The sp passed in is the original, and this needs
-         * to be restored, so we stick it in separately.
-         */
-        err |= copy_to_user(&SC_SP(to), &sp, sizeof(sp));
-
-        if(from_fp != NULL){
-                err |= copy_to_user(&to->fpstate, &to_fp, sizeof(to->fpstate));
-                err |= copy_to_user(to_fp, from_fp, fpsize);
-        }
-        return err;
-}
-#endif
 
 static int copy_sc_from_user(struct pt_regs *to, void __user *from)
 {
diff --git a/arch/um/sys-i386/tls.c b/arch/um/sys-i386/tls.c
index fea8e5e15cc4..0340b96d101b 100644
--- a/arch/um/sys-i386/tls.c
+++ b/arch/um/sys-i386/tls.c
@@ -18,10 +18,7 @@
 #include "mode_kern.h"
 #include "os.h"
 #include "mode.h"
-
-#ifdef CONFIG_MODE_SKAS
 #include "skas.h"
-#endif
 
 /*
  * If needed we can detect when it's uninitialized.
@@ -31,7 +28,6 @@
 static int host_supports_tls = -1;
 int host_gdt_entry_tls_min;
 
-#ifdef CONFIG_MODE_SKAS
 int do_set_thread_area_skas(struct user_desc *info)
 {
         int ret;
@@ -53,7 +49,6 @@ int do_get_thread_area_skas(struct user_desc *info)
         put_cpu();
         return ret;
 }
-#endif
 
 /*
  * sys_get_thread_area: get a yet unused TLS descriptor index.
@@ -187,17 +182,6 @@ int arch_switch_tls_skas(struct task_struct *from, struct task_struct *to)
         return 0;
 }
 
-int arch_switch_tls_tt(struct task_struct *from, struct task_struct *to)
-{
-        if (!host_supports_tls)
-                return 0;
-
-        if (needs_TLS_update(to))
-                return load_TLS(0, to);
-
-        return 0;
-}
-
 static int set_tls_entry(struct task_struct* task, struct user_desc *info,
                          int idx, int flushed)
 {
diff --git a/arch/um/sys-i386/unmap.c b/arch/um/sys-i386/unmap.c
deleted file mode 100644
index 1b0ad0e4adcd..000000000000
--- a/arch/um/sys-i386/unmap.c
+++ /dev/null
@@ -1,25 +0,0 @@
-/*
- * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
- * Licensed under the GPL
- */
-
-#include <linux/mman.h>
-#include <asm/unistd.h>
-
-static int errno;
-
-static inline _syscall2(int,munmap,void *,start,size_t,len)
-static inline _syscall6(void *,mmap2,void *,addr,size_t,len,int,prot,int,flags,int,fd,off_t,offset)
-int switcheroo(int fd, int prot, void *from, void *to, int size)
-{
-        if(munmap(to, size) < 0){
-                return(-1);
-        }
-        if(mmap2(to, size, prot, MAP_SHARED | MAP_FIXED, fd, 0) == (void*) -1 ){
-                return(-1);
-        }
-        if(munmap(from, size) < 0){
-                return(-1);
-        }
-        return(0);
-}