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>

8 files changed, 3 insertions, 136 deletions

diff --git a/arch/um/os-Linux/Makefile b/arch/um/os-Linux/Makefile
index f1bb58fe3207..1dbb45dfc49b 100644
--- a/arch/um/os-Linux/Makefile
+++ b/arch/um/os-Linux/Makefile
@@ -5,12 +5,7 @@
 
 obj-y = aio.o elf_aux.o execvp.o file.o helper.o irq.o main.o mem.o process.o \
         registers.o sigio.o signal.o start_up.o time.o trap.o tty.o uaccess.o \
-        umid.o tls.o user_syms.o util.o drivers/ sys-$(SUBARCH)/
-
-obj-$(CONFIG_MODE_SKAS) += skas/
-
-obj-$(CONFIG_MODE_TT) += tt.o
-user-objs-$(CONFIG_MODE_TT) += tt.o
+        umid.o tls.o user_syms.o util.o drivers/ sys-$(SUBARCH)/ skas/
 
 obj-$(CONFIG_TTY_LOG) += tty_log.o
 user-objs-$(CONFIG_TTY_LOG) += tty_log.o
diff --git a/arch/um/os-Linux/main.c b/arch/um/os-Linux/main.c
index 919c25be254a..425aa8960649 100644
--- a/arch/um/os-Linux/main.c
+++ b/arch/um/os-Linux/main.c
@@ -25,9 +25,6 @@
 #include "um_malloc.h"
 #include "kern_constants.h"
 
-/* Set in main, unchanged thereafter */
-char *linux_prog;
-
 #define PGD_BOUND (4 * 1024 * 1024)
 #define STACKSIZE (8 * 1024 * 1024)
 #define THREAD_NAME_LEN (256)
@@ -125,35 +122,6 @@ int __init main(int argc, char **argv, char **envp)
         char **new_argv;
         int ret, i, err;
 
-#ifdef UML_CONFIG_CMDLINE_ON_HOST
-        /* Allocate memory for thread command lines */
-        if(argc < 2 || strlen(argv[1]) < THREAD_NAME_LEN - 1){
-
-                char padding[THREAD_NAME_LEN] = {
-                        [ 0 ...  THREAD_NAME_LEN - 2] = ' ', '\0'
-                };
-
-                new_argv = malloc((argc + 2) * sizeof(char*));
-                if(!new_argv) {
-                        perror("Allocating extended argv");
-                        exit(1);
-                }
-
-                new_argv[0] = argv[0];
-                new_argv[1] = padding;
-
-                for(i = 2; i <= argc; i++)
-                        new_argv[i] = argv[i - 1];
-                new_argv[argc + 1] = NULL;
-
-                execvp(new_argv[0], new_argv);
-                perror("execing with extended args");
-                exit(1);
-        }
-#endif
-
-        linux_prog = argv[0];
-
         set_stklim();
 
         setup_env_path();
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index e9c143297512..d5fef4ce0112 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -133,13 +133,6 @@ void os_kill_ptraced_process(int pid, int reap_child)
                 CATCH_EINTR(waitpid(pid, NULL, 0));
 }
 
-#ifdef UML_CONFIG_MODE_TT
-void os_usr1_process(int pid)
-{
-        kill(pid, SIGUSR1);
-}
-#endif
-
 /* Don't use the glibc version, which caches the result in TLS. It misses some
  * syscalls, and also breaks with clone(), which does not unshare the TLS.
  */
@@ -239,30 +232,6 @@ out:
         return ok;
 }
 
-#ifdef UML_CONFIG_MODE_TT
-void init_new_thread_stack(void *sig_stack, void (*usr1_handler)(int))
-{
-        int flags = 0, pages;
-
-        if(sig_stack != NULL){
-                pages = (1 << UML_CONFIG_KERNEL_STACK_ORDER);
-                set_sigstack(sig_stack, pages * UM_KERN_PAGE_SIZE);
-                flags = SA_ONSTACK;
-        }
-        if(usr1_handler){
-                struct sigaction sa;
-
-                sa.sa_handler = usr1_handler;
-                sigemptyset(&sa.sa_mask);
-                sa.sa_flags = flags;
-                sa.sa_restorer = NULL;
-                if(sigaction(SIGUSR1, &sa, NULL) < 0)
-                        panic("init_new_thread_stack - sigaction failed - "
-                              "errno = %d\n", errno);
-        }
-}
-#endif
-
 void init_new_thread_signals(void)
 {
         set_handler(SIGSEGV, (__sighandler_t) sig_handler, SA_ONSTACK,
diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c
index f4f2981f74b9..acf52ea4ff52 100644
--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -35,12 +35,9 @@
 #include "mode.h"
 #include "tempfile.h"
 #include "kern_constants.h"
-
-#ifdef UML_CONFIG_MODE_SKAS
 #include "skas.h"
 #include "skas_ptrace.h"
 #include "registers.h"
-#endif
 
 static int ptrace_child(void *arg)
 {
@@ -407,7 +404,6 @@ __uml_setup("noptraceldt", noptraceldt_cmd_param,
 "    To support PTRACE_LDT, the host needs to be patched using\n"
 "    the current skas3 patch.\n\n");
 
-#ifdef UML_CONFIG_MODE_SKAS
 static inline void check_skas3_ptrace_faultinfo(void)
 {
         struct ptrace_faultinfo fi;
@@ -504,12 +500,6 @@ int can_do_skas(void)
 
         return 1;
 }
-#else
-int can_do_skas(void)
-{
-        return 0;
-}
-#endif
 
 int __init parse_iomem(char *str, int *add)
 {
diff --git a/arch/um/os-Linux/sys-i386/Makefile b/arch/um/os-Linux/sys-i386/Makefile
index 37806621b25d..dc7208f0b741 100644
--- a/arch/um/os-Linux/sys-i386/Makefile
+++ b/arch/um/os-Linux/sys-i386/Makefile
@@ -3,7 +3,7 @@
 # Licensed under the GPL
 #
 
-obj-$(CONFIG_MODE_SKAS) = registers.o signal.o tls.o
+obj-y = registers.o signal.o tls.o
 
 USER_OBJS := $(obj-y)
 
diff --git a/arch/um/os-Linux/sys-x86_64/Makefile b/arch/um/os-Linux/sys-x86_64/Makefile
index eac8c0db3001..a42a4ef02e1e 100644
--- a/arch/um/os-Linux/sys-x86_64/Makefile
+++ b/arch/um/os-Linux/sys-x86_64/Makefile
@@ -3,7 +3,7 @@
 # Licensed under the GPL
 #
 
-obj-$(CONFIG_MODE_SKAS) = registers.o prctl.o signal.o
+obj-y = registers.o prctl.o signal.o
 
 USER_OBJS := $(obj-y)
 
diff --git a/arch/um/os-Linux/time.c b/arch/um/os-Linux/time.c
index 5de169b168f6..5eb32d24ba58 100644
--- a/arch/um/os-Linux/time.c
+++ b/arch/um/os-Linux/time.c
@@ -30,13 +30,6 @@ int set_interval(int is_virtual)
         return 0;
 }
 
-#ifdef UML_CONFIG_MODE_TT
-void enable_timer(void)
-{
-        set_interval(1);
-}
-#endif
-
 void disable_timer(void)
 {
         struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
@@ -71,18 +64,6 @@ void switch_timers(int to_real)
                        errno);
 }
 
-#ifdef UML_CONFIG_MODE_TT
-void uml_idle_timer(void)
-{
-        if(signal(SIGVTALRM, SIG_IGN) == SIG_ERR)
-                panic("Couldn't unset SIGVTALRM handler");
-
-        set_handler(SIGALRM, (__sighandler_t) alarm_handler,
-                    SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
-        set_interval(0);
-}
-#endif
-
 unsigned long long os_nsecs(void)
 {
         struct timeval tv;
diff --git a/arch/um/os-Linux/tls.c b/arch/um/os-Linux/tls.c
index 16215b990804..282bd25e19ef 100644
--- a/arch/um/os-Linux/tls.c
+++ b/arch/um/os-Linux/tls.c
@@ -8,11 +8,6 @@
 
 /* TLS support - we basically rely on the host's one.*/
 
-/* In TT mode, this should be called only by the tracing thread, and makes sense
- * only for PTRACE_SET_THREAD_AREA. In SKAS mode, it's used normally.
- *
- */
-
 #ifndef PTRACE_GET_THREAD_AREA
 #define PTRACE_GET_THREAD_AREA 25
 #endif
@@ -32,8 +27,6 @@ int os_set_thread_area(user_desc_t *info, int pid)
         return ret;
 }
 
-#ifdef UML_CONFIG_MODE_SKAS
-
 int os_get_thread_area(user_desc_t *info, int pid)
 {
         int ret;
@@ -44,32 +37,3 @@ int os_get_thread_area(user_desc_t *info, int pid)
                 ret = -errno;
         return ret;
 }
-
-#endif
-
-#ifdef UML_CONFIG_MODE_TT
-#include "linux/unistd.h"
-
-int do_set_thread_area_tt(user_desc_t *info)
-{
-        int ret;
-
-        ret = syscall(__NR_set_thread_area,info);
-        if (ret < 0) {
-                ret = -errno;
-        }
-        return ret;
-}
-
-int do_get_thread_area_tt(user_desc_t *info)
-{
-        int ret;
-
-        ret = syscall(__NR_get_thread_area,info);
-        if (ret < 0) {
-                ret = -errno;
-        }
-        return ret;
-}
-
-#endif /* UML_CONFIG_MODE_TT */