[POC][PATCH 54/83] um: store stacks as pointers

[Al Viro <viro@ZenIV.linux.org.uk>]

From: Al Viro <viro@zeniv.linux.org.uk>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
---
 arch/um/drivers/chan_user.c         |  6 +++---
 arch/um/drivers/chan_user.h         |  2 +-
 arch/um/drivers/line.c              |  8 ++++----
 arch/um/drivers/ubd.h               |  2 +-
 arch/um/drivers/ubd_kern.c          |  2 +-
 arch/um/drivers/ubd_user.c          |  4 ++--
 arch/um/include/shared/kern_util.h  |  4 ++--
 arch/um/include/shared/os.h         |  6 +++---
 arch/um/include/shared/skas/mm_id.h |  2 +-
 arch/um/include/shared/skas/skas.h  |  2 +-
 arch/um/kernel/process.c            | 11 ++++-------
 arch/um/kernel/skas/mmu.c           | 17 ++++++++---------
 arch/um/kernel/skas/process.c       |  4 ++--
 arch/um/os-Linux/aio.c              |  2 +-
 arch/um/os-Linux/helper.c           | 14 +++++++-------
 arch/um/os-Linux/sigio.c            |  2 +-
 arch/um/os-Linux/skas/process.c     | 19 +++++++++----------
 17 files changed, 51 insertions(+), 56 deletions(-)

diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c
index 3fd7c3e..bbda889 100644
--- a/arch/um/drivers/chan_user.c
+++ b/arch/um/drivers/chan_user.c
@@ -217,7 +217,7 @@ static int winch_thread(void *arg)
 }
 
 static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
-		       unsigned long *stack_out)
+		       void **stack_out)
 {
 	struct winch_data data;
 	int fds[2], n, err;
@@ -273,7 +273,7 @@ static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
 
 void register_winch(int fd, struct tty_port *port)
 {
-	unsigned long stack;
+	void *stack;
 	int pid, thread, count, thread_fd = -1;
 	char c = 1;
 
@@ -282,7 +282,7 @@ void register_winch(int fd, struct tty_port *port)
 
 	pid = tcgetpgrp(fd);
 	if (is_skas_winch(pid, fd, port)) {
-		register_winch_irq(-1, fd, -1, port, 0);
+		register_winch_irq(-1, fd, -1, port, NULL);
 		return;
 	}
 
diff --git a/arch/um/drivers/chan_user.h b/arch/um/drivers/chan_user.h
index 03f1b56..9cc900b 100644
--- a/arch/um/drivers/chan_user.h
+++ b/arch/um/drivers/chan_user.h
@@ -41,7 +41,7 @@ extern void generic_free(void *data);
 struct tty_port;
 extern void register_winch(int fd,  struct tty_port *port);
 extern void register_winch_irq(int fd, int tty_fd, int pid,
-			       struct tty_port *port, unsigned long stack);
+			       struct tty_port *port, void *stack);
 
 #define __channel_help(fn, prefix) \
 __uml_help(fn, prefix "[0-9]*=<channel description>\n" \
diff --git a/arch/um/drivers/line.c b/arch/um/drivers/line.c
index 6208702..ae8a5b1 100644
--- a/arch/um/drivers/line.c
+++ b/arch/um/drivers/line.c
@@ -598,7 +598,7 @@ struct winch {
 	int tty_fd;
 	int pid;
 	struct tty_port *port;
-	unsigned long stack;
+	void *stack;
 	struct work_struct work;
 };
 
@@ -609,7 +609,7 @@ static void __free_winch(struct work_struct *work)
 
 	if (winch->pid != -1)
 		os_kill_process(winch->pid, 1);
-	if (winch->stack != 0)
+	if (winch->stack)
 		free_stack(winch->stack, 0);
 	kfree(winch);
 }
@@ -672,7 +672,7 @@ static irqreturn_t winch_interrupt(int irq, void *data)
 }
 
 void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port,
-			unsigned long stack)
+			void *stack)
 {
 	struct winch *winch;
 
@@ -707,7 +707,7 @@ void register_winch_irq(int fd, int tty_fd, int pid, struct tty_port *port,
  cleanup:
 	os_kill_process(pid, 1);
 	os_close_file(fd);
-	if (stack != 0)
+	if (stack)
 		free_stack(stack, 0);
 }
 
diff --git a/arch/um/drivers/ubd.h b/arch/um/drivers/ubd.h
index 3b48cd2..5507e2c 100644
--- a/arch/um/drivers/ubd.h
+++ b/arch/um/drivers/ubd.h
@@ -7,7 +7,7 @@
 #ifndef __UM_UBD_USER_H
 #define __UM_UBD_USER_H
 
-extern int start_io_thread(unsigned long sp, int *fds_out);
+extern int start_io_thread(void *sp, int *fds_out);
 extern int io_thread(void *arg);
 extern int kernel_fd;
 
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index e8ab93c..e88fe7c 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -1082,7 +1082,7 @@ static int __init ubd_init(void)
 late_initcall(ubd_init);
 
 static int __init ubd_driver_init(void){
-	unsigned long stack;
+	void *stack;
 	int err;
 
 	/* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/
diff --git a/arch/um/drivers/ubd_user.c b/arch/um/drivers/ubd_user.c
index e376f9b..47791d4 100644
--- a/arch/um/drivers/ubd_user.c
+++ b/arch/um/drivers/ubd_user.c
@@ -21,7 +21,7 @@
 #include "ubd.h"
 #include <os.h>
 
-int start_io_thread(unsigned long sp, int *fd_out)
+int start_io_thread(void *sp, int *fd_out)
 {
 	int pid, fds[2], err;
 
@@ -40,7 +40,7 @@ int start_io_thread(unsigned long sp, int *fd_out)
 		goto out_close;
 	}
 
-	pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM, NULL);
+	pid = clone(io_thread, sp, CLONE_FILES | CLONE_VM, NULL);
 	if(pid < 0){
 		err = -errno;
 		printk("start_io_thread - clone failed : errno = %d\n", errno);
diff --git a/arch/um/include/shared/kern_util.h b/arch/um/include/shared/kern_util.h
index 35ab97e..886e362 100644
--- a/arch/um/include/shared/kern_util.h
+++ b/arch/um/include/shared/kern_util.h
@@ -19,8 +19,8 @@ extern int kmalloc_ok;
 #define UML_ROUND_UP(addr) \
 	((((unsigned long) addr) + PAGE_SIZE - 1) & PAGE_MASK)
 
-extern unsigned long alloc_stack(int order, int atomic);
-extern void free_stack(unsigned long stack, int order);
+extern void *alloc_stack(int order, int atomic);
+extern void free_stack(void *stack, int order);
 
 struct pt_regs;
 extern void do_signal(struct pt_regs *regs);
diff --git a/arch/um/include/shared/os.h b/arch/um/include/shared/os.h
index 868e6c3..fc47885 100644
--- a/arch/um/include/shared/os.h
+++ b/arch/um/include/shared/os.h
@@ -210,7 +210,7 @@ extern int execvp_noalloc(char *buf, const char *file, char *const argv[]);
 /* helper.c */
 extern int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv);
 extern int run_helper_thread(int (*proc)(void *), void *arg,
-			     unsigned int flags, unsigned long *stack_out);
+			     unsigned int flags, void **stack_out);
 extern int helper_wait(int pid);
 
 
@@ -270,8 +270,8 @@ extern int protect(struct mm_id * mm_idp, unsigned long addr,
 
 /* skas/process.c */
 extern int is_skas_winch(int pid, int fd, void *data);
-extern int start_userspace(unsigned long stub_stack);
-extern int copy_context_skas0(unsigned long stack, int pid);
+extern int start_userspace(void *stub_stack);
+extern int copy_context_skas0(void *stack, int pid);
 extern void userspace(struct uml_pt_regs *regs);
 extern int map_stub_pages(int fd, unsigned long code, unsigned long data,
 			  unsigned long stack);
diff --git a/arch/um/include/shared/skas/mm_id.h b/arch/um/include/shared/skas/mm_id.h
index 48dd098..b75c535 100644
--- a/arch/um/include/shared/skas/mm_id.h
+++ b/arch/um/include/shared/skas/mm_id.h
@@ -11,7 +11,7 @@ struct mm_id {
 		int mm_fd;
 		int pid;
 	} u;
-	unsigned long stack;
+	void *stack;
 };
 
 #endif
diff --git a/arch/um/include/shared/skas/skas.h b/arch/um/include/shared/skas/skas.h
index 911f3c4..689d0c6 100644
--- a/arch/um/include/shared/skas/skas.h
+++ b/arch/um/include/shared/skas/skas.h
@@ -14,6 +14,6 @@ extern int user_thread(unsigned long stack, int flags);
 extern void new_thread_handler(void);
 extern void handle_syscall(struct uml_pt_regs *regs);
 extern long execute_syscall_skas(void *r);
-extern unsigned long current_stub_stack(void);
+extern void *current_stub_stack(void);
 
 #endif
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index b77685b..69c8d56 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -55,21 +55,18 @@ int pid_to_processor_id(int pid)
 	return -1;
 }
 
-void free_stack(unsigned long stack, int order)
+void free_stack(void *stack, int order)
 {
-	free_pages((void *)stack, order);
+	free_pages(stack, order);
 }
 
-unsigned long alloc_stack(int order, int atomic)
+void *alloc_stack(int order, int atomic)
 {
-	unsigned long page;
 	gfp_t flags = GFP_KERNEL;
 
 	if (atomic)
 		flags = GFP_ATOMIC;
-	page = __get_free_pages(flags, order);
-
-	return page;
+	return (void *)__get_free_pages(flags, order);
 }
 
 static inline void set_current(struct task_struct *task)
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 6898b23..a0e5758 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -15,7 +15,7 @@
 #include <skas.h>
 
 static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
-			 unsigned long kernel)
+			 void *kernel)
 {
 	pgd_t *pgd;
 	pud_t *pud;
@@ -51,11 +51,11 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
 {
  	struct mm_context *from_mm = NULL;
 	struct mm_context *to_mm = &mm->context;
-	unsigned long stack = 0;
+	void *stack;
 	int ret = -ENOMEM;
 
-	stack = (unsigned long)get_zeroed_page(GFP_KERNEL);
-	if (stack == 0)
+	stack = get_zeroed_page(GFP_KERNEL);
+	if (!stack)
 		goto out;
 
 	to_mm->id.stack = stack;
@@ -84,8 +84,8 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm)
 	return 0;
 
  out_free:
-	if (to_mm->id.stack != 0)
-		free_page((void *)to_mm->id.stack);
+	if (to_mm->id.stack)
+		free_page(to_mm->id.stack);
  out:
 	return ret;
 }
@@ -94,8 +94,7 @@ void uml_setup_stubs(struct mm_struct *mm)
 {
 	int err, ret;
 
-	ret = init_stub_pte(mm, STUB_CODE,
-			    (unsigned long) __syscall_stub_start);
+	ret = init_stub_pte(mm, STUB_CODE, __syscall_stub_start);
 	if (ret)
 		goto out;
 
@@ -153,6 +152,6 @@ void destroy_context(struct mm_struct *mm)
 	}
 	os_kill_ptraced_process(mmu->id.u.pid, 1);
 
-	free_page((void *)mmu->id.stack);
+	free_page(mmu->id.stack);
 	free_ldt(mmu);
 }
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index 527fa58..1a2d485 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -43,10 +43,10 @@ int __init start_uml(void)
 				 &init_task.thread.switch_buf);
 }
 
-unsigned long current_stub_stack(void)
+void *current_stub_stack(void)
 {
 	if (current->mm == NULL)
-		return 0;
+		return NULL;
 
 	return current->mm->context.id.stack;
 }
diff --git a/arch/um/os-Linux/aio.c b/arch/um/os-Linux/aio.c
index 014eb35..e029471 100644
--- a/arch/um/os-Linux/aio.c
+++ b/arch/um/os-Linux/aio.c
@@ -164,7 +164,7 @@ static int do_not_aio(struct aio_thread_req *req)
 static int aio_req_fd_r = -1;
 static int aio_req_fd_w = -1;
 static int aio_pid = -1;
-static unsigned long aio_stack;
+static void *aio_stack;
 
 static int not_aio_thread(void *arg)
 {
diff --git a/arch/um/os-Linux/helper.c b/arch/um/os-Linux/helper.c
index 3f02d42..8653db7 100644
--- a/arch/um/os-Linux/helper.c
+++ b/arch/um/os-Linux/helper.c
@@ -42,11 +42,11 @@ static int helper_child(void *arg)
 int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
 {
 	struct helper_data data;
-	unsigned long stack, sp;
+	void *stack, *sp;
 	int pid, fds[2], ret, n;
 
 	stack = alloc_stack(0, __cant_sleep());
-	if (stack == 0)
+	if (!stack)
 		return -ENOMEM;
 
 	ret = socketpair(AF_UNIX, SOCK_STREAM, 0, fds);
@@ -71,7 +71,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
 	data.fd = fds[1];
 	data.buf = __cant_sleep() ? uml_kmalloc(PATH_MAX, UM_GFP_ATOMIC) :
 					uml_kmalloc(PATH_MAX, UM_GFP_KERNEL);
-	pid = clone(helper_child, (void *) sp, CLONE_VM, &data);
+	pid = clone(helper_child, sp, CLONE_VM, &data);
 	if (pid < 0) {
 		ret = -errno;
 		printk(UM_KERN_ERR "run_helper : clone failed, errno = %d\n",
@@ -111,17 +111,17 @@ out_free:
 }
 
 int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
-		      unsigned long *stack_out)
+		      void **stack_out)
 {
-	unsigned long stack, sp;
+	void *stack, *sp;
 	int pid, status, err;
 
 	stack = alloc_stack(0, __cant_sleep());
-	if (stack == 0)
+	if (!stack)
 		return -ENOMEM;
 
 	sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
-	pid = clone(proc, (void *) sp, flags, arg);
+	pid = clone(proc, sp, flags, arg);
 	if (pid < 0) {
 		err = -errno;
 		printk(UM_KERN_ERR "run_helper_thread : clone failed, "
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 46e762f..a5f8fa5 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -22,7 +22,7 @@
  * exitcall.
  */
 static int write_sigio_pid = -1;
-static unsigned long write_sigio_stack;
+static void *write_sigio_stack;
 
 /*
  * These arrays are initialized before the sigio thread is started, and
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index b856c66..ec32886 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -85,7 +85,7 @@ bad_wait:
 	fatal_sigsegv();
 }
 
-extern unsigned long current_stub_stack(void);
+extern void *current_stub_stack(void);
 
 static void get_skas_faultinfo(int pid, struct faultinfo *fi)
 {
@@ -110,7 +110,7 @@ static void get_skas_faultinfo(int pid, struct faultinfo *fi)
 	 * faultinfo is prepared by the stub-segv-handler at start of
 	 * the stub stack page. We just have to copy it.
 	 */
-	memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
+	memcpy(fi, current_stub_stack(), sizeof(*fi));
 
 	err = put_fp_registers(pid, fpregs);
 	if (err < 0) {
@@ -245,10 +245,9 @@ static int userspace_tramp(void *stack)
 #define NR_CPUS 1
 int userspace_pid[NR_CPUS];
 
-int start_userspace(unsigned long stub_stack)
+int start_userspace(void *stub_stack)
 {
-	void *stack;
-	unsigned long sp;
+	void *stack, *sp;
 	int pid, status, n, flags, err;
 
 	stack = mmap(NULL, UM_KERN_PAGE_SIZE,
@@ -261,11 +260,11 @@ int start_userspace(unsigned long stub_stack)
 		return err;
 	}
 
-	sp = (unsigned long) stack + UM_KERN_PAGE_SIZE - sizeof(void *);
+	sp = stack + UM_KERN_PAGE_SIZE - sizeof(void *);
 
 	flags = CLONE_FILES | SIGCHLD;
 
-	pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
+	pid = clone(userspace_tramp, sp, flags, stub_stack);
 	if (pid < 0) {
 		err = -errno;
 		printk(UM_KERN_ERR "start_userspace : clone failed, "
@@ -439,14 +438,14 @@ static int __init init_thread_regs(void)
 
 __initcall(init_thread_regs);
 
-int copy_context_skas0(unsigned long new_stack, int pid)
+int copy_context_skas0(void *new_stack, int pid)
 {
 	int err;
-	unsigned long current_stack = current_stub_stack();
+	void *current_stack = current_stub_stack();
 	struct stub_data *data = (struct stub_data *) current_stack;
 	struct stub_data *child_data = (struct stub_data *) new_stack;
 	unsigned long long new_offset;
-	int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
+	int new_fd = phys_mapping(to_phys(new_stack), &new_offset);
 
 	/*
 	 * prepare offset and fd of child's stack as argument for parent's
-- 
2.1.4