Commit 342528ff authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'uml-for-linus-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux 

Pull uml updates from Richard Weinberger:

 - Make stub data pages configurable

 - Make it harder to mix user and kernel code by accident

* tag 'uml-for-linus-6.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/uml/linux:
  um: make stub data pages size tweakable
  um: prevent user code in modules
  um: further clean up user_syms
  um: don't export printf()
  um: hostfs: define our own API boundary
  um: add __weak for exported functions
parents 9f269232 6032aca0

arch/um/include/shared/as-layout.h

+2 −1
Original line number Diff line number Diff line
@@ -23,7 +23,8 @@ 
#define STUB_START stub_start

#define STUB_CODE STUB_START

#define STUB_DATA (STUB_CODE + UM_KERN_PAGE_SIZE)

#define STUB_END (STUB_DATA + UM_KERN_PAGE_SIZE)

#define STUB_DATA_PAGES 1 /* must be a power of two */

#define STUB_END (STUB_DATA + STUB_DATA_PAGES * UM_KERN_PAGE_SIZE)



#ifndef __ASSEMBLY__

arch/um/kernel/skas/clone.c

+3 −2
Original line number Diff line number Diff line
@@ -24,11 +24,12 @@ 
void __attribute__ ((__section__ (".__syscall_stub")))

stub_clone_handler(void)

{

	struct stub_data *data = get_stub_page();

	struct stub_data *data = get_stub_data();

	long err;



	err = stub_syscall2(__NR_clone, CLONE_PARENT | CLONE_FILES | SIGCHLD,

			    (unsigned long)data + UM_KERN_PAGE_SIZE / 2);

			    (unsigned long)data +

				STUB_DATA_PAGES * UM_KERN_PAGE_SIZE / 2);

	if (err) {

		data->parent_err = err;

		goto done;

arch/um/kernel/skas/mmu.c

+3 −3
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm) 
	unsigned long stack = 0;

	int ret = -ENOMEM;



	stack = get_zeroed_page(GFP_KERNEL);

	stack = __get_free_pages(GFP_KERNEL | __GFP_ZERO, ilog2(STUB_DATA_PAGES));

	if (stack == 0)

		goto out;
@@ -52,7 +52,7 @@ int init_new_context(struct task_struct *task, struct mm_struct *mm) 


 out_free:

	if (to_mm->id.stack != 0)

		free_page(to_mm->id.stack);

		free_pages(to_mm->id.stack, ilog2(STUB_DATA_PAGES));

 out:

	return ret;

}
@@ -74,6 +74,6 @@ void destroy_context(struct mm_struct *mm) 
	}

	os_kill_ptraced_process(mmu->id.u.pid, 1);



	free_page(mmu->id.stack);

	free_pages(mmu->id.stack, ilog2(STUB_DATA_PAGES));

	free_ldt(mmu);

}

arch/um/kernel/um_arch.c

+7 −3
Original line number Diff line number Diff line
@@ -326,9 +326,13 @@ int __init linux_main(int argc, char **argv) 
		add_arg(DEFAULT_COMMAND_LINE_CONSOLE);



	host_task_size = os_get_top_address();

	/* reserve two pages for the stubs */

	host_task_size -= 2 * PAGE_SIZE;

	stub_start = host_task_size;

	/* reserve a few pages for the stubs (taking care of data alignment) */

	/* align the data portion */

	BUILD_BUG_ON(!is_power_of_2(STUB_DATA_PAGES));

	stub_start = (host_task_size - 1) & ~(STUB_DATA_PAGES * PAGE_SIZE - 1);

	/* another page for the code portion */

	stub_start -= PAGE_SIZE;

	host_task_size = stub_start;



	/*

	 * TASK_SIZE needs to be PGDIR_SIZE aligned or else exit_mmap craps

arch/um/os-Linux/skas/process.c

+3 −3
Original line number Diff line number Diff line
@@ -262,7 +262,7 @@ static int userspace_tramp(void *stack) 
	if (stack != NULL) {

		fd = phys_mapping(uml_to_phys(stack), &offset);

		addr = mmap((void *) STUB_DATA,

			    UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,

			    STUB_DATA_PAGES * UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,

			    MAP_FIXED | MAP_SHARED, fd, offset);

		if (addr == MAP_FAILED) {

			printk(UM_KERN_ERR "mapping segfault stack at 0x%lx failed, errno = %d\n",
@@ -277,7 +277,7 @@ static int userspace_tramp(void *stack) 
				  (unsigned long) stub_segv_handler -

				  (unsigned long) __syscall_stub_start;



		set_sigstack((void *) STUB_DATA, UM_KERN_PAGE_SIZE);

		set_sigstack((void *) STUB_DATA, STUB_DATA_PAGES * UM_KERN_PAGE_SIZE);

		sigemptyset(&sa.sa_mask);

		sa.sa_flags = SA_ONSTACK | SA_NODEFER | SA_SIGINFO;

		sa.sa_sigaction = (void *) v;
@@ -515,7 +515,7 @@ static int __init init_thread_regs(void) 
	thread_regs[REGS_IP_INDEX] = STUB_CODE +

				(unsigned long) stub_clone_handler -

				(unsigned long) __syscall_stub_start;

	thread_regs[REGS_SP_INDEX] = STUB_DATA + UM_KERN_PAGE_SIZE -

	thread_regs[REGS_SP_INDEX] = STUB_DATA + STUB_DATA_PAGES * UM_KERN_PAGE_SIZE -

		sizeof(void *);

#ifdef __SIGNAL_FRAMESIZE

	thread_regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;