Merge branch 'for-linus-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML updates from Richard Weinberger:

 - remove hppfs ("HonePot ProcFS")

 - initial support for musl libc

 - uaccess cleanup

 - random cleanups and bug fixes all over the place

* 'for-linus-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml: (21 commits)
  um: Don't pollute kernel namespace with uapi
  um: Include sys/types.h for makedev(), major(), minor()
  um: Do not use stdin and stdout identifiers for struct members
  um: Do not use __ptr_t type for stack_t's .ss pointer
  um: Fix mconsole dependency
  um: Handle tracehook_report_syscall_entry() result
  um: Remove copy&paste code from init.h
  um: Stop abusing __KERNEL__
  um: Catch unprotected user memory access
  um: Fix warning in setup_signal_stack_si()
  um: Rework uaccess code
  um: Add uaccess.h to ldt.c
  um: Add uaccess.h to syscalls_64.c
  um: Add asm/elf.h to vma.c
  um: Cleanup mem_32/64.c headers
  um: Remove hppfs
  um: Move syscall() declaration into os.h
  um: kernel: ksyms: Export symbol syscall() for fixing modpost issue
  um/os-Linux: Use char[] for syscall_stub declarations
  um: Use char[] for linker script address declarations
  ...

8 files changed, 40 insertions, 45 deletions

diff --git a/arch/um/kernel/ksyms.c b/arch/um/kernel/ksyms.c
index 543c047..232b2230 100644
--- a/arch/um/kernel/ksyms.c
+++ b/arch/um/kernel/ksyms.c
@@ -42,3 +42,5 @@ EXPORT_SYMBOL(os_makedev);
 EXPORT_SYMBOL(add_sigio_fd);
 EXPORT_SYMBOL(ignore_sigio_fd);
 EXPORT_SYMBOL(sigio_broken);
+
+EXPORT_SYMBOL(syscall);
diff --git a/arch/um/kernel/physmem.c b/arch/um/kernel/physmem.c
index 9034fc8..4c9861b 100644
--- a/arch/um/kernel/physmem.c
+++ b/arch/um/kernel/physmem.c
@@ -8,6 +8,7 @@
 #include <linux/mm.h>
 #include <linux/pfn.h>
 #include <asm/page.h>
+#include <asm/sections.h>
 #include <as-layout.h>
 #include <init.h>
 #include <kern.h>
@@ -55,8 +56,6 @@ void map_memory(unsigned long virt, unsigned long phys, unsigned long len,
 	}
 }
 
-extern int __syscall_stub_start;
-
 /**
  * setup_physmem() - Setup physical memory for UML
  * @start:	Start address of the physical kernel memory,
@@ -110,8 +109,8 @@ void __init setup_physmem(unsigned long start, unsigned long reserve_end,
 	 * Special kludge - This page will be mapped in to userspace processes
 	 * from physmem_fd, so it needs to be written out there.
 	 */
-	os_seek_file(physmem_fd, __pa(&__syscall_stub_start));
-	os_write_file(physmem_fd, &__syscall_stub_start, PAGE_SIZE);
+	os_seek_file(physmem_fd, __pa(__syscall_stub_start));
+	os_write_file(physmem_fd, __syscall_stub_start, PAGE_SIZE);
 	os_fsync_file(physmem_fd);
 
 	bootmap_size = init_bootmem(pfn, pfn + delta);
diff --git a/arch/um/kernel/ptrace.c b/arch/um/kernel/ptrace.c
index 174ee50..6a826cb 100644
--- a/arch/um/kernel/ptrace.c
+++ b/arch/um/kernel/ptrace.c
@@ -8,6 +8,7 @@
 #include <linux/sched.h>
 #include <linux/tracehook.h>
 #include <asm/uaccess.h>
+#include <asm/ptrace-abi.h>
 
 void user_enable_single_step(struct task_struct *child)
 {
@@ -131,7 +132,7 @@ static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
  * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
  */
-void syscall_trace_enter(struct pt_regs *regs)
+int syscall_trace_enter(struct pt_regs *regs)
 {
 	audit_syscall_entry(UPT_SYSCALL_NR(&regs->regs),
 			    UPT_SYSCALL_ARG1(&regs->regs),
@@ -140,9 +141,9 @@ void syscall_trace_enter(struct pt_regs *regs)
 			    UPT_SYSCALL_ARG4(&regs->regs));
 
 	if (!test_thread_flag(TIF_SYSCALL_TRACE))
-		return;
+		return 0;
 
-	tracehook_report_syscall_entry(regs);
+	return tracehook_report_syscall_entry(regs);
 }
 
 void syscall_trace_leave(struct pt_regs *regs)
diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c
index 94abdcc..fda1deb 100644
--- a/arch/um/kernel/skas/mmu.c
+++ b/arch/um/kernel/skas/mmu.c
@@ -8,12 +8,11 @@
 #include <linux/slab.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
+#include <asm/sections.h>
 #include <as-layout.h>
 #include <os.h>
 #include <skas.h>
 
-extern int __syscall_stub_start;
-
 static int init_stub_pte(struct mm_struct *mm, unsigned long proc,
 			 unsigned long kernel)
 {
@@ -93,7 +92,7 @@ void uml_setup_stubs(struct mm_struct *mm)
 	int err, ret;
 
 	ret = init_stub_pte(mm, STUB_CODE,
-			    (unsigned long) &__syscall_stub_start);
+			    (unsigned long) __syscall_stub_start);
 	if (ret)
 		goto out;
 
@@ -101,7 +100,7 @@ void uml_setup_stubs(struct mm_struct *mm)
 	if (ret)
 		goto out;
 
-	mm->context.stub_pages[0] = virt_to_page(&__syscall_stub_start);
+	mm->context.stub_pages[0] = virt_to_page(__syscall_stub_start);
 	mm->context.stub_pages[1] = virt_to_page(mm->context.id.stack);
 
 	/* dup_mmap already holds mmap_sem */
diff --git a/arch/um/kernel/skas/syscall.c b/arch/um/kernel/skas/syscall.c
index c0681e0..d9ec006 100644
--- a/arch/um/kernel/skas/syscall.c
+++ b/arch/um/kernel/skas/syscall.c
@@ -18,7 +18,10 @@ void handle_syscall(struct uml_pt_regs *r)
 	long result;
 	int syscall;
 
-	syscall_trace_enter(regs);
+	if (syscall_trace_enter(regs)) {
+		result = -ENOSYS;
+		goto out;
+	}
 
 	/*
 	 * This should go in the declaration of syscall, but when I do that,
@@ -34,6 +37,7 @@ void handle_syscall(struct uml_pt_regs *r)
 		result = -ENOSYS;
 	else result = EXECUTE_SYSCALL(syscall, regs);
 
+out:
 	PT_REGS_SET_SYSCALL_RETURN(regs, result);
 
 	syscall_trace_leave(regs);
diff --git a/arch/um/kernel/skas/uaccess.c b/arch/um/kernel/skas/uaccess.c
index 4ffb644..85ac8ad 100644
--- a/arch/um/kernel/skas/uaccess.c
+++ b/arch/um/kernel/skas/uaccess.c
@@ -87,10 +87,10 @@ static int do_op_one_page(unsigned long addr, int len, int is_write,
 	return n;
 }
 
-static int buffer_op(unsigned long addr, int len, int is_write,
-		     int (*op)(unsigned long, int, void *), void *arg)
+static long buffer_op(unsigned long addr, int len, int is_write,
+		      int (*op)(unsigned long, int, void *), void *arg)
 {
-	int size, remain, n;
+	long size, remain, n;
 
 	size = min(PAGE_ALIGN(addr) - addr, (unsigned long) len);
 	remain = len;
@@ -139,18 +139,16 @@ static int copy_chunk_from_user(unsigned long from, int len, void *arg)
 	return 0;
 }
 
-int copy_from_user(void *to, const void __user *from, int n)
+long __copy_from_user(void *to, const void __user *from, unsigned long n)
 {
 	if (segment_eq(get_fs(), KERNEL_DS)) {
 		memcpy(to, (__force void*)from, n);
 		return 0;
 	}
 
-	return access_ok(VERIFY_READ, from, n) ?
-	       buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to):
-	       n;
+	return buffer_op((unsigned long) from, n, 0, copy_chunk_from_user, &to);
 }
-EXPORT_SYMBOL(copy_from_user);
+EXPORT_SYMBOL(__copy_from_user);
 
 static int copy_chunk_to_user(unsigned long to, int len, void *arg)
 {
@@ -161,18 +159,16 @@ static int copy_chunk_to_user(unsigned long to, int len, void *arg)
 	return 0;
 }
 
-int copy_to_user(void __user *to, const void *from, int n)
+long __copy_to_user(void __user *to, const void *from, unsigned long n)
 {
 	if (segment_eq(get_fs(), KERNEL_DS)) {
 		memcpy((__force void *) to, from, n);
 		return 0;
 	}
 
-	return access_ok(VERIFY_WRITE, to, n) ?
-	       buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from) :
-	       n;
+	return buffer_op((unsigned long) to, n, 1, copy_chunk_to_user, &from);
 }
-EXPORT_SYMBOL(copy_to_user);
+EXPORT_SYMBOL(__copy_to_user);
 
 static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
 {
@@ -188,9 +184,9 @@ static int strncpy_chunk_from_user(unsigned long from, int len, void *arg)
 	return 0;
 }
 
-int strncpy_from_user(char *dst, const char __user *src, int count)
+long __strncpy_from_user(char *dst, const char __user *src, long count)
 {
-	int n;
+	long n;
 	char *ptr = dst;
 
 	if (segment_eq(get_fs(), KERNEL_DS)) {
@@ -198,16 +194,13 @@ int strncpy_from_user(char *dst, const char __user *src, int count)
 		return strnlen(dst, count);
 	}
 
-	if (!access_ok(VERIFY_READ, src, 1))
-		return -EFAULT;
-
 	n = buffer_op((unsigned long) src, count, 0, strncpy_chunk_from_user,
 		      &ptr);
 	if (n != 0)
 		return -EFAULT;
 	return strnlen(dst, count);
 }
-EXPORT_SYMBOL(strncpy_from_user);
+EXPORT_SYMBOL(__strncpy_from_user);
 
 static int clear_chunk(unsigned long addr, int len, void *unused)
 {
@@ -215,22 +208,16 @@ static int clear_chunk(unsigned long addr, int len, void *unused)
 	return 0;
 }
 
-int __clear_user(void __user *mem, int len)
-{
-	return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
-}
-
-int clear_user(void __user *mem, int len)
+unsigned long __clear_user(void __user *mem, unsigned long len)
 {
 	if (segment_eq(get_fs(), KERNEL_DS)) {
 		memset((__force void*)mem, 0, len);
 		return 0;
 	}
 
-	return access_ok(VERIFY_WRITE, mem, len) ?
-	       buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL) : len;
+	return buffer_op((unsigned long) mem, len, 1, clear_chunk, NULL);
 }
-EXPORT_SYMBOL(clear_user);
+EXPORT_SYMBOL(__clear_user);
 
 static int strnlen_chunk(unsigned long str, int len, void *arg)
 {
@@ -244,7 +231,7 @@ static int strnlen_chunk(unsigned long str, int len, void *arg)
 	return 0;
 }
 
-int strnlen_user(const void __user *str, int len)
+long __strnlen_user(const void __user *str, long len)
 {
 	int count = 0, n;
 
@@ -256,4 +243,4 @@ int strnlen_user(const void __user *str, int len)
 		return count + 1;
 	return 0;
 }
-EXPORT_SYMBOL(strnlen_user);
+EXPORT_SYMBOL(__strnlen_user);
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c
index 47ff9b7..557232f 100644
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -220,6 +220,11 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
 		show_regs(container_of(regs, struct pt_regs, regs));
 		panic("Segfault with no mm");
 	}
+	else if (!is_user && address < TASK_SIZE) {
+		show_regs(container_of(regs, struct pt_regs, regs));
+		panic("Kernel tried to access user memory at addr 0x%lx, ip 0x%lx",
+		       address, ip);
+	}
 
 	if (SEGV_IS_FIXABLE(&fi))
 		err = handle_page_fault(address, ip, is_write, is_user,
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 07f798f..16630e7 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -248,8 +248,6 @@ EXPORT_SYMBOL(end_iomem);
 
 #define MIN_VMALLOC (32 * 1024 * 1024)
 
-extern char __binary_start;
-
 int __init linux_main(int argc, char **argv)
 {
 	unsigned long avail, diff;
@@ -294,7 +292,7 @@ int __init linux_main(int argc, char **argv)
 		physmem_size += UML_ROUND_UP(brk_start) - UML_ROUND_UP(&_end);
 	}
 
-	uml_physmem = (unsigned long) &__binary_start & PAGE_MASK;
+	uml_physmem = (unsigned long) __binary_start & PAGE_MASK;
 
 	/* Reserve up to 4M after the current brk */
 	uml_reserved = ROUND_4M(brk_start) + (1 << 22);