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

2 files changed, 19 insertions, 91 deletions

diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index b1ea53285af1..9464833e741a 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -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;
diff --git a/arch/um/os-Linux/user_syms.c b/arch/um/os-Linux/user_syms.c
index fd575ecbcaec..9b62a9d352b3 100644
--- a/arch/um/os-Linux/user_syms.c
+++ b/arch/um/os-Linux/user_syms.c
@@ -3,112 +3,40 @@
 #include <linux/types.h>
 #include <linux/module.h>
 
-/* Some of this are builtin function (some are not but could in the future),
- * so I *must* declare good prototypes for them and then EXPORT them.
- * The kernel code uses the macro defined by include/linux/string.h,
- * so I undef macros; the userspace code does not include that and I
- * add an EXPORT for the glibc one.
+/*
+ * This file exports some critical string functions and compiler
+ * built-in functions (where calls are emitted by the compiler
+ * itself that we cannot avoid even in kernel code) to modules.
+ *
+ * "_user.c" code that previously used exports here such as hostfs
+ * really should be considered part of the 'hypervisor' and define
+ * its own API boundary like hostfs does now; don't add exports to
+ * this file for such cases.
  */
 
-#undef strlen
-#undef strstr
-#undef memcpy
-#undef memset
-
-extern size_t strlen(const char *);
-extern void *memmove(void *, const void *, size_t);
-extern void *memset(void *, int, size_t);
-extern int printf(const char *, ...);
-
 /* If it's not defined, the export is included in lib/string.c.*/
 #ifdef __HAVE_ARCH_STRSTR
+#undef strstr
 EXPORT_SYMBOL(strstr);
 #endif
 
 #ifndef __x86_64__
+#undef memcpy
 extern void *memcpy(void *, const void *, size_t);
 EXPORT_SYMBOL(memcpy);
+extern void *memmove(void *, const void *, size_t);
 EXPORT_SYMBOL(memmove);
+#undef memset
+extern void *memset(void *, int, size_t);
 EXPORT_SYMBOL(memset);
 #endif
 
-EXPORT_SYMBOL(printf);
-
-/* Here, instead, I can provide a fake prototype. Yes, someone cares: genksyms.
- * However, the modules will use the CRC defined *here*, no matter if it is
- * good; so the versions of these symbols will always match
- */
-#define EXPORT_SYMBOL_PROTO(sym)       \
-	int sym(void);                  \
-	EXPORT_SYMBOL(sym);
-
-extern void readdir64(void) __attribute__((weak));
-EXPORT_SYMBOL(readdir64);
-extern void truncate64(void) __attribute__((weak));
-EXPORT_SYMBOL(truncate64);
-
 #ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
+/* needed for __access_ok() */
 EXPORT_SYMBOL(vsyscall_ehdr);
 EXPORT_SYMBOL(vsyscall_end);
 #endif
 
-EXPORT_SYMBOL_PROTO(__errno_location);
-
-EXPORT_SYMBOL_PROTO(access);
-EXPORT_SYMBOL_PROTO(open);
-EXPORT_SYMBOL_PROTO(open64);
-EXPORT_SYMBOL_PROTO(close);
-EXPORT_SYMBOL_PROTO(read);
-EXPORT_SYMBOL_PROTO(write);
-EXPORT_SYMBOL_PROTO(dup2);
-EXPORT_SYMBOL_PROTO(__xstat);
-EXPORT_SYMBOL_PROTO(__lxstat);
-EXPORT_SYMBOL_PROTO(__lxstat64);
-EXPORT_SYMBOL_PROTO(__fxstat64);
-EXPORT_SYMBOL_PROTO(lseek);
-EXPORT_SYMBOL_PROTO(lseek64);
-EXPORT_SYMBOL_PROTO(chown);
-EXPORT_SYMBOL_PROTO(fchown);
-EXPORT_SYMBOL_PROTO(truncate);
-EXPORT_SYMBOL_PROTO(ftruncate64);
-EXPORT_SYMBOL_PROTO(utime);
-EXPORT_SYMBOL_PROTO(utimes);
-EXPORT_SYMBOL_PROTO(futimes);
-EXPORT_SYMBOL_PROTO(chmod);
-EXPORT_SYMBOL_PROTO(fchmod);
-EXPORT_SYMBOL_PROTO(rename);
-EXPORT_SYMBOL_PROTO(__xmknod);
-
-EXPORT_SYMBOL_PROTO(symlink);
-EXPORT_SYMBOL_PROTO(link);
-EXPORT_SYMBOL_PROTO(unlink);
-EXPORT_SYMBOL_PROTO(readlink);
-
-EXPORT_SYMBOL_PROTO(mkdir);
-EXPORT_SYMBOL_PROTO(rmdir);
-EXPORT_SYMBOL_PROTO(opendir);
-EXPORT_SYMBOL_PROTO(readdir);
-EXPORT_SYMBOL_PROTO(closedir);
-EXPORT_SYMBOL_PROTO(seekdir);
-EXPORT_SYMBOL_PROTO(telldir);
-
-EXPORT_SYMBOL_PROTO(ioctl);
-
-EXPORT_SYMBOL_PROTO(pread64);
-EXPORT_SYMBOL_PROTO(pwrite64);
-
-EXPORT_SYMBOL_PROTO(statfs);
-EXPORT_SYMBOL_PROTO(statfs64);
-
-EXPORT_SYMBOL_PROTO(getuid);
-
-EXPORT_SYMBOL_PROTO(fsync);
-EXPORT_SYMBOL_PROTO(fdatasync);
-
-EXPORT_SYMBOL_PROTO(lstat64);
-EXPORT_SYMBOL_PROTO(fstat64);
-EXPORT_SYMBOL_PROTO(mknod);
-
 /* Export symbols used by GCC for the stack protector. */
 extern void __stack_smash_handler(void *) __attribute__((weak));
 EXPORT_SYMBOL(__stack_smash_handler);
@@ -117,6 +45,6 @@ extern long __guard __attribute__((weak));
 EXPORT_SYMBOL(__guard);
 
 #ifdef _FORTIFY_SOURCE
-extern int __sprintf_chk(char *str, int flag, size_t strlen, const char *format);
+extern int __sprintf_chk(char *str, int flag, size_t len, const char *format);
 EXPORT_SYMBOL(__sprintf_chk);
 #endif