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authorJohannes Berg <johannes.berg@intel.com>2023-02-11 00:05:10 +0300
committerRichard Weinberger <richard@nod.at>2023-04-21 00:05:52 +0300
commit5d90cf6dcc6a4cb85a51ffe007a8e34375799164 (patch)
tree683953413f0aa369453a1522d5f5d2163050641f /arch/um
parent6d708d1a0d81fe85a114766ff6beb3037fa77429 (diff)
downloadlinux-5d90cf6dcc6a4cb85a51ffe007a8e34375799164.tar.xz
um: further clean up user_syms
Make some cleanups, add and fix some comments and document here that we shouldn't export (libc) symbols for "_user.c" code, rather such should work like hostfs does now. Signed-off-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um')
-rw-r--r--arch/um/os-Linux/user_syms.c31
1 files changed, 16 insertions, 15 deletions
diff --git a/arch/um/os-Linux/user_syms.c b/arch/um/os-Linux/user_syms.c
index 1e9e92740b32..9b62a9d352b3 100644
--- a/arch/um/os-Linux/user_syms.c
+++ b/arch/um/os-Linux/user_syms.c
@@ -3,35 +3,36 @@
#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);
-
/* 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
#ifdef CONFIG_ARCH_REUSE_HOST_VSYSCALL_AREA
+/* needed for __access_ok() */
EXPORT_SYMBOL(vsyscall_ehdr);
EXPORT_SYMBOL(vsyscall_end);
#endif
@@ -44,6 +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