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authorMark Rutland <mark.rutland@arm.com>2023-08-21 17:35:26 +0100
committerThomas Gleixner <tglx@linutronix.de>2023-08-23 10:32:39 +0200
commit1dfe3a5a7cefbe2162cecb759f3933baea22c393 (patch)
treef78b2a7b553e2feb8ebe183ac97413f4e7b3c6a5 /include/linux/syscalls.h
parent6eaae198076080886b9e7d57f4ae06fa782f90ef (diff)
entry: Remove empty addr_limit_user_check()
Back when set_fs() was a generic API for altering the address limit, addr_limit_user_check() was a safety measure to prevent userspace being able to issue syscalls with an unbound limit. With the the removal of set_fs() as a generic API, the last user of addr_limit_user_check() was removed in commit: b5a5a01d8e9a44ec ("arm64: uaccess: remove addr_limit_user_check()") ... as since that commit, no architecture defines TIF_FSCHECK, and hence addr_limit_user_check() always expands to nothing. Remove addr_limit_user_check(), updating the comment in exit_to_user_mode_prepare() to no longer refer to it. At the same time, the comment is reworded to be a little more generic so as to cover kmap_assert_nomap() in addition to lockdep_sys_exit(). No functional change. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20230821163526.2319443-1-mark.rutland@arm.com
Diffstat (limited to 'include/linux/syscalls.h')
-rw-r--r--include/linux/syscalls.h16
1 files changed, 0 insertions, 16 deletions
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 03e3d0121d5e..c4b9b66b0d05 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -284,22 +284,6 @@ static inline int is_syscall_trace_event(struct trace_event_call *tp_event)
#endif
/*
- * Called before coming back to user-mode. Returning to user-mode with an
- * address limit different than USER_DS can allow to overwrite kernel memory.
- */
-static inline void addr_limit_user_check(void)
-{
-#ifdef TIF_FSCHECK
- if (!test_thread_flag(TIF_FSCHECK))
- return;
-#endif
-
-#ifdef TIF_FSCHECK
- clear_thread_flag(TIF_FSCHECK);
-#endif
-}
-
-/*
* These syscall function prototypes are kept in the same order as
* include/uapi/asm-generic/unistd.h. Architecture specific entries go below,
* followed by deprecated or obsolete system calls.