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| -rw-r--r-- | man7/pkeys.7 | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/man7/pkeys.7 b/man7/pkeys.7 index 22370a6a46..39e44fc250 100644 --- a/man7/pkeys.7 +++ b/man7/pkeys.7 @@ -135,6 +135,22 @@ appropriate for child threads at the time when .BR clone (2) is called, or ensure that each child thread can perform its own initialization of protection key rights. + +.SS Signal Handler Behavior +Each time a signal handler is invoked (including nested signals), the +thread is temporarily given a new, default set of protection key rights +that override the rights from the interrupted context. +This means that applications must re-establish their desired protection +key rights upon entering a signal handler if the desired rights differ +from the defaults. +The rights of any interrupted context are restored when the signal +handler returns. + +This signal behavior is unusual and is due to the fact that the x86 PKRU +register (which stores protection key access rights) is managed with the +same hardware mechanism (XSAVE) that manages floating-point registers. +The signal behavior is the same as that of floating point registers. + .SS Protection Keys system calls The Linux kernel implements the following pkey-related system calls: .BR pkey_mprotect (2), |