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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2023-04-04 10:42:21 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2024-02-02 15:58:11 +0000 |
| commit | 54e90582aabdb44f010ad5dfd64ce9c3e6d33914 (patch) | |
| tree | d9fb977650c38e5ff7395ccfd977acd3b117f53e /sysdeps/unix/sysv/linux/aarch64/setcontext.S | |
| parent | 99f884d57f17afea877006284f469747711e1d51 (diff) | |
| download | glibc-54e90582aabdb44f010ad5dfd64ce9c3e6d33914.tar.gz glibc-54e90582aabdb44f010ad5dfd64ce9c3e6d33914.tar.xz glibc-54e90582aabdb44f010ad5dfd64ce9c3e6d33914.zip | |
aarch64: Add GCS support for makecontext
Changed the makecontext logic: previously the first setcontext jumped straight to the user callback function and the return address is set to __startcontext. This does not work when GCS is enabled as the integrity of the return address is protected, so instead the context is setup such that setcontext jumps to __startcontext which calls the user callback (passed in x20). The map_shadow_stack syscall is used to allocate a suitably sized GCS (which includes some reserved area to account for altstack signal handlers and otherwise supports maximum number of 16 byte aligned stack frames on the given stack) however the GCS is never freed as the lifetime of ucontext and related stack is user managed.
Diffstat (limited to 'sysdeps/unix/sysv/linux/aarch64/setcontext.S')
| -rw-r--r-- | sysdeps/unix/sysv/linux/aarch64/setcontext.S | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/aarch64/setcontext.S b/sysdeps/unix/sysv/linux/aarch64/setcontext.S index c08e83ee60..6aa7236693 100644 --- a/sysdeps/unix/sysv/linux/aarch64/setcontext.S +++ b/sysdeps/unix/sysv/linux/aarch64/setcontext.S @@ -181,7 +181,11 @@ L(gcs_done): PSEUDO_END (__setcontext) weak_alias (__setcontext, setcontext) +/* makecontext start function: receives uc_link in x19 and func in x20. + Arguments of func, x29, x30 and sp are set up by the caller. */ ENTRY (__startcontext) + cfi_undefined (x30) + blr x20 mov x0, x19 cbnz x0, __setcontext 1: b HIDDEN_JUMPTARGET (exit) |