* Szabolcs Nagy: > AAELF64: in the Symbol Table section add > > st_other Values > The st_other member of a symbol table entry specifies the symbol's > visibility in the lowest 2 bits. The top 6 bits are unused in the > generic ELF ABI [SCO-ELF], and while there are no values reserved for > processor-specific semantics, many other architectures have used these > bits. > > The defined processor-specific st_other flag values are listed in > Table 4-5-1. > > Table 4-5-1, Processor specific st_other flags > +------------------------+------+---------------------+ > |Name | Mask | Comment | > +------------------------+------+---------------------+ > |STO_AARCH64_VARIANT_PCS | 0x80 | The function | > | | | associated with the | > | | | symbol may follow a | > | | | variant procedure | > | | | call standard with | > | | | different register | > | | | usage convention. | > +------------------------+------+---------------------+ > > A symbol table entry that is marked with the STO_AARCH64_VARIANT_PCS > flag set in its st_other field may be associated with a function that > follows a variant procedure call standard with different register > usage convention from the one defined in the base procedure call > standard for the list of argument, caller-saved and callee-saved > registers [AAPCS64]. The rules in the Call and Jump relocations > section still apply to such functions, and if a subroutine is called > via a symbol reference that is marked with STO_AARCH64_VARIANT_PCS > then code that runs between the calling routine and called subroutine > must preserve the contents of all registers except IP0, IP1 and the > condition code flags [AAPCS64].
Can you clarify if there has to be a valid stack at this point which can be used during the call transfer? What about the stack alignment requirement? Thanks, Florian
