path: root/src/signal/sh
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2015-09-23fix signal return for sh/fdpicRich Felker-2/+0
the restorer function pointer provided in the kernel sigaction structure is interpreted by the kernel as a raw code address, not a function descriptor. this commit moves the declarations of the __restore and __restore_rt symbols to ksigaction.h so that arch versions of the file can override them, and introduces a version for sh which declares them as objects rather than functions. an alternate solution would have been defining SA_RESTORER to 0 so that the functions are not used, but this both requires executable stack (since the sh kernel does not have a vdso page with permanent restorer functions) and crashes on qemu user-level emulation.
2015-06-16switch to using trap number 31 for syscalls on shRich Felker-2/+2
nominally the low bits of the trap number on sh are the number of syscall arguments, but they have never been used by the kernel, and some code making syscalls does not even know the number of arguments and needs to pass an arbitrary high number anyway. sh3/sh4 traditionally used the trap range 16-31 for syscalls, but part of this range overlapped with hardware exceptions/interrupts on sh2 hardware, so an incompatible range 32-47 was chosen for sh2. using trap number 31 everywhere, since it's in the existing sh3/sh4 range and does not conflict with sh2 hardware, is a proposed unification of the kernel syscall convention that will allow binaries to be shared between sh2 and sh3/sh4. if this is not accepted into the kernel, we can refit the sh2 target with runtime selection mechanisms for the trap number, but doing so would be invasive and would entail non-trivial overhead.
2015-04-27fix sh jmp_buf size to match ABIRich Felker-2/+2
while the sh port is still experimental and subject to ABI instability, this is not actually an application/libc boundary ABI change. it only affects third-party APIs where jmp_buf is used in a shared structure at the ABI boundary, because nothing anywhere near the end of the jmp_buf object (which includes the oversized sigset_t) is accessed by libc. both glibc and uclibc have 15-slot jmp_buf for sh. presumably the smaller version was used in musl because the slots for fpu status register and thread pointer register (gbr) were incorrect and must not be restored by longjmp, but the size should have been preserved, as it's generally treated as a libc-agnostic ABI property for the arch, and having extra slots free in case we ever need them for something is useful anyway.
2015-04-19remove invalid PLT calls from sh asmRich Felker-2/+3
these are perfectly fine with ld-time symbol binding, but if the calls go through a PLT thunk, they are invalid because the caller does not setup a GOT register. use a hidden alias to bypass the issue.
2015-04-17redesign sigsetjmp so that signal mask is restored after longjmpRich Felker-17/+27
the conventional way to implement sigsetjmp is to save the signal mask then tail-call to setjmp; siglongjmp then restores the signal mask and calls longjmp. the problem with this approach is that a signal already pending, or arriving between unmasking of signals and restoration of the saved stack pointer, will have its signal handler run on the stack that was active before siglongjmp was called. this can lead to unbounded stack usage when siglongjmp is used to leave a signal handler. in the new design, sigsetjmp saves its own return address inside the extended part of the sigjmp_buf (outside the __jmp_buf part used by setjmp) then calls setjmp to save a jmp_buf inside its own execution. it then tail-calls to __sigsetjmp_tail, which uses the return value of setjmp to determine whether to save the current signal mask or restore a previously-saved mask. as an added bonus, this design makes it so that siglongjmp and longjmp are identical. this is useful because the __longjmp_chk function we need to add for ABI-compatibility assumes siglongjmp and longjmp are the same, but for different reasons -- it was designed assuming either can access a flag just past the __jmp_buf indicating whether the signal masked was saved, and act on that flag. however, early versions of musl did not have space past the __jmp_buf for the non-sigjmp_buf version of jmp_buf, so our setjmp cannot store such a flag without risking clobbering memory on (very) old binaries.
2014-04-02add __sigsetjmp ABI-compat alias for sigsetjmpRich Felker-1/+4
2014-02-27rename superh port to "sh" for consistencyRich Felker-0/+51
linux, gcc, etc. all use "sh" as the name for the superh arch. there was already some inconsistency internally in musl: the dynamic linker was searching for "ld-musl-sh.path" as its path file despite its own name being "". there was some sentiment in both directions as to how to resolve the inconsistency, but overall "sh" was favored.