This is a quick RFC to see if something like this is worth doing. I've created a new interface host_signal_set_pc. This allows us to move all the nearly identical copies of rewind_if_in_safe_syscall into signal.c. This reduces the amount of code that needs to be rewritten for bsd-user's adaptation of both the safe signal handling and the sigsegv/sigbus changes that have happened. Since BSD's mcontext_t differs in some cases, we wouldn't be able to share this between platforms, but it reduces the number of nearly identical routines I'd have to write.
In addition, the assembler glue for the safe system calls is almost identical between linux and bsd-user's fork. The only difference is inverting the system call return to comply with the -ERRNO convention *-user uses in the rest of the code which is native to Linux, but differs for the BSDs and other traditional unix targets. I know the patches may not be sliced and diced in the typical desired fashion. This is a RFC, and the changes are short enough to be easily digested though since it's quite repetitive. These were extracted from the 'blitz' branch we have in the bsd-user fork and then that was adapted to use the common code. I've pushed a branch to gitlab (viewable at https://gitlab.com/bsdimp/qemu/-/tree/blitz if you prefer that to fetching) that shows how these will be used. I'm working on upstreaming bsd-user/signal.c next which will take a little bit of time to work into a place where it can be reviewed here. I wanted to get feedback because this is one chunk I can cleave off and make landing that easier. Warner Losh (4): linux-user: Add host_signal_set_pc to set pc in mcontext linux-user/signal.c: Create a common rewind_if_in_safe_syscall linux-user/safe-syscall.inc.S: Move to common-user common-user: Allow return codes to be adjusted after sytsem call .../host/aarch64/safe-syscall.inc.S | 1 + .../host/arm/safe-syscall.inc.S | 1 + .../host/i386/safe-syscall.inc.S | 1 + .../host/ppc64/safe-syscall.inc.S | 1 + .../host/riscv/safe-syscall.inc.S | 1 + .../host/s390x/safe-syscall.inc.S | 1 + .../host/x86_64/safe-syscall.inc.S | 1 + linux-user/host/aarch64/host-signal.h | 5 +++++ linux-user/host/aarch64/hostdep.h | 20 ------------------- linux-user/host/alpha/host-signal.h | 5 +++++ linux-user/host/arm/host-signal.h | 5 +++++ linux-user/host/arm/hostdep.h | 20 ------------------- linux-user/host/i386/host-signal.h | 5 +++++ linux-user/host/i386/hostdep.h | 20 ------------------- linux-user/host/mips/host-signal.h | 5 +++++ linux-user/host/ppc/host-signal.h | 5 +++++ linux-user/host/ppc64/hostdep.h | 20 ------------------- linux-user/host/riscv/host-signal.h | 5 +++++ linux-user/host/riscv/hostdep.h | 20 ------------------- linux-user/host/s390/host-signal.h | 5 +++++ linux-user/host/s390x/hostdep.h | 20 ------------------- linux-user/host/sparc/host-signal.h | 9 +++++++++ linux-user/host/x86_64/host-signal.h | 5 +++++ linux-user/host/x86_64/hostdep.h | 20 ------------------- linux-user/safe-syscall.S | 1 + linux-user/signal.c | 18 ++++++++++++++++- meson.build | 1 + 27 files changed, 80 insertions(+), 141 deletions(-) rename {linux-user => common-user}/host/aarch64/safe-syscall.inc.S (99%) rename {linux-user => common-user}/host/arm/safe-syscall.inc.S (99%) rename {linux-user => common-user}/host/i386/safe-syscall.inc.S (99%) rename {linux-user => common-user}/host/ppc64/safe-syscall.inc.S (99%) rename {linux-user => common-user}/host/riscv/safe-syscall.inc.S (99%) rename {linux-user => common-user}/host/s390x/safe-syscall.inc.S (99%) rename {linux-user => common-user}/host/x86_64/safe-syscall.inc.S (99%) -- 2.33.0
