| Message ID | 20211116110256.365484-1-richard.henderson@linaro.org |
|---|---|
| Headers | show |
| Series | linux-user: simplify safe signal handling | expand |
On Tue, Nov 16, 2021 at 4:02 AM Richard Henderson < richard.henderson@linaro.org> wrote: > Warner's v3: > https://patchew.org/QEMU/20211113045603.60391-1-imp@bsdimp.com/ > > Changes for v4: > * Move errno handling into the assembly. While returning the > raw -errno is handy for x86 linux (and a few others), it is > in fact more complex for other hosts that return a separate > error indicator. At which point we wind up jumping through > hoops to return -errno, only to have the caller put it right > back into +errno with -1 result, just like syscall(3). > > Pass in &errno, because the method of calculating this > varies wildly between glibc, musl, etc. This means that > the assembly need only store to a provided pointer. > > * Add mips and sparc safe-syscall implementations. > Both of which, btw, have separate error indicators. ;-) > > * All hosts now have it, so remove HAVE_SAFE_SYSCALL. > > * Add meson.build rules for common-user/safe-syscall.S, so > that we don't have to have weird includes from *-user. > > I'll note that this last patch will at present break bsd-user, > because TARGET_ERESTARTSYS and the header from whence it comes > is currently missing there. > > In addition, I think that this should be reorganized further > so that TARGET_ERESTARTSYS is (1) renamed because in *this* > context it is pretending to be a host errno, and (2) placed > in a file of its own under include/user/. At which point, > meson.build could be simplified further so that safe-syscall.S > is compiled once, not per target. > > Anyway, the final patch needs some bsd-user changes sorted first. > I've got bsd-user to compile with these changes by creating bsd-user/target_errno_defs.h that was just #include "errno_defs.h", which suggests a simple rename and #include adjustment in bsd-user/syscall_defs.h would also work. On *BSD, the errno namespace is the same for all architectures since they never followed the rather divergent System V ABIs that Linux follows (or at least did for the early ports). I've noted a couple of other tweaks I needed as well, but there seemed to be no good place to share this. I'd be happy to change these vague descriptions into actual code I can push to gitlab that you can pull into the patch series as well (or I can send them to the list, I'm not sure about this finer point of qemu and want to fit in). Thanks for expanding my start at this. Warner > > r~ > > > Richard Henderson (4): > common-user: Move syscall error detection into safe_syscall_base > common-user/host/mips: Add safe-syscall.inc.S > common-user/host/sparc64: Add safe-syscall.inc.S > linux-user: Remove HAVE_SAFE_SYSCALL and hostdep.h > > Warner Losh (5): > 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: Adjust system call return on FreeBSD > common-user: Move safe-syscall.* from *-user > > meson.build | 9 +- > {linux-user => include/user}/safe-syscall.h | 31 ++-- > linux-user/host/aarch64/host-signal.h | 5 + > linux-user/host/aarch64/hostdep.h | 38 ----- > linux-user/host/alpha/host-signal.h | 5 + > linux-user/host/arm/host-signal.h | 5 + > linux-user/host/arm/hostdep.h | 38 ----- > linux-user/host/i386/host-signal.h | 5 + > linux-user/host/i386/hostdep.h | 38 ----- > linux-user/host/ia64/hostdep.h | 15 -- > linux-user/host/mips/host-signal.h | 5 + > linux-user/host/mips/hostdep.h | 15 -- > linux-user/host/ppc/host-signal.h | 5 + > linux-user/host/ppc/hostdep.h | 15 -- > linux-user/host/ppc64/hostdep.h | 38 ----- > linux-user/host/riscv/host-signal.h | 5 + > linux-user/host/riscv/hostdep.h | 34 ----- > linux-user/host/s390/host-signal.h | 5 + > linux-user/host/s390/hostdep.h | 15 -- > linux-user/host/s390x/hostdep.h | 38 ----- > linux-user/host/sparc/host-signal.h | 9 ++ > linux-user/host/sparc/hostdep.h | 15 -- > linux-user/host/sparc64/hostdep.h | 15 -- > linux-user/host/x32/hostdep.h | 15 -- > linux-user/host/x86_64/host-signal.h | 5 + > linux-user/host/x86_64/hostdep.h | 38 ----- > linux-user/user-internals.h | 1 - > linux-user/signal.c | 13 +- > linux-user/syscall.c | 2 +- > .../host/aarch64/safe-syscall.inc.S | 65 ++++++--- > .../host/arm/safe-syscall.inc.S | 69 ++++++--- > .../host/i386/safe-syscall.inc.S | 61 +++++--- > common-user/host/mips/safe-syscall.inc.S | 135 ++++++++++++++++++ > .../host/ppc64/safe-syscall.inc.S | 63 ++++---- > .../host/riscv/safe-syscall.inc.S | 50 ++++--- > .../host/s390x/safe-syscall.inc.S | 50 ++++--- > common-user/host/sparc64/safe-syscall.inc.S | 91 ++++++++++++ > .../host/x86_64/safe-syscall.inc.S | 80 +++++++---- > common-user/meson.build | 2 + > {linux-user => common-user}/safe-syscall.S | 3 - > linux-user/meson.build | 1 - > 41 files changed, 585 insertions(+), 562 deletions(-) > rename {linux-user => include/user}/safe-syscall.h (85%) > delete mode 100644 linux-user/host/aarch64/hostdep.h > delete mode 100644 linux-user/host/arm/hostdep.h > delete mode 100644 linux-user/host/i386/hostdep.h > delete mode 100644 linux-user/host/ia64/hostdep.h > delete mode 100644 linux-user/host/mips/hostdep.h > delete mode 100644 linux-user/host/ppc/hostdep.h > delete mode 100644 linux-user/host/ppc64/hostdep.h > delete mode 100644 linux-user/host/riscv/hostdep.h > delete mode 100644 linux-user/host/s390/hostdep.h > delete mode 100644 linux-user/host/s390x/hostdep.h > delete mode 100644 linux-user/host/sparc/hostdep.h > delete mode 100644 linux-user/host/sparc64/hostdep.h > delete mode 100644 linux-user/host/x32/hostdep.h > delete mode 100644 linux-user/host/x86_64/hostdep.h > rename {linux-user => common-user}/host/aarch64/safe-syscall.inc.S (64%) > rename {linux-user => common-user}/host/arm/safe-syscall.inc.S (64%) > rename {linux-user => common-user}/host/i386/safe-syscall.inc.S (71%) > create mode 100644 common-user/host/mips/safe-syscall.inc.S > rename {linux-user => common-user}/host/ppc64/safe-syscall.inc.S (68%) > rename {linux-user => common-user}/host/riscv/safe-syscall.inc.S (77%) > rename {linux-user => common-user}/host/s390x/safe-syscall.inc.S (71%) > create mode 100644 common-user/host/sparc64/safe-syscall.inc.S > rename {linux-user => common-user}/host/x86_64/safe-syscall.inc.S (64%) > create mode 100644 common-user/meson.build > rename {linux-user => common-user}/safe-syscall.S (94%) > > -- > 2.25.1 > >
Warner's v3: https://patchew.org/QEMU/20211113045603.60391-1-imp@bsdimp.com/ Changes for v4: * Move errno handling into the assembly. While returning the raw -errno is handy for x86 linux (and a few others), it is in fact more complex for other hosts that return a separate error indicator. At which point we wind up jumping through hoops to return -errno, only to have the caller put it right back into +errno with -1 result, just like syscall(3). Pass in &errno, because the method of calculating this varies wildly between glibc, musl, etc. This means that the assembly need only store to a provided pointer. * Add mips and sparc safe-syscall implementations. Both of which, btw, have separate error indicators. ;-) * All hosts now have it, so remove HAVE_SAFE_SYSCALL. * Add meson.build rules for common-user/safe-syscall.S, so that we don't have to have weird includes from *-user. I'll note that this last patch will at present break bsd-user, because TARGET_ERESTARTSYS and the header from whence it comes is currently missing there. In addition, I think that this should be reorganized further so that TARGET_ERESTARTSYS is (1) renamed because in *this* context it is pretending to be a host errno, and (2) placed in a file of its own under include/user/. At which point, meson.build could be simplified further so that safe-syscall.S is compiled once, not per target. Anyway, the final patch needs some bsd-user changes sorted first. r~ Richard Henderson (4): common-user: Move syscall error detection into safe_syscall_base common-user/host/mips: Add safe-syscall.inc.S common-user/host/sparc64: Add safe-syscall.inc.S linux-user: Remove HAVE_SAFE_SYSCALL and hostdep.h Warner Losh (5): 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: Adjust system call return on FreeBSD common-user: Move safe-syscall.* from *-user meson.build | 9 +- {linux-user => include/user}/safe-syscall.h | 31 ++-- linux-user/host/aarch64/host-signal.h | 5 + linux-user/host/aarch64/hostdep.h | 38 ----- linux-user/host/alpha/host-signal.h | 5 + linux-user/host/arm/host-signal.h | 5 + linux-user/host/arm/hostdep.h | 38 ----- linux-user/host/i386/host-signal.h | 5 + linux-user/host/i386/hostdep.h | 38 ----- linux-user/host/ia64/hostdep.h | 15 -- linux-user/host/mips/host-signal.h | 5 + linux-user/host/mips/hostdep.h | 15 -- linux-user/host/ppc/host-signal.h | 5 + linux-user/host/ppc/hostdep.h | 15 -- linux-user/host/ppc64/hostdep.h | 38 ----- linux-user/host/riscv/host-signal.h | 5 + linux-user/host/riscv/hostdep.h | 34 ----- linux-user/host/s390/host-signal.h | 5 + linux-user/host/s390/hostdep.h | 15 -- linux-user/host/s390x/hostdep.h | 38 ----- linux-user/host/sparc/host-signal.h | 9 ++ linux-user/host/sparc/hostdep.h | 15 -- linux-user/host/sparc64/hostdep.h | 15 -- linux-user/host/x32/hostdep.h | 15 -- linux-user/host/x86_64/host-signal.h | 5 + linux-user/host/x86_64/hostdep.h | 38 ----- linux-user/user-internals.h | 1 - linux-user/signal.c | 13 +- linux-user/syscall.c | 2 +- .../host/aarch64/safe-syscall.inc.S | 65 ++++++--- .../host/arm/safe-syscall.inc.S | 69 ++++++--- .../host/i386/safe-syscall.inc.S | 61 +++++--- common-user/host/mips/safe-syscall.inc.S | 135 ++++++++++++++++++ .../host/ppc64/safe-syscall.inc.S | 63 ++++---- .../host/riscv/safe-syscall.inc.S | 50 ++++--- .../host/s390x/safe-syscall.inc.S | 50 ++++--- common-user/host/sparc64/safe-syscall.inc.S | 91 ++++++++++++ .../host/x86_64/safe-syscall.inc.S | 80 +++++++---- common-user/meson.build | 2 + {linux-user => common-user}/safe-syscall.S | 3 - linux-user/meson.build | 1 - 41 files changed, 585 insertions(+), 562 deletions(-) rename {linux-user => include/user}/safe-syscall.h (85%) delete mode 100644 linux-user/host/aarch64/hostdep.h delete mode 100644 linux-user/host/arm/hostdep.h delete mode 100644 linux-user/host/i386/hostdep.h delete mode 100644 linux-user/host/ia64/hostdep.h delete mode 100644 linux-user/host/mips/hostdep.h delete mode 100644 linux-user/host/ppc/hostdep.h delete mode 100644 linux-user/host/ppc64/hostdep.h delete mode 100644 linux-user/host/riscv/hostdep.h delete mode 100644 linux-user/host/s390/hostdep.h delete mode 100644 linux-user/host/s390x/hostdep.h delete mode 100644 linux-user/host/sparc/hostdep.h delete mode 100644 linux-user/host/sparc64/hostdep.h delete mode 100644 linux-user/host/x32/hostdep.h delete mode 100644 linux-user/host/x86_64/hostdep.h rename {linux-user => common-user}/host/aarch64/safe-syscall.inc.S (64%) rename {linux-user => common-user}/host/arm/safe-syscall.inc.S (64%) rename {linux-user => common-user}/host/i386/safe-syscall.inc.S (71%) create mode 100644 common-user/host/mips/safe-syscall.inc.S rename {linux-user => common-user}/host/ppc64/safe-syscall.inc.S (68%) rename {linux-user => common-user}/host/riscv/safe-syscall.inc.S (77%) rename {linux-user => common-user}/host/s390x/safe-syscall.inc.S (71%) create mode 100644 common-user/host/sparc64/safe-syscall.inc.S rename {linux-user => common-user}/host/x86_64/safe-syscall.inc.S (64%) create mode 100644 common-user/meson.build rename {linux-user => common-user}/safe-syscall.S (94%)