| Message ID | 20211108023738.42125-3-imp@bsdimp.com |
|---|---|
| State | New |
| Headers | show |
| Series | linux-user: simplify safe signal handling | expand |
On 11/8/21 3:37 AM, Warner Losh wrote: > All instances of rewind_if_in_safe_syscall are the same, differing only > in how the instruction point is fetched from the ucontext and the size > of the registers. Use host_signal_pc and new host_signal_set_pc > interfaces to fetch the pointer to the PC and adjust if needed. Delete > all the old copies of rewind_if_in_safe_syscall. > > Signed-off-by: Warner Losh<imp@bsdimp.com> > --- > linux-user/host/aarch64/hostdep.h | 20 -------------------- > linux-user/host/arm/hostdep.h | 20 -------------------- > linux-user/host/i386/hostdep.h | 20 -------------------- > linux-user/host/ppc64/hostdep.h | 20 -------------------- > linux-user/host/riscv/hostdep.h | 20 -------------------- > linux-user/host/s390x/hostdep.h | 20 -------------------- > linux-user/host/x86_64/hostdep.h | 20 -------------------- > linux-user/signal.c | 18 +++++++++++++++++- > 8 files changed, 17 insertions(+), 141 deletions(-) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Although I think we can fairly safely drop HAVE_SAFE_SYSCALL. It is required for proper operation. As with host-signal.h, really. r~
On Mon, Nov 8, 2021 at 8:07 AM Richard Henderson < richard.henderson@linaro.org> wrote: > On 11/8/21 3:37 AM, Warner Losh wrote: > > All instances of rewind_if_in_safe_syscall are the same, differing only > > in how the instruction point is fetched from the ucontext and the size > > of the registers. Use host_signal_pc and new host_signal_set_pc > > interfaces to fetch the pointer to the PC and adjust if needed. Delete > > all the old copies of rewind_if_in_safe_syscall. > > > > Signed-off-by: Warner Losh<imp@bsdimp.com> > > --- > > linux-user/host/aarch64/hostdep.h | 20 -------------------- > > linux-user/host/arm/hostdep.h | 20 -------------------- > > linux-user/host/i386/hostdep.h | 20 -------------------- > > linux-user/host/ppc64/hostdep.h | 20 -------------------- > > linux-user/host/riscv/hostdep.h | 20 -------------------- > > linux-user/host/s390x/hostdep.h | 20 -------------------- > > linux-user/host/x86_64/hostdep.h | 20 -------------------- > > linux-user/signal.c | 18 +++++++++++++++++- > > 8 files changed, 17 insertions(+), 141 deletions(-) > > Reviewed-by: Richard Henderson <richard.henderson@linaro.org> > > Although I think we can fairly safely drop HAVE_SAFE_SYSCALL. It is > required for proper > operation. As with host-signal.h, really. > Yes. The only possible use I can see for it is to allow people to bring up new platforms more easily by deferring the signal-safe system call details until later in that process. Warner
On 11/8/21 03:37, Warner Losh wrote: > All instances of rewind_if_in_safe_syscall are the same, differing only > in how the instruction point is fetched from the ucontext and the size > of the registers. Use host_signal_pc and new host_signal_set_pc > interfaces to fetch the pointer to the PC and adjust if needed. Delete > all the old copies of rewind_if_in_safe_syscall. > > Signed-off-by: Warner Losh <imp@bsdimp.com> > --- > linux-user/host/aarch64/hostdep.h | 20 -------------------- > linux-user/host/arm/hostdep.h | 20 -------------------- > linux-user/host/i386/hostdep.h | 20 -------------------- > linux-user/host/ppc64/hostdep.h | 20 -------------------- > linux-user/host/riscv/hostdep.h | 20 -------------------- > linux-user/host/s390x/hostdep.h | 20 -------------------- > linux-user/host/x86_64/hostdep.h | 20 -------------------- > linux-user/signal.c | 18 +++++++++++++++++- > 8 files changed, 17 insertions(+), 141 deletions(-) Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
On Mon, Nov 8, 2021 at 9:39 AM Warner Losh <imp@bsdimp.com> wrote: > > > On Mon, Nov 8, 2021 at 8:07 AM Richard Henderson < > richard.henderson@linaro.org> wrote: > >> On 11/8/21 3:37 AM, Warner Losh wrote: >> > All instances of rewind_if_in_safe_syscall are the same, differing only >> > in how the instruction point is fetched from the ucontext and the size >> > of the registers. Use host_signal_pc and new host_signal_set_pc >> > interfaces to fetch the pointer to the PC and adjust if needed. Delete >> > all the old copies of rewind_if_in_safe_syscall. >> > >> > Signed-off-by: Warner Losh<imp@bsdimp.com> >> > --- >> > linux-user/host/aarch64/hostdep.h | 20 -------------------- >> > linux-user/host/arm/hostdep.h | 20 -------------------- >> > linux-user/host/i386/hostdep.h | 20 -------------------- >> > linux-user/host/ppc64/hostdep.h | 20 -------------------- >> > linux-user/host/riscv/hostdep.h | 20 -------------------- >> > linux-user/host/s390x/hostdep.h | 20 -------------------- >> > linux-user/host/x86_64/hostdep.h | 20 -------------------- >> > linux-user/signal.c | 18 +++++++++++++++++- >> > 8 files changed, 17 insertions(+), 141 deletions(-) >> >> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> >> >> Although I think we can fairly safely drop HAVE_SAFE_SYSCALL. It is >> required for proper >> operation. As with host-signal.h, really. >> > > Yes. The only possible use I can see for it is to allow people to bring up > new platforms more easily by deferring the signal-safe system call details > until later in that process. > If we do, we'd need to remove the linux-user on a mips host tests from the CI pipeline. Those are the only ones left that don't use this that we test. Warner
On 11/10/21 5:20 PM, Warner Losh wrote: > Although I think we can fairly safely drop HAVE_SAFE_SYSCALL. It is required for > proper > operation. As with host-signal.h, really. > > Yes. The only possible use I can see for it is to allow people to bring up new > platforms more easily by deferring the signal-safe system call details until later in > that process. > > If we do, we'd need to remove the linux-user on a mips host tests from the CI pipeline. > Those are the only ones left that don't use this that we test. Ack, thanks. I'll take care of this next release. r~
diff --git a/linux-user/host/aarch64/hostdep.h b/linux-user/host/aarch64/hostdep.h index a8d41a21ad..39299d798a 100644 --- a/linux-user/host/aarch64/hostdep.h +++ b/linux-user/host/aarch64/hostdep.h @@ -15,24 +15,4 @@ /* We have a safe-syscall.inc.S */ #define HAVE_SAFE_SYSCALL -#ifndef __ASSEMBLER__ - -/* These are defined by the safe-syscall.inc.S file */ -extern char safe_syscall_start[]; -extern char safe_syscall_end[]; - -/* Adjust the signal context to rewind out of safe-syscall if we're in it */ -static inline void rewind_if_in_safe_syscall(void *puc) -{ - ucontext_t *uc = puc; - __u64 *pcreg = &uc->uc_mcontext.pc; - - if (*pcreg > (uintptr_t)safe_syscall_start - && *pcreg < (uintptr_t)safe_syscall_end) { - *pcreg = (uintptr_t)safe_syscall_start; - } -} - -#endif /* __ASSEMBLER__ */ - #endif diff --git a/linux-user/host/arm/hostdep.h b/linux-user/host/arm/hostdep.h index 9276fe6ceb..86b137875a 100644 --- a/linux-user/host/arm/hostdep.h +++ b/linux-user/host/arm/hostdep.h @@ -15,24 +15,4 @@ /* We have a safe-syscall.inc.S */ #define HAVE_SAFE_SYSCALL -#ifndef __ASSEMBLER__ - -/* These are defined by the safe-syscall.inc.S file */ -extern char safe_syscall_start[]; -extern char safe_syscall_end[]; - -/* Adjust the signal context to rewind out of safe-syscall if we're in it */ -static inline void rewind_if_in_safe_syscall(void *puc) -{ - ucontext_t *uc = puc; - unsigned long *pcreg = &uc->uc_mcontext.arm_pc; - - if (*pcreg > (uintptr_t)safe_syscall_start - && *pcreg < (uintptr_t)safe_syscall_end) { - *pcreg = (uintptr_t)safe_syscall_start; - } -} - -#endif /* __ASSEMBLER__ */ - #endif diff --git a/linux-user/host/i386/hostdep.h b/linux-user/host/i386/hostdep.h index 073be74d87..ce7136501f 100644 --- a/linux-user/host/i386/hostdep.h +++ b/linux-user/host/i386/hostdep.h @@ -15,24 +15,4 @@ /* We have a safe-syscall.inc.S */ #define HAVE_SAFE_SYSCALL -#ifndef __ASSEMBLER__ - -/* These are defined by the safe-syscall.inc.S file */ -extern char safe_syscall_start[]; -extern char safe_syscall_end[]; - -/* Adjust the signal context to rewind out of safe-syscall if we're in it */ -static inline void rewind_if_in_safe_syscall(void *puc) -{ - ucontext_t *uc = puc; - greg_t *pcreg = &uc->uc_mcontext.gregs[REG_EIP]; - - if (*pcreg > (uintptr_t)safe_syscall_start - && *pcreg < (uintptr_t)safe_syscall_end) { - *pcreg = (uintptr_t)safe_syscall_start; - } -} - -#endif /* __ASSEMBLER__ */ - #endif diff --git a/linux-user/host/ppc64/hostdep.h b/linux-user/host/ppc64/hostdep.h index 98979ad917..0c290dd904 100644 --- a/linux-user/host/ppc64/hostdep.h +++ b/linux-user/host/ppc64/hostdep.h @@ -15,24 +15,4 @@ /* We have a safe-syscall.inc.S */ #define HAVE_SAFE_SYSCALL -#ifndef __ASSEMBLER__ - -/* These are defined by the safe-syscall.inc.S file */ -extern char safe_syscall_start[]; -extern char safe_syscall_end[]; - -/* Adjust the signal context to rewind out of safe-syscall if we're in it */ -static inline void rewind_if_in_safe_syscall(void *puc) -{ - ucontext_t *uc = puc; - unsigned long *pcreg = &uc->uc_mcontext.gp_regs[PT_NIP]; - - if (*pcreg > (uintptr_t)safe_syscall_start - && *pcreg < (uintptr_t)safe_syscall_end) { - *pcreg = (uintptr_t)safe_syscall_start; - } -} - -#endif /* __ASSEMBLER__ */ - #endif diff --git a/linux-user/host/riscv/hostdep.h b/linux-user/host/riscv/hostdep.h index 2ba07456ae..7f67c22868 100644 --- a/linux-user/host/riscv/hostdep.h +++ b/linux-user/host/riscv/hostdep.h @@ -11,24 +11,4 @@ /* We have a safe-syscall.inc.S */ #define HAVE_SAFE_SYSCALL -#ifndef __ASSEMBLER__ - -/* These are defined by the safe-syscall.inc.S file */ -extern char safe_syscall_start[]; -extern char safe_syscall_end[]; - -/* Adjust the signal context to rewind out of safe-syscall if we're in it */ -static inline void rewind_if_in_safe_syscall(void *puc) -{ - ucontext_t *uc = puc; - unsigned long *pcreg = &uc->uc_mcontext.__gregs[REG_PC]; - - if (*pcreg > (uintptr_t)safe_syscall_start - && *pcreg < (uintptr_t)safe_syscall_end) { - *pcreg = (uintptr_t)safe_syscall_start; - } -} - -#endif /* __ASSEMBLER__ */ - #endif diff --git a/linux-user/host/s390x/hostdep.h b/linux-user/host/s390x/hostdep.h index 4f0171f36f..d801145854 100644 --- a/linux-user/host/s390x/hostdep.h +++ b/linux-user/host/s390x/hostdep.h @@ -15,24 +15,4 @@ /* We have a safe-syscall.inc.S */ #define HAVE_SAFE_SYSCALL -#ifndef __ASSEMBLER__ - -/* These are defined by the safe-syscall.inc.S file */ -extern char safe_syscall_start[]; -extern char safe_syscall_end[]; - -/* Adjust the signal context to rewind out of safe-syscall if we're in it */ -static inline void rewind_if_in_safe_syscall(void *puc) -{ - ucontext_t *uc = puc; - unsigned long *pcreg = &uc->uc_mcontext.psw.addr; - - if (*pcreg > (uintptr_t)safe_syscall_start - && *pcreg < (uintptr_t)safe_syscall_end) { - *pcreg = (uintptr_t)safe_syscall_start; - } -} - -#endif /* __ASSEMBLER__ */ - #endif diff --git a/linux-user/host/x86_64/hostdep.h b/linux-user/host/x86_64/hostdep.h index a4fefb5114..9c62bd26bd 100644 --- a/linux-user/host/x86_64/hostdep.h +++ b/linux-user/host/x86_64/hostdep.h @@ -15,24 +15,4 @@ /* We have a safe-syscall.inc.S */ #define HAVE_SAFE_SYSCALL -#ifndef __ASSEMBLER__ - -/* These are defined by the safe-syscall.inc.S file */ -extern char safe_syscall_start[]; -extern char safe_syscall_end[]; - -/* Adjust the signal context to rewind out of safe-syscall if we're in it */ -static inline void rewind_if_in_safe_syscall(void *puc) -{ - ucontext_t *uc = puc; - greg_t *pcreg = &uc->uc_mcontext.gregs[REG_RIP]; - - if (*pcreg > (uintptr_t)safe_syscall_start - && *pcreg < (uintptr_t)safe_syscall_end) { - *pcreg = (uintptr_t)safe_syscall_start; - } -} - -#endif /* __ASSEMBLER__ */ - #endif diff --git a/linux-user/signal.c b/linux-user/signal.c index 81c45bfce9..dafdf46b93 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -793,7 +793,23 @@ int queue_signal(CPUArchState *env, int sig, int si_type, return 1; /* indicates that the signal was queued */ } -#ifndef HAVE_SAFE_SYSCALL +#ifdef HAVE_SAFE_SYSCALL +/* These are defined by the safe-syscall.inc.S file */ +extern char safe_syscall_start[]; +extern char safe_syscall_end[]; + +/* Adjust the signal context to rewind out of safe-syscall if we're in it */ +static inline void rewind_if_in_safe_syscall(void *puc) +{ + ucontext_t *uc = (ucontext_t *)puc; + uintptr_t pcreg = host_signal_pc(uc); + + if (pcreg > (uintptr_t)safe_syscall_start + && pcreg < (uintptr_t)safe_syscall_end) { + host_signal_set_pc(uc, (uintptr_t)safe_syscall_start); + } +} +#else static inline void rewind_if_in_safe_syscall(void *puc) { /* Default version: never rewind */
All instances of rewind_if_in_safe_syscall are the same, differing only in how the instruction point is fetched from the ucontext and the size of the registers. Use host_signal_pc and new host_signal_set_pc interfaces to fetch the pointer to the PC and adjust if needed. Delete all the old copies of rewind_if_in_safe_syscall. Signed-off-by: Warner Losh <imp@bsdimp.com> --- linux-user/host/aarch64/hostdep.h | 20 -------------------- linux-user/host/arm/hostdep.h | 20 -------------------- linux-user/host/i386/hostdep.h | 20 -------------------- linux-user/host/ppc64/hostdep.h | 20 -------------------- linux-user/host/riscv/hostdep.h | 20 -------------------- linux-user/host/s390x/hostdep.h | 20 -------------------- linux-user/host/x86_64/hostdep.h | 20 -------------------- linux-user/signal.c | 18 +++++++++++++++++- 8 files changed, 17 insertions(+), 141 deletions(-)