From: Warner Losh <imp@bsdimp.com>

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>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20211113045603.60391-3-imp@bsdimp.com>
[rth: include safe-syscall.h, simplify ifdefs]
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 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/safe-syscall.h         |  3 +++
 linux-user/signal.c               | 15 ++++++++++++---
 9 files changed, 15 insertions(+), 143 deletions(-)

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/safe-syscall.h b/linux-user/safe-syscall.h
index 6bc0390262..aaa9ffc0e2 100644
--- a/linux-user/safe-syscall.h
+++ b/linux-user/safe-syscall.h
@@ -127,6 +127,9 @@
 #ifdef HAVE_SAFE_SYSCALL
 /* The core part of this function is implemented in assembly */
 extern long safe_syscall_base(int *pending, long number, ...);
+/* These are defined by the safe-syscall.inc.S file */
+extern char safe_syscall_start[];
+extern char safe_syscall_end[];
 
 #define safe_syscall(...)                                               \
     ({                                                                  \
diff --git a/linux-user/signal.c b/linux-user/signal.c
index 81c45bfce9..6d5e5b698c 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -31,6 +31,7 @@
 #include "trace.h"
 #include "signal-common.h"
 #include "host-signal.h"
+#include "safe-syscall.h"
 
 static struct target_sigaction sigact_table[TARGET_NSIG];
 
@@ -793,12 +794,20 @@ int queue_signal(CPUArchState *env, int sig, int si_type,
     return 1; /* indicates that the signal was queued */
 }
 
-#ifndef HAVE_SAFE_SYSCALL
+
+/* 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)
 {
-    /* Default version: never rewind */
-}
+#ifdef HAVE_SAFE_SYSCALL
+    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);
+    }
 #endif
+}
 
 static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
 {
-- 
2.25.1

Richard Henderson <richard.henderson@linaro.org> writes:

> From: Warner Losh <imp@bsdimp.com>
>
> 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>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Message-Id: <20211113045603.60391-3-imp@bsdimp.com>
> [rth: include safe-syscall.h, simplify ifdefs]
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

-- 
Alex Bennée

On Wed, Nov 17, 2021 at 9:04 AM Richard Henderson <
richard.henderson@linaro.org> wrote:

> From: Warner Losh <imp@bsdimp.com>
>
> 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>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Message-Id: <20211113045603.60391-3-imp@bsdimp.com>
> [rth: include safe-syscall.h, simplify ifdefs]
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  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/safe-syscall.h         |  3 +++
>  linux-user/signal.c               | 15 ++++++++++++---
>  9 files changed, 15 insertions(+), 143 deletions(-)
>


Reviewed by: Warner Losh <imp@bsdimp.com>

(this one I'm sure it's ok since things changed from my original
and the changes are good).


> 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/safe-syscall.h b/linux-user/safe-syscall.h
> index 6bc0390262..aaa9ffc0e2 100644
> --- a/linux-user/safe-syscall.h
> +++ b/linux-user/safe-syscall.h
> @@ -127,6 +127,9 @@
>  #ifdef HAVE_SAFE_SYSCALL
>  /* The core part of this function is implemented in assembly */
>  extern long safe_syscall_base(int *pending, long number, ...);
> +/* These are defined by the safe-syscall.inc.S file */
> +extern char safe_syscall_start[];
> +extern char safe_syscall_end[];
>
>  #define safe_syscall(...)                                               \
>      ({                                                                  \
> diff --git a/linux-user/signal.c b/linux-user/signal.c
> index 81c45bfce9..6d5e5b698c 100644
> --- a/linux-user/signal.c
> +++ b/linux-user/signal.c
> @@ -31,6 +31,7 @@
>  #include "trace.h"
>  #include "signal-common.h"
>  #include "host-signal.h"
> +#include "safe-syscall.h"
>
>  static struct target_sigaction sigact_table[TARGET_NSIG];
>
> @@ -793,12 +794,20 @@ int queue_signal(CPUArchState *env, int sig, int
> si_type,
>      return 1; /* indicates that the signal was queued */
>  }
>
> -#ifndef HAVE_SAFE_SYSCALL
> +
> +/* 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)
>  {
> -    /* Default version: never rewind */
> -}
> +#ifdef HAVE_SAFE_SYSCALL
> +    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);
> +    }
>  #endif
> +}
>
>  static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
>  {
> --
> 2.25.1
>
>