linux-user: Add host_signal_set_pc to set pc in mcontext

Add a new function host_signal_set_pc to set the next pc in an
mcontext. The caller should ensure this is a valid PC for execution.

Acked-by: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211113045603.60391-2-imp@bsdimp.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

linux-user/host/aarch64/host-signal.h

@@ -35,6 +35,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.pc;
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.pc = pc;
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     struct _aarch64_ctx *hdr;

linux-user/host/alpha/host-signal.h

@@ -16,6 +16,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.sc_pc;
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.sc_pc = pc;
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     uint32_t *pc = (uint32_t *)host_signal_pc(uc);

linux-user/host/arm/host-signal.h

@@ -16,6 +16,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.arm_pc;
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.arm_pc = pc;
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     /*

linux-user/host/i386/host-signal.h

@@ -16,6 +16,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.gregs[REG_EIP];
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.gregs[REG_EIP] = pc;
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     return uc->uc_mcontext.gregs[REG_TRAPNO] == 0xe

linux-user/host/mips/host-signal.h

@@ -16,6 +16,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.pc;
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.pc = pc;
+}
+
 #if defined(__misp16) || defined(__mips_micromips)
 #error "Unsupported encoding"
 #endif

linux-user/host/ppc/host-signal.h

@@ -16,6 +16,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.regs->nip;
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.regs->nip = pc;
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     return uc->uc_mcontext.regs->trap != 0x400

linux-user/host/riscv/host-signal.h

@@ -16,6 +16,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.__gregs[REG_PC];
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.__gregs[REG_PC] = pc;
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     /*

linux-user/host/s390/host-signal.h

@@ -16,6 +16,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.psw.addr;
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.psw.addr = pc;
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     uint16_t *pinsn = (uint16_t *)host_signal_pc(uc);

linux-user/host/sparc/host-signal.h

@@ -20,6 +20,15 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
 #endif
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+#ifdef __arch64__
+    uc->uc_mcontext.mc_gregs[MC_PC] = pc;
+#else
+    uc->uc_mcontext.gregs[REG_PC] = pc;
+#endif
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     uint32_t insn = *(uint32_t *)host_signal_pc(uc);

linux-user/host/x86_64/host-signal.h

@@ -15,6 +15,11 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
     return uc->uc_mcontext.gregs[REG_RIP];
 }
 
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.gregs[REG_RIP] = pc;
+}
+
 static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
 {
     return uc->uc_mcontext.gregs[REG_TRAPNO] == 0xe