diff --git a/linux-user/include/host/aarch64/host-signal.h b/linux-user/include/host/aarch64/host-signal.h
index 76ab078069..be079684a2 100644
--- a/linux-user/include/host/aarch64/host-signal.h
+++ b/linux-user/include/host/aarch64/host-signal.h
@@ -11,6 +11,9 @@
 #ifndef AARCH64_HOST_SIGNAL_H
 #define AARCH64_HOST_SIGNAL_H
 
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
 /* Pre-3.16 kernel headers don't have these, so provide fallback definitions */
 #ifndef ESR_MAGIC
 #define ESR_MAGIC 0x45535201
@@ -20,7 +23,7 @@ struct esr_context {
 };
 #endif
 
-static inline struct _aarch64_ctx *first_ctx(ucontext_t *uc)
+static inline struct _aarch64_ctx *first_ctx(host_sigcontext *uc)
 {
     return (struct _aarch64_ctx *)&uc->uc_mcontext.__reserved;
 }
@@ -30,22 +33,22 @@ static inline struct _aarch64_ctx *next_ctx(struct _aarch64_ctx *hdr)
     return (struct _aarch64_ctx *)((char *)hdr + hdr->size);
 }
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.pc;
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.pc = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     struct _aarch64_ctx *hdr;
     uint32_t insn;
diff --git a/linux-user/include/host/alpha/host-signal.h b/linux-user/include/host/alpha/host-signal.h
index a44d670f2b..4f9e2abc4b 100644
--- a/linux-user/include/host/alpha/host-signal.h
+++ b/linux-user/include/host/alpha/host-signal.h
@@ -11,22 +11,25 @@
 #ifndef ALPHA_HOST_SIGNAL_H
 #define ALPHA_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.sc_pc;
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.sc_pc = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     uint32_t *pc = (uint32_t *)host_signal_pc(uc);
     uint32_t insn = *pc;
diff --git a/linux-user/include/host/arm/host-signal.h b/linux-user/include/host/arm/host-signal.h
index bbeb4ffefb..faba496d24 100644
--- a/linux-user/include/host/arm/host-signal.h
+++ b/linux-user/include/host/arm/host-signal.h
@@ -11,22 +11,25 @@
 #ifndef ARM_HOST_SIGNAL_H
 #define ARM_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.arm_pc;
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.arm_pc = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     /*
      * In the FSR, bit 11 is WnR, assuming a v6 or
diff --git a/linux-user/include/host/i386/host-signal.h b/linux-user/include/host/i386/host-signal.h
index fd36f06bda..e2b64f077f 100644
--- a/linux-user/include/host/i386/host-signal.h
+++ b/linux-user/include/host/i386/host-signal.h
@@ -11,22 +11,25 @@
 #ifndef I386_HOST_SIGNAL_H
 #define I386_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.gregs[REG_EIP];
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.gregs[REG_EIP] = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     return uc->uc_mcontext.gregs[REG_TRAPNO] == 0xe
         && (uc->uc_mcontext.gregs[REG_ERR] & 0x2);
diff --git a/linux-user/include/host/loongarch64/host-signal.h b/linux-user/include/host/loongarch64/host-signal.h
index a9dfe0c688..d33c3fc03e 100644
--- a/linux-user/include/host/loongarch64/host-signal.h
+++ b/linux-user/include/host/loongarch64/host-signal.h
@@ -11,22 +11,25 @@
 #ifndef LOONGARCH64_HOST_SIGNAL_H
 #define LOONGARCH64_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.__pc;
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.__pc = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     const uint32_t *pinsn = (const uint32_t *)host_signal_pc(uc);
     uint32_t insn = pinsn[0];
diff --git a/linux-user/include/host/mips/host-signal.h b/linux-user/include/host/mips/host-signal.h
index ff840dd491..0dbc5cecfd 100644
--- a/linux-user/include/host/mips/host-signal.h
+++ b/linux-user/include/host/mips/host-signal.h
@@ -11,17 +11,20 @@
 #ifndef MIPS_HOST_SIGNAL_H
 #define MIPS_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.pc;
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.pc = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
@@ -30,7 +33,7 @@ static inline void *host_signal_mask(ucontext_t *uc)
 #error "Unsupported encoding"
 #endif
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     uint32_t insn = *(uint32_t *)host_signal_pc(uc);
 
diff --git a/linux-user/include/host/ppc/host-signal.h b/linux-user/include/host/ppc/host-signal.h
index 730a321d98..b80384d135 100644
--- a/linux-user/include/host/ppc/host-signal.h
+++ b/linux-user/include/host/ppc/host-signal.h
@@ -11,22 +11,25 @@
 #ifndef PPC_HOST_SIGNAL_H
 #define PPC_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.regs->nip;
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.regs->nip = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     return uc->uc_mcontext.regs->trap != 0x400
         && (uc->uc_mcontext.regs->dsisr & 0x02000000);
diff --git a/linux-user/include/host/riscv/host-signal.h b/linux-user/include/host/riscv/host-signal.h
index aceae544f2..decacb2325 100644
--- a/linux-user/include/host/riscv/host-signal.h
+++ b/linux-user/include/host/riscv/host-signal.h
@@ -11,22 +11,25 @@
 #ifndef RISCV_HOST_SIGNAL_H
 #define RISCV_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.__gregs[REG_PC];
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.__gregs[REG_PC] = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     /*
      * Detect store by reading the instruction at the program counter.
diff --git a/linux-user/include/host/s390/host-signal.h b/linux-user/include/host/s390/host-signal.h
index e454cea54a..6f191e64d7 100644
--- a/linux-user/include/host/s390/host-signal.h
+++ b/linux-user/include/host/s390/host-signal.h
@@ -11,22 +11,25 @@
 #ifndef S390_HOST_SIGNAL_H
 #define S390_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.psw.addr;
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.psw.addr = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     uint16_t *pinsn = (uint16_t *)host_signal_pc(uc);
 
diff --git a/linux-user/include/host/sparc/host-signal.h b/linux-user/include/host/sparc/host-signal.h
index 158918f2ec..871b6bb269 100644
--- a/linux-user/include/host/sparc/host-signal.h
+++ b/linux-user/include/host/sparc/host-signal.h
@@ -11,7 +11,10 @@
 #ifndef SPARC_HOST_SIGNAL_H
 #define SPARC_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* FIXME: the third argument to a SA_SIGINFO handler is *not* ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
 #ifdef __arch64__
     return uc->uc_mcontext.mc_gregs[MC_PC];
@@ -20,7 +23,7 @@ static inline uintptr_t host_signal_pc(ucontext_t *uc)
 #endif
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
 #ifdef __arch64__
     uc->uc_mcontext.mc_gregs[MC_PC] = pc;
@@ -29,12 +32,12 @@ static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
 #endif
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     uint32_t insn = *(uint32_t *)host_signal_pc(uc);
 
diff --git a/linux-user/include/host/x86_64/host-signal.h b/linux-user/include/host/x86_64/host-signal.h
index d64d076625..5a7627fedc 100644
--- a/linux-user/include/host/x86_64/host-signal.h
+++ b/linux-user/include/host/x86_64/host-signal.h
@@ -10,22 +10,25 @@
 #ifndef X86_64_HOST_SIGNAL_H
 #define X86_64_HOST_SIGNAL_H
 
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
+/* The third argument to a SA_SIGINFO handler is ucontext_t. */
+typedef ucontext_t host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *uc)
 {
     return uc->uc_mcontext.gregs[REG_RIP];
 }
 
-static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
 {
     uc->uc_mcontext.gregs[REG_RIP] = pc;
 }
 
-static inline void *host_signal_mask(ucontext_t *uc)
+static inline void *host_signal_mask(host_sigcontext *uc)
 {
     return &uc->uc_sigmask;
 }
 
-static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
 {
     return uc->uc_mcontext.gregs[REG_TRAPNO] == 0xe
         && (uc->uc_mcontext.gregs[REG_ERR] & 0x2);
diff --git a/linux-user/signal.c b/linux-user/signal.c
index 0c61459d4a..27a0ff30e9 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -800,7 +800,7 @@ void queue_signal(CPUArchState *env, int sig, int si_type,
 /* 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;
+    host_sigcontext *uc = (host_sigcontext *)puc;
     uintptr_t pcreg = host_signal_pc(uc);
 
     if (pcreg > (uintptr_t)safe_syscall_start
@@ -815,7 +815,7 @@ static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
     CPUState *cpu = env_cpu(env);
     TaskState *ts = cpu->opaque;
     target_siginfo_t tinfo;
-    ucontext_t *uc = puc;
+    host_sigcontext *uc = puc;
     struct emulated_sigtable *k;
     int guest_sig;
     uintptr_t pc = 0;
