Merge remote-tracking branch 'remotes/rth-gitlab/tags/pull-tcg-20220211' into staging

Fix safe_syscall_base for sparc64.
Fix host signal handling for sparc64-linux.
Speedups for jump cache and work list probing.
Fix for exception replays.
Raise guest SIGBUS for user-only misaligned accesses.

# gpg: Signature made Fri 11 Feb 2022 01:27:16 GMT
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [full]
# Primary key fingerprint: 7A48 1E78 868B 4DB6 A85A  05C0 64DF 38E8 AF7E 215F

* remotes/rth-gitlab/tags/pull-tcg-20220211: (34 commits)
  tests/tcg/multiarch: Add sigbus.c
  tcg/sparc: Support unaligned access for user-only
  tcg/sparc: Add tcg_out_jmpl_const for better tail calls
  tcg/sparc: Use the constant pool for 64-bit constants
  tcg/sparc: Convert patch_reloc to return bool
  tcg/sparc: Improve code gen for shifted 32-bit constants
  tcg/sparc: Add scratch argument to tcg_out_movi_int
  tcg/sparc: Split out tcg_out_movi_imm32
  tcg/sparc: Use tcg_out_movi_imm13 in tcg_out_addsub2_i64
  tcg/mips: Support unaligned access for softmmu
  tcg/mips: Support unaligned access for user-only
  tcg/arm: Support raising sigbus for user-only
  tcg/arm: Reserve a register for guest_base
  tcg/arm: Support unaligned access for softmmu
  tcg/arm: Check alignment for ldrd and strd
  tcg/arm: Remove use_armv6_instructions
  tcg/arm: Remove use_armv5t_instructions
  tcg/arm: Drop support for armv4 and armv5 hosts
  tcg/loongarch64: Support raising sigbus for user-only
  tcg/tci: Support raising sigbus for user-only
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

13 files changed, 185 insertions, 107 deletions

diff --git a/linux-user/include/host/aarch64/host-signal.h b/linux-user/include/host/aarch64/host-signal.h
index 9770b36dc1..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;
 }
@@ -30,17 +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 bool host_signal_write(siginfo_t *info, 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, 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 f4c942948a..4f9e2abc4b 100644
--- a/linux-user/include/host/alpha/host-signal.h
+++ b/linux-user/include/host/alpha/host-signal.h
@@ -11,17 +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 bool host_signal_write(siginfo_t *info, 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, 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 6c095773c0..faba496d24 100644
--- a/linux-user/include/host/arm/host-signal.h
+++ b/linux-user/include/host/arm/host-signal.h
@@ -11,17 +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 bool host_signal_write(siginfo_t *info, 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, 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 abe1ece5c9..e2b64f077f 100644
--- a/linux-user/include/host/i386/host-signal.h
+++ b/linux-user/include/host/i386/host-signal.h
@@ -11,17 +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 bool host_signal_write(siginfo_t *info, 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, 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 7effa24251..d33c3fc03e 100644
--- a/linux-user/include/host/loongarch64/host-signal.h
+++ b/linux-user/include/host/loongarch64/host-signal.h
@@ -11,17 +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 bool host_signal_write(siginfo_t *info, 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, 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 c666ed8c3f..0dbc5cecfd 100644
--- a/linux-user/include/host/mips/host-signal.h
+++ b/linux-user/include/host/mips/host-signal.h
@@ -11,21 +11,29 @@
 #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(host_sigcontext *uc)
+{
+    return &uc->uc_sigmask;
+}
+
 #if defined(__misp16) || defined(__mips_micromips)
 #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 1d8e658ff7..b80384d135 100644
--- a/linux-user/include/host/ppc/host-signal.h
+++ b/linux-user/include/host/ppc/host-signal.h
@@ -11,17 +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 bool host_signal_write(siginfo_t *info, 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, 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 a4f170efb0..decacb2325 100644
--- a/linux-user/include/host/riscv/host-signal.h
+++ b/linux-user/include/host/riscv/host-signal.h
@@ -11,17 +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 bool host_signal_write(siginfo_t *info, 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, 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 a524f2ab00..6f191e64d7 100644
--- a/linux-user/include/host/s390/host-signal.h
+++ b/linux-user/include/host/s390/host-signal.h
@@ -11,17 +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 bool host_signal_write(siginfo_t *info, 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, 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
deleted file mode 100644
index 7342936071..0000000000
--- a/linux-user/include/host/sparc/host-signal.h
+++ /dev/null
@@ -1,63 +0,0 @@
-/*
- * host-signal.h: signal info dependent on the host architecture
- *
- * Copyright (c) 2003-2005 Fabrice Bellard
- * Copyright (c) 2021 Linaro Limited
- *
- * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
- * See the COPYING file in the top-level directory.
- */
-
-#ifndef SPARC_HOST_SIGNAL_H
-#define SPARC_HOST_SIGNAL_H
-
-static inline uintptr_t host_signal_pc(ucontext_t *uc)
-{
-#ifdef __arch64__
-    return uc->uc_mcontext.mc_gregs[MC_PC];
-#else
-    return uc->uc_mcontext.gregs[REG_PC];
-#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);
-
-    if ((insn >> 30) == 3) {
-        switch ((insn >> 19) & 0x3f) {
-        case 0x05: /* stb */
-        case 0x15: /* stba */
-        case 0x06: /* sth */
-        case 0x16: /* stha */
-        case 0x04: /* st */
-        case 0x14: /* sta */
-        case 0x07: /* std */
-        case 0x17: /* stda */
-        case 0x0e: /* stx */
-        case 0x1e: /* stxa */
-        case 0x24: /* stf */
-        case 0x34: /* stfa */
-        case 0x27: /* stdf */
-        case 0x37: /* stdfa */
-        case 0x26: /* stqf */
-        case 0x36: /* stqfa */
-        case 0x25: /* stfsr */
-        case 0x3c: /* casa */
-        case 0x3e: /* casxa */
-            return true;
-        }
-    }
-    return false;
-}
-
-#endif
diff --git a/linux-user/include/host/sparc64/host-signal.h b/linux-user/include/host/sparc64/host-signal.h
index 1191fe2d40..64957c2bca 100644
--- a/linux-user/include/host/sparc64/host-signal.h
+++ b/linux-user/include/host/sparc64/host-signal.h
@@ -1 +1,64 @@
-#include "../sparc/host-signal.h"
+/*
+ * host-signal.h: signal info dependent on the host architecture
+ *
+ * Copyright (c) 2003-2005 Fabrice Bellard
+ * Copyright (c) 2021 Linaro Limited
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef SPARC64_HOST_SIGNAL_H
+#define SPARC64_HOST_SIGNAL_H
+
+/* The third argument to a SA_SIGINFO handler is struct sigcontext.  */
+typedef struct sigcontext host_sigcontext;
+
+static inline uintptr_t host_signal_pc(host_sigcontext *sc)
+{
+    return sc->sigc_regs.tpc;
+}
+
+static inline void host_signal_set_pc(host_sigcontext *sc, uintptr_t pc)
+{
+    sc->sigc_regs.tpc = pc;
+    sc->sigc_regs.tnpc = pc + 4;
+}
+
+static inline void *host_signal_mask(host_sigcontext *sc)
+{
+    return &sc->sigc_mask;
+}
+
+static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
+{
+    uint32_t insn = *(uint32_t *)host_signal_pc(uc);
+
+    if ((insn >> 30) == 3) {
+        switch ((insn >> 19) & 0x3f) {
+        case 0x05: /* stb */
+        case 0x15: /* stba */
+        case 0x06: /* sth */
+        case 0x16: /* stha */
+        case 0x04: /* st */
+        case 0x14: /* sta */
+        case 0x07: /* std */
+        case 0x17: /* stda */
+        case 0x0e: /* stx */
+        case 0x1e: /* stxa */
+        case 0x24: /* stf */
+        case 0x34: /* stfa */
+        case 0x27: /* stdf */
+        case 0x37: /* stdfa */
+        case 0x26: /* stqf */
+        case 0x36: /* stqfa */
+        case 0x25: /* stfsr */
+        case 0x3c: /* casa */
+        case 0x3e: /* casxa */
+            return true;
+        }
+    }
+    return false;
+}
+
+#endif
diff --git a/linux-user/include/host/x86_64/host-signal.h b/linux-user/include/host/x86_64/host-signal.h
index c71d597eb2..5a7627fedc 100644
--- a/linux-user/include/host/x86_64/host-signal.h
+++ b/linux-user/include/host/x86_64/host-signal.h
@@ -10,17 +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 bool host_signal_write(siginfo_t *info, 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, 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 32854bb375..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
@@ -815,11 +815,12 @@ 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;
     bool sync_sig = false;
+    void *sigmask = host_signal_mask(uc);
 
     /*
      * Non-spoofed SIGSEGV and SIGBUS are synchronous, and need special
@@ -849,8 +850,7 @@ static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
             if (info->si_code == SEGV_ACCERR && h2g_valid(host_addr)) {
                 /* If this was a write to a TB protected page, restart. */
                 if (is_write &&
-                    handle_sigsegv_accerr_write(cpu, &uc->uc_sigmask,
-                                                pc, guest_addr)) {
+                    handle_sigsegv_accerr_write(cpu, sigmask, pc, guest_addr)) {
                     return;
                 }
 
@@ -865,10 +865,10 @@ static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
                 }
             }
 
-            sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
+            sigprocmask(SIG_SETMASK, sigmask, NULL);
             cpu_loop_exit_sigsegv(cpu, guest_addr, access_type, maperr, pc);
         } else {
-            sigprocmask(SIG_SETMASK, &uc->uc_sigmask, NULL);
+            sigprocmask(SIG_SETMASK, sigmask, NULL);
             if (info->si_code == BUS_ADRALN) {
                 cpu_loop_exit_sigbus(cpu, guest_addr, access_type, pc);
             }
@@ -909,17 +909,15 @@ static void host_signal_handler(int host_sig, siginfo_t *info, void *puc)
      * now and it getting out to the main loop. Signals will be
      * unblocked again in process_pending_signals().
      *
-     * WARNING: we cannot use sigfillset() here because the uc_sigmask
+     * WARNING: we cannot use sigfillset() here because the sigmask
      * field is a kernel sigset_t, which is much smaller than the
      * libc sigset_t which sigfillset() operates on. Using sigfillset()
      * would write 0xff bytes off the end of the structure and trash
      * data on the struct.
-     * We can't use sizeof(uc->uc_sigmask) either, because the libc
-     * headers define the struct field with the wrong (too large) type.
      */
-    memset(&uc->uc_sigmask, 0xff, SIGSET_T_SIZE);
-    sigdelset(&uc->uc_sigmask, SIGSEGV);
-    sigdelset(&uc->uc_sigmask, SIGBUS);
+    memset(sigmask, 0xff, SIGSET_T_SIZE);
+    sigdelset(sigmask, SIGSEGV);
+    sigdelset(sigmask, SIGBUS);
 
     /* interrupt the virtual CPU as soon as possible */
     cpu_exit(thread_cpu);