- Split out host signal handing from accel/tcg/user-exec.c

to linux-user/host/arch/host-signal.h
 - Replace TCGCPUOps.tlb_fill with TCGCPUOps.record_sigsegv for user-only
 - Add TCGCPUOps.record_sigbus for user-only
 - Remove a lot of target-specific cpu_loop handling for signals,
   now accomplished with generic code.
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Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20211102' into staging

- Split out host signal handing from accel/tcg/user-exec.c
  to linux-user/host/arch/host-signal.h
- Replace TCGCPUOps.tlb_fill with TCGCPUOps.record_sigsegv for user-only
- Add TCGCPUOps.record_sigbus for user-only
- Remove a lot of target-specific cpu_loop handling for signals,
  now accomplished with generic code.

# gpg: Signature made Tue 02 Nov 2021 07:06:14 AM EDT
# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
# gpg: Good signature from "Richard Henderson <richard.henderson@linaro.org>" [ultimate]

* remotes/rth/tags/pull-tcg-20211102: (60 commits)
  linux-user: Handle BUS_ADRALN in host_signal_handler
  tcg: Add helper_unaligned_{ld,st} for user-only sigbus
  accel/tcg: Report unaligned load/store for user-only
  accel/tcg: Report unaligned atomics for user-only
  target/sparc: Set fault address in sparc_cpu_do_unaligned_access
  target/sparc: Split out build_sfsr
  target/sparc: Remove DEBUG_UNALIGNED
  target/sh4: Set fault address in superh_cpu_do_unaligned_access
  target/s390x: Implement s390x_cpu_record_sigbus
  linux-user/ppc: Remove POWERPC_EXCP_ALIGN handling
  target/ppc: Restrict ppc_cpu_do_unaligned_access to sysemu
  target/ppc: Set fault address in ppc_cpu_do_unaligned_access
  target/ppc: Move SPR_DSISR setting to powerpc_excp
  target/microblaze: Do not set MO_ALIGN for user-only
  linux-user/hppa: Remove EXCP_UNALIGN handling
  target/arm: Implement arm_cpu_record_sigbus
  target/alpha: Implement alpha_cpu_record_sigbus
  linux-user: Add cpu_loop_exit_sigbus
  hw/core: Add TCGCPUOps.record_sigbus
  accel/tcg: Restrict TCGCPUOps::tlb_fill() to sysemu
  ...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

include/exec/exec-all.h

@@ -664,16 +664,55 @@ static inline tb_page_addr_t get_page_addr_code_hostp(CPUArchState *env,
 }
 
 /**
- * cpu_signal_handler
- * @signum: host signal number
- * @pinfo: host siginfo_t
- * @puc: host ucontext_t
+ * adjust_signal_pc:
+ * @pc: raw pc from the host signal ucontext_t.
+ * @is_write: host memory operation was write, or read-modify-write.
  *
- * To be called from the SIGBUS and SIGSEGV signal handler to inform the
- * virtual cpu of exceptions.  Returns true if the signal was handled by
- * the virtual CPU.
+ * Alter @pc as required for unwinding.  Return the type of the
+ * guest memory access -- host reads may be for guest execution.
  */
-int cpu_signal_handler(int signum, void *pinfo, void *puc);
+MMUAccessType adjust_signal_pc(uintptr_t *pc, bool is_write);
+
+/**
+ * handle_sigsegv_accerr_write:
+ * @cpu: the cpu context
+ * @old_set: the sigset_t from the signal ucontext_t
+ * @host_pc: the host pc, adjusted for the signal
+ * @host_addr: the host address of the fault
+ *
+ * Return true if the write fault has been handled, and should be re-tried.
+ */
+bool handle_sigsegv_accerr_write(CPUState *cpu, sigset_t *old_set,
+                                 uintptr_t host_pc, abi_ptr guest_addr);
+
+/**
+ * cpu_loop_exit_sigsegv:
+ * @cpu: the cpu context
+ * @addr: the guest address of the fault
+ * @access_type: access was read/write/execute
+ * @maperr: true for invalid page, false for permission fault
+ * @ra: host pc for unwinding
+ *
+ * Use the TCGCPUOps hook to record cpu state, do guest operating system
+ * specific things to raise SIGSEGV, and jump to the main cpu loop.
+ */
+void QEMU_NORETURN cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr,
+                                         MMUAccessType access_type,
+                                         bool maperr, uintptr_t ra);
+
+/**
+ * cpu_loop_exit_sigbus:
+ * @cpu: the cpu context
+ * @addr: the guest address of the alignment fault
+ * @access_type: access was read/write/execute
+ * @ra: host pc for unwinding
+ *
+ * Use the TCGCPUOps hook to record cpu state, do guest operating system
+ * specific things to raise SIGBUS, and jump to the main cpu loop.
+ */
+void QEMU_NORETURN cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr,
+                                        MMUAccessType access_type,
+                                        uintptr_t ra);
 
 #else
 static inline void mmap_lock(void) {}