target/s390x: Implement s390_cpu_record_sigsegv

Move the masking of the address from cpu_loop into
s390_cpu_record_sigsegv -- this is governed by hw, not linux.
This does mean we have to raise our own exception, rather
than return to the fallback.

Use maperr to choose between PGM_PROTECTION and PGM_ADDRESSING.
Use the appropriate si_code for each in cpu_loop.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

3 files changed, 25 insertions, 12 deletions

diff --git a/target/s390x/cpu.c b/target/s390x/cpu.c
index 7b7b05f..593dda7 100644
--- a/target/s390x/cpu.c
+++ b/target/s390x/cpu.c
@@ -266,9 +266,11 @@ static void s390_cpu_reset_full(DeviceState *dev)
 
 static const struct TCGCPUOps s390_tcg_ops = {
     .initialize = s390x_translate_init,
-    .tlb_fill = s390_cpu_tlb_fill,
 
-#if !defined(CONFIG_USER_ONLY)
+#ifdef CONFIG_USER_ONLY
+    .record_sigsegv = s390_cpu_record_sigsegv,
+#else
+    .tlb_fill = s390_cpu_tlb_fill,
     .cpu_exec_interrupt = s390_cpu_exec_interrupt,
     .do_interrupt = s390_cpu_do_interrupt,
     .debug_excp_handler = s390x_cpu_debug_excp_handler,
diff --git a/target/s390x/s390x-internal.h b/target/s390x/s390x-internal.h
index 27d4a03..163aa4f 100644
--- a/target/s390x/s390x-internal.h
+++ b/target/s390x/s390x-internal.h
@@ -270,13 +270,20 @@ ObjectClass *s390_cpu_class_by_name(const char *name);
 void s390x_cpu_debug_excp_handler(CPUState *cs);
 void s390_cpu_do_interrupt(CPUState *cpu);
 bool s390_cpu_exec_interrupt(CPUState *cpu, int int_req);
-bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
-                       MMUAccessType access_type, int mmu_idx,
-                       bool probe, uintptr_t retaddr);
 void s390x_cpu_do_unaligned_access(CPUState *cs, vaddr addr,
                                    MMUAccessType access_type, int mmu_idx,
                                    uintptr_t retaddr) QEMU_NORETURN;
 
+#ifdef CONFIG_USER_ONLY
+void s390_cpu_record_sigsegv(CPUState *cs, vaddr address,
+                             MMUAccessType access_type,
+                             bool maperr, uintptr_t retaddr);
+#else
+bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
+                       MMUAccessType access_type, int mmu_idx,
+                       bool probe, uintptr_t retaddr);
+#endif
+
 
 /* fpu_helper.c */
 uint32_t set_cc_nz_f32(float32 v);
diff --git a/target/s390x/tcg/excp_helper.c b/target/s390x/tcg/excp_helper.c
index 3d6662a..b923d08 100644
--- a/target/s390x/tcg/excp_helper.c
+++ b/target/s390x/tcg/excp_helper.c
@@ -89,16 +89,20 @@ void s390_cpu_do_interrupt(CPUState *cs)
     cs->exception_index = -1;
 }
 
-bool s390_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
-                       MMUAccessType access_type, int mmu_idx,
-                       bool probe, uintptr_t retaddr)
+void s390_cpu_record_sigsegv(CPUState *cs, vaddr address,
+                             MMUAccessType access_type,
+                             bool maperr, uintptr_t retaddr)
 {
     S390CPU *cpu = S390_CPU(cs);
 
-    trigger_pgm_exception(&cpu->env, PGM_ADDRESSING);
-    /* On real machines this value is dropped into LowMem.  Since this
-       is userland, simply put this someplace that cpu_loop can find it.  */
-    cpu->env.__excp_addr = address;
+    trigger_pgm_exception(&cpu->env, maperr ? PGM_ADDRESSING : PGM_PROTECTION);
+    /*
+     * On real machines this value is dropped into LowMem. Since this
+     * is userland, simply put this someplace that cpu_loop can find it.
+     * S390 only gives the page of the fault, not the exact address.
+     * C.f. the construction of TEC in mmu_translate().
+     */
+    cpu->env.__excp_addr = address & TARGET_PAGE_MASK;
     cpu_loop_exit_restore(cs, retaddr);
 }