Because the linux-user kuser page handling is currently implemented
by detecting magic addresses in the unnamed 0xaa trap, we cannot
simply remove nios2_cpu_tlb_fill and rely on the fallback code.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/nios2/cpu.h    | 6 ++++++
 target/nios2/cpu.c    | 6 ++++--
 target/nios2/helper.c | 7 ++++---
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/target/nios2/cpu.h b/target/nios2/cpu.h
index a80587338a..1a69ed7a49 100644
--- a/target/nios2/cpu.h
+++ b/target/nios2/cpu.h
@@ -218,9 +218,15 @@ static inline int cpu_mmu_index(CPUNios2State *env, bool ifetch)
                                                   MMU_SUPERVISOR_IDX;
 }
 
+#ifdef CONFIG_USER_ONLY
+void nios2_cpu_record_sigsegv(CPUState *cpu, vaddr addr,
+                              MMUAccessType access_type,
+                              bool maperr, uintptr_t ra);
+#else
 bool nios2_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                         MMUAccessType access_type, int mmu_idx,
                         bool probe, uintptr_t retaddr);
+#endif
 
 static inline int cpu_interrupts_enabled(CPUNios2State *env)
 {
diff --git a/target/nios2/cpu.c b/target/nios2/cpu.c
index 947bb09bc1..421cad114a 100644
--- a/target/nios2/cpu.c
+++ b/target/nios2/cpu.c
@@ -220,9 +220,11 @@ static const struct SysemuCPUOps nios2_sysemu_ops = {
 
 static const struct TCGCPUOps nios2_tcg_ops = {
     .initialize = nios2_tcg_init,
-    .tlb_fill = nios2_cpu_tlb_fill,
 
-#ifndef CONFIG_USER_ONLY
+#ifdef CONFIG_USER_ONLY
+    .record_sigsegv = nios2_cpu_record_sigsegv,
+#else
+    .tlb_fill = nios2_cpu_tlb_fill,
     .cpu_exec_interrupt = nios2_cpu_exec_interrupt,
     .do_interrupt = nios2_cpu_do_interrupt,
     .do_unaligned_access = nios2_cpu_do_unaligned_access,
diff --git a/target/nios2/helper.c b/target/nios2/helper.c
index 53be8398e9..e5c98650e1 100644
--- a/target/nios2/helper.c
+++ b/target/nios2/helper.c
@@ -38,10 +38,11 @@ void nios2_cpu_do_interrupt(CPUState *cs)
     env->regs[R_EA] = env->regs[R_PC] + 4;
 }
 
-bool nios2_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
-                        MMUAccessType access_type, int mmu_idx,
-                        bool probe, uintptr_t retaddr)
+void nios2_cpu_record_sigsegv(CPUState *cs, vaddr addr,
+                              MMUAccessType access_type,
+                              bool maperr, uintptr_t retaddr)
 {
+    /* FIXME: Disentangle kuser page from linux-user sigsegv handling. */
     cs->exception_index = 0xaa;
     cpu_loop_exit_restore(cs, retaddr);
 }
-- 
2.25.1

On 10/1/21 19:11, Richard Henderson wrote:
> Because the linux-user kuser page handling is currently implemented
> by detecting magic addresses in the unnamed 0xaa trap, we cannot
> simply remove nios2_cpu_tlb_fill and rely on the fallback code.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/nios2/cpu.h    | 6 ++++++
>  target/nios2/cpu.c    | 6 ++++--
>  target/nios2/helper.c | 7 ++++---
>  3 files changed, 14 insertions(+), 5 deletions(-)

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>