target/ppc: Implement ppc_cpu_record_sigsegv

Record DAR, DSISR, and exception_index.  That last means
that we must exit to cpu_loop ourselves, instead of letting
exception_index being overwritten.

This is exactly what the user-mode ppc_cpu_tlb_fill does,
so simply rename it as ppc_cpu_record_sigsegv.

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

1 files changed, 11 insertions, 4 deletions

diff --git a/target/ppc/user_only_helper.c b/target/ppc/user_only_helper.c
index aa3f867596..7ff76f7a06 100644
--- a/target/ppc/user_only_helper.c
+++ b/target/ppc/user_only_helper.c
@@ -21,16 +21,23 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "exec/exec-all.h"
+#include "internal.h"
 
-
-bool ppc_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
-                      MMUAccessType access_type, int mmu_idx,
-                      bool probe, uintptr_t retaddr)
+void ppc_cpu_record_sigsegv(CPUState *cs, vaddr address,
+                            MMUAccessType access_type,
+                            bool maperr, uintptr_t retaddr)
 {
     PowerPCCPU *cpu = POWERPC_CPU(cs);
     CPUPPCState *env = &cpu->env;
     int exception, error_code;
 
+    /*
+     * Both DSISR and the "trap number" (exception vector offset,
+     * looked up from exception_index) are present in the linux-user
+     * signal frame.
+     * FIXME: we don't actually populate the trap number properly.
+     * It would be easiest to fill in an env->trap value now.
+     */
     if (access_type == MMU_INST_FETCH) {
         exception = POWERPC_EXCP_ISI;
         error_code = 0x40000000;