The comment re ELF_NREG is incorrect or out-of-date.
Make use of the fact that target_elf_gregset_t is a
proper structure by using target_user_regs_struct.

Drop target_elf_greg_t and tswapreg.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/i386/target_elf.h | 14 +++++---------
 linux-user/i386/elfload.c    | 36 +++++++++++++++++-------------------
 2 files changed, 22 insertions(+), 28 deletions(-)

diff --git a/linux-user/i386/target_elf.h b/linux-user/i386/target_elf.h
index eb286868e1..f89ac0b611 100644
--- a/linux-user/i386/target_elf.h
+++ b/linux-user/i386/target_elf.h
@@ -8,22 +8,18 @@
 #ifndef I386_TARGET_ELF_H
 #define I386_TARGET_ELF_H
 
+#include "target_ptrace.h"
+
 #define HAVE_ELF_HWCAP          1
 #define HAVE_ELF_PLATFORM       1
 #define HAVE_ELF_CORE_DUMP      1
 
 /*
- * Note that ELF_NREG should be 19 as there should be place for
- * TRAPNO and ERR "registers" as well but linux doesn't dump those.
- *
- * See linux kernel: arch/x86/include/asm/elf.h
+ * See linux kernel: arch/x86/include/asm/elf.h, where elf_gregset_t
+ * is mapped to struct user_regs_struct via sizeof.
  */
-#define ELF_NREG                17
-
-typedef abi_ulong target_elf_greg_t;
-
 typedef struct target_elf_gregset_t {
-    target_elf_greg_t regs[ELF_NREG];
+    struct target_user_regs_struct pt;
 } target_elf_gregset_t;
 
 #endif
diff --git a/linux-user/i386/elfload.c b/linux-user/i386/elfload.c
index 279aeb8116..26b12001a3 100644
--- a/linux-user/i386/elfload.c
+++ b/linux-user/i386/elfload.c
@@ -25,25 +25,23 @@ const char *get_elf_platform(CPUState *cs)
     return elf_platform[family - 3];
 }
 
-#define tswapreg(ptr)   tswapal(ptr)
-
 void elf_core_copy_regs(target_elf_gregset_t *r, const CPUX86State *env)
 {
-    r->regs[0] = tswapreg(env->regs[R_EBX]);
-    r->regs[1] = tswapreg(env->regs[R_ECX]);
-    r->regs[2] = tswapreg(env->regs[R_EDX]);
-    r->regs[3] = tswapreg(env->regs[R_ESI]);
-    r->regs[4] = tswapreg(env->regs[R_EDI]);
-    r->regs[5] = tswapreg(env->regs[R_EBP]);
-    r->regs[6] = tswapreg(env->regs[R_EAX]);
-    r->regs[7] = tswapreg(env->segs[R_DS].selector & 0xffff);
-    r->regs[8] = tswapreg(env->segs[R_ES].selector & 0xffff);
-    r->regs[9] = tswapreg(env->segs[R_FS].selector & 0xffff);
-    r->regs[10] = tswapreg(env->segs[R_GS].selector & 0xffff);
-    r->regs[11] = tswapreg(get_task_state(env_cpu_const(env))->orig_ax);
-    r->regs[12] = tswapreg(env->eip);
-    r->regs[13] = tswapreg(env->segs[R_CS].selector & 0xffff);
-    r->regs[14] = tswapreg(env->eflags);
-    r->regs[15] = tswapreg(env->regs[R_ESP]);
-    r->regs[16] = tswapreg(env->segs[R_SS].selector & 0xffff);
+    r->pt.bx = tswapal(env->regs[R_EBX]);
+    r->pt.cx = tswapal(env->regs[R_ECX]);
+    r->pt.dx = tswapal(env->regs[R_EDX]);
+    r->pt.si = tswapal(env->regs[R_ESI]);
+    r->pt.di = tswapal(env->regs[R_EDI]);
+    r->pt.bp = tswapal(env->regs[R_EBP]);
+    r->pt.ax = tswapal(env->regs[R_EAX]);
+    r->pt.ds = tswapal(env->segs[R_DS].selector & 0xffff);
+    r->pt.es = tswapal(env->segs[R_ES].selector & 0xffff);
+    r->pt.fs = tswapal(env->segs[R_FS].selector & 0xffff);
+    r->pt.gs = tswapal(env->segs[R_GS].selector & 0xffff);
+    r->pt.orig_ax = tswapal(get_task_state(env_cpu_const(env))->orig_ax);
+    r->pt.ip = tswapal(env->eip);
+    r->pt.cs = tswapal(env->segs[R_CS].selector & 0xffff);
+    r->pt.flags = tswapal(env->eflags);
+    r->pt.sp = tswapal(env->regs[R_ESP]);
+    r->pt.ss = tswapal(env->segs[R_SS].selector & 0xffff);
 }
-- 
2.43.0