[PATCH] linux-user/elfload: add s390x core dumping support

[Ilya Leoshkevich <iii@linux.ibm.com>]

Provide the following definitions required by the common code:

* ELF_NREG: with the value of sizeof(s390_regs) / sizeof(long).
* target_elf_gregset_t: define it like all the other arches do.
* elf_core_copy_regs(): similar to kernel's s390_regs_get().
* USE_ELF_CORE_DUMP.
* ELF_EXEC_PAGESIZE.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 linux-user/elfload.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index c6731013fd..4e45bd1539 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -1385,6 +1385,39 @@ static inline void init_thread(struct target_pt_regs *regs, struct image_info *i
     regs->gprs[15] = infop->start_stack;
 }
 
+/* See linux kernel: arch/s390/include/uapi/asm/ptrace.h (s390_regs).  */
+#define ELF_NREG 27
+typedef target_elf_greg_t target_elf_gregset_t[ELF_NREG];
+
+enum {
+    TARGET_REG_PSWM = 0,
+    TARGET_REG_PSWA = 1,
+    TARGET_REG_GPRS = 2,
+    TARGET_REG_ARS = 18,
+    TARGET_REG_ORIG_R2 = 26,
+};
+
+static void elf_core_copy_regs(target_elf_gregset_t *regs,
+                               const CPUS390XState *env)
+{
+    int i;
+    uint32_t *aregs;
+
+    (*regs)[TARGET_REG_PSWM] = tswapreg(env->psw.mask);
+    (*regs)[TARGET_REG_PSWA] = tswapreg(env->psw.addr);
+    for (i = 0; i < 16; i++) {
+        (*regs)[TARGET_REG_GPRS + i] = tswapreg(env->regs[i]);
+    }
+    aregs = (uint32_t *)&((*regs)[TARGET_REG_ARS]);
+    for (i = 0; i < 16; i++) {
+        aregs[i] = tswap32(env->aregs[i]);
+    }
+    (*regs)[TARGET_REG_ORIG_R2] = 0;
+}
+
+#define USE_ELF_CORE_DUMP
+#define ELF_EXEC_PAGESIZE 4096
+
 #endif /* TARGET_S390X */
 
 #ifdef TARGET_RISCV
-- 
2.29.2