linux-user: Extract MIPS abiflags from ELF file

Read MIPS.abiflags section from ELF file into Mips_elf_abiflags_v0 struct.

Reviewed-by: Aleksandar Markovic <amarkovic@wavecomp.com>
Signed-off-by: Stefan Markovic <smarkovic@wavecomp.com>

linux-user/elfload.c

@@ -1517,11 +1517,25 @@ static void bswap_sym(struct elf_sym *sym)
     bswaptls(&sym->st_size);
     bswap16s(&sym->st_shndx);
 }
+
+#ifdef TARGET_MIPS
+static void bswap_mips_abiflags(Mips_elf_abiflags_v0 *abiflags)
+{
+    bswap16s(&abiflags->version);
+    bswap32s(&abiflags->ases);
+    bswap32s(&abiflags->isa_ext);
+    bswap32s(&abiflags->flags1);
+    bswap32s(&abiflags->flags2);
+}
+#endif
 #else
 static inline void bswap_ehdr(struct elfhdr *ehdr) { }
 static inline void bswap_phdr(struct elf_phdr *phdr, int phnum) { }
 static inline void bswap_shdr(struct elf_shdr *shdr, int shnum) { }
 static inline void bswap_sym(struct elf_sym *sym) { }
+#ifdef TARGET_MIPS
+static inline void bswap_mips_abiflags(Mips_elf_abiflags_v0 *abiflags) { }
+#endif
 #endif
 
 #ifdef USE_ELF_CORE_DUMP
@@ -2364,6 +2378,25 @@ static void load_elf_image(const char *image_name, int image_fd,
                 goto exit_errmsg;
             }
             *pinterp_name = interp_name;
+#ifdef TARGET_MIPS
+        } else if (eppnt->p_type == PT_MIPS_ABIFLAGS) {
+            Mips_elf_abiflags_v0 abiflags;
+            if (eppnt->p_filesz < sizeof(Mips_elf_abiflags_v0)) {
+                errmsg = "Invalid PT_MIPS_ABIFLAGS entry";
+                goto exit_errmsg;
+            }
+            if (eppnt->p_offset + eppnt->p_filesz <= BPRM_BUF_SIZE) {
+                memcpy(&abiflags, bprm_buf + eppnt->p_offset,
+                       sizeof(Mips_elf_abiflags_v0));
+            } else {
+                retval = pread(image_fd, &abiflags, sizeof(Mips_elf_abiflags_v0),
+                               eppnt->p_offset);
+                if (retval != sizeof(Mips_elf_abiflags_v0)) {
+                    goto exit_perror;
+                }
+            }
+            bswap_mips_abiflags(&abiflags);
+#endif
         }
     }