Commit 768fe76e authored by YunQiang Su's avatar YunQiang Su Committed by Laurent Vivier
Browse files

linux-user: introduce functions to detect CPU type 



Add a function to return ELF e_flags and use it
to select the CPU model.

Signed-off-by: default avatarYunQiang Su <syq@debian.org>
[lv: split the patch and some cleanup in get_elf_eflags()]
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Message-Id: <20180220173307.25125-3-laurent@vivier.eu>
parent 542ca434

linux-user/elfload.c

+35 −0
Original line number Diff line number Diff line
@@ -2396,6 +2396,41 @@ give_up: 
    g_free(syms);

}



uint32_t get_elf_eflags(int fd)

{

    struct elfhdr ehdr;

    off_t offset;

    int ret;



    /* Read ELF header */

    offset = lseek(fd, 0, SEEK_SET);

    if (offset == (off_t) -1) {

        return 0;

    }

    ret = read(fd, &ehdr, sizeof(ehdr));

    if (ret < sizeof(ehdr)) {

        return 0;

    }

    offset = lseek(fd, offset, SEEK_SET);

    if (offset == (off_t) -1) {

        return 0;

    }



    /* Check ELF signature */

    if (!elf_check_ident(&ehdr)) {

        return 0;

    }



    /* check header */

    bswap_ehdr(&ehdr);

    if (!elf_check_ehdr(&ehdr)) {

        return 0;

    }



    /* return architecture id */

    return ehdr.e_flags;

}



int load_elf_binary(struct linux_binprm *bprm, struct image_info *info)

{

    struct image_info interp_info;

linux-user/main.c

+10 −10
Original line number Diff line number Diff line
@@ -4344,8 +4344,17 @@ int main(int argc, char **argv, char **envp) 


    init_qemu_uname_release();



    execfd = qemu_getauxval(AT_EXECFD);

    if (execfd == 0) {

        execfd = open(filename, O_RDONLY);

        if (execfd < 0) {

            printf("Error while loading %s: %s\n", filename, strerror(errno));

            _exit(EXIT_FAILURE);

        }

    }



    if (cpu_model == NULL) {

        cpu_model = cpu_get_model(0);

        cpu_model = cpu_get_model(get_elf_eflags(execfd));

    }

    tcg_exec_init(0);

    /* NOTE: we need to init the CPU at this stage to get
@@ -4438,15 +4447,6 @@ int main(int argc, char **argv, char **envp) 
    cpu->opaque = ts;

    task_settid(ts);



    execfd = qemu_getauxval(AT_EXECFD);

    if (execfd == 0) {

        execfd = open(filename, O_RDONLY);

        if (execfd < 0) {

            printf("Error while loading %s: %s\n", filename, strerror(errno));

            _exit(EXIT_FAILURE);

        }

    }



    ret = loader_exec(execfd, filename, target_argv, target_environ, regs,

        info, &bprm);

    if (ret != 0) {

linux-user/qemu.h

+1 −0
Original line number Diff line number Diff line
@@ -186,6 +186,7 @@ int loader_exec(int fdexec, const char *filename, char **argv, char **envp, 
             struct target_pt_regs * regs, struct image_info *infop,

             struct linux_binprm *);



uint32_t get_elf_eflags(int fd);

int load_elf_binary(struct linux_binprm *bprm, struct image_info *info);

int load_flt_binary(struct linux_binprm *bprm, struct image_info *info);