Commit ab89acd0 authored by David Hildenbrand's avatar David Hildenbrand
Browse files

s390x/tcg: MVO: Fault-safe handling 



Each operand can have a maximum length of 16. Make sure to prepare all
reads/writes before writing.

Reviewed-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Signed-off-by: default avatarDavid Hildenbrand <david@redhat.com>
parent bb36ed88

target/s390x/mem_helper.c

+15 −12
Original line number Diff line number Diff line
@@ -522,31 +522,34 @@ void HELPER(mvn)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src) 
/* move with offset  */

void HELPER(mvo)(CPUS390XState *env, uint32_t l, uint64_t dest, uint64_t src)

{

    const int mmu_idx = cpu_mmu_index(env, false);

    /* MVO always processes one more byte than specified - maximum is 16 */

    const int len_dest = (l >> 4) + 1;

    const int len_src = (l & 0xf) + 1;

    uintptr_t ra = GETPC();

    int len_dest = l >> 4;

    int len_src = l & 0xf;

    uint8_t byte_dest, byte_src;

    int i;

    S390Access srca, desta;

    int i, j;



    src += len_src;

    dest += len_dest;

    srca = access_prepare(env, src, len_src, MMU_DATA_LOAD, mmu_idx, ra);

    desta = access_prepare(env, dest, len_dest, MMU_DATA_STORE, mmu_idx, ra);



    /* Handle rightmost byte */

    byte_src = cpu_ldub_data_ra(env, src, ra);

    byte_dest = cpu_ldub_data_ra(env, dest, ra);

    byte_dest = cpu_ldub_data_ra(env, dest + len_dest - 1, ra);

    byte_src = access_get_byte(env, &srca, len_src - 1, ra);

    byte_dest = (byte_dest & 0x0f) | (byte_src << 4);

    cpu_stb_data_ra(env, dest, byte_dest, ra);

    access_set_byte(env, &desta, len_dest - 1, byte_dest, ra);



    /* Process remaining bytes from right to left */

    for (i = 1; i <= len_dest; i++) {

    for (i = len_dest - 2, j = len_src - 2; i >= 0; i--, j--) {

        byte_dest = byte_src >> 4;

        if (len_src - i >= 0) {

            byte_src = cpu_ldub_data_ra(env, src - i, ra);

        if (j >= 0) {

            byte_src = access_get_byte(env, &srca, j, ra);

        } else {

            byte_src = 0;

        }

        byte_dest |= byte_src << 4;

        cpu_stb_data_ra(env, dest - i, byte_dest, ra);

        access_set_byte(env, &desta, i, byte_dest, ra);

    }

}