Commit fa97e38e authored by Richard Henderson's avatar Richard Henderson Committed by Laurent Vivier
Browse files

linux-user/ppc: Implement swapcontext syscall 



This allows the tests generated by debian-powerpc-user-cross
to function properly, especially tests/test-coroutine.

Technically this syscall is available to both ppc32 and ppc64,
but only ppc32 glibc actually uses it.  Thus the ppc64 path is
untested.

Signed-off-by: default avatarRichard Henderson <richard.henderson@linaro.org>
Tested-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: default avatarLaurent Vivier <laurent@vivier.eu>
Message-Id: <20180718200648.22529-1-richard.henderson@linaro.org>
parent 33143c44

linux-user/ppc/signal.c

+56 −0
Original line number Diff line number Diff line
@@ -675,3 +675,59 @@ sigsegv: 
    force_sig(TARGET_SIGSEGV);

    return -TARGET_QEMU_ESIGRETURN;

}



/* This syscall implements {get,set,swap}context for userland.  */

abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,

                        abi_ulong unew_ctx, abi_long ctx_size)

{

    struct target_ucontext *uctx;

    struct target_mcontext *mctx;



    /* For ppc32, ctx_size is "reserved for future use".

     * For ppc64, we do not yet support the VSX extension.

     */

    if (ctx_size < sizeof(struct target_ucontext)) {

        return -TARGET_EINVAL;

    }



    if (uold_ctx) {

        TaskState *ts = (TaskState *)thread_cpu->opaque;



        if (!lock_user_struct(VERIFY_WRITE, uctx, uold_ctx, 1)) {

            return -TARGET_EFAULT;

        }



#ifdef TARGET_PPC64

        mctx = &uctx->tuc_sigcontext.mcontext;

#else

        /* ??? The kernel aligns the pointer down here into padding, but

         * in setup_rt_frame we don't.  Be self-compatible for now.

         */

        mctx = &uctx->tuc_mcontext;

        __put_user(h2g(mctx), &uctx->tuc_regs);

#endif



        save_user_regs(env, mctx);

        host_to_target_sigset(&uctx->tuc_sigmask, &ts->signal_mask);



        unlock_user_struct(uctx, uold_ctx, 1);

    }



    if (unew_ctx) {

        int err;



        if (!lock_user_struct(VERIFY_READ, uctx, unew_ctx, 1)) {

            return -TARGET_EFAULT;

        }

        err = do_setcontext(uctx, env, 0);

        unlock_user_struct(uctx, unew_ctx, 1);



        if (err) {

            /* We cannot return to a partially updated context.  */

            force_sig(TARGET_SIGSEGV);

        }

        return -TARGET_QEMU_ESIGRETURN;

    }



    return 0;

}

linux-user/qemu.h

+2 −0
Original line number Diff line number Diff line
@@ -396,6 +396,8 @@ long do_sigreturn(CPUArchState *env); 
long do_rt_sigreturn(CPUArchState *env);

abi_long do_sigaltstack(abi_ulong uss_addr, abi_ulong uoss_addr, abi_ulong sp);

int do_sigprocmask(int how, const sigset_t *set, sigset_t *oldset);

abi_long do_swapcontext(CPUArchState *env, abi_ulong uold_ctx,

                        abi_ulong unew_ctx, abi_long ctx_size);

/**

 * block_signals: block all signals while handling this guest syscall

 *

linux-user/syscall.c

+6 −0
Original line number Diff line number Diff line
@@ -12790,6 +12790,12 @@ abi_long do_syscall(void *cpu_env, int num, abi_long arg1, 
        ret = get_errno(kcmp(arg1, arg2, arg3, arg4, arg5));

        break;

#endif

#ifdef TARGET_NR_swapcontext

    case TARGET_NR_swapcontext:

        /* PowerPC specific.  */

        ret = do_swapcontext(cpu_env, arg1, arg2, arg3);

        break;

#endif



    default:

    unimplemented: