[DTrace-devel] [PATCH v2] Add support for getmajor() and getminor() subroutines

[Kris Van Hees]

On Wed, Feb 16, 2022 at 09:36:51PM -0500, eugene.loh--- via DTrace-devel wrote:
> From: Eugene Loh <eugene.loh at oracle.com>
> 
> Signed-off-by: Eugene Loh <eugene.loh at oracle.com>

Reviewed-by: Kris Van Hees <kris.van.hees at oracle.com>

... and I'm adding it to dev

> ---
>  libdtrace/dt_cg.c                  | 30 ++++++++++++++++++++++++++++--
>  test/unittest/funcs/tst.getmajor.d | 19 +++++++++++++++++++
>  test/unittest/funcs/tst.getmajor.r |  1 +
>  test/unittest/funcs/tst.getminor.d | 19 +++++++++++++++++++
>  test/unittest/funcs/tst.getminor.r |  1 +
>  5 files changed, 68 insertions(+), 2 deletions(-)
>  create mode 100644 test/unittest/funcs/tst.getmajor.d
>  create mode 100644 test/unittest/funcs/tst.getmajor.r
>  create mode 100644 test/unittest/funcs/tst.getminor.d
>  create mode 100644 test/unittest/funcs/tst.getminor.r
> 
> diff --git a/libdtrace/dt_cg.c b/libdtrace/dt_cg.c
> index b6b39617..2652b5fc 100644
> --- a/libdtrace/dt_cg.c
> +++ b/libdtrace/dt_cg.c
> @@ -3374,6 +3374,32 @@ dt_cg_subr_dirname(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
>  	dt_cg_subr_path_helper(dnp, dlp, drp, "dt_dirname");
>  }
>  
> +/*
> + * For getmajor and getminor, use MAJOR(dev) and MINOR(dev)
> + * as defined in kernel header include/linux/kdev_t.h, not
> + * as defined in user header /usr/include/linux/kdev_t.h.
> + */
> +static void
> +dt_cg_subr_getmajor(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> +{
> +	dt_node_t	*arg = dnp->dn_args;
> +
> +	dt_cg_node(arg, dlp, drp);
> +	dnp->dn_reg = arg->dn_reg;
> +	emit(dlp, BPF_ALU64_IMM(BPF_LSH, dnp->dn_reg, 32));
> +	emit(dlp, BPF_ALU64_IMM(BPF_RSH, dnp->dn_reg, 32 + 20));
> +}
> +
> +static void
> +dt_cg_subr_getminor(dt_node_t *dnp, dt_irlist_t *dlp, dt_regset_t *drp)
> +{
> +	dt_node_t	*arg = dnp->dn_args;
> +
> +	dt_cg_node(arg, dlp, drp);
> +	dnp->dn_reg = arg->dn_reg;
> +	emit(dlp, BPF_ALU64_IMM(BPF_AND, dnp->dn_reg, 0xfffff));
> +}
> +
>  /*
>   * Get and return a new speculation ID.  These are unallocated entries in the
>   * specs map, obtained by calling dt_speculation().  Return zero if none is
> @@ -4120,8 +4146,8 @@ static dt_cg_subr_f *_dt_cg_subr[DIF_SUBR_MAX + 1] = {
>  	[DIF_SUBR_COPYINTO]		= NULL,
>  	[DIF_SUBR_MSGDSIZE]		= NULL,
>  	[DIF_SUBR_MSGSIZE]		= NULL,
> -	[DIF_SUBR_GETMAJOR]		= NULL,
> -	[DIF_SUBR_GETMINOR]		= NULL,
> +	[DIF_SUBR_GETMAJOR]		= &dt_cg_subr_getmajor,
> +	[DIF_SUBR_GETMINOR]		= &dt_cg_subr_getminor,
>  	[DIF_SUBR_DDI_PATHNAME]		= NULL,
>  	[DIF_SUBR_STRJOIN]		= dt_cg_subr_strjoin,
>  	[DIF_SUBR_LLTOSTR]		= &dt_cg_subr_lltostr,
> diff --git a/test/unittest/funcs/tst.getmajor.d b/test/unittest/funcs/tst.getmajor.d
> new file mode 100644
> index 00000000..de0e4800
> --- /dev/null
> +++ b/test/unittest/funcs/tst.getmajor.d
> @@ -0,0 +1,19 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +#pragma D option quiet
> +
> +BEGIN
> +{
> +	printf("%x", getmajor(0xabcdef0123456789ll));
> +	exit(0);
> +}
> +
> +ERROR
> +{
> +	exit(1);
> +}
> diff --git a/test/unittest/funcs/tst.getmajor.r b/test/unittest/funcs/tst.getmajor.r
> new file mode 100644
> index 00000000..7b5813c6
> --- /dev/null
> +++ b/test/unittest/funcs/tst.getmajor.r
> @@ -0,0 +1 @@
> +234
> diff --git a/test/unittest/funcs/tst.getminor.d b/test/unittest/funcs/tst.getminor.d
> new file mode 100644
> index 00000000..d1619234
> --- /dev/null
> +++ b/test/unittest/funcs/tst.getminor.d
> @@ -0,0 +1,19 @@
> +/*
> + * Oracle Linux DTrace.
> + * Copyright (c) 2022, Oracle and/or its affiliates. All rights reserved.
> + * Licensed under the Universal Permissive License v 1.0 as shown at
> + * http://oss.oracle.com/licenses/upl.
> + */
> +
> +#pragma D option quiet
> +
> +BEGIN
> +{
> +	printf("%x", getminor(0xabcdef0123456789ll));
> +	exit(0);
> +}
> +
> +ERROR
> +{
> +	exit(1);
> +}
> diff --git a/test/unittest/funcs/tst.getminor.r b/test/unittest/funcs/tst.getminor.r
> new file mode 100644
> index 00000000..e2f2476c
> --- /dev/null
> +++ b/test/unittest/funcs/tst.getminor.r
> @@ -0,0 +1 @@
> +56789
> -- 
> 2.18.4
> 
> 
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