Commit e4ff70a8 authored by Dan Williams's avatar Dan Williams Committed by Dave Jiang
Browse files

cxl/acpi: Cleanup __cxl_parse_cfmws() 

As a follow on to the recent rework of __cxl_parse_cfmws() to always
return errors [1], use cleanup.h helpers to remove goto and other cleanups
now that logging is moved to the cxl_parse_cfmws() wrapper.

This ends up adding more code than it deletes, but __cxl_parse_cfmws()
itself does get smaller. The takeaway from the cond_no_free_ptr()
discussion [2] was to not add new macros to handle the cases where
no_free_ptr() is awkward, instead rework the code to have helpers and
clearer delineation of responsibility.

Now one might say that  __free(del_cxl_resource) is excessive given it
is immediately registered with add_or_reset_cxl_resource(). The
rationale for keeping it is that it forces use of "no_free_ptr()" on the
argument passed to add_or_reset_cxl_resource(). That in turn makes it
clear that @res is NULL for the rest of the function which is part of
the point of the cleanup helpers, to turn subtle use after free errors
[3] into loud NULL pointer de-references.

Link: http://lore.kernel.org/r/170820177238.631006.1012639681618409284.stgit@dwillia2-xfh.jf.intel.com [1]
Link: http://lore.kernel.org/r/CAHk-=whBVhnh=KSeBBRet=E7qJAwnPR_aj5em187Q3FiD+LXnA@mail.gmail.com [2]
Link: http://lore.kernel.org/r/20230714093146.2253438-1-leitao@debian.org

 [3]
Reported-by: default avatarJonathan Cameron <Jonathan.Cameron@Huawei.com>
Closes: http://lore.kernel.org/r/20240219124041.00002bda@Huawei.com


Reviewed-by: default avatarAlison Schofield <alison.schofield@intel.com>
Reviewed-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/171235474028.2718248.14109646123143505522.stgit@dwillia2-xfh.jf.intel.com


Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
parent 1c987cf2

drivers/cxl/acpi.c

+51 −42
Original line number Diff line number Diff line
@@ -316,28 +316,59 @@ static const struct cxl_root_ops acpi_root_ops = { 
	.qos_class = cxl_acpi_qos_class,

};



static void del_cxl_resource(struct resource *res)

{

	if (!res)

		return;

	kfree(res->name);

	kfree(res);

}



static struct resource *alloc_cxl_resource(resource_size_t base,

					   resource_size_t n, int id)

{

	struct resource *res __free(kfree) = kzalloc(sizeof(*res), GFP_KERNEL);



	if (!res)

		return NULL;



	res->start = base;

	res->end = base + n - 1;

	res->flags = IORESOURCE_MEM;

	res->name = kasprintf(GFP_KERNEL, "CXL Window %d", id);

	if (!res->name)

		return NULL;



	return no_free_ptr(res);

}



static int add_or_reset_cxl_resource(struct resource *parent, struct resource *res)

{

	int rc = insert_resource(parent, res);



	if (rc)

		del_cxl_resource(res);

	return rc;

}



DEFINE_FREE(put_cxlrd, struct cxl_root_decoder *,

	    if (!IS_ERR_OR_NULL(_T)) put_device(&_T->cxlsd.cxld.dev))

DEFINE_FREE(del_cxl_resource, struct resource *, if (_T) del_cxl_resource(_T))

static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws,

			     struct cxl_cfmws_context *ctx)

{

	int target_map[CXL_DECODER_MAX_INTERLEAVE];

	struct cxl_port *root_port = ctx->root_port;

	struct resource *cxl_res = ctx->cxl_res;

	struct cxl_cxims_context cxims_ctx;

	struct cxl_root_decoder *cxlrd;

	struct device *dev = ctx->dev;

	cxl_calc_hb_fn cxl_calc_hb;

	struct cxl_decoder *cxld;

	unsigned int ways, i, ig;

	struct resource *res;

	int rc;



	rc = cxl_acpi_cfmws_verify(dev, cfmws);

	if (rc) {

		dev_err(dev, "CFMWS range %#llx-%#llx not registered\n",

			cfmws->base_hpa,

			cfmws->base_hpa + cfmws->window_size - 1);

	if (rc)

		return rc;

	}



	rc = eiw_to_ways(cfmws->interleave_ways, &ways);

	if (rc)
@@ -348,29 +379,23 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws, 
	for (i = 0; i < ways; i++)

		target_map[i] = cfmws->interleave_targets[i];



	res = kzalloc(sizeof(*res), GFP_KERNEL);

	struct resource *res __free(del_cxl_resource) = alloc_cxl_resource(

		cfmws->base_hpa, cfmws->window_size, ctx->id++);

	if (!res)

		return -ENOMEM;



	res->name = kasprintf(GFP_KERNEL, "CXL Window %d", ctx->id++);

	if (!res->name)

		goto err_name;



	res->start = cfmws->base_hpa;

	res->end = cfmws->base_hpa + cfmws->window_size - 1;

	res->flags = IORESOURCE_MEM;



	/* add to the local resource tracking to establish a sort order */

	rc = insert_resource(cxl_res, res);

	rc = add_or_reset_cxl_resource(ctx->cxl_res, no_free_ptr(res));

	if (rc)

		goto err_insert;

		return rc;



	if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_MODULO)

		cxl_calc_hb = cxl_hb_modulo;

	else

		cxl_calc_hb = cxl_hb_xor;



	cxlrd = cxl_root_decoder_alloc(root_port, ways, cxl_calc_hb);

	struct cxl_root_decoder *cxlrd __free(put_cxlrd) =

		cxl_root_decoder_alloc(root_port, ways, cxl_calc_hb);

	if (IS_ERR(cxlrd))

		return PTR_ERR(cxlrd);
@@ -378,8 +403,8 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws, 
	cxld->flags = cfmws_to_decoder_flags(cfmws->restrictions);

	cxld->target_type = CXL_DECODER_HOSTONLYMEM;

	cxld->hpa_range = (struct range) {

		.start = res->start,

		.end = res->end,

		.start = cfmws->base_hpa,

		.end = cfmws->base_hpa + cfmws->window_size - 1,

	};

	cxld->interleave_ways = ways;

	/*
@@ -399,11 +424,10 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws, 
			rc = acpi_table_parse_cedt(ACPI_CEDT_TYPE_CXIMS,

						   cxl_parse_cxims, &cxims_ctx);

			if (rc < 0)

				goto err_xormap;

				return rc;

			if (!cxlrd->platform_data) {

				dev_err(dev, "No CXIMS for HBIG %u\n", ig);

				rc = -EINVAL;

				goto err_xormap;

				return -EINVAL;

			}

		}

	}
@@ -411,18 +435,9 @@ static int __cxl_parse_cfmws(struct acpi_cedt_cfmws *cfmws, 
	cxlrd->qos_class = cfmws->qtg_id;



	rc = cxl_decoder_add(cxld, target_map);

err_xormap:

	if (rc)

		put_device(&cxld->dev);

	else

		rc = cxl_decoder_autoremove(dev, cxld);

		return rc;



err_insert:

	kfree(res->name);

err_name:

	kfree(res);

	return -ENOMEM;

	return cxl_root_decoder_autoremove(dev, no_free_ptr(cxlrd));

}



static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
@@ -683,12 +698,6 @@ static void cxl_acpi_lock_reset_class(void *dev) 
	device_lock_reset_class(dev);

}



static void del_cxl_resource(struct resource *res)

{

	kfree(res->name);

	kfree(res);

}



static void cxl_set_public_resource(struct resource *priv, struct resource *pub)

{

	priv->desc = (unsigned long) pub;

drivers/cxl/cxl.h

+5 −0
Original line number Diff line number Diff line
@@ -781,6 +781,11 @@ int cxl_decoder_add(struct cxl_decoder *cxld, int *target_map); 
struct cxl_endpoint_decoder *cxl_endpoint_decoder_alloc(struct cxl_port *port);

int cxl_decoder_add_locked(struct cxl_decoder *cxld, int *target_map);

int cxl_decoder_autoremove(struct device *host, struct cxl_decoder *cxld);

static inline int cxl_root_decoder_autoremove(struct device *host,

					      struct cxl_root_decoder *cxlrd)

{

	return cxl_decoder_autoremove(host, &cxlrd->cxlsd.cxld);

}

int cxl_endpoint_autoremove(struct cxl_memdev *cxlmd, struct cxl_port *endpoint);



/**