From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Lucas Stach <l.stach@pengutronix.de>,
Russell King <linux+etnaviv@armlinux.org.uk>,
Christian Gmeiner <christian.gmeiner@gmail.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Patrik Jakobsson <patrik.r.jakobsson@gmail.com>,
Jani Nikula <jani.nikula@linux.intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
Rob Clark <robdclark@gmail.com>, Sean Paul <sean@poorly.run>,
Dave Airlie <airlied@redhat.com>,
Gerd Hoffmann <kraxel@redhat.com>,
Hans de Goede <hdegoede@redhat.com>,
Eric Anholt <eric@anholt.net>,
VMware Graphics <linux-graphics-maintainer@vmware.com>,
Thomas Hellstrom <thellstrom@vmware.com>,
Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <mripard@kernel.org>,
Thomas Zimmermann <tzimmermann@suse.de>
Cc: etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org,
linux-arm-msm@vger.kernel.org, freedreno@lists.freedesktop.org,
virtualization@lists.linux-foundation.org,
spice-devel@lists.freedesktop.org,
"Gustavo A. R. Silva" <gustavo@embeddedor.com>
Subject: [PATCH][next] drm: Replace zero-length array with flexible-array member
Date: Tue, 25 Feb 2020 08:03:47 -0600 [thread overview]
Message-ID: <20200225140347.GA22864@embeddedor> (raw)
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
drivers/gpu/drm/etnaviv/etnaviv_gem.h | 2 +-
drivers/gpu/drm/gma500/intel_bios.h | 2 +-
drivers/gpu/drm/i915/display/intel_vbt_defs.h | 4 ++--
drivers/gpu/drm/i915/gt/intel_lrc.c | 2 +-
drivers/gpu/drm/i915/i915_gpu_error.h | 2 +-
drivers/gpu/drm/msm/msm_gem.h | 2 +-
drivers/gpu/drm/qxl/qxl_cmd.c | 2 +-
drivers/gpu/drm/vboxvideo/vboxvideo.h | 2 +-
drivers/gpu/drm/vc4/vc4_drv.h | 2 +-
drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c | 2 +-
drivers/gpu/drm/vmwgfx/vmwgfx_surface.c | 2 +-
include/drm/bridge/mhl.h | 4 ++--
include/drm/drm_displayid.h | 2 +-
include/uapi/drm/i915_drm.h | 4 ++--
14 files changed, 17 insertions(+), 17 deletions(-)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gem.h b/drivers/gpu/drm/etnaviv/etnaviv_gem.h
index 6b68fe16041b..98e60df882b6 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gem.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gem.h
@@ -105,7 +105,7 @@ struct etnaviv_gem_submit {
unsigned int nr_pmrs;
struct etnaviv_perfmon_request *pmrs;
unsigned int nr_bos;
- struct etnaviv_gem_submit_bo bos[0];
+ struct etnaviv_gem_submit_bo bos[];
/* No new members here, the previous one is variable-length! */
};
diff --git a/drivers/gpu/drm/gma500/intel_bios.h b/drivers/gpu/drm/gma500/intel_bios.h
index a1f9ce9465a5..0e6facf21e33 100644
--- a/drivers/gpu/drm/gma500/intel_bios.h
+++ b/drivers/gpu/drm/gma500/intel_bios.h
@@ -227,7 +227,7 @@ struct bdb_general_definitions {
* number = (block_size - sizeof(bdb_general_definitions))/
* sizeof(child_device_config);
*/
- struct child_device_config devices[0];
+ struct child_device_config devices[];
};
struct bdb_lvds_options {
diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
index 05c7cbe32eb4..aef7fe932d1a 100644
--- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
@@ -462,7 +462,7 @@ struct bdb_general_definitions {
* number = (block_size - sizeof(bdb_general_definitions))/
* defs->child_dev_size;
*/
- u8 devices[0];
+ u8 devices[];
} __packed;
/*
@@ -839,7 +839,7 @@ struct bdb_mipi_config {
struct bdb_mipi_sequence {
u8 version;
- u8 data[0]; /* up to 6 variable length blocks */
+ u8 data[]; /* up to 6 variable length blocks */
} __packed;
/*
diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 47561dc29304..5cec79152f17 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -216,7 +216,7 @@ struct virtual_engine {
/* And finally, which physical engines this virtual engine maps onto. */
unsigned int num_siblings;
- struct intel_engine_cs *siblings[0];
+ struct intel_engine_cs *siblings[];
};
static struct virtual_engine *to_virtual_engine(struct intel_engine_cs *engine)
diff --git a/drivers/gpu/drm/i915/i915_gpu_error.h b/drivers/gpu/drm/i915/i915_gpu_error.h
index 0d1f6c8ff355..5a6561f7a210 100644
--- a/drivers/gpu/drm/i915/i915_gpu_error.h
+++ b/drivers/gpu/drm/i915/i915_gpu_error.h
@@ -42,7 +42,7 @@ struct i915_vma_coredump {
int num_pages;
int page_count;
int unused;
- u32 *pages[0];
+ u32 *pages[];
};
struct i915_request_coredump {
diff --git a/drivers/gpu/drm/msm/msm_gem.h b/drivers/gpu/drm/msm/msm_gem.h
index 9e0953c2b7ce..37aa556c5f92 100644
--- a/drivers/gpu/drm/msm/msm_gem.h
+++ b/drivers/gpu/drm/msm/msm_gem.h
@@ -157,7 +157,7 @@ struct msm_gem_submit {
uint32_t handle;
};
uint64_t iova;
- } bos[0];
+ } bos[];
};
#endif /* __MSM_GEM_H__ */
diff --git a/drivers/gpu/drm/qxl/qxl_cmd.c b/drivers/gpu/drm/qxl/qxl_cmd.c
index ef09dc6bc635..d1086b2a6892 100644
--- a/drivers/gpu/drm/qxl/qxl_cmd.c
+++ b/drivers/gpu/drm/qxl/qxl_cmd.c
@@ -36,7 +36,7 @@ static int qxl_reap_surface_id(struct qxl_device *qdev, int max_to_reap);
struct ring {
struct qxl_ring_header header;
- uint8_t elements[0];
+ uint8_t elements[];
};
struct qxl_ring {
diff --git a/drivers/gpu/drm/vboxvideo/vboxvideo.h b/drivers/gpu/drm/vboxvideo/vboxvideo.h
index 0592004f71aa..a5de40fe1a76 100644
--- a/drivers/gpu/drm/vboxvideo/vboxvideo.h
+++ b/drivers/gpu/drm/vboxvideo/vboxvideo.h
@@ -138,7 +138,7 @@ struct vbva_buffer {
u32 data_len;
/* variable size for the rest of the vbva_buffer area in VRAM. */
- u8 data[0];
+ u8 data[];
} __packed;
#define VBVA_MAX_RECORD_SIZE (128 * 1024 * 1024)
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
index 6627b20c99e9..282293e6f751 100644
--- a/drivers/gpu/drm/vc4/vc4_drv.h
+++ b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -65,7 +65,7 @@ struct vc4_perfmon {
* Note that counter values can't be reset, but you can fake a reset by
* destroying the perfmon and creating a new one.
*/
- u64 counters[0];
+ u64 counters[];
};
struct vc4_dev {
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
index f07aa857587c..60cfbfadd3f2 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
@@ -69,7 +69,7 @@ struct vmw_bo_dirty {
unsigned int ref_count;
unsigned long bitmap_size;
size_t size;
- unsigned long bitmap[0];
+ unsigned long bitmap[];
};
/**
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
index 3ce630aa4fde..ec893cd17b50 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_surface.c
@@ -79,7 +79,7 @@ struct vmw_surface_dirty {
struct svga3dsurface_cache cache;
size_t size;
u32 num_subres;
- SVGA3dBox boxes[0];
+ SVGA3dBox boxes[];
};
static void vmw_user_surface_free(struct vmw_resource *res);
diff --git a/include/drm/bridge/mhl.h b/include/drm/bridge/mhl.h
index 1cc77bf38324..d96626a0e3fa 100644
--- a/include/drm/bridge/mhl.h
+++ b/include/drm/bridge/mhl.h
@@ -327,13 +327,13 @@ struct mhl_burst_bits_per_pixel_fmt {
struct {
u8 stream_id;
u8 pixel_format;
- } __packed desc[0];
+ } __packed desc[];
} __packed;
struct mhl_burst_emsc_support {
struct mhl3_burst_header hdr;
u8 num_entries;
- __be16 burst_id[0];
+ __be16 burst_id[];
} __packed;
struct mhl_burst_audio_descr {
diff --git a/include/drm/drm_displayid.h b/include/drm/drm_displayid.h
index 9d3b745c3107..94b4390bf990 100644
--- a/include/drm/drm_displayid.h
+++ b/include/drm/drm_displayid.h
@@ -89,7 +89,7 @@ struct displayid_detailed_timings_1 {
struct displayid_detailed_timing_block {
struct displayid_block base;
- struct displayid_detailed_timings_1 timings[0];
+ struct displayid_detailed_timings_1 timings[];
};
#define for_each_displayid_db(displayid, block, idx, length) \
diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h
index 829c0a48577f..33de5dfadaf5 100644
--- a/include/uapi/drm/i915_drm.h
+++ b/include/uapi/drm/i915_drm.h
@@ -1708,7 +1708,7 @@ struct i915_context_engines_load_balance {
__u64 mbz64; /* reserved for future use; must be zero */
- struct i915_engine_class_instance engines[0];
+ struct i915_engine_class_instance engines[];
} __attribute__((packed));
#define I915_DEFINE_CONTEXT_ENGINES_LOAD_BALANCE(name__, N__) struct { \
@@ -1746,7 +1746,7 @@ struct i915_context_engines_bond {
__u64 flags; /* all undefined flags must be zero */
__u64 mbz64[4]; /* reserved for future use; must be zero */
- struct i915_engine_class_instance engines[0];
+ struct i915_engine_class_instance engines[];
} __attribute__((packed));
#define I915_DEFINE_CONTEXT_ENGINES_BOND(name__, N__) struct { \
--
2.25.0
next reply other threads:[~2020-02-25 14:23 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 14:03 Gustavo A. R. Silva [this message]
2020-02-25 14:17 ` [PATCH][next] drm: Replace zero-length array with flexible-array member Jani Nikula
2020-03-03 18:20 ` Gustavo A. R. Silva
2020-03-09 7:49 ` Thomas Zimmermann
2020-02-25 15:04 ` Chris Wilson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200225140347.GA22864@embeddedor \
--to=gustavo@embeddedor.com \
--cc=airlied@linux.ie \
--cc=airlied@redhat.com \
--cc=christian.gmeiner@gmail.com \
--cc=daniel@ffwll.ch \
--cc=dri-devel@lists.freedesktop.org \
--cc=eric@anholt.net \
--cc=etnaviv@lists.freedesktop.org \
--cc=freedreno@lists.freedesktop.org \
--cc=hdegoede@redhat.com \
--cc=intel-gfx@lists.freedesktop.org \
--cc=jani.nikula@linux.intel.com \
--cc=joonas.lahtinen@linux.intel.com \
--cc=kraxel@redhat.com \
--cc=l.stach@pengutronix.de \
--cc=linux+etnaviv@armlinux.org.uk \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-graphics-maintainer@vmware.com \
--cc=linux-kernel@vger.kernel.org \
--cc=maarten.lankhorst@linux.intel.com \
--cc=mripard@kernel.org \
--cc=patrik.r.jakobsson@gmail.com \
--cc=robdclark@gmail.com \
--cc=rodrigo.vivi@intel.com \
--cc=sean@poorly.run \
--cc=spice-devel@lists.freedesktop.org \
--cc=thellstrom@vmware.com \
--cc=tzimmermann@suse.de \
--cc=virtualization@lists.linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).