| Message ID | 78951564F9FEA017+20250311141701.1626533-1-wangyuli@uniontech.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | mlxsw: spectrum_acl_bloom_filter: Fix compilation warning on s390x | expand |
On Tue, Mar 11, 2025 at 10:17:00PM +0800, WangYuli wrote: > This is a workaround to mitigate a compiler anomaly. > > During LLVM toolchain compilation of this driver on s390x architecture, an > unreasonable __write_overflow_field warning occurs. > > Contextually, chunk_index is restricted to 0, 1 or 2. By expanding these > possibilities, the compile warning is suppressed. I'm not sure why the fix suppresses the warning when the warning is about the destination buffer and the fix is about the source. Can you check if the below helps? It removes the parameterization from __mlxsw_sp_acl_bf_key_encode() and instead splits it to two variants. diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c index a54eedb69a3f..3e1e4be72da2 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c @@ -110,7 +110,6 @@ static const u16 mlxsw_sp2_acl_bf_crc16_tab[256] = { * +-----------+----------+-----------------------------------+ */ -#define MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES 0 #define MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES 18 #define MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES 20 @@ -229,10 +228,9 @@ static u16 mlxsw_sp2_acl_bf_crc(const u8 *buffer, size_t len) } static void -__mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, - struct mlxsw_sp_acl_atcam_entry *aentry, - char *output, u8 *len, u8 max_chunks, u8 pad_bytes, - u8 key_offset, u8 chunk_key_len, u8 chunk_len) +mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, + struct mlxsw_sp_acl_atcam_entry *aentry, + char *output, u8 *len) { struct mlxsw_afk_key_info *key_info = aregion->region->key_info; u8 chunk_index, chunk_count, block_count; @@ -243,30 +241,17 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, chunk_count = 1 + ((block_count - 1) >> 2); erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | (aregion->region->id << 4)); - for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks; - chunk_index++) { - memset(chunk, 0, pad_bytes); - memcpy(chunk + pad_bytes, &erp_region_id, + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { + memset(chunk, 0, MLXSW_SP2_BLOOM_CHUNK_PAD_BYTES); + memcpy(chunk + MLXSW_SP2_BLOOM_CHUNK_PAD_BYTES, &erp_region_id, sizeof(erp_region_id)); - memcpy(chunk + key_offset, + memcpy(chunk + MLXSW_SP2_BLOOM_CHUNK_KEY_OFFSET, &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]], - chunk_key_len); - chunk += chunk_len; + MLXSW_SP2_BLOOM_CHUNK_KEY_BYTES); + chunk += MLXSW_SP2_BLOOM_KEY_CHUNK_BYTES; } - *len = chunk_count * chunk_len; -} - -static void -mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, - struct mlxsw_sp_acl_atcam_entry *aentry, - char *output, u8 *len) -{ - __mlxsw_sp_acl_bf_key_encode(aregion, aentry, output, len, - MLXSW_BLOOM_KEY_CHUNKS, - MLXSW_SP2_BLOOM_CHUNK_PAD_BYTES, - MLXSW_SP2_BLOOM_CHUNK_KEY_OFFSET, - MLXSW_SP2_BLOOM_CHUNK_KEY_BYTES, - MLXSW_SP2_BLOOM_KEY_CHUNK_BYTES); + *len = chunk_count * MLXSW_SP2_BLOOM_KEY_CHUNK_BYTES; } static unsigned int @@ -375,15 +360,24 @@ mlxsw_sp4_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, char *output, u8 *len) { struct mlxsw_afk_key_info *key_info = aregion->region->key_info; - u8 block_count = mlxsw_afk_key_info_blocks_count_get(key_info); - u8 chunk_count = 1 + ((block_count - 1) >> 2); - - __mlxsw_sp_acl_bf_key_encode(aregion, aentry, output, len, - MLXSW_BLOOM_KEY_CHUNKS, - MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES, - MLXSW_SP4_BLOOM_CHUNK_KEY_OFFSET, - MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES, - MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES); + u8 chunk_index, chunk_count, block_count; + char *chunk = output; + __be16 erp_region_id; + + block_count = mlxsw_afk_key_info_blocks_count_get(key_info); + chunk_count = 1 + ((block_count - 1) >> 2); + erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | + (aregion->region->id << 4)); + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { + memcpy(chunk, &erp_region_id, sizeof(erp_region_id)); + memcpy(chunk + MLXSW_SP4_BLOOM_CHUNK_KEY_OFFSET, + &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]], + MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES); + chunk += MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES; + } + *len = chunk_count * MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES; + mlxsw_sp4_bf_key_shift_chunks(chunk_count, output); } > > Fix follow error with clang-19 when -Werror: > In file included from drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c:5: > In file included from ./include/linux/gfp.h:7: > In file included from ./include/linux/mmzone.h:8: > In file included from ./include/linux/spinlock.h:63: > In file included from ./include/linux/lockdep.h:14: > In file included from ./include/linux/smp.h:13: > In file included from ./include/linux/cpumask.h:12: > In file included from ./include/linux/bitmap.h:13: > In file included from ./include/linux/string.h:392: > ./include/linux/fortify-string.h:571:4: error: call to '__write_overflow_field' declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror,-Wattribute-warning] > 571 | __write_overflow_field(p_size_field, size); > | ^ > 1 error generated. > > Co-developed-by: Zijian Chen <czj2441@163.com> > Signed-off-by: Zijian Chen <czj2441@163.com> > Co-developed-by: Wentao Guan <guanwentao@uniontech.com> > Signed-off-by: Wentao Guan <guanwentao@uniontech.com> > Signed-off-by: WangYuli <wangyuli@uniontech.com> > --- > .../mlxsw/spectrum_acl_bloom_filter.c | 39 ++++++++++++------- > 1 file changed, 25 insertions(+), 14 deletions(-) > > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > index a54eedb69a3f..96105bab680b 100644 > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > @@ -203,17 +203,6 @@ static const u8 mlxsw_sp4_acl_bf_crc6_tab[256] = { > 0x2f, 0x02, 0x18, 0x35, 0x2c, 0x01, 0x1b, 0x36, > }; > > -/* Each chunk contains 4 key blocks. Chunk 2 uses key blocks 11-8, > - * and we need to populate it with 4 key blocks copied from the entry encoded > - * key. The original keys layout is same for Spectrum-{2,3,4}. > - * Since the encoded key contains a 2 bytes padding, key block 11 starts at > - * offset 2. block 7 that is used in chunk 1 starts at offset 20 as 4 key blocks > - * take 18 bytes. See 'MLXSW_SP2_AFK_BLOCK_LAYOUT' for more details. > - * This array defines key offsets for easy access when copying key blocks from > - * entry key to Bloom filter chunk. > - */ > -static const u8 chunk_key_offsets[MLXSW_BLOOM_KEY_CHUNKS] = {2, 20, 38}; > - > static u16 mlxsw_sp2_acl_bf_crc16_byte(u16 crc, u8 c) > { > return (crc << 8) ^ mlxsw_sp2_acl_bf_crc16_tab[(crc >> 8) ^ c]; > @@ -237,6 +226,7 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > struct mlxsw_afk_key_info *key_info = aregion->region->key_info; > u8 chunk_index, chunk_count, block_count; > char *chunk = output; > + char *enc_key_src_ptr; > __be16 erp_region_id; > > block_count = mlxsw_afk_key_info_blocks_count_get(key_info); > @@ -248,9 +238,30 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > memset(chunk, 0, pad_bytes); > memcpy(chunk + pad_bytes, &erp_region_id, > sizeof(erp_region_id)); > - memcpy(chunk + key_offset, > - &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]], > - chunk_key_len); > +/* Each chunk contains 4 key blocks. Chunk 2 uses key blocks 11-8, > + * and we need to populate it with 4 key blocks copied from the entry encoded > + * key. The original keys layout is same for Spectrum-{2,3,4}. > + * Since the encoded key contains a 2 bytes padding, key block 11 starts at > + * offset 2. block 7 that is used in chunk 1 starts at offset 20 as 4 key blocks > + * take 18 bytes. See 'MLXSW_SP2_AFK_BLOCK_LAYOUT' for more details. > + * This array defines key offsets for easy access when copying key blocks from > + * entry key to Bloom filter chunk. > + * > + * Define the acceptable values for chunk_index to prevent LLVM from failing > + * compilation in certain circumstances. > + */ > + switch (chunk_index) { > + case 0: > + enc_key_src_ptr = &aentry->ht_key.enc_key[2]; > + break; > + case 1: > + enc_key_src_ptr = &aentry->ht_key.enc_key[20]; > + break; > + case 2: > + enc_key_src_ptr = &aentry->ht_key.enc_key[38]; > + break; > + } > + memcpy(chunk + key_offset, enc_key_src_ptr, chunk_key_len); > chunk += chunk_len; > } > *len = chunk_count * chunk_len; > -- > 2.47.2 >
Hi Ido Schimme, On 2025/3/12 21:20, Ido Schimmel wrote: > I'm not sure why the fix suppresses the warning when the warning is > about the destination buffer and the fix is about the source. Can you > check if the below helps? It removes the parameterization from > __mlxsw_sp_acl_bf_key_encode() and instead splits it to two variants. > > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > index a54eedb69a3f..3e1e4be72da2 100644 > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > @@ -110,7 +110,6 @@ static const u16 mlxsw_sp2_acl_bf_crc16_tab[256] = { > * +-----------+----------+-----------------------------------+ > */ > > -#define MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES 0 > #define MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES 18 > #define MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES 20 > > @@ -229,10 +228,9 @@ static u16 mlxsw_sp2_acl_bf_crc(const u8 *buffer, size_t len) > } > > static void > -__mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > - struct mlxsw_sp_acl_atcam_entry *aentry, > - char *output, u8 *len, u8 max_chunks, u8 pad_bytes, > - u8 key_offset, u8 chunk_key_len, u8 chunk_len) > +mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > + struct mlxsw_sp_acl_atcam_entry *aentry, > + char *output, u8 *len) > { > struct mlxsw_afk_key_info *key_info = aregion->region->key_info; > u8 chunk_index, chunk_count, block_count; > @@ -243,30 +241,17 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > chunk_count = 1 + ((block_count - 1) >> 2); > erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | > (aregion->region->id << 4)); > - for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks; > - chunk_index++) { > - memset(chunk, 0, pad_bytes); > - memcpy(chunk + pad_bytes, &erp_region_id, > + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; > + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { > + memset(chunk, 0, MLXSW_SP2_BLOOM_CHUNK_PAD_BYTES); > + memcpy(chunk + MLXSW_SP2_BLOOM_CHUNK_PAD_BYTES, &erp_region_id, > sizeof(erp_region_id)); > - memcpy(chunk + key_offset, > + memcpy(chunk + MLXSW_SP2_BLOOM_CHUNK_KEY_OFFSET, > &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]], > - chunk_key_len); > - chunk += chunk_len; > + MLXSW_SP2_BLOOM_CHUNK_KEY_BYTES); > + chunk += MLXSW_SP2_BLOOM_KEY_CHUNK_BYTES; > } > - *len = chunk_count * chunk_len; > -} > - > -static void > -mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > - struct mlxsw_sp_acl_atcam_entry *aentry, > - char *output, u8 *len) > -{ > - __mlxsw_sp_acl_bf_key_encode(aregion, aentry, output, len, > - MLXSW_BLOOM_KEY_CHUNKS, > - MLXSW_SP2_BLOOM_CHUNK_PAD_BYTES, > - MLXSW_SP2_BLOOM_CHUNK_KEY_OFFSET, > - MLXSW_SP2_BLOOM_CHUNK_KEY_BYTES, > - MLXSW_SP2_BLOOM_KEY_CHUNK_BYTES); > + *len = chunk_count * MLXSW_SP2_BLOOM_KEY_CHUNK_BYTES; > } > > static unsigned int > @@ -375,15 +360,24 @@ mlxsw_sp4_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > char *output, u8 *len) > { > struct mlxsw_afk_key_info *key_info = aregion->region->key_info; > - u8 block_count = mlxsw_afk_key_info_blocks_count_get(key_info); > - u8 chunk_count = 1 + ((block_count - 1) >> 2); > - > - __mlxsw_sp_acl_bf_key_encode(aregion, aentry, output, len, > - MLXSW_BLOOM_KEY_CHUNKS, > - MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES, > - MLXSW_SP4_BLOOM_CHUNK_KEY_OFFSET, > - MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES, > - MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES); > + u8 chunk_index, chunk_count, block_count; > + char *chunk = output; > + __be16 erp_region_id; > + > + block_count = mlxsw_afk_key_info_blocks_count_get(key_info); > + chunk_count = 1 + ((block_count - 1) >> 2); > + erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | > + (aregion->region->id << 4)); > + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; > + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { > + memcpy(chunk, &erp_region_id, sizeof(erp_region_id)); > + memcpy(chunk + MLXSW_SP4_BLOOM_CHUNK_KEY_OFFSET, > + &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]], > + MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES); > + chunk += MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES; > + } > + *len = chunk_count * MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES; > + > mlxsw_sp4_bf_key_shift_chunks(chunk_count, output); > } > Sadly, it would appear your modifications haven't taken effect. The same error output is still present. I can also detail how to reproduce the error. You can verify this via LLVM cross-compilation using the [1] config on any computer. [1]. https://github.com/deepin-community/kernel/blob/linux-6.6.y/arch/s390/configs/deepin_s390x_z13_defconfig The command I've been employing is: make ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- CC="ccache clang" -j$(nproc) Thanks,
On 3/12/25 2:20 PM, Ido Schimmel wrote: > On Tue, Mar 11, 2025 at 10:17:00PM +0800, WangYuli wrote: >> This is a workaround to mitigate a compiler anomaly. >> >> During LLVM toolchain compilation of this driver on s390x architecture, an >> unreasonable __write_overflow_field warning occurs. >> >> Contextually, chunk_index is restricted to 0, 1 or 2. By expanding these >> possibilities, the compile warning is suppressed. > > I'm not sure why the fix suppresses the warning when the warning is > about the destination buffer and the fix is about the source. Can you > check if the below helps? It removes the parameterization from > __mlxsw_sp_acl_bf_key_encode() and instead splits it to two variants. > > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > index a54eedb69a3f..3e1e4be72da2 100644 > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > @@ -110,7 +110,6 @@ static const u16 mlxsw_sp2_acl_bf_crc16_tab[256] = { > * +-----------+----------+-----------------------------------+ > */ > > -#define MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES 0 > #define MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES 18 > #define MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES 20 > > @@ -229,10 +228,9 @@ static u16 mlxsw_sp2_acl_bf_crc(const u8 *buffer, size_t len) > } > > static void > -__mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > - struct mlxsw_sp_acl_atcam_entry *aentry, > - char *output, u8 *len, u8 max_chunks, u8 pad_bytes, > - u8 key_offset, u8 chunk_key_len, u8 chunk_len) > +mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > + struct mlxsw_sp_acl_atcam_entry *aentry, > + char *output, u8 *len) > { > struct mlxsw_afk_key_info *key_info = aregion->region->key_info; > u8 chunk_index, chunk_count, block_count; > @@ -243,30 +241,17 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > chunk_count = 1 + ((block_count - 1) >> 2); > erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | > (aregion->region->id << 4)); > - for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks; > - chunk_index++) { > - memset(chunk, 0, pad_bytes); > - memcpy(chunk + pad_bytes, &erp_region_id, > + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; > + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { Possibly the compiler is inferring chunck count can be greater then MLXSW_BLOOM_KEY_CHUNKS? something alike: chunk_index = min_t(0, MLXSW_BLOOM_KEY_CHUNKS - chunk_count, u8); Could possibly please it? /P
On 3/11/25 3:17 PM, WangYuli wrote: > .../mlxsw/spectrum_acl_bloom_filter.c | 39 ++++++++++++------- > 1 file changed, 25 insertions(+), 14 deletions(-) > > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > index a54eedb69a3f..96105bab680b 100644 > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > @@ -203,17 +203,6 @@ static const u8 mlxsw_sp4_acl_bf_crc6_tab[256] = { > 0x2f, 0x02, 0x18, 0x35, 0x2c, 0x01, 0x1b, 0x36, > }; > > -/* Each chunk contains 4 key blocks. Chunk 2 uses key blocks 11-8, > - * and we need to populate it with 4 key blocks copied from the entry encoded > - * key. The original keys layout is same for Spectrum-{2,3,4}. > - * Since the encoded key contains a 2 bytes padding, key block 11 starts at > - * offset 2. block 7 that is used in chunk 1 starts at offset 20 as 4 key blocks > - * take 18 bytes. See 'MLXSW_SP2_AFK_BLOCK_LAYOUT' for more details. > - * This array defines key offsets for easy access when copying key blocks from > - * entry key to Bloom filter chunk. > - */ > -static const u8 chunk_key_offsets[MLXSW_BLOOM_KEY_CHUNKS] = {2, 20, 38}; > - > static u16 mlxsw_sp2_acl_bf_crc16_byte(u16 crc, u8 c) > { > return (crc << 8) ^ mlxsw_sp2_acl_bf_crc16_tab[(crc >> 8) ^ c]; > @@ -237,6 +226,7 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > struct mlxsw_afk_key_info *key_info = aregion->region->key_info; > u8 chunk_index, chunk_count, block_count; > char *chunk = output; > + char *enc_key_src_ptr; Please respect the reverse christmas tree order (same in the next patch) > __be16 erp_region_id; > > block_count = mlxsw_afk_key_info_blocks_count_get(key_info); > @@ -248,9 +238,30 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > memset(chunk, 0, pad_bytes); > memcpy(chunk + pad_bytes, &erp_region_id, > sizeof(erp_region_id)); > - memcpy(chunk + key_offset, > - &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]], > - chunk_key_len); Please try instead explicitly cap-ing the loop to the expected boundaries (0-3) Thanks, Paolo
On Thu, Mar 13, 2025 at 02:52:11PM +0100, Paolo Abeni wrote: > On 3/12/25 2:20 PM, Ido Schimmel wrote: > > On Tue, Mar 11, 2025 at 10:17:00PM +0800, WangYuli wrote: > >> This is a workaround to mitigate a compiler anomaly. > >> > >> During LLVM toolchain compilation of this driver on s390x architecture, an > >> unreasonable __write_overflow_field warning occurs. > >> > >> Contextually, chunk_index is restricted to 0, 1 or 2. By expanding these > >> possibilities, the compile warning is suppressed. > > > > I'm not sure why the fix suppresses the warning when the warning is > > about the destination buffer and the fix is about the source. Can you > > check if the below helps? It removes the parameterization from > > __mlxsw_sp_acl_bf_key_encode() and instead splits it to two variants. > > > > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > > index a54eedb69a3f..3e1e4be72da2 100644 > > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > > @@ -110,7 +110,6 @@ static const u16 mlxsw_sp2_acl_bf_crc16_tab[256] = { > > * +-----------+----------+-----------------------------------+ > > */ > > > > -#define MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES 0 > > #define MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES 18 > > #define MLXSW_SP4_BLOOM_KEY_CHUNK_BYTES 20 > > > > @@ -229,10 +228,9 @@ static u16 mlxsw_sp2_acl_bf_crc(const u8 *buffer, size_t len) > > } > > > > static void > > -__mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > > - struct mlxsw_sp_acl_atcam_entry *aentry, > > - char *output, u8 *len, u8 max_chunks, u8 pad_bytes, > > - u8 key_offset, u8 chunk_key_len, u8 chunk_len) > > +mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > > + struct mlxsw_sp_acl_atcam_entry *aentry, > > + char *output, u8 *len) > > { > > struct mlxsw_afk_key_info *key_info = aregion->region->key_info; > > u8 chunk_index, chunk_count, block_count; > > @@ -243,30 +241,17 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > > chunk_count = 1 + ((block_count - 1) >> 2); > > erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | > > (aregion->region->id << 4)); > > - for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks; > > - chunk_index++) { > > - memset(chunk, 0, pad_bytes); > > - memcpy(chunk + pad_bytes, &erp_region_id, > > + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; > > + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { > > Possibly the compiler is inferring chunck count can be greater then > MLXSW_BLOOM_KEY_CHUNKS? I think so. > > something alike: > > chunk_index = min_t(0, MLXSW_BLOOM_KEY_CHUNKS - chunk_count, u8); > > Could possibly please it? I would like to get a warning if 'chunk_count' is larger than 'MLXSW_BLOOM_KEY_CHUNKS' since it should never happen. I was able to reproduce the build failure and the following patch seems to solve it for me. It removes the 'max_chunks' argument since it's always 'MLXSW_BLOOM_KEY_CHUNKS' (3) and verifies that the number of chunks that was calculated is never greater than it. WangYuli, can you please test it? Also, if you want it in net.git (as opposed to net-next.git), then it needs a Fixes tag: Fixes: 7585cacdb978 ("mlxsw: spectrum_acl: Add Bloom filter handling") And I don't think we need patch #2. diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c index a54eedb69a3f..a1ab5b09a6c5 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c @@ -231,7 +231,7 @@ static u16 mlxsw_sp2_acl_bf_crc(const u8 *buffer, size_t len) static void __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, struct mlxsw_sp_acl_atcam_entry *aentry, - char *output, u8 *len, u8 max_chunks, u8 pad_bytes, + char *output, u8 *len, u8 pad_bytes, u8 key_offset, u8 chunk_key_len, u8 chunk_len) { struct mlxsw_afk_key_info *key_info = aregion->region->key_info; @@ -241,10 +241,14 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, block_count = mlxsw_afk_key_info_blocks_count_get(key_info); chunk_count = 1 + ((block_count - 1) >> 2); + if (WARN_ON_ONCE(chunk_count > MLXSW_BLOOM_KEY_CHUNKS)) { + *len = 0; + return; + } erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | (aregion->region->id << 4)); - for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks; - chunk_index++) { + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { memset(chunk, 0, pad_bytes); memcpy(chunk + pad_bytes, &erp_region_id, sizeof(erp_region_id)); @@ -262,7 +266,6 @@ mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, char *output, u8 *len) { __mlxsw_sp_acl_bf_key_encode(aregion, aentry, output, len, - MLXSW_BLOOM_KEY_CHUNKS, MLXSW_SP2_BLOOM_CHUNK_PAD_BYTES, MLXSW_SP2_BLOOM_CHUNK_KEY_OFFSET, MLXSW_SP2_BLOOM_CHUNK_KEY_BYTES, @@ -379,7 +382,6 @@ mlxsw_sp4_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, u8 chunk_count = 1 + ((block_count - 1) >> 2); __mlxsw_sp_acl_bf_key_encode(aregion, aentry, output, len, - MLXSW_BLOOM_KEY_CHUNKS, MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES, MLXSW_SP4_BLOOM_CHUNK_KEY_OFFSET, MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES,
Hi Ido Schimmel, On 2025/3/13 23:25, Ido Schimmel wrote: > I would like to get a warning if 'chunk_count' is larger than > 'MLXSW_BLOOM_KEY_CHUNKS' since it should never happen. > > I was able to reproduce the build failure and the following patch seems > to solve it for me. It removes the 'max_chunks' argument since it's > always 'MLXSW_BLOOM_KEY_CHUNKS' (3) and verifies that the number of > chunks that was calculated is never greater than it. > > WangYuli, can you please test it? My tests still show the same compilation failing. Indeed, I have already tried similar fixes during my investigation, but to no avail. > Also, if you want it in net.git (as opposed to net-next.git), then it > needs a Fixes tag: > > Fixes: 7585cacdb978 ("mlxsw: spectrum_acl: Add Bloom filter handling") OK > > And I don't think we need patch #2. While #2 is admittedly a secondary modification compared to #1, should you be agreeable, I believe it's still preferable to combine #2 with #1 instead of outright discarding #2. > > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > index a54eedb69a3f..a1ab5b09a6c5 100644 > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c > @@ -231,7 +231,7 @@ static u16 mlxsw_sp2_acl_bf_crc(const u8 *buffer, size_t len) > static void > __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > struct mlxsw_sp_acl_atcam_entry *aentry, > - char *output, u8 *len, u8 max_chunks, u8 pad_bytes, > + char *output, u8 *len, u8 pad_bytes, > u8 key_offset, u8 chunk_key_len, u8 chunk_len) > { > struct mlxsw_afk_key_info *key_info = aregion->region->key_info; > @@ -241,10 +241,14 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > > block_count = mlxsw_afk_key_info_blocks_count_get(key_info); > chunk_count = 1 + ((block_count - 1) >> 2); > + if (WARN_ON_ONCE(chunk_count > MLXSW_BLOOM_KEY_CHUNKS)) { > + *len = 0; > + return; > + } > erp_region_id = cpu_to_be16(aentry->ht_key.erp_id | > (aregion->region->id << 4)); > - for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks; > - chunk_index++) { > + for (chunk_index = MLXSW_BLOOM_KEY_CHUNKS - chunk_count; > + chunk_index < MLXSW_BLOOM_KEY_CHUNKS; chunk_index++) { > memset(chunk, 0, pad_bytes); > memcpy(chunk + pad_bytes, &erp_region_id, > sizeof(erp_region_id)); > @@ -262,7 +266,6 @@ mlxsw_sp2_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > char *output, u8 *len) > { > __mlxsw_sp_acl_bf_key_encode(aregion, aentry, output, len, > - MLXSW_BLOOM_KEY_CHUNKS, > MLXSW_SP2_BLOOM_CHUNK_PAD_BYTES, > MLXSW_SP2_BLOOM_CHUNK_KEY_OFFSET, > MLXSW_SP2_BLOOM_CHUNK_KEY_BYTES, > @@ -379,7 +382,6 @@ mlxsw_sp4_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, > u8 chunk_count = 1 + ((block_count - 1) >> 2); > > __mlxsw_sp_acl_bf_key_encode(aregion, aentry, output, len, > - MLXSW_BLOOM_KEY_CHUNKS, > MLXSW_SP4_BLOOM_CHUNK_PAD_BYTES, > MLXSW_SP4_BLOOM_CHUNK_KEY_OFFSET, > MLXSW_SP4_BLOOM_CHUNK_KEY_BYTES, >
Please use plain text emails.
On Fri, Mar 14, 2025 at 12:10:42AM +0800, WangYuli wrote:
> My tests still show the same compilation failing.
It passed with clang 18 on Fedora 40, but now I tested with clang 19 on
Fedora 41 and it's indeed failing.
How about [1]? It's similar to yours and passes with both clang
versions.
Thanks
[1]
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c
index a54eedb69a3f..9c54dba5ad12 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c
@@ -212,7 +212,22 @@ static const u8 mlxsw_sp4_acl_bf_crc6_tab[256] = {
* This array defines key offsets for easy access when copying key blocks from
* entry key to Bloom filter chunk.
*/
-static const u8 chunk_key_offsets[MLXSW_BLOOM_KEY_CHUNKS] = {2, 20, 38};
+static char *
+mlxsw_sp_acl_bf_enc_key_get(struct mlxsw_sp_acl_atcam_entry *aentry,
+ u8 chunk_index)
+{
+ switch (chunk_index) {
+ case 0:
+ return &aentry->ht_key.enc_key[2];
+ case 1:
+ return &aentry->ht_key.enc_key[20];
+ case 2:
+ return &aentry->ht_key.enc_key[38];
+ default:
+ WARN_ON_ONCE(1);
+ return &aentry->ht_key.enc_key[0];
+ }
+}
static u16 mlxsw_sp2_acl_bf_crc16_byte(u16 crc, u8 c)
{
@@ -245,12 +260,13 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion,
(aregion->region->id << 4));
for (chunk_index = max_chunks - chunk_count; chunk_index < max_chunks;
chunk_index++) {
+ char *enc_key;
+
memset(chunk, 0, pad_bytes);
memcpy(chunk + pad_bytes, &erp_region_id,
sizeof(erp_region_id));
- memcpy(chunk + key_offset,
- &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]],
- chunk_key_len);
+ enc_key = mlxsw_sp_acl_bf_enc_key_get(aentry, chunk_index);
+ memcpy(chunk + key_offset, enc_key, chunk_key_len);
chunk += chunk_len;
}
*len = chunk_count * chunk_len;
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c index a54eedb69a3f..96105bab680b 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c @@ -203,17 +203,6 @@ static const u8 mlxsw_sp4_acl_bf_crc6_tab[256] = { 0x2f, 0x02, 0x18, 0x35, 0x2c, 0x01, 0x1b, 0x36, }; -/* Each chunk contains 4 key blocks. Chunk 2 uses key blocks 11-8, - * and we need to populate it with 4 key blocks copied from the entry encoded - * key. The original keys layout is same for Spectrum-{2,3,4}. - * Since the encoded key contains a 2 bytes padding, key block 11 starts at - * offset 2. block 7 that is used in chunk 1 starts at offset 20 as 4 key blocks - * take 18 bytes. See 'MLXSW_SP2_AFK_BLOCK_LAYOUT' for more details. - * This array defines key offsets for easy access when copying key blocks from - * entry key to Bloom filter chunk. - */ -static const u8 chunk_key_offsets[MLXSW_BLOOM_KEY_CHUNKS] = {2, 20, 38}; - static u16 mlxsw_sp2_acl_bf_crc16_byte(u16 crc, u8 c) { return (crc << 8) ^ mlxsw_sp2_acl_bf_crc16_tab[(crc >> 8) ^ c]; @@ -237,6 +226,7 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, struct mlxsw_afk_key_info *key_info = aregion->region->key_info; u8 chunk_index, chunk_count, block_count; char *chunk = output; + char *enc_key_src_ptr; __be16 erp_region_id; block_count = mlxsw_afk_key_info_blocks_count_get(key_info); @@ -248,9 +238,30 @@ __mlxsw_sp_acl_bf_key_encode(struct mlxsw_sp_acl_atcam_region *aregion, memset(chunk, 0, pad_bytes); memcpy(chunk + pad_bytes, &erp_region_id, sizeof(erp_region_id)); - memcpy(chunk + key_offset, - &aentry->ht_key.enc_key[chunk_key_offsets[chunk_index]], - chunk_key_len); +/* Each chunk contains 4 key blocks. Chunk 2 uses key blocks 11-8, + * and we need to populate it with 4 key blocks copied from the entry encoded + * key. The original keys layout is same for Spectrum-{2,3,4}. + * Since the encoded key contains a 2 bytes padding, key block 11 starts at + * offset 2. block 7 that is used in chunk 1 starts at offset 20 as 4 key blocks + * take 18 bytes. See 'MLXSW_SP2_AFK_BLOCK_LAYOUT' for more details. + * This array defines key offsets for easy access when copying key blocks from + * entry key to Bloom filter chunk. + * + * Define the acceptable values for chunk_index to prevent LLVM from failing + * compilation in certain circumstances. + */ + switch (chunk_index) { + case 0: + enc_key_src_ptr = &aentry->ht_key.enc_key[2]; + break; + case 1: + enc_key_src_ptr = &aentry->ht_key.enc_key[20]; + break; + case 2: + enc_key_src_ptr = &aentry->ht_key.enc_key[38]; + break; + } + memcpy(chunk + key_offset, enc_key_src_ptr, chunk_key_len); chunk += chunk_len; } *len = chunk_count * chunk_len;
This is a workaround to mitigate a compiler anomaly. During LLVM toolchain compilation of this driver on s390x architecture, an unreasonable __write_overflow_field warning occurs. Contextually, chunk_index is restricted to 0, 1 or 2. By expanding these possibilities, the compile warning is suppressed. Fix follow error with clang-19 when -Werror: In file included from drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_bloom_filter.c:5: In file included from ./include/linux/gfp.h:7: In file included from ./include/linux/mmzone.h:8: In file included from ./include/linux/spinlock.h:63: In file included from ./include/linux/lockdep.h:14: In file included from ./include/linux/smp.h:13: In file included from ./include/linux/cpumask.h:12: In file included from ./include/linux/bitmap.h:13: In file included from ./include/linux/string.h:392: ./include/linux/fortify-string.h:571:4: error: call to '__write_overflow_field' declared with 'warning' attribute: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror,-Wattribute-warning] 571 | __write_overflow_field(p_size_field, size); | ^ 1 error generated. Co-developed-by: Zijian Chen <czj2441@163.com> Signed-off-by: Zijian Chen <czj2441@163.com> Co-developed-by: Wentao Guan <guanwentao@uniontech.com> Signed-off-by: Wentao Guan <guanwentao@uniontech.com> Signed-off-by: WangYuli <wangyuli@uniontech.com> --- .../mlxsw/spectrum_acl_bloom_filter.c | 39 ++++++++++++------- 1 file changed, 25 insertions(+), 14 deletions(-)