diff mbox series

iommu/arm-smmu-v3: Fix endianness annotations

Message ID 20200918141856.629722-1-jean-philippe@linaro.org (mailing list archive)
State New, archived
Headers show
Series iommu/arm-smmu-v3: Fix endianness annotations | expand

Commit Message

Jean-Philippe Brucker Sept. 18, 2020, 2:18 p.m. UTC
When building with C=1, sparse reports some issues regarding endianness
annotations:

arm-smmu-v3.c:221:26: warning: cast to restricted __le64
arm-smmu-v3.c:221:24: warning: incorrect type in assignment (different base types)
arm-smmu-v3.c:221:24:    expected restricted __le64 [usertype]
arm-smmu-v3.c:221:24:    got unsigned long long [usertype]
arm-smmu-v3.c:229:20: warning: incorrect type in argument 1 (different base types)
arm-smmu-v3.c:229:20:    expected restricted __le64 [usertype] *[assigned] dst
arm-smmu-v3.c:229:20:    got unsigned long long [usertype] *ent
arm-smmu-v3.c:229:25: warning: incorrect type in argument 2 (different base types)
arm-smmu-v3.c:229:25:    expected unsigned long long [usertype] *[assigned] src
arm-smmu-v3.c:229:25:    got restricted __le64 [usertype] *
arm-smmu-v3.c:396:20: warning: incorrect type in argument 1 (different base types)
arm-smmu-v3.c:396:20:    expected restricted __le64 [usertype] *[assigned] dst
arm-smmu-v3.c:396:20:    got unsigned long long *
arm-smmu-v3.c:396:25: warning: incorrect type in argument 2 (different base types)
arm-smmu-v3.c:396:25:    expected unsigned long long [usertype] *[assigned] src
arm-smmu-v3.c:396:25:    got restricted __le64 [usertype] *
arm-smmu-v3.c:1349:32: warning: invalid assignment: |=
arm-smmu-v3.c:1349:32:    left side has type restricted __le64
arm-smmu-v3.c:1349:32:    right side has type unsigned long
arm-smmu-v3.c:1396:53: warning: incorrect type in argument 3 (different base types)
arm-smmu-v3.c:1396:53:    expected restricted __le64 [usertype] *dst
arm-smmu-v3.c:1396:53:    got unsigned long long [usertype] *strtab
arm-smmu-v3.c:1424:39: warning: incorrect type in argument 1 (different base types)
arm-smmu-v3.c:1424:39:    expected unsigned long long [usertype] *[assigned] strtab
arm-smmu-v3.c:1424:39:    got restricted __le64 [usertype] *l2ptr

While harmless, they are incorrect and could hide actual errors during
development. Fix them.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---

There is another false positive due to passing INT_MIN to cmpxchg, and
__cmpxchg* to truncate them to u8 and u16:

arch/arm64/include/asm/cmpxchg.h:172:1: warning: cast truncates bits from constant value (ffffffff80000000 becomes 0)
arch/arm64/include/asm/cmpxchg.h:172:1: warning: cast truncates bits from constant value (ffffffff80000000 becomes 0)

I haven't found a satisfying fix so far, except adding __force to
__cmpxchg_case* which could hide actual bugs.
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Robin Murphy Sept. 18, 2020, 3:02 p.m. UTC | #1
On 2020-09-18 15:18, Jean-Philippe Brucker wrote:
> When building with C=1, sparse reports some issues regarding endianness
> annotations:
> 
> arm-smmu-v3.c:221:26: warning: cast to restricted __le64
> arm-smmu-v3.c:221:24: warning: incorrect type in assignment (different base types)
> arm-smmu-v3.c:221:24:    expected restricted __le64 [usertype]
> arm-smmu-v3.c:221:24:    got unsigned long long [usertype]
> arm-smmu-v3.c:229:20: warning: incorrect type in argument 1 (different base types)
> arm-smmu-v3.c:229:20:    expected restricted __le64 [usertype] *[assigned] dst
> arm-smmu-v3.c:229:20:    got unsigned long long [usertype] *ent
> arm-smmu-v3.c:229:25: warning: incorrect type in argument 2 (different base types)
> arm-smmu-v3.c:229:25:    expected unsigned long long [usertype] *[assigned] src
> arm-smmu-v3.c:229:25:    got restricted __le64 [usertype] *
> arm-smmu-v3.c:396:20: warning: incorrect type in argument 1 (different base types)
> arm-smmu-v3.c:396:20:    expected restricted __le64 [usertype] *[assigned] dst
> arm-smmu-v3.c:396:20:    got unsigned long long *
> arm-smmu-v3.c:396:25: warning: incorrect type in argument 2 (different base types)
> arm-smmu-v3.c:396:25:    expected unsigned long long [usertype] *[assigned] src
> arm-smmu-v3.c:396:25:    got restricted __le64 [usertype] *
> arm-smmu-v3.c:1349:32: warning: invalid assignment: |=
> arm-smmu-v3.c:1349:32:    left side has type restricted __le64
> arm-smmu-v3.c:1349:32:    right side has type unsigned long
> arm-smmu-v3.c:1396:53: warning: incorrect type in argument 3 (different base types)
> arm-smmu-v3.c:1396:53:    expected restricted __le64 [usertype] *dst
> arm-smmu-v3.c:1396:53:    got unsigned long long [usertype] *strtab
> arm-smmu-v3.c:1424:39: warning: incorrect type in argument 1 (different base types)
> arm-smmu-v3.c:1424:39:    expected unsigned long long [usertype] *[assigned] strtab
> arm-smmu-v3.c:1424:39:    got restricted __le64 [usertype] *l2ptr
> 
> While harmless, they are incorrect and could hide actual errors during
> development. Fix them.

Reviewed-by: Robin Murphy <robin.murphy@arm.com>

> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
> 
> There is another false positive due to passing INT_MIN to cmpxchg, and
> __cmpxchg* to truncate them to u8 and u16:
> 
> arch/arm64/include/asm/cmpxchg.h:172:1: warning: cast truncates bits from constant value (ffffffff80000000 becomes 0)
> arch/arm64/include/asm/cmpxchg.h:172:1: warning: cast truncates bits from constant value (ffffffff80000000 becomes 0)
> 
> I haven't found a satisfying fix so far, except adding __force to
> __cmpxchg_case* which could hide actual bugs.

I guess that's a general issue with the switch(sizeof()) idiom of sparse 
not being aware that those cases are unreachable?

Robin.

> ---
>   drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> index c192544e874b..83acc1e5888e 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -867,7 +867,7 @@ static void queue_write(__le64 *dst, u64 *src, size_t n_dwords)
>   		*dst++ = cpu_to_le64(*src++);
>   }
>   
> -static void queue_read(__le64 *dst, u64 *src, size_t n_dwords)
> +static void queue_read(u64 *dst, __le64 *src, size_t n_dwords)
>   {
>   	int i;
>   
> @@ -1939,7 +1939,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
>   		arm_smmu_cmdq_issue_cmd(smmu, &prefetch_cmd);
>   }
>   
> -static void arm_smmu_init_bypass_stes(u64 *strtab, unsigned int nent)
> +static void arm_smmu_init_bypass_stes(__le64 *strtab, unsigned int nent)
>   {
>   	unsigned int i;
>   
>
Jean-Philippe Brucker Sept. 18, 2020, 3:08 p.m. UTC | #2
On Fri, Sep 18, 2020 at 04:02:26PM +0100, Robin Murphy wrote:
> On 2020-09-18 15:18, Jean-Philippe Brucker wrote:
> > When building with C=1, sparse reports some issues regarding endianness
> > annotations:
> > 
> > arm-smmu-v3.c:221:26: warning: cast to restricted __le64
> > arm-smmu-v3.c:221:24: warning: incorrect type in assignment (different base types)
> > arm-smmu-v3.c:221:24:    expected restricted __le64 [usertype]
> > arm-smmu-v3.c:221:24:    got unsigned long long [usertype]
> > arm-smmu-v3.c:229:20: warning: incorrect type in argument 1 (different base types)
> > arm-smmu-v3.c:229:20:    expected restricted __le64 [usertype] *[assigned] dst
> > arm-smmu-v3.c:229:20:    got unsigned long long [usertype] *ent
> > arm-smmu-v3.c:229:25: warning: incorrect type in argument 2 (different base types)
> > arm-smmu-v3.c:229:25:    expected unsigned long long [usertype] *[assigned] src
> > arm-smmu-v3.c:229:25:    got restricted __le64 [usertype] *
> > arm-smmu-v3.c:396:20: warning: incorrect type in argument 1 (different base types)
> > arm-smmu-v3.c:396:20:    expected restricted __le64 [usertype] *[assigned] dst
> > arm-smmu-v3.c:396:20:    got unsigned long long *
> > arm-smmu-v3.c:396:25: warning: incorrect type in argument 2 (different base types)
> > arm-smmu-v3.c:396:25:    expected unsigned long long [usertype] *[assigned] src
> > arm-smmu-v3.c:396:25:    got restricted __le64 [usertype] *
> > arm-smmu-v3.c:1349:32: warning: invalid assignment: |=
> > arm-smmu-v3.c:1349:32:    left side has type restricted __le64
> > arm-smmu-v3.c:1349:32:    right side has type unsigned long
> > arm-smmu-v3.c:1396:53: warning: incorrect type in argument 3 (different base types)
> > arm-smmu-v3.c:1396:53:    expected restricted __le64 [usertype] *dst
> > arm-smmu-v3.c:1396:53:    got unsigned long long [usertype] *strtab
> > arm-smmu-v3.c:1424:39: warning: incorrect type in argument 1 (different base types)
> > arm-smmu-v3.c:1424:39:    expected unsigned long long [usertype] *[assigned] strtab
> > arm-smmu-v3.c:1424:39:    got restricted __le64 [usertype] *l2ptr
> > 
> > While harmless, they are incorrect and could hide actual errors during
> > development. Fix them.
> 
> Reviewed-by: Robin Murphy <robin.murphy@arm.com>

Thanks!

> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> > ---
> > 
> > There is another false positive due to passing INT_MIN to cmpxchg, and
> > __cmpxchg* to truncate them to u8 and u16:
> > 
> > arch/arm64/include/asm/cmpxchg.h:172:1: warning: cast truncates bits from constant value (ffffffff80000000 becomes 0)
> > arch/arm64/include/asm/cmpxchg.h:172:1: warning: cast truncates bits from constant value (ffffffff80000000 becomes 0)
> > 
> > I haven't found a satisfying fix so far, except adding __force to
> > __cmpxchg_case* which could hide actual bugs.
> 
> I guess that's a general issue with the switch(sizeof()) idiom of sparse not
> being aware that those cases are unreachable?

Precisely. I wondered if _Generic could help, but it looks like the
problem is the same.

Thanks,
Jean
Will Deacon Sept. 21, 2020, 6:17 p.m. UTC | #3
On Fri, 18 Sep 2020 16:18:57 +0200, Jean-Philippe Brucker wrote:
> When building with C=1, sparse reports some issues regarding endianness
> annotations:
> 
> arm-smmu-v3.c:221:26: warning: cast to restricted __le64
> arm-smmu-v3.c:221:24: warning: incorrect type in assignment (different base types)
> arm-smmu-v3.c:221:24:    expected restricted __le64 [usertype]
> arm-smmu-v3.c:221:24:    got unsigned long long [usertype]
> arm-smmu-v3.c:229:20: warning: incorrect type in argument 1 (different base types)
> arm-smmu-v3.c:229:20:    expected restricted __le64 [usertype] *[assigned] dst
> arm-smmu-v3.c:229:20:    got unsigned long long [usertype] *ent
> arm-smmu-v3.c:229:25: warning: incorrect type in argument 2 (different base types)
> arm-smmu-v3.c:229:25:    expected unsigned long long [usertype] *[assigned] src
> arm-smmu-v3.c:229:25:    got restricted __le64 [usertype] *
> arm-smmu-v3.c:396:20: warning: incorrect type in argument 1 (different base types)
> arm-smmu-v3.c:396:20:    expected restricted __le64 [usertype] *[assigned] dst
> arm-smmu-v3.c:396:20:    got unsigned long long *
> arm-smmu-v3.c:396:25: warning: incorrect type in argument 2 (different base types)
> arm-smmu-v3.c:396:25:    expected unsigned long long [usertype] *[assigned] src
> arm-smmu-v3.c:396:25:    got restricted __le64 [usertype] *
> arm-smmu-v3.c:1349:32: warning: invalid assignment: |=
> arm-smmu-v3.c:1349:32:    left side has type restricted __le64
> arm-smmu-v3.c:1349:32:    right side has type unsigned long
> arm-smmu-v3.c:1396:53: warning: incorrect type in argument 3 (different base types)
> arm-smmu-v3.c:1396:53:    expected restricted __le64 [usertype] *dst
> arm-smmu-v3.c:1396:53:    got unsigned long long [usertype] *strtab
> arm-smmu-v3.c:1424:39: warning: incorrect type in argument 1 (different base types)
> arm-smmu-v3.c:1424:39:    expected unsigned long long [usertype] *[assigned] strtab
> arm-smmu-v3.c:1424:39:    got restricted __le64 [usertype] *l2ptr
> 
> [...]

Applied to will (for-joerg/arm-smmu/updates), thanks!

[1/1] iommu/arm-smmu-v3: Fix endianness annotations
      https://git.kernel.org/will/c/376cdf66f624

Cheers,
diff mbox series

Patch

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index c192544e874b..83acc1e5888e 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -867,7 +867,7 @@  static void queue_write(__le64 *dst, u64 *src, size_t n_dwords)
 		*dst++ = cpu_to_le64(*src++);
 }
 
-static void queue_read(__le64 *dst, u64 *src, size_t n_dwords)
+static void queue_read(u64 *dst, __le64 *src, size_t n_dwords)
 {
 	int i;
 
@@ -1939,7 +1939,7 @@  static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid,
 		arm_smmu_cmdq_issue_cmd(smmu, &prefetch_cmd);
 }
 
-static void arm_smmu_init_bypass_stes(u64 *strtab, unsigned int nent)
+static void arm_smmu_init_bypass_stes(__le64 *strtab, unsigned int nent)
 {
 	unsigned int i;