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iommupt: Avoid a compiler bug with sw_bit

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gcc 13, in some cases, gets confused if the __builtin_constant_p() is
inside the switch. It thinks that bitnr can have the value max+1 and
fails. Lift the check outside the switch to avoid it.

Fixes: ef7bfe5bbf ("iommupt/x86: Support SW bits and permit PT_FEAT_DMA_INCOHERENT")
Fixes: 5448c1558f ("iommupt: Add the Intel VT-d second stage page table format")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202511242012.I7g504Ab-lkp@intel.com/
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
This commit is contained in:
Jason Gunthorpe
2025-11-26 15:21:27 -04:00
committed by Joerg Roedel
parent 152c862c17
commit 5de863efbf
2 changed files with 8 additions and 8 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/iommu/generic_pt/fmt/vtdss.h
View File

@@ -174,6 +174,9 @@ static inline unsigned int vtdss_pt_max_sw_bit(struct pt_common *common)
static inline u64 vtdss_pt_sw_bit(unsigned int bitnr)
{
if (__builtin_constant_p(bitnr) && bitnr > 10)
BUILD_BUG();
/* Bits marked Ignored in the specification */
switch (bitnr) {
case 0:
@@ -184,10 +187,7 @@ static inline u64 vtdss_pt_sw_bit(unsigned int bitnr)
return BIT_ULL(63);
/* Some bits in 9-3 are available in some entries */
default:
if (__builtin_constant_p(bitnr))
BUILD_BUG();
else
PT_WARN_ON(true);
PT_WARN_ON(true);
return 0;
}
}

8
drivers/iommu/generic_pt/fmt/x86_64.h
View File

@@ -175,6 +175,9 @@ static inline unsigned int x86_64_pt_max_sw_bit(struct pt_common *common)
static inline u64 x86_64_pt_sw_bit(unsigned int bitnr)
{
if (__builtin_constant_p(bitnr) && bitnr > 12)
BUILD_BUG();
/* Bits marked Ignored/AVL in the specification */
switch (bitnr) {
case 0:
@@ -185,10 +188,7 @@ static inline u64 x86_64_pt_sw_bit(unsigned int bitnr)
return BIT_ULL((bitnr - 2) + 52);
/* Some bits in 8,6,4,3 are available in some entries */
default:
if (__builtin_constant_p(bitnr))
BUILD_BUG();
else
PT_WARN_ON(true);
PT_WARN_ON(true);
return 0;
}
}