[RFC PATCH v1 48/57] arm64: Convert switch to if for non-const comparison values

Ryan Roberts
2024-10-14T12:31:46Z

When we enable boot-time page size, some macros are no longer
compile-time constants. Where these macros are used as cases in switch
statements, the switch statements no longer compile.

Let's convert these to if/else blocks, which can handle the runtime
values.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---

***NOTE***
Any confused maintainers may want to read the cover note here for context:
https://lore.kernel.org/all/20241014105514.3206191-1-ryan.roberts@arm.com/

arch/arm64/kvm/mmu.c | 32 +++++++++++++++-----------------
arch/arm64/mm/hugetlbpage.c | 34 +++++++++++-----------------------
2 files changed, 26 insertions(+), 40 deletions(-)

diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
index a509b63bd4dd5..248a2d7ad6dbb 100644
--- a/arch/arm64/kvm/mmu.c
+++ b/arch/arm64/kvm/mmu.c
@@ -1487,29 +1487,27 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa,
vma_shift = get_vma_page_shift(vma, hva);
}

- switch (vma_shift) {
#ifndef __PAGETABLE_PMD_FOLDED
- case PUD_SHIFT:
- if (fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
- break;
- fallthrough;
+ if (vma_shift == PUD_SHIFT) {
+ if (!fault_supports_stage2_huge_mapping(memslot, hva, PUD_SIZE))
+ vma_shift = PMD_SHIFT;
+ }
#endif
- case CONT_PMD_SHIFT:
+ if (vma_shift == CONT_PMD_SHIFT) {
vma_shift = PMD_SHIFT;
- fallthrough;
- case PMD_SHIFT:
- if (fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE))
- break;
- fallthrough;
- case CONT_PTE_SHIFT:
+ }
+ if (vma_shift == PMD_SHIFT) {
+ if (!fault_supports_stage2_huge_mapping(memslot, hva, PMD_SIZE))
+ vma_shift = PAGE_SHIFT;
+ }
+ if (vma_shift == CONT_PTE_SHIFT) {
vma_shift = PAGE_SHIFT;
force_pte = true;
- fallthrough;
- case PAGE_SHIFT:
- break;
- default:
- WARN_ONCE(1, "Unknown vma_shift %d", vma_shift);
}
+ if (vma_shift != PUD_SHIFT &&
+ vma_shift != PMD_SHIFT &&
+ vma_shift != PAGE_SHIFT)
+ WARN_ONCE(1, "Unknown vma_shift %d", vma_shift);

vma_pagesize = 1UL << vma_shift;

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 5f1e2103888b7..bc98c20655bba 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -51,16 +51,12 @@ void __init arm64_hugetlb_cma_reserve(void)

static bool __hugetlb_valid_size(unsigned long size)
{
- switch (size) {
#ifndef __PAGETABLE_PMD_FOLDED
- case PUD_SIZE:
+ if (size == PUD_SIZE)
return pud_sect_supported();
#endif
- case CONT_PMD_SIZE:
- case PMD_SIZE:
- case CONT_PTE_SIZE:
+ if (size == CONT_PMD_SIZE || size == PMD_SIZE || size == CONT_PTE_SIZE)
return true;
- }

return false;
}
@@ -104,24 +100,20 @@ static inline int num_contig_ptes(unsigned long size, size_t *pgsize)

*pgsize = size;

- switch (size) {
#ifndef __PAGETABLE_PMD_FOLDED
- case PUD_SIZE:
+ if (size == PUD_SIZE) {
if (pud_sect_supported())
contig_ptes = 1;
- break;
+ } else
#endif
- case PMD_SIZE:
+ if (size == PMD_SIZE) {
contig_ptes = 1;
- break;
- case CONT_PMD_SIZE:
+ } else if (size == CONT_PMD_SIZE) {
*pgsize = PMD_SIZE;
contig_ptes = CONT_PMDS;
- break;
- case CONT_PTE_SIZE:
+ } else if (size == CONT_PTE_SIZE) {
*pgsize = PAGE_SIZE;
contig_ptes = CONT_PTES;
- break;
}

return contig_ptes;
@@ -339,20 +331,16 @@ unsigned long hugetlb_mask_last_page(struct hstate *h)
{
unsigned long hp_size = huge_page_size(h);

- switch (hp_size) {
#ifndef __PAGETABLE_PMD_FOLDED
- case PUD_SIZE:
+ if (hp_size == PUD_SIZE)
return PGDIR_SIZE - PUD_SIZE;
#endif
- case CONT_PMD_SIZE:
+ if (hp_size == CONT_PMD_SIZE)
return PUD_SIZE - CONT_PMD_SIZE;
- case PMD_SIZE:
+ if (hp_size == PMD_SIZE)
return PUD_SIZE - PMD_SIZE;
- case CONT_PTE_SIZE:
+ if (hp_size == CONT_PTE_SIZE)
return PMD_SIZE - CONT_PTE_SIZE;
- default:
- break;
- }

return 0UL;
}
--
2.43.0