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sparc32: srmmu: improve type safety of __nocache_fix()

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The __nocache_fix(VADDR) macro is used to add an offset for pointers and
its "return type" is 'void *'.

We can do better and keep the type information with simply by casting the
return value to (__typeof__(VADDR)).

This will  ".. show when those pgd/p4d/pud pointers get mis-used because
they don't end up dropping the type info.."

The addition of the casting to __nocache_fix() also allows to remove
explicit casts at its call sites.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lkml.kernel.org/r/CAHk-=wisORTa7QVPnFqNw9pFs62UiwgsD4C4d=MtYy1o4JPyGQ@mail.gmail.com
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Mike Rapoport 2020-06-27 11:16:53 +03:00 committed by David S. Miller
parent 72a7af33e0
commit c0d5b0c721
2 changed files with 9 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
arch/sparc/include/asm/pgtsrmmu.h
View File

@ -113,7 +113,7 @@ extern unsigned long last_valid_pfn;
extern void *srmmu_nocache_pool;
#define __nocache_pa(VADDR) (((unsigned long)VADDR) - SRMMU_NOCACHE_VADDR + __pa((unsigned long)srmmu_nocache_pool))
#define __nocache_va(PADDR) (__va((unsigned long)PADDR) - (unsigned long)srmmu_nocache_pool + SRMMU_NOCACHE_VADDR)
#define __nocache_fix(VADDR) __va(__nocache_pa(VADDR))
#define __nocache_fix(VADDR) ((__typeof__(VADDR))__va(__nocache_pa(VADDR)))
/* Accessing the MMU control register. */
unsigned int srmmu_get_mmureg(void);

16
arch/sparc/mm/srmmu.c
View File

@ -689,7 +689,7 @@ static void __init srmmu_early_allocate_ptable_skeleton(unsigned long start,
pgdp = pgd_offset_k(start);
p4dp = p4d_offset(pgdp, start);
pudp = pud_offset(p4dp, start);
if (pud_none(*(pud_t *)__nocache_fix(pudp))) {
if (pud_none(*__nocache_fix(pudp))) {
pmdp = __srmmu_get_nocache(
SRMMU_PMD_TABLE_SIZE, SRMMU_PMD_TABLE_SIZE);
if (pmdp == NULL)
@ -698,7 +698,7 @@ static void __init srmmu_early_allocate_ptable_skeleton(unsigned long start,
pud_set(__nocache_fix(pudp), pmdp);
}
pmdp = pmd_offset(__nocache_fix(pudp), start);
if (srmmu_pmd_none(*(pmd_t *)__nocache_fix(pmdp))) {
if (srmmu_pmd_none(*__nocache_fix(pmdp))) {
ptep = __srmmu_get_nocache(PTE_SIZE, PTE_SIZE);
if (ptep == NULL)
early_pgtable_allocfail("pte");
@ -810,11 +810,11 @@ static void __init srmmu_inherit_prom_mappings(unsigned long start,
p4dp = p4d_offset(pgdp, start);
pudp = pud_offset(p4dp, start);
if (what == 2) {
*(pgd_t *)__nocache_fix(pgdp) = __pgd(probed);
*__nocache_fix(pgdp) = __pgd(probed);
start += PGDIR_SIZE;
continue;
}
if (pud_none(*(pud_t *)__nocache_fix(pudp))) {
if (pud_none(*__nocache_fix(pudp))) {
pmdp = __srmmu_get_nocache(SRMMU_PMD_TABLE_SIZE,
SRMMU_PMD_TABLE_SIZE);
if (pmdp == NULL)
@ -828,7 +828,7 @@ static void __init srmmu_inherit_prom_mappings(unsigned long start,
start += PMD_SIZE;
continue;
}
if (srmmu_pmd_none(*(pmd_t *)__nocache_fix(pmdp))) {
if (srmmu_pmd_none(*__nocache_fix(pmdp))) {
ptep = __srmmu_get_nocache(PTE_SIZE, PTE_SIZE);
if (ptep == NULL)
early_pgtable_allocfail("pte");
@ -836,7 +836,7 @@ static void __init srmmu_inherit_prom_mappings(unsigned long start,
pmd_set(__nocache_fix(pmdp), ptep);
}
ptep = pte_offset_kernel(__nocache_fix(pmdp), start);
*(pte_t *)__nocache_fix(ptep) = __pte(probed);
*__nocache_fix(ptep) = __pte(probed);
start += PAGE_SIZE;
}
}
@ -850,7 +850,7 @@ static void __init do_large_mapping(unsigned long vaddr, unsigned long phys_base
unsigned long big_pte;
big_pte = KERNEL_PTE(phys_base >> 4);
*(pgd_t *)__nocache_fix(pgdp) = __pgd(big_pte);
*__nocache_fix(pgdp) = __pgd(big_pte);
}
/* Map sp_bank entry SP_ENTRY, starting at virtual address VBASE. */
@ -940,7 +940,7 @@ void __init srmmu_paging_init(void)
srmmu_ctx_table_phys = (ctxd_t *)__nocache_pa(srmmu_context_table);
for (i = 0; i < num_contexts; i++)
srmmu_ctxd_set((ctxd_t *)__nocache_fix(&srmmu_context_table[i]), srmmu_swapper_pg_dir);
srmmu_ctxd_set(__nocache_fix(&srmmu_context_table[i]), srmmu_swapper_pg_dir);
flush_cache_all();
srmmu_set_ctable_ptr((unsigned long)srmmu_ctx_table_phys);