Commit c0d5b0c7 authored by Mike Rapoport's avatar Mike Rapoport Committed by David S. Miller
Browse files

sparc32: srmmu: improve type safety of __nocache_fix() 



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: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarMike Rapoport <rppt@linux.ibm.com>
Link: https://lkml.kernel.org/r/CAHk-=wisORTa7QVPnFqNw9pFs62UiwgsD4C4d=MtYy1o4JPyGQ@mail.gmail.com


Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 72a7af33

arch/sparc/include/asm/pgtsrmmu.h

+1 −1
Original line number Diff line number Diff line
@@ -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);

arch/sparc/mm/srmmu.c

+8 −8
Original line number Diff line number Diff line
@@ -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);