[PATCHv3 2/5] arm64/mm: disable WARN_ON() and BUG_ON() in __create_pgd_mapping() if too early
Pingfan Liu
kernelfans at gmail.com
Mon May 31 01:45:37 PDT 2021
This patch is still one of the preparation for calling
__create_pgd_mapping() from head.S
When calling from head.S, printk() is not ready to work. Hence define
SAFE_BUG_ON()/SAFE_WARN_ON(), wrapping around BUG_ON()/WARN_ON() to
protect against early calling.
Signed-off-by: Pingfan Liu <kernelfans at gmail.com>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Ard Biesheuvel <ardb at kernel.org>
Cc: Marc Zyngier <maz at kernel.org>
Cc: Kristina Martsenko <kristina.martsenko at arm.com>
Cc: James Morse <james.morse at arm.com>
Cc: Steven Price <steven.price at arm.com>
Cc: Jonathan Cameron <Jonathan.Cameron at huawei.com>
Cc: Pavel Tatashin <pasha.tatashin at soleen.com>
Cc: Anshuman Khandual <anshuman.khandual at arm.com>
Cc: Atish Patra <atish.patra at wdc.com>
Cc: Mike Rapoport <rppt at kernel.org>
Cc: Logan Gunthorpe <logang at deltatee.com>
Cc: Mark Brown <broonie at kernel.org>
To: linux-arm-kernel at lists.infradead.org
---
arch/arm64/mm/mmu.c | 42 ++++++++++++++++++++++++++----------------
1 file changed, 26 insertions(+), 16 deletions(-)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index f4fc905718ca..fe16f235d1fa 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -40,6 +40,7 @@
#define NO_BLOCK_MAPPINGS BIT(0)
#define NO_CONT_MAPPINGS BIT(1)
#define NO_EXEC_MAPPINGS BIT(2) /* assumes FEAT_HPDS is not used */
+#define BOOT_HEAD BIT(3)
u64 idmap_t0sz = TCR_T0SZ(VA_BITS_MIN);
u64 idmap_ptrs_per_pgd = PTRS_PER_PGD;
@@ -139,6 +140,15 @@ static phys_addr_t __init early_pgtable_alloc(int shift)
return phys;
}
+/*
+ * printk is not ready in the very early stage. And this pair macro should be used
+ * instead
+ */
+#define SAFE_BUG_ON(flags, cond) \
+ do { if (likely(!(flags & BOOT_HEAD))) BUG_ON(cond); } while (0)
+#define SAFE_WARN_ON(flags, cond) \
+ ({ (flags & BOOT_HEAD) ? false : WARN_ON(cond); })
+
static bool pgattr_change_is_safe(u64 old, u64 new)
{
/*
@@ -174,7 +184,7 @@ static bool pgattr_change_is_safe(u64 old, u64 new)
}
static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
- phys_addr_t phys, pgprot_t prot)
+ phys_addr_t phys, pgprot_t prot, int flags)
{
pte_t *ptep;
@@ -188,7 +198,7 @@ static void init_pte(pmd_t *pmdp, unsigned long addr, unsigned long end,
* After the PTE entry has been populated once, we
* only allow updates to the permission attributes.
*/
- BUG_ON(!pgattr_change_is_safe(pte_val(old_pte),
+ SAFE_BUG_ON(flags, !pgattr_change_is_safe(pte_val(old_pte),
READ_ONCE(pte_val(*ptep))));
phys += PAGE_SIZE;
@@ -206,19 +216,19 @@ static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
unsigned long next;
pmd_t pmd = READ_ONCE(*pmdp);
- BUG_ON(pmd_sect(pmd));
+ SAFE_BUG_ON(flags, pmd_sect(pmd));
if (pmd_none(pmd)) {
pmdval_t pmdval = PMD_TYPE_TABLE | PMD_TABLE_UXN;
phys_addr_t pte_phys;
if (flags & NO_EXEC_MAPPINGS)
pmdval |= PMD_TABLE_PXN;
- BUG_ON(!pgtable_alloc);
+ SAFE_BUG_ON(flags, !pgtable_alloc);
pte_phys = pgtable_alloc(PAGE_SHIFT);
__pmd_populate(pmdp, pte_phys, pmdval);
pmd = READ_ONCE(*pmdp);
}
- BUG_ON(pmd_bad(pmd));
+ SAFE_BUG_ON(flags, pmd_bad(pmd));
do {
pgprot_t __prot = prot;
@@ -230,7 +240,7 @@ static void alloc_init_cont_pte(pmd_t *pmdp, unsigned long addr,
(flags & NO_CONT_MAPPINGS) == 0)
__prot = __pgprot(pgprot_val(prot) | PTE_CONT);
- init_pte(pmdp, addr, next, phys, __prot);
+ init_pte(pmdp, addr, next, phys, __prot, flags);
phys += next - addr;
} while (addr = next, addr != end);
@@ -258,13 +268,13 @@ static void init_pmd(pud_t *pudp, unsigned long addr, unsigned long end,
* After the PMD entry has been populated once, we
* only allow updates to the permission attributes.
*/
- BUG_ON(!pgattr_change_is_safe(pmd_val(old_pmd),
+ SAFE_BUG_ON(flags, !pgattr_change_is_safe(pmd_val(old_pmd),
READ_ONCE(pmd_val(*pmdp))));
} else {
alloc_init_cont_pte(pmdp, addr, next, phys, prot,
pgtable_alloc, flags);
- BUG_ON(pmd_val(old_pmd) != 0 &&
+ SAFE_BUG_ON(flags, pmd_val(old_pmd) != 0 &&
pmd_val(old_pmd) != READ_ONCE(pmd_val(*pmdp)));
}
phys += next - addr;
@@ -284,19 +294,19 @@ static void alloc_init_cont_pmd(pud_t *pudp, unsigned long addr,
/*
* Check for initial section mappings in the pgd/pud.
*/
- BUG_ON(pud_sect(pud));
+ SAFE_BUG_ON(flags, pud_sect(pud));
if (pud_none(pud)) {
pudval_t pudval = PUD_TYPE_TABLE | PUD_TABLE_UXN;
phys_addr_t pmd_phys;
if (flags & NO_EXEC_MAPPINGS)
pudval |= PUD_TABLE_PXN;
- BUG_ON(!pgtable_alloc);
+ SAFE_BUG_ON(flags, !pgtable_alloc);
pmd_phys = pgtable_alloc(PMD_SHIFT);
__pud_populate(pudp, pmd_phys, pudval);
pud = READ_ONCE(*pudp);
}
- BUG_ON(pud_bad(pud));
+ SAFE_BUG_ON(flags, pud_bad(pud));
do {
pgprot_t __prot = prot;
@@ -342,12 +352,12 @@ static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
if (flags & NO_EXEC_MAPPINGS)
p4dval |= P4D_TABLE_PXN;
- BUG_ON(!pgtable_alloc);
+ SAFE_BUG_ON(flags, !pgtable_alloc);
pud_phys = pgtable_alloc(PUD_SHIFT);
__p4d_populate(p4dp, pud_phys, p4dval);
p4d = READ_ONCE(*p4dp);
}
- BUG_ON(p4d_bad(p4d));
+ SAFE_BUG_ON(flags, p4d_bad(p4d));
pudp = pud_set_fixmap_offset(p4dp, addr);
do {
@@ -366,13 +376,13 @@ static void alloc_init_pud(pgd_t *pgdp, unsigned long addr, unsigned long end,
* After the PUD entry has been populated once, we
* only allow updates to the permission attributes.
*/
- BUG_ON(!pgattr_change_is_safe(pud_val(old_pud),
+ SAFE_BUG_ON(flags, !pgattr_change_is_safe(pud_val(old_pud),
READ_ONCE(pud_val(*pudp))));
} else {
alloc_init_cont_pmd(pudp, addr, next, phys, prot,
pgtable_alloc, flags);
- BUG_ON(pud_val(old_pud) != 0 &&
+ SAFE_BUG_ON(flags, pud_val(old_pud) != 0 &&
pud_val(old_pud) != READ_ONCE(pud_val(*pudp)));
}
phys += next - addr;
@@ -394,7 +404,7 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
* If the virtual and physical address don't have the same offset
* within a page, we cannot map the region as the caller expects.
*/
- if (WARN_ON((phys ^ virt) & ~PAGE_MASK))
+ if (SAFE_WARN_ON(flags, (phys ^ virt) & ~PAGE_MASK))
return;
phys &= PAGE_MASK;
--
2.29.2
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