ARM: Fix ioremap() of address zero
Murali Nalajala reports a regression that ioremapping address zero
results in an oops dump:
Unable to handle kernel paging request at virtual address fa200000
pgd = d4f80000
[fa200000] *pgd=00000000
Internal error: Oops: 5 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 0 Tainted: G W (3.4.0-g3b5f728-00009-g638207a #13)
PC is at msm_pm_config_rst_vector_before_pc+0x8/0x30
LR is at msm_pm_boot_config_before_pc+0x18/0x20
pc : [<c0078f84>] lr : [<c007903c>] psr: a0000093
sp : c0837ef0 ip : cfe00000 fp : 0000000d
r10: da7efc17 r9 : 225c4278 r8 : 00000006
r7 : 0003c000 r6 : c085c824 r5 : 00000001 r4 : fa101000
r3 : fa200000 r2 : c095080c r1 : 002250fc r0 : 00000000
Flags: NzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c5387d Table: 25180059 DAC: 00000015
[<c0078f84>] (msm_pm_config_rst_vector_before_pc+0x8/0x30) from [<c007903c>] (msm_pm_boot_config_before_pc+0x18/0x20)
[<c007903c>] (msm_pm_boot_config_before_pc+0x18/0x20) from [<c007a55c>] (msm_pm_power_collapse+0x410/0xb04)
[<c007a55c>] (msm_pm_power_collapse+0x410/0xb04) from [<c007b17c>] (arch_idle+0x294/0x3e0)
[<c007b17c>] (arch_idle+0x294/0x3e0) from [<c000eed8>] (default_idle+0x18/0x2c)
[<c000eed8>] (default_idle+0x18/0x2c) from [<c000f254>] (cpu_idle+0x90/0xe4)
[<c000f254>] (cpu_idle+0x90/0xe4) from [<c057231c>] (rest_init+0x88/0xa0)
[<c057231c>] (rest_init+0x88/0xa0) from [<c07ff890>] (start_kernel+0x3a8/0x40c)
Code: c0704256 e12fff1e e59f2020 e5923000 (e5930000)
This is caused by the 'reserved' entries which we insert (see
19b52abe3c5d7 - ARM: 7438/1: fill possible PMD empty section gaps)
which get matched for physical address zero.
Resolve this by marking these reserved entries with a different flag.
Cc: <stable@vger.kernel.org>
Tested-by: Murali Nalajala <mnalajal@codeaurora.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index 6776160..a8ee92d 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -55,6 +55,9 @@
/* permanent static mappings from iotable_init() */
#define VM_ARM_STATIC_MAPPING 0x40000000
+/* empty mapping */
+#define VM_ARM_EMPTY_MAPPING 0x20000000
+
/* mapping type (attributes) for permanent static mappings */
#define VM_ARM_MTYPE(mt) ((mt) << 20)
#define VM_ARM_MTYPE_MASK (0x1f << 20)
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4c2d045..eab94bc 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -807,7 +807,7 @@
vm = early_alloc_aligned(sizeof(*vm), __alignof__(*vm));
vm->addr = (void *)addr;
vm->size = SECTION_SIZE;
- vm->flags = VM_IOREMAP | VM_ARM_STATIC_MAPPING;
+ vm->flags = VM_IOREMAP | VM_ARM_EMPTY_MAPPING;
vm->caller = pmd_empty_section_gap;
vm_area_add_early(vm);
}
@@ -820,7 +820,7 @@
/* we're still single threaded hence no lock needed here */
for (vm = vmlist; vm; vm = vm->next) {
- if (!(vm->flags & VM_ARM_STATIC_MAPPING))
+ if (!(vm->flags & (VM_ARM_STATIC_MAPPING | VM_ARM_EMPTY_MAPPING)))
continue;
addr = (unsigned long)vm->addr;
if (addr < next)