Commit a849088a authored by Russell King's avatar Russell King

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
19b52abe - 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: default avatarMurali Nalajala <mnalajal@codeaurora.org>
Acked-by: default avatarNicolas Pitre <nico@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent fea7a08a
...@@ -55,6 +55,9 @@ extern void __flush_dcache_page(struct address_space *mapping, struct page *page ...@@ -55,6 +55,9 @@ extern void __flush_dcache_page(struct address_space *mapping, struct page *page
/* permanent static mappings from iotable_init() */ /* permanent static mappings from iotable_init() */
#define VM_ARM_STATIC_MAPPING 0x40000000 #define VM_ARM_STATIC_MAPPING 0x40000000
/* empty mapping */
#define VM_ARM_EMPTY_MAPPING 0x20000000
/* mapping type (attributes) for permanent static mappings */ /* mapping type (attributes) for permanent static mappings */
#define VM_ARM_MTYPE(mt) ((mt) << 20) #define VM_ARM_MTYPE(mt) ((mt) << 20)
#define VM_ARM_MTYPE_MASK (0x1f << 20) #define VM_ARM_MTYPE_MASK (0x1f << 20)
......
...@@ -807,7 +807,7 @@ static void __init pmd_empty_section_gap(unsigned long addr) ...@@ -807,7 +807,7 @@ static void __init pmd_empty_section_gap(unsigned long addr)
vm = early_alloc_aligned(sizeof(*vm), __alignof__(*vm)); vm = early_alloc_aligned(sizeof(*vm), __alignof__(*vm));
vm->addr = (void *)addr; vm->addr = (void *)addr;
vm->size = SECTION_SIZE; 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->caller = pmd_empty_section_gap;
vm_area_add_early(vm); vm_area_add_early(vm);
} }
...@@ -820,7 +820,7 @@ static void __init fill_pmd_gaps(void) ...@@ -820,7 +820,7 @@ static void __init fill_pmd_gaps(void)
/* we're still single threaded hence no lock needed here */ /* we're still single threaded hence no lock needed here */
for (vm = vmlist; vm; vm = vm->next) { 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; continue;
addr = (unsigned long)vm->addr; addr = (unsigned long)vm->addr;
if (addr < next) if (addr < next)
......
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