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Subject[PATCH v4 2/3] lib: logic_pio: Reject accesses to unregistered CPU MMIO regions
Date
Currently when accessing logical indirect PIO addresses in
logic_{in, out}{,s}, we first ensure that the region is registered.

However, no such check exists for CPU MMIO regions. The CPU MMIO regions
would be registered by the PCI host (when PCI_IOBASE is defined) in
pci_register_io_range().

We have seen scenarios when systems which don't have a PCI host, or they
do but the PCI host probe fails, certain drivers attempts to still attempt
to access PCI IO ports; examples are in [1] and [2].

Such is a case on an ARM64 system without a PCI host:

root@(none)$ insmod hwmon/f71805f.ko
Unable to handle kernel paging request at virtual address ffff7dfffee0002e
Mem abort info:
ESR = 0x96000046
Exception class = DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000046
CM = 0, WnR = 1
swapper pgtable: 4k pages, 48-bit VAs, pgdp = (____ptrval____)
[ffff7dfffee0002e] pgd=000000000141c003, pud=000000000141d003, pmd=0000000000000000
Internal error: Oops: 96000046 [#1] PREEMPT SMP
Modules linked in: f71805f(+)
CPU: 20 PID: 2736 Comm: insmod Not tainted 5.1.0-rc1-00003-g6f1bfec2a620-dirty #99
Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon D05 IT21 Nemo 2.0 RC0 04/18/2018
pstate: 80000005 (Nzcv daif -PAN -UAO)
pc : logic_outb+0x54/0xb8
lr : f71805f_find+0x2c/0x1b8 [f71805f]
sp : ffff000025fbba90
x29: ffff000025fbba90 x28: ffff000008b944d0
x27: ffff000025fbbdf0 x26: 0000000000000100
x25: ffff801f8c270580 x24: ffff000011420000
x23: ffff000025fbbb3e x22: ffff000025fbbb40
x21: ffff000008b991b8 x20: 0000000000000087
x19: 000000000000002e x18: ffffffffffffffff
x17: 0000000000000000 x16: 0000000000000000
x15: ffff00001127d6c8 x14: 0000000000000000
x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000010820 x10: 0000841fdac40000
x9 : 0000000000000001 x8 : 0000000040000000
x7 : 0000000000210d00 x6 : 0000000000000000
x5 : ffff801fb6a46040 x4 : ffff841febeaeda0
x3 : 0000000000ffbffe x2 : ffff000025fbbb40
x1 : ffff7dfffee0002e x0 : ffff7dfffee00000
Process insmod (pid: 2736, stack limit = 0x(____ptrval____))
Call trace:
logic_outb+0x54/0xb8
f71805f_find+0x2c/0x1b8 [f71805f]
f71805f_init+0x38/0xe48 [f71805f]
do_one_initcall+0x5c/0x198
do_init_module+0x54/0x1b0
load_module+0x1dc4/0x2158
__se_sys_init_module+0x14c/0x1e8
__arm64_sys_init_module+0x18/0x20
el0_svc_common+0x5c/0x100
el0_svc_handler+0x2c/0x80
el0_svc+0x8/0xc
Code: d2bfdc00 f2cfbfe0 f2ffffe0 8b000021 (39000034)
---[ end trace 10ea80bde051bbfc ]---
root@(none)$

Well-behaved drivers call request_{muxed_}region() to grab the IO port
region, but success here still doesn't actually mean that there is some IO
port mapped in this region.

This patch adds a check to ensure that the CPU MMIO region is registered
prior to accessing the PCI IO ports.

Any failed checks silently return.

[1] https://lore.kernel.org/linux-pci/56F209A9.4040304@huawei.com
[2] https://lore.kernel.org/linux-arm-kernel/e6995b4a-184a-d8d4-f4d4-9ce75d8f47c0@huawei.com/

Signed-off-by: John Garry <john.garry@huawei.com>
---
lib/logic_pio.c | 60 +++++++++++++++++++++++++++++++++----------------
1 file changed, 41 insertions(+), 19 deletions(-)

diff --git a/lib/logic_pio.c b/lib/logic_pio.c
index 40d9428010e1..47d24f428908 100644
--- a/lib/logic_pio.c
+++ b/lib/logic_pio.c
@@ -126,7 +126,7 @@ static struct logic_pio_hwaddr *find_io_range(unsigned long pio)
if (in_range(pio, range->io_start, range->size))
return range;
}
- pr_err("PIO entry token %lx invalid\n", pio);
+
return NULL;
}

@@ -197,11 +197,12 @@ unsigned long logic_pio_trans_cpuaddr(resource_size_t addr)
type logic_in##bw(unsigned long addr) \
{ \
type ret = (type)~0; \
+ struct logic_pio_hwaddr *range = find_io_range(addr); \
\
if (addr < MMIO_UPPER_LIMIT) { \
- ret = read##bw(PCI_IOBASE + addr); \
+ if (range) \
+ ret = read##bw(PCI_IOBASE + addr); \
} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
- struct logic_pio_hwaddr *range = find_io_range(addr); \
size_t sz = sizeof(type); \
\
if (range && range->ops) \
@@ -214,10 +215,12 @@ type logic_in##bw(unsigned long addr) \
\
void logic_out##bw(type value, unsigned long addr) \
{ \
+ struct logic_pio_hwaddr *range = find_io_range(addr); \
+ \
if (addr < MMIO_UPPER_LIMIT) { \
- write##bw(value, PCI_IOBASE + addr); \
+ if (range) \
+ write##bw(value, PCI_IOBASE + addr); \
} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
- struct logic_pio_hwaddr *range = find_io_range(addr); \
size_t sz = sizeof(type); \
\
if (range && range->ops) \
@@ -230,10 +233,12 @@ void logic_out##bw(type value, unsigned long addr) \
\
void logic_ins##bw(unsigned long addr, void *buf, unsigned int cnt) \
{ \
+ struct logic_pio_hwaddr *range = find_io_range(addr); \
+ \
if (addr < MMIO_UPPER_LIMIT) { \
- reads##bw(PCI_IOBASE + addr, buf, cnt); \
+ if (range) \
+ reads##bw(PCI_IOBASE + addr, buf, cnt); \
} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
- struct logic_pio_hwaddr *range = find_io_range(addr); \
size_t sz = sizeof(type); \
\
if (range && range->ops) \
@@ -242,16 +247,17 @@ void logic_ins##bw(unsigned long addr, void *buf, unsigned int cnt) \
else \
WARN_ON_ONCE(1); \
} \
- \
} \
\
void logic_outs##bw(unsigned long addr, const void *buf, \
unsigned int cnt) \
{ \
+ struct logic_pio_hwaddr *range = find_io_range(addr); \
+ \
if (addr < MMIO_UPPER_LIMIT) { \
- writes##bw(PCI_IOBASE + addr, buf, cnt); \
+ if (range) \
+ writes##bw(PCI_IOBASE + addr, buf, cnt); \
} else if (addr >= MMIO_UPPER_LIMIT && addr < IO_SPACE_LIMIT) { \
- struct logic_pio_hwaddr *range = find_io_range(addr); \
size_t sz = sizeof(type); \
\
if (range && range->ops) \
@@ -269,28 +275,44 @@ type logic_in##bw(unsigned long addr) \
{ \
type ret = (type)~0; \
\
- if (addr < MMIO_UPPER_LIMIT) \
- ret = read##bw(PCI_IOBASE + addr); \
+ if (addr < MMIO_UPPER_LIMIT) { \
+ struct logic_pio_hwaddr *range = find_io_range(addr); \
+ \
+ if (range) \
+ ret = read##bw(PCI_IOBASE + addr); \
+ } \
return ret; \
} \
\
-void logic_out##bw(type value, unsigned long addr) \
+void logic_out##bw(type val, unsigned long addr) \
{ \
- if (addr < MMIO_UPPER_LIMIT) \
- write##bw(value, PCI_IOBASE + addr); \
+ if (addr < MMIO_UPPER_LIMIT) { \
+ struct logic_pio_hwaddr *range = find_io_range(addr); \
+ \
+ if (range) \
+ write##bw(val, PCI_IOBASE + addr); \
+ } \
} \
\
void logic_ins##bw(unsigned long addr, void *buf, unsigned int cnt) \
{ \
- if (addr < MMIO_UPPER_LIMIT) \
- reads##bw(PCI_IOBASE + addr, buf, cnt); \
+ if (addr < MMIO_UPPER_LIMIT) { \
+ struct logic_pio_hwaddr *range = find_io_range(addr); \
+ \
+ if (range) \
+ reads##bw(PCI_IOBASE + addr, buf, cnt); \
+ } \
} \
\
void logic_outs##bw(unsigned long addr, const void *buf, \
unsigned int cnt) \
{ \
- if (addr < MMIO_UPPER_LIMIT) \
- writes##bw(PCI_IOBASE + addr, buf, cnt); \
+ if (addr < MMIO_UPPER_LIMIT) { \
+ struct logic_pio_hwaddr *range = find_io_range(addr); \
+ \
+ if (range) \
+ writes##bw(PCI_IOBASE + addr, buf, cnt); \
+ } \
}
#endif /* CONFIG_INDIRECT_PIO */

--
2.17.1
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