| Message ID | 1610729929-188490-1-git-send-email-john.garry@huawei.com |
|---|---|
| Headers | show |
| Series | Fix arm64 crash for accessing unmapped IO port regions (reboot) | expand |
在 2021/1/16 上午12:58, John Garry 写道: > This is a reboot of my original series to address the problem of drivers > for legacy ISA devices accessing unmapped IO port regions on arm64 systems > and causing the system to crash. > > There was another recent report of such an issue [0], and some old ones > [1] and [2] for reference. > > The background is that many systems do not include PCI host controllers, > or they do and controller probe may have failed. For these cases, no IO > ports are mapped. However, loading drivers for legacy ISA devices can > crash the system as there is nothing to stop them accessing those IO > ports (which have not been io remap'ed). > > My original solution tried to keep the kernel alive in these situations by > rejecting logical PIO access to PCI IO regions until PCI IO port regions > have been mapped. > > This series goes one step further, by just reserving the complete legacy > IO port range in 0x0--0xffff for arm64. The motivation for doing this is > to make the request_region() calls for those drivers fail, like this: > > root@ubuntu:/home/john# insmod mk712.ko > [ 3415.575800] mk712: unable to get IO region > insmod: ERROR: could not insert module mk712.ko: No such device > > Otherwise, in theory, those drivers could initiate rogue accesses to > mapped IO port regions for other devices and cause corruptions or > side-effects. Indeed, those drivers should not be allowed to access > IO ports at all in such a system. > > As a secondary defence, for broken drivers who do not call > request_region(), IO port accesses in range 0--0xffff will be ignored, > again preserving the system. > > I am sending as an RFC as I am not sure of any problem with reserving > first 0x10000 of IO space like this. There is reserve= commandline > argument, which does allow this already. Hi John, Is it ok with ACPI? I'm not really familiar with ACPI on arm64 but my impression is ACPI would use legacy I/O ports to communicate with kbd controller, EC and power management facilities. We'd better have a method to detect if ISA bus is not present on the system instead of reserve them unconditionally. Thanks. - Jiaxun > > For reference, here's how /proc/ioports looks on my arm64 system with > this change: > > root@ubuntu:/home/john# more /proc/ioports > 00010000-0001ffff : PCI Bus 0002:f8 > 00010000-00010fff : PCI Bus 0002:f9 > 00010000-00010007 : 0002:f9:00.0 > 00010000-00010007 : serial > 00010008-0001000f : 0002:f9:00.1 > 00010008-0001000f : serial > 00010010-00010017 : 0002:f9:00.2 > 00010018-0001001f : 0002:f9:00.2 > 00020000-0002ffff : PCI Bus 0004:88 > 00030000-0003ffff : PCI Bus 0005:78 > 00040000-0004ffff : PCI Bus 0006:c0 > 00050000-0005ffff : PCI Bus 0007:90 > 00060000-0006ffff : PCI Bus 000a:10 > 00070000-0007ffff : PCI Bus 000c:20 > 00080000-0008ffff : PCI Bus 000d:30 > > [0] https://lore.kernel.org/linux-input/20210112055129.7840-1-song.bao.hua@hisilicon.com/T/#mf86445470160c44ac110e9d200b09245169dc5b6 > [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/ > > Difference since v4: > https://lore.kernel.org/linux-pci/1560262374-67875-1-git-send-email-john.garry@huawei.com/ > - Reserve legacy ISA region > > John Garry (4): > arm64: io: Introduce IO_SPACE_BASE > asm-generic/io.h: Add IO_SPACE_BASE > kernel/resource: Make ioport_resource.start configurable > logic_pio: Warn on and discard accesses to addresses below > IO_SPACE_BASE > > arch/arm64/include/asm/io.h | 1 + > include/asm-generic/io.h | 4 ++++ > include/linux/logic_pio.h | 5 +++++ > kernel/resource.c | 2 +- > lib/logic_pio.c | 20 ++++++++++++++------ > 5 files changed, 25 insertions(+), 7 deletions(-) >
On 18/01/2021 01:59, Jiaxun Yang wrote: > 在 2021/1/16 上午12:58, John Garry 写道: >> This is a reboot of my original series to address the problem of drivers >> for legacy ISA devices accessing unmapped IO port regions on arm64 >> systems >> and causing the system to crash. >> >> There was another recent report of such an issue [0], and some old ones >> [1] and [2] for reference. >> >> The background is that many systems do not include PCI host controllers, >> or they do and controller probe may have failed. For these cases, no IO >> ports are mapped. However, loading drivers for legacy ISA devices can >> crash the system as there is nothing to stop them accessing those IO >> ports (which have not been io remap'ed). >> >> My original solution tried to keep the kernel alive in these >> situations by >> rejecting logical PIO access to PCI IO regions until PCI IO port regions >> have been mapped. >> >> This series goes one step further, by just reserving the complete legacy >> IO port range in 0x0--0xffff for arm64. The motivation for doing this is >> to make the request_region() calls for those drivers fail, like this: >> >> root@ubuntu:/home/john# insmod mk712.ko >> [ 3415.575800] mk712: unable to get IO region >> insmod: ERROR: could not insert module mk712.ko: No such device >> >> Otherwise, in theory, those drivers could initiate rogue accesses to >> mapped IO port regions for other devices and cause corruptions or >> side-effects. Indeed, those drivers should not be allowed to access >> IO ports at all in such a system. >> >> As a secondary defence, for broken drivers who do not call >> request_region(), IO port accesses in range 0--0xffff will be ignored, >> again preserving the system. >> >> I am sending as an RFC as I am not sure of any problem with reserving >> first 0x10000 of IO space like this. There is reserve= commandline >> argument, which does allow this already. > Hi Jiaxun, > > Is it ok with ACPI? I'm not really familiar with ACPI on arm64 but my > impression > is ACPI would use legacy I/O ports to communicate with kbd controller, > EC and > power management facilities. I tested for ACPI. As far as I'm concerned, fixed IO ports should not be used on arm64 systems. Indeed, ACPI spec says IO port addresses should be CPU addressable, and it is the job of the kernel to io remap those correctly for systems which do not support IO ports natively, i.e. those that define PCI_IOBASE. > > We'd better have a method to detect if ISA bus is not present on the system > instead of reserve them unconditionally. > For ISA bus or any IO ports region, they would/should be behind PCI host bridge or modeled as INDIRECT IO host and we should allocate logic PIO region for them, and there should be no assumption on the IO port address in drivers, i.e. not fixed. Thanks, John > >> >> For reference, here's how /proc/ioports looks on my arm64 system with >> this change: >> >> root@ubuntu:/home/john# more /proc/ioports >> 00010000-0001ffff : PCI Bus 0002:f8 >> 00010000-00010fff : PCI Bus 0002:f9 >> 00010000-00010007 : 0002:f9:00.0 >> 00010000-00010007 : serial >> 00010008-0001000f : 0002:f9:00.1 >> 00010008-0001000f : serial >> 00010010-00010017 : 0002:f9:00.2 >> 00010018-0001001f : 0002:f9:00.2 >> 00020000-0002ffff : PCI Bus 0004:88 >> 00030000-0003ffff : PCI Bus 0005:78 >> 00040000-0004ffff : PCI Bus 0006:c0 >> 00050000-0005ffff : PCI Bus 0007:90 >> 00060000-0006ffff : PCI Bus 000a:10 >> 00070000-0007ffff : PCI Bus 000c:20 >> 00080000-0008ffff : PCI Bus 000d:30 >> >> [0] >> https://lore.kernel.org/linux-input/20210112055129.7840-1-song.bao.hua@hisilicon.com/T/#mf86445470160c44ac110e9d200b09245169dc5b6 >> >> [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/ >> >> >> Difference since v4: >> https://lore.kernel.org/linux-pci/1560262374-67875-1-git-send-email-john.garry@huawei.com/ >> >> - Reserve legacy ISA region >> >> John Garry (4): >> arm64: io: Introduce IO_SPACE_BASE >> asm-generic/io.h: Add IO_SPACE_BASE >> kernel/resource: Make ioport_resource.start configurable >> logic_pio: Warn on and discard accesses to addresses below >> IO_SPACE_BASE >> >> arch/arm64/include/asm/io.h | 1 + >> include/asm-generic/io.h | 4 ++++ >> include/linux/logic_pio.h | 5 +++++ >> kernel/resource.c | 2 +- >> lib/logic_pio.c | 20 ++++++++++++++------ >> 5 files changed, 25 insertions(+), 7 deletions(-) >> > > .
On Fri, Jan 15, 2021 at 5:58 PM John Garry <john.garry@huawei.com> wrote: > > This is a reboot of my original series to address the problem of drivers > for legacy ISA devices accessing unmapped IO port regions on arm64 systems > and causing the system to crash. > > There was another recent report of such an issue [0], and some old ones > [1] and [2] for reference. > > The background is that many systems do not include PCI host controllers, > or they do and controller probe may have failed. For these cases, no IO > ports are mapped. However, loading drivers for legacy ISA devices can > crash the system as there is nothing to stop them accessing those IO > ports (which have not been io remap'ed). > > My original solution tried to keep the kernel alive in these situations by > rejecting logical PIO access to PCI IO regions until PCI IO port regions > have been mapped. > > This series goes one step further, by just reserving the complete legacy > IO port range in 0x0--0xffff for arm64. The motivation for doing this is > to make the request_region() calls for those drivers fail, like this: > > root@ubuntu:/home/john# insmod mk712.ko > [ 3415.575800] mk712: unable to get IO region > insmod: ERROR: could not insert module mk712.ko: No such device > > Otherwise, in theory, those drivers could initiate rogue accesses to > mapped IO port regions for other devices and cause corruptions or > side-effects. Indeed, those drivers should not be allowed to access > IO ports at all in such a system. > > As a secondary defence, for broken drivers who do not call > request_region(), IO port accesses in range 0--0xffff will be ignored, > again preserving the system. > > I am sending as an RFC as I am not sure of any problem with reserving > first 0x10000 of IO space like this. There is reserve= commandline > argument, which does allow this already. > > For reference, here's how /proc/ioports looks on my arm64 system with > this change: > > root@ubuntu:/home/john# more /proc/ioports > 00010000-0001ffff : PCI Bus 0002:f8 > 00010000-00010fff : PCI Bus 0002:f9 > 00010000-00010007 : 0002:f9:00.0 > 00010000-00010007 : serial > 00010008-0001000f : 0002:f9:00.1 > 00010008-0001000f : serial > 00010010-00010017 : 0002:f9:00.2 > 00010018-0001001f : 0002:f9:00.2 > 00020000-0002ffff : PCI Bus 0004:88 > 00030000-0003ffff : PCI Bus 0005:78 > 00040000-0004ffff : PCI Bus 0006:c0 > 00050000-0005ffff : PCI Bus 0007:90 > 00060000-0006ffff : PCI Bus 000a:10 > 00070000-0007ffff : PCI Bus 000c:20 > 00080000-0008ffff : PCI Bus 000d:30 Doesn't this mean we lose the ability to access PCI devices with legacy ISA compatibility? Most importantly, any GPU today should in theory still support VGA frame buffer mode or text console, but both of these stop working if the low I/O ports are not mapped to the corresponding PCI bus. There is of course already a problem if you have multiple PCI host bridges, and each one gets its own PIO range, which means that only one of them can have an ISA bridge with working PIO behind it. Another such case would be a BMC that has legacy ISA devices behind a (real or emulated) LPC bus, e.g. a 8250 UART, ps2 keyboard, RTC, or an ATA CDROM. Not sure if any of those are ever used on Arm machines. Regarding the size of the reservation, does this actually need to cover the 0x0fff...0xffff range or just 0x0000...0x0fff? I don't think there are any drivers that hardcode I/O ports beyond 0x0fff because those would not work on ISA buses but require PCI assigned BARs. One more thought: There are two common ways in which PCI host bridges map their PIO ports: either each host bridge has its own 0x0...0xffff BAR range but gets remapped to an arbitrary range of port numbers in the kernel, or each host bridge uses a distinct range of port numbers, and the kernel can use a 1:1 mapping between hardware and software port numbers, i.e. the number in the BAR is the same as in the kernel. If all numbers are shifted by 0x10000, that second case no longer works, and there is always an offset. Arnd
>> >> For reference, here's how /proc/ioports looks on my arm64 system with >> this change: >> >> root@ubuntu:/home/john# more /proc/ioports >> 00010000-0001ffff : PCI Bus 0002:f8 >> 00010000-00010fff : PCI Bus 0002:f9 >> 00010000-00010007 : 0002:f9:00.0 >> 00010000-00010007 : serial >> 00010008-0001000f : 0002:f9:00.1 >> 00010008-0001000f : serial >> 00010010-00010017 : 0002:f9:00.2 >> 00010018-0001001f : 0002:f9:00.2 >> 00020000-0002ffff : PCI Bus 0004:88 >> 00030000-0003ffff : PCI Bus 0005:78 >> 00040000-0004ffff : PCI Bus 0006:c0 >> 00050000-0005ffff : PCI Bus 0007:90 >> 00060000-0006ffff : PCI Bus 000a:10 >> 00070000-0007ffff : PCI Bus 000c:20 >> 00080000-0008ffff : PCI Bus 000d:30 Hi Arnd, > Doesn't this mean we lose the ability to access PCI devices > with legacy ISA compatibility? Most importantly, any GPU today > should in theory still support VGA frame buffer mode or text > console, but both of these stop working if the low I/O ports are > not mapped to the corresponding PCI bus. Hmmm.. so are you saying that there is an expectation that the kernel PIO region assigned for these devices must start at 0x0? If so, I assume it's because fixed IO ports are used. > There is of course > already a problem if you have multiple PCI host bridges, and > each one gets its own PIO range, which means that only one > of them can have an ISA bridge with working PIO behind it. The answer to my question, above, seems to be 'yes' now. > > Another such case would be a BMC that has legacy ISA devices > behind a (real or emulated) LPC bus, e.g. a 8250 UART, ps2 > keyboard, RTC, or an ATA CDROM. Not sure if any of those are > ever used on Arm machines. > > Regarding the size of the reservation, does this actually need > to cover the 0x0fff...0xffff range or just 0x0000...0x0fff? I don't > think there are any drivers that hardcode I/O ports beyond 0x0fff > because those would not work on ISA buses but require PCI > assigned BARs. I just chose the complete legacy IO port range, that being 0x0--0xffff. If there would be no hardcoded ports beyond 0x0fff, then reserving 0x0--0xfff would work. > > One more thought: There are two common ways in which PCI > host bridges map their PIO ports: either each host bridge has > its own 0x0...0xffff BAR range but gets remapped to an > arbitrary range of port numbers in the kernel, or each host bridge > uses a distinct range of port numbers, and the kernel can use > a 1:1 mapping between hardware and software port numbers, > i.e. the number in the BAR is the same as in the kernel. > > If all numbers are shifted by 0x10000, that second case no > longer works, and there is always an offset. Yes, this change would definitely break the second. But does - or could - anyone use it on arm64? I didn't think that it was possible. Thanks, John
This is a reboot of my original series to address the problem of drivers for legacy ISA devices accessing unmapped IO port regions on arm64 systems and causing the system to crash. There was another recent report of such an issue [0], and some old ones [1] and [2] for reference. The background is that many systems do not include PCI host controllers, or they do and controller probe may have failed. For these cases, no IO ports are mapped. However, loading drivers for legacy ISA devices can crash the system as there is nothing to stop them accessing those IO ports (which have not been io remap'ed). My original solution tried to keep the kernel alive in these situations by rejecting logical PIO access to PCI IO regions until PCI IO port regions have been mapped. This series goes one step further, by just reserving the complete legacy IO port range in 0x0--0xffff for arm64. The motivation for doing this is to make the request_region() calls for those drivers fail, like this: root@ubuntu:/home/john# insmod mk712.ko [ 3415.575800] mk712: unable to get IO region insmod: ERROR: could not insert module mk712.ko: No such device Otherwise, in theory, those drivers could initiate rogue accesses to mapped IO port regions for other devices and cause corruptions or side-effects. Indeed, those drivers should not be allowed to access IO ports at all in such a system. As a secondary defence, for broken drivers who do not call request_region(), IO port accesses in range 0--0xffff will be ignored, again preserving the system. I am sending as an RFC as I am not sure of any problem with reserving first 0x10000 of IO space like this. There is reserve= commandline argument, which does allow this already. For reference, here's how /proc/ioports looks on my arm64 system with this change: root@ubuntu:/home/john# more /proc/ioports 00010000-0001ffff : PCI Bus 0002:f8 00010000-00010fff : PCI Bus 0002:f9 00010000-00010007 : 0002:f9:00.0 00010000-00010007 : serial 00010008-0001000f : 0002:f9:00.1 00010008-0001000f : serial 00010010-00010017 : 0002:f9:00.2 00010018-0001001f : 0002:f9:00.2 00020000-0002ffff : PCI Bus 0004:88 00030000-0003ffff : PCI Bus 0005:78 00040000-0004ffff : PCI Bus 0006:c0 00050000-0005ffff : PCI Bus 0007:90 00060000-0006ffff : PCI Bus 000a:10 00070000-0007ffff : PCI Bus 000c:20 00080000-0008ffff : PCI Bus 000d:30 [0] https://lore.kernel.org/linux-input/20210112055129.7840-1-song.bao.hua@hisilicon.com/T/#mf86445470160c44ac110e9d200b09245169dc5b6 [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/ Difference since v4: https://lore.kernel.org/linux-pci/1560262374-67875-1-git-send-email-john.garry@huawei.com/ - Reserve legacy ISA region John Garry (4): arm64: io: Introduce IO_SPACE_BASE asm-generic/io.h: Add IO_SPACE_BASE kernel/resource: Make ioport_resource.start configurable logic_pio: Warn on and discard accesses to addresses below IO_SPACE_BASE arch/arm64/include/asm/io.h | 1 + include/asm-generic/io.h | 4 ++++ include/linux/logic_pio.h | 5 +++++ kernel/resource.c | 2 +- lib/logic_pio.c | 20 ++++++++++++++------ 5 files changed, 25 insertions(+), 7 deletions(-)