| Message ID | 20181015162833.7544-2-jbrunet@baylibre.com |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: dts: meson: reserved memory updates | expand |
Hi Mark, On 15/10/2018 18:42, Mark Rutland wrote: > On Mon, Oct 15, 2018 at 06:28:32PM +0200, Jerome Brunet wrote: >> Since commit 50d7ba36b916 ("arm64: export memblock_reserve()d regions via /proc/iomem") >> was merged Amlogic's boards using mainline u-boot started showing the >> following warning: >> >> WARNING: CPU: 0 PID: 1 at arch/arm64/kernel/setup.c:271 reserve_memblock_reserved_regions+0xd8/0x144 >> Modules linked in: >> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7-00263-g385684b3eb27-dirty #254 >> pstate: 40000005 (nZcv daif -PAN -UAO) >> pc : reserve_memblock_reserved_regions+0xd8/0x144 >> lr : reserve_memblock_reserved_regions+0xd0/0x144 >> [...] >> >> This is due to u-boot setting some /reservedmem/ region while our >> dts declares reserved memory on the same region with no-map. >> >> The conflict produce the warning. This is fixed by using /reservedmem/ >> in our dts as well, which is probably something we should have done from >> the beginning. > > A /memreserve/ does not ensure no-map, and the kernel will map regions > which are described in a memory node and only protected with a > /memreserve/ entry. > > Is it safe for the kernel to map these? e.g. speculative fetches won't > trigger a TrustZone controller to reboot the system? > > ... or are they not in memory nodes to begin with? Do you ask if these memory zones are protected by an Hardware Protection on the AXI bus instead of simply protected by the ARM TZ MMU entries ? In the later case, a speculative fetch won't fail, is that right ? These zones are mapped on the DDR, and seems to be simply protected by the MMU from the ATF code, there are other HW protected RAM zones we haven't modeled. BTW Can the Cortex-A53 do speculative fetches ? I thought no. Neil > > Thanks, > Mark. > >> >> Cc: stable@vger.kernel.org >> Cc: Neil Armstrong <narmstrong@baylibre.com> >> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> >> --- >> >> Hi Kevin, >> >> I would have liked to put a Fixes tag above but I could not figure out >> which commit to pick, considering how much we changed those regions in >> the past. If you have suggestion, I'll be happy to repost this patch. >> If you prefer, feel free to amend this patch directly. >> >> Cheers >> Jerome >> >> arch/arm64/boot/dts/amlogic/meson-axg.dtsi | 24 +++++-------------- >> arch/arm64/boot/dts/amlogic/meson-gx.dtsi | 27 ++++++++-------------- >> 2 files changed, 15 insertions(+), 36 deletions(-) >> [...]
On Tue, Oct 16, 2018 at 10:23:50AM +0200, Neil Armstrong wrote: > Hi Mark, > > On 15/10/2018 18:42, Mark Rutland wrote: > > On Mon, Oct 15, 2018 at 06:28:32PM +0200, Jerome Brunet wrote: > >> Since commit 50d7ba36b916 ("arm64: export memblock_reserve()d regions via /proc/iomem") > >> was merged Amlogic's boards using mainline u-boot started showing the > >> following warning: > >> > >> WARNING: CPU: 0 PID: 1 at arch/arm64/kernel/setup.c:271 reserve_memblock_reserved_regions+0xd8/0x144 > >> Modules linked in: > >> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7-00263-g385684b3eb27-dirty #254 > >> pstate: 40000005 (nZcv daif -PAN -UAO) > >> pc : reserve_memblock_reserved_regions+0xd8/0x144 > >> lr : reserve_memblock_reserved_regions+0xd0/0x144 > >> [...] > >> > >> This is due to u-boot setting some /reservedmem/ region while our > >> dts declares reserved memory on the same region with no-map. > >> > >> The conflict produce the warning. This is fixed by using /reservedmem/ > >> in our dts as well, which is probably something we should have done from > >> the beginning. > > > > A /memreserve/ does not ensure no-map, and the kernel will map regions > > which are described in a memory node and only protected with a > > /memreserve/ entry. > > > > Is it safe for the kernel to map these? e.g. speculative fetches won't > > trigger a TrustZone controller to reboot the system? > > > > ... or are they not in memory nodes to begin with? > > Do you ask if these memory zones are protected by an Hardware > Protection on the AXI bus Yes. > instead of simply protected by the ARM TZ MMU entries ? The secure world MMU has no impact whatsoever on SW running in the normal world. Only the HW (like a TZC on the bus) can enforce restrictions. > In the later case, a speculative fetch won't fail, is that right ? > These zones are mapped on the DDR, and seems to be simply protected by the MMU > from the ATF code, there are other HW protected RAM zones we haven't modeled. If the bus does not protect these ranges, a speculative fetch from the normal world will not fail. However, this means that the normal world can trivially escalate privilege to the secure world, and any bug in normal world software could corrupt secure world SW. So I *hope* there is some protection in place. > BTW Can the Cortex-A53 do speculative fetches ? I thought no. I believe COrtex-A53 can prefetch, so yes. Thanks, Mark.
diff --git a/arch/arm64/boot/dts/amlogic/meson-axg.dtsi b/arch/arm64/boot/dts/amlogic/meson-axg.dtsi index 178d8e8c56b8..06a06f11f114 100644 --- a/arch/arm64/boot/dts/amlogic/meson-axg.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-axg.dtsi @@ -13,6 +13,12 @@ #include <dt-bindings/reset/amlogic,meson-axg-audio-arb.h> #include <dt-bindings/reset/amlogic,meson-axg-reset.h> +/* 16 MiB reserved for Hardware ROM Firmware */ +/memreserve/ 0x0 0x1000000; + +/* 3 MiB reserved for ARM Trusted Firmware (BL31) */ +/memreserve/ 0x05000000 0x300000; + / { compatible = "amlogic,meson-axg"; @@ -115,24 +121,6 @@ method = "smc"; }; - reserved-memory { - #address-cells = <2>; - #size-cells = <2>; - ranges; - - /* 16 MiB reserved for Hardware ROM Firmware */ - hwrom_reserved: hwrom@0 { - reg = <0x0 0x0 0x0 0x1000000>; - no-map; - }; - - /* Alternate 3 MiB reserved for ARM Trusted Firmware (BL31) */ - secmon_reserved: secmon@5000000 { - reg = <0x0 0x05000000 0x0 0x300000>; - no-map; - }; - }; - soc { compatible = "simple-bus"; #address-cells = <2>; diff --git a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi index 676a995fb912..23e879b29b1e 100644 --- a/arch/arm64/boot/dts/amlogic/meson-gx.dtsi +++ b/arch/arm64/boot/dts/amlogic/meson-gx.dtsi @@ -13,6 +13,15 @@ #include <dt-bindings/interrupt-controller/irq.h> #include <dt-bindings/interrupt-controller/arm-gic.h> +/* 16 MiB reserved for Hardware ROM Firmware */ +/memreserve/ 0x0 0x1000000; + +/* 2 MiB reserved for ARM Trusted Firmware (BL31) */ +/memreserve/ 0x10000000 0x200000; + +/* Alternate 3 MiB reserved for ARM Trusted Firmware (BL31) */ +/memreserve/ 0x05000000 0x300000; + / { interrupt-parent = <&gic>; #address-cells = <2>; @@ -23,24 +32,6 @@ #size-cells = <2>; ranges; - /* 16 MiB reserved for Hardware ROM Firmware */ - hwrom_reserved: hwrom@0 { - reg = <0x0 0x0 0x0 0x1000000>; - no-map; - }; - - /* 2 MiB reserved for ARM Trusted Firmware (BL31) */ - secmon_reserved: secmon@10000000 { - reg = <0x0 0x10000000 0x0 0x200000>; - no-map; - }; - - /* Alternate 3 MiB reserved for ARM Trusted Firmware (BL31) */ - secmon_reserved_alt: secmon@5000000 { - reg = <0x0 0x05000000 0x0 0x300000>; - no-map; - }; - linux,cma { compatible = "shared-dma-pool"; reusable;
Since commit 50d7ba36b916 ("arm64: export memblock_reserve()d regions via /proc/iomem") was merged Amlogic's boards using mainline u-boot started showing the following warning: WARNING: CPU: 0 PID: 1 at arch/arm64/kernel/setup.c:271 reserve_memblock_reserved_regions+0xd8/0x144 Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.0-rc7-00263-g385684b3eb27-dirty #254 pstate: 40000005 (nZcv daif -PAN -UAO) pc : reserve_memblock_reserved_regions+0xd8/0x144 lr : reserve_memblock_reserved_regions+0xd0/0x144 [...] This is due to u-boot setting some /reservedmem/ region while our dts declares reserved memory on the same region with no-map. The conflict produce the warning. This is fixed by using /reservedmem/ in our dts as well, which is probably something we should have done from the beginning. Cc: stable@vger.kernel.org Cc: Neil Armstrong <narmstrong@baylibre.com> Signed-off-by: Jerome Brunet <jbrunet@baylibre.com> --- Hi Kevin, I would have liked to put a Fixes tag above but I could not figure out which commit to pick, considering how much we changed those regions in the past. If you have suggestion, I'll be happy to repost this patch. If you prefer, feel free to amend this patch directly. Cheers Jerome arch/arm64/boot/dts/amlogic/meson-axg.dtsi | 24 +++++-------------- arch/arm64/boot/dts/amlogic/meson-gx.dtsi | 27 ++++++++-------------- 2 files changed, 15 insertions(+), 36 deletions(-) -- 2.17.2