diff options
Diffstat (limited to 'results/scraper/launchpad-without-comments/1907137')
| -rw-r--r-- | results/scraper/launchpad-without-comments/1907137 | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/results/scraper/launchpad-without-comments/1907137 b/results/scraper/launchpad-without-comments/1907137 new file mode 100644 index 00000000..08186229 --- /dev/null +++ b/results/scraper/launchpad-without-comments/1907137 @@ -0,0 +1,36 @@ +LDTR not properly emulated when MTE tag checks enabled at EL0 + +I am trying to boot Android (just the non-GUI parts for now) under QEMU with MTE enabled. This can be done by following the instructions here to build the fvp-eng target with MTE support: + +https://cs.android.com/android/platform/superproject/+/master:device/generic/goldfish/fvpbase/ + +and launching QEMU with the following command: + +qemu-system-aarch64 -kernel $ANDROID_PRODUCT_OUT/kernel -initrd $ANDROID_PRODUCT_OUT/combined-ramdisk.img -machine virt,mte=on -cpu max -drive driver=raw,file=$ANDROID_PRODUCT_OUT/system-qemu.img,if=none,id=system -device virtio-blk-device,drive=system -append "console=ttyAMA0 earlyprintk=ttyAMA0 androidboot.hardware=fvpbase androidboot.boot_devices=a003e00.virtio_mmio loglevel=9 printk.devkmsg=on buildvariant=eng" -m 512 -nographic -no-reboot + +If I do this then QEMU crashes like so: + +** +ERROR:../target/arm/mte_helper.c:558:mte_check_fail: code should not be reached +Bail out! ERROR:../target/arm/mte_helper.c:558:mte_check_fail: code should not be reached + +The error is caused by an MTE tag check fault from an LDTR instruction in __arch_copy_from_user. At this point TCF=0 and TCF0=2. + +I have this patch that gets me past the error but it is unclear whether this is the correct fix since there may be other confusion between TCF and TCF0 elsewhere. + +diff --git a/target/arm/mte_helper.c b/target/arm/mte_helper.c +index 153bd1e9df..aa5db4eac4 100644 +--- a/target/arm/mte_helper.c ++++ b/target/arm/mte_helper.c +@@ -552,10 +552,8 @@ static void mte_check_fail(CPUARMState *env, uint32_t desc, + case 0: + /* + * Tag check fail does not affect the PE. +- * We eliminate this case by not setting MTE_ACTIVE +- * in tb_flags, so that we never make this runtime call. + */ +- g_assert_not_reached(); ++ break; + + case 2: + /* Tag check fail causes asynchronous flag set. */ \ No newline at end of file |