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Diffstat (limited to 'gitlab/issues/target_arm/host_missing/accel_missing/970.toml')
| -rw-r--r-- | gitlab/issues/target_arm/host_missing/accel_missing/970.toml | 45 |
1 files changed, 0 insertions, 45 deletions
diff --git a/gitlab/issues/target_arm/host_missing/accel_missing/970.toml b/gitlab/issues/target_arm/host_missing/accel_missing/970.toml deleted file mode 100644 index e9eafec99..000000000 --- a/gitlab/issues/target_arm/host_missing/accel_missing/970.toml +++ /dev/null @@ -1,45 +0,0 @@ -id = 970 -title = "ARM SCTLR allows writes to \"write ignore\" bits" -state = "opened" -created_at = "2022-04-08T10:02:27.346Z" -closed_at = "n/a" -labels = ["target: arm"] -url = "https://gitlab.com/qemu-project/qemu/-/issues/970" -host-os = "Windows 11" -host-arch = "x64" -qemu-version = "5.0.1" -guest-os = "arm firmware" -guest-arch = "firmware compiled for arm cortex-a5 (qemu set to cortex-a9)" -description = """The firmware I have executed in qemu sets up pagetables and then enables the MMU. -A few instructions later, a prefetch abort was occurring. After debugging it turned out the problem was because get_phys_addr_v5 was being used to walk the pagetable instead of get_phys_addr_v6. -qemu has this code: -```c -regime_sctlr(env, mmu_idx) & SCTLR_XP -// where SCTLR_XP is commented as -#define SCTLR_XP (1U << 23) /* up to v6; v7 onward RAO */ -``` -Somewhat interestingly, A5 has a lot of bits marked as `/WI`: https://developer.arm.com/documentation/ddi0433/c/system-control/register-descriptions/system-control-register - -A9 has less, but still a few which qemu is not handling: https://developer.arm.com/documentation/ddi0388/e/the-system-control-coprocessors/summary-of-system-control-coprocessor-registers/system-control-register -I've made this hacky patch to fix it for myself: -```diff -diff --git a/qemu/target/arm/helper.c b/qemu/target/arm/helper.c -index 60c9db9e..d8fd5a7d 100644 ---- a/qemu/target/arm/helper.c -+++ b/qemu/target/arm/helper.c -@@ -4306,6 +4306,11 @@ static void sctlr_write(CPUARMState *env, const ARMCPRegInfo *ri, - { - ARMCPU *cpu = env_archcpu(env); - -+ // for cortex-a5 specifically -+ value |= (0b11 << 22) | (1 << 18) | (1 << 16) | (0b1111 << 3); -+ value &= ~((1 << 31) | (0b11 << 26) | (1 << 24) | (0b111 << 19) | -+ (1 << 17) | (0b11 << 14) | (0b111 << 7)); -+ - if (raw_read(env, ri) == value) { - /* Skip the TLB flush if nothing actually changed; Linux likes - * to do a lot of pointless SCTLR writes. -``` -I think the real fix would allow expressing the ones/zeros mask as part of `ARMCPU` per-arch.""" -reproduce = "n/a" -additional = "n/a" |