From 9238fa35a3c04835a77988a14e1397763cf0eabe Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 24 Nov 2025 13:08:43 +0000 Subject: [PATCH 1/3] Revert "arm64: acpi: Enable ACPI CCEL support" This reverts commit d02c2e45b1e7767b177f6854026e4ad0d70b4a4d. Mauro reports that this breaks APEI notifications on his QEMU setup because the "reserved for firmware" region still needs to be writable by Linux in order to signal _back_ to the firmware after processing the reported error: | {1}[Hardware Error]: Hardware error from APEI Generic Hardware Error Source: 1 | ... | [Firmware Warn]: GHES: Unhandled processor error type 0x02: cache error | Unable to handle kernel write to read-only memory at virtual address ffff800080035018 | Mem abort info: | ESR = 0x000000009600004f | EC = 0x25: DABT (current EL), IL = 32 bits | SET = 0, FnV = 0 | EA = 0, S1PTW = 0 | FSC = 0x0f: level 3 permission fault | Data abort info: | ISV = 0, ISS = 0x0000004f, ISS2 = 0x00000000 | CM = 0, WnR = 1, TnD = 0, TagAccess = 0 | GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 | swapper pgtable: 4k pages, 52-bit VAs, pgdp=00000000505d7000 | pgd=10000000510bc003, p4d=1000000100229403, pud=100000010022a403, pmd=100000010022b403, pte=0060000139b90483 | Internal error: Oops: 000000009600004f [#1] SMP For now, revert the offending commit. We can presumably switch back to PAGE_KERNEL when bringing this back in the future. Link: https://lore.kernel.org/r/20251121224611.07efa95a@foz.lan Reported-by: Mauro Carvalho Chehab Signed-off-by: Will Deacon --- arch/arm64/kernel/acpi.c | 10 ---------- 1 file changed, 10 deletions(-) diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c index c022c1acb8c7..f1cb2447afc9 100644 --- a/arch/arm64/kernel/acpi.c +++ b/arch/arm64/kernel/acpi.c @@ -351,16 +351,6 @@ void __iomem *acpi_os_ioremap(acpi_physical_address phys, acpi_size size) * as long as we take care not to create a writable * mapping for executable code. */ - fallthrough; - - case EFI_ACPI_MEMORY_NVS: - /* - * ACPI NVS marks an area reserved for use by the - * firmware, even after exiting the boot service. - * This may be used by the firmware for sharing dynamic - * tables/data (e.g., ACPI CCEL) with the OS. Map it - * as read-only. - */ prot = PAGE_KERNEL_RO; break; From 7c16c02e86081355a54c50c045b0caa172e72028 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 30 Oct 2025 11:01:15 +0000 Subject: [PATCH 2/3] ACPI: GTDT: Correctly number platform devices for MMIO timers Use the actual timer counter instead of the watchdog counter. Fixes: 5669d92f3efa ("ACPI: GTDT: Generate platform devices for MMIO timers") Reported-by: Pavan Kondeti Signed-off-by: Marc Zyngier Cc: Hanjun Guo Cc: Sudeep Holla Cc: Rafael J. Wysocki Cc: Daniel Lezcano Cc: Thomas Gleixner Cc: Mark Rutland Acked-by: Hanjun Guo Signed-off-by: Will Deacon --- drivers/acpi/arm64/gtdt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/acpi/arm64/gtdt.c b/drivers/acpi/arm64/gtdt.c index fd995a1d3d24..8cc8af8fd408 100644 --- a/drivers/acpi/arm64/gtdt.c +++ b/drivers/acpi/arm64/gtdt.c @@ -430,10 +430,10 @@ static int __init gtdt_platform_timer_init(void) continue; pdev = platform_device_register_data(NULL, "gtdt-arm-mmio-timer", - gwdt_count, &atm, + mmio_timer_count, &atm, sizeof(atm)); if (IS_ERR(pdev)) { - pr_err("Can't register timer %d\n", gwdt_count); + pr_err("Can't register timer %d\n", mmio_timer_count); continue; } From 165eb13e485c5c25c7cb276ac85f788a2bd200cb Mon Sep 17 00:00:00 2001 From: Jonathan Marek Date: Mon, 17 Nov 2025 00:12:08 -0500 Subject: [PATCH 3/3] arm64: proton-pack: Fix hard lockup when !MITIGATE_SPECTRE_BRANCH_HISTORY The "drop print" commit removed the whole branch and not just the print. For some ARM64 cpus, this leads to hard lockup when CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY is not enabled. Fixes: 62e72463ca71 ("arm64: proton-pack: Drop print when !CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY") Signed-off-by: Jonathan Marek Signed-off-by: Will Deacon --- arch/arm64/kernel/proton-pack.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm64/kernel/proton-pack.c b/arch/arm64/kernel/proton-pack.c index c7d70d04c164..80a580e019c5 100644 --- a/arch/arm64/kernel/proton-pack.c +++ b/arch/arm64/kernel/proton-pack.c @@ -1032,6 +1032,8 @@ void spectre_bhb_enable_mitigation(const struct arm64_cpu_capabilities *entry) if (arm64_get_spectre_v2_state() == SPECTRE_VULNERABLE) { /* No point mitigating Spectre-BHB alone. */ + } else if (!IS_ENABLED(CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY)) { + /* Do nothing */ } else if (supports_ecbhb(SCOPE_LOCAL_CPU)) { state = SPECTRE_MITIGATED; set_bit(BHB_HW, &system_bhb_mitigations);