From 70b70a4307cccebe91388337b1c85735ce4de6ff Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Mon, 18 Sep 2023 14:48:01 +0200 Subject: PCI/sysfs: Protect driver's D3cold preference from user space struct pci_dev contains two flags which govern whether the device may suspend to D3cold: * no_d3cold provides an opt-out for drivers (e.g. if a device is known to not wake from D3cold) * d3cold_allowed provides an opt-out for user space (default is true, user space may set to false) Since commit 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend"), the user space setting overwrites the driver setting. Essentially user space is trusted to know better than the driver whether D3cold is working. That feels unsafe and wrong. Assume that the change was introduced inadvertently and do not overwrite no_d3cold when d3cold_allowed is modified. Instead, consider d3cold_allowed in addition to no_d3cold when choosing a suspend state for the device. That way, user space may opt out of D3cold if the driver hasn't, but it may no longer force an opt in if the driver has opted out. Fixes: 9d26d3a8f1b0 ("PCI: Put PCIe ports into D3 during suspend") Link: https://lore.kernel.org/r/b8a7f4af2b73f6b506ad8ddee59d747cbf834606.1695025365.git.lukas@wunner.de Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Mika Westerberg Reviewed-by: Mario Limonciello Cc: stable@vger.kernel.org # v4.8+ --- drivers/pci/pci-acpi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pci/pci-acpi.c') diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index a05350a4e49c..05b7357bd258 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -911,7 +911,7 @@ pci_power_t acpi_pci_choose_state(struct pci_dev *pdev) { int acpi_state, d_max; - if (pdev->no_d3cold) + if (pdev->no_d3cold || !pdev->d3cold_allowed) d_max = ACPI_STATE_D3_HOT; else d_max = ACPI_STATE_D3_COLD; -- cgit v1.2.3 From 8624ebc300b2418b498cb85463682afc9bde5d54 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Mon, 2 Oct 2023 16:53:52 +0300 Subject: PCI/ACPI: Use acpi_evaluate_dsm_typed() The acpi_evaluate_dsm_typed() provides a way to check the type of the object evaluated by _DSM call. Use it instead of open coded variant. Link: https://lore.kernel.org/r/20231002135352.2603096-1-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Signed-off-by: Bjorn Helgaas Acked-by: "Rafael J. Wysocki" --- drivers/pci/pci-acpi.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) (limited to 'drivers/pci/pci-acpi.c') diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c index a05350a4e49c..cf108259aef6 100644 --- a/drivers/pci/pci-acpi.c +++ b/drivers/pci/pci-acpi.c @@ -1215,12 +1215,12 @@ void acpi_pci_add_bus(struct pci_bus *bus) if (!pci_is_root_bus(bus)) return; - obj = acpi_evaluate_dsm(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 3, - DSM_PCI_POWER_ON_RESET_DELAY, NULL); + obj = acpi_evaluate_dsm_typed(ACPI_HANDLE(bus->bridge), &pci_acpi_dsm_guid, 3, + DSM_PCI_POWER_ON_RESET_DELAY, NULL, ACPI_TYPE_INTEGER); if (!obj) return; - if (obj->type == ACPI_TYPE_INTEGER && obj->integer.value == 1) { + if (obj->integer.value == 1) { bridge = pci_find_host_bridge(bus); bridge->ignore_reset_delay = 1; } @@ -1376,12 +1376,13 @@ static void pci_acpi_optimize_delay(struct pci_dev *pdev, if (bridge->ignore_reset_delay) pdev->d3cold_delay = 0; - obj = acpi_evaluate_dsm(handle, &pci_acpi_dsm_guid, 3, - DSM_PCI_DEVICE_READINESS_DURATIONS, NULL); + obj = acpi_evaluate_dsm_typed(handle, &pci_acpi_dsm_guid, 3, + DSM_PCI_DEVICE_READINESS_DURATIONS, NULL, + ACPI_TYPE_PACKAGE); if (!obj) return; - if (obj->type == ACPI_TYPE_PACKAGE && obj->package.count == 5) { + if (obj->package.count == 5) { elements = obj->package.elements; if (elements[0].type == ACPI_TYPE_INTEGER) { value = (int)elements[0].integer.value / 1000; -- cgit v1.2.3