From 6e460c3d611009a1d1c2c1f61c96578284a14fba Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Mon, 30 Jun 2025 17:26:39 +0300 Subject: PCI: Ensure relaxed tail alignment does not increase min_align MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When using relaxed tail alignment for the bridge window, pbus_size_mem() also tries to minimize min_align, which can under certain scenarios end up increasing min_align from that found by calculate_mem_align(). Ensure min_align is not increased by the relaxed tail alignment. Eventually, it would be better to add calculate_relaxed_head_align() similar to calculate_mem_align() which finds out what alignment can be used for the head without introducing any gaps into the bridge window to give flexibility on head address too. But that looks relatively complex so it requires much more testing than fixing the immediate problem causing a regression. Fixes: 67f9085596ee ("PCI: Allow relaxed bridge window tail sizing for optional resources") Reported-by: Rio Liu Closes: https://lore.kernel.org/all/o2bL8MtD_40-lf8GlslTw-AZpUPzm8nmfCnJKvS8RQ3NOzOW1uq1dVCEfRpUjJ2i7G2WjfQhk2IWZ7oGp-7G-jXN4qOdtnyOcjRR0PZWK5I=@r26.me/ Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Tested-by: Rio Liu Cc: stable@vger.kernel.org # v6.15+ Link: https://patch.msgid.link/20250822123359.16305-2-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 7853ac6999e2..527f0479e983 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1169,6 +1169,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, resource_size_t children_add_size = 0; resource_size_t children_add_align = 0; resource_size_t add_align = 0; + resource_size_t relaxed_align; if (!b_res) return -ENOSPC; @@ -1246,8 +1247,9 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, if (bus->self && size0 && !pbus_upstream_space_available(bus, mask | IORESOURCE_PREFETCH, type, size0, min_align)) { - min_align = 1ULL << (max_order + __ffs(SZ_1M)); - min_align = max(min_align, win_align); + relaxed_align = 1ULL << (max_order + __ffs(SZ_1M)); + relaxed_align = max(relaxed_align, win_align); + min_align = min(min_align, relaxed_align); size0 = calculate_memsize(size, min_size, 0, 0, resource_size(b_res), win_align); pci_info(bus->self, "bridge window %pR to %pR requires relaxed alignment rules\n", b_res, &bus->busn_res); @@ -1261,8 +1263,9 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, if (bus->self && size1 && !pbus_upstream_space_available(bus, mask | IORESOURCE_PREFETCH, type, size1, add_align)) { - min_align = 1ULL << (max_order + __ffs(SZ_1M)); - min_align = max(min_align, win_align); + relaxed_align = 1ULL << (max_order + __ffs(SZ_1M)); + relaxed_align = max(relaxed_align, win_align); + min_align = min(min_align, relaxed_align); size1 = calculate_memsize(size, min_size, add_size, children_add_size, resource_size(b_res), win_align); pci_info(bus->self, -- cgit v1.2.3 From ff77c5219747d6b78e8b0ffc4c43d3dd8173d1b2 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Mon, 30 Jun 2025 17:26:40 +0300 Subject: PCI: Fix pdev_resources_assignable() disparity MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit pdev_sort_resources() uses pdev_resources_assignable() helper to decide if device's resources cannot be assigned, so it ignores class 0 (PCI_CLASS_NOT_DEFINED) devices. pbus_size_mem(), on the other hand, does not do the same check. This could lead into a situation where a resource ends up on realloc_head list but is not on the head list, which in turn prevents emptying the resource from the realloc_head list in __assign_resources_sorted(). A non-empty realloc_head is unacceptable because it triggers an internal sanity check as shown in this log with a device that has class 0 (PCI_CLASS_NOT_DEFINED): pci 0001:01:00.0: [144d:a5a5] type 00 class 0x000000 PCIe Endpoint pci 0001:01:00.0: BAR 0 [mem 0x00000000-0x000fffff 64bit] pci 0001:01:00.0: ROM [mem 0x00000000-0x0000ffff pref] pcieport 0001:00:00.0: bridge window [mem 0x00100000-0x001fffff] to [bus 01-ff] add_size 100000 add_align 100000 pcieport 0001:00:00.0: bridge window [mem 0x40000000-0x401fffff]: assigned ------------[ cut here ]------------ kernel BUG at drivers/pci/setup-bus.c:2532! Internal error: Oops - BUG: 00000000f2000800 [#1] SMP ... Call trace: pci_assign_unassigned_bus_resources+0x110/0x114 (P) pci_rescan_bus+0x28/0x48 Use pdev_resources_assignable() also within pbus_size_mem() to skip processing of non-assignable resources which removes the disparity in between what resources pdev_sort_resources() and pbus_size_mem() consider. As non-assignable resources are no longer processed, they are not added to the realloc_head list, thus the sanity check no longer triggers. This disparity problem is very old but only now became apparent after 2499f5348431 ("PCI: Rework optional resource handling") that made the ROM resources optional when calculating bridge window sizes which required adding the resource to the realloc_head list. Previously, bridge windows were just sized larger than necessary. Fixes: 2499f5348431 ("PCI: Rework optional resource handling") Reported-by: Tudor Ambarus Closes: https://lore.kernel.org/all/5f103643-5e1c-43c6-b8fe-9617d3b5447c@linaro.org/ Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v6.15+ Link: https://patch.msgid.link/20250822123359.16305-3-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 527f0479e983..df5aec46c29d 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -1191,6 +1191,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, resource_size_t r_size; if (r->parent || (r->flags & IORESOURCE_PCI_FIXED) || + !pdev_resources_assignable(dev) || ((r->flags & mask) != type && (r->flags & mask) != type2 && (r->flags & mask) != type3)) -- cgit v1.2.3 From 31af09b3eaf3603870ce9fd5a7b6c8693129c4cf Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Mon, 30 Jun 2025 17:26:41 +0300 Subject: PCI: Fix failure detection during resource resize MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Since 96336ec70264 ("PCI: Perform reset_resource() and build fail list in sync") the failed list is always built and returned to let the caller decide what to do with the failures. The caller may want to retry resource fitting and assignment and before that can happen, the resources should be restored to their original state (a reset effectively clears the struct resource), which requires returning them to the failed list so the original state remains stored in the associated struct pci_dev_resource. Resource resizing is different from the ordinary resource fitting and assignment in that it only considers part of the resources. This means failures for other resource types are not relevant at all and should be ignored. As resize doesn't unassign such unrelated resources, those resources ending up in the failed list implies assignment of that resource must have failed before resize too. The check in pci_reassign_bridge_resources() to decide if the whole assignment is successful, however, is based on list emptiness which will cause false negatives when the failed list has resources with an unrelated type. If the failed list is not empty, call pci_required_resource_failed() and extend it to be able to filter on specific resource types too (if provided). Calling pci_required_resource_failed() at this point is slightly problematic because the resource itself is reset when the failed list is constructed in __assign_resources_sorted(). As a result, pci_resource_is_optional() does not have access to the original resource flags. This could be worked around by restoring and re-resetting the resource around the call to pci_resource_is_optional(), however, it shouldn't cause issue as resource resizing is meant for 64-bit prefetchable resources according to Christian König (see the Link which unfortunately doesn't point directly to Christian's reply because lore didn't store that email at all). Fixes: 96336ec70264 ("PCI: Perform reset_resource() and build fail list in sync") Link: https://lore.kernel.org/all/c5d1b5d8-8669-5572-75a7-0b480f581ac1@linux.intel.com/ Reported-by: D Scott Phillips Closes: https://lore.kernel.org/all/86plf0lgit.fsf@scott-ph-mail.amperecomputing.com/ Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Tested-by: D Scott Phillips Reviewed-by: D Scott Phillips Cc: Christian König Cc: stable@vger.kernel.org # v6.15+ Link: https://patch.msgid.link/20250822123359.16305-4-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index df5aec46c29d..def29506700e 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -28,6 +28,10 @@ #include #include "pci.h" +#define PCI_RES_TYPE_MASK \ + (IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH |\ + IORESOURCE_MEM_64) + unsigned int pci_flags; EXPORT_SYMBOL_GPL(pci_flags); @@ -384,13 +388,19 @@ static bool pci_need_to_release(unsigned long mask, struct resource *res) } /* Return: @true if assignment of a required resource failed. */ -static bool pci_required_resource_failed(struct list_head *fail_head) +static bool pci_required_resource_failed(struct list_head *fail_head, + unsigned long type) { struct pci_dev_resource *fail_res; + type &= PCI_RES_TYPE_MASK; + list_for_each_entry(fail_res, fail_head, list) { int idx = pci_resource_num(fail_res->dev, fail_res->res); + if (type && (fail_res->flags & PCI_RES_TYPE_MASK) != type) + continue; + if (!pci_resource_is_optional(fail_res->dev, idx)) return true; } @@ -504,7 +514,7 @@ assign: } /* Without realloc_head and only optional fails, nothing more to do. */ - if (!pci_required_resource_failed(&local_fail_head) && + if (!pci_required_resource_failed(&local_fail_head, 0) && list_empty(realloc_head)) { list_for_each_entry(save_res, &save_head, list) { struct resource *res = save_res->res; @@ -1708,10 +1718,6 @@ static void __pci_bridge_assign_resources(const struct pci_dev *bridge, } } -#define PCI_RES_TYPE_MASK \ - (IORESOURCE_IO | IORESOURCE_MEM | IORESOURCE_PREFETCH |\ - IORESOURCE_MEM_64) - static void pci_bridge_release_resources(struct pci_bus *bus, unsigned long type) { @@ -2450,8 +2456,12 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type) free_list(&added); if (!list_empty(&failed)) { - ret = -ENOSPC; - goto cleanup; + if (pci_required_resource_failed(&failed, type)) { + ret = -ENOSPC; + goto cleanup; + } + /* Only resources with unrelated types failed (again) */ + free_list(&failed); } list_for_each_entry(dev_res, &saved, list) { -- cgit v1.2.3 From 2657a0c982239fecc41d0df5a69091ca4297647c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:50 +0300 Subject: m68k/PCI: Use pci_enable_resources() in pcibios_enable_device() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit m68k has a resource enable (check) loop in its pcibios_enable_device() which for some reason differs from pci_enable_resources(). This could lead to inconsistencies in behavior, especially now as pci_enable_resources() and the bridge window resource flags behavior are going to be altered by upcoming changes. The check for !r->start && r->end is already covered by the more generic checks done in pci_enable_resources(). The entire pcibios_enable_device() suspiciously looks copy-paste from some other arch as also indicated by the preceding comment. However, it also enables PCI_COMMAND_IO | PCI_COMMAND_MEMORY always for bridges. It is not clear why that is being done as the commit e93a6bbeb5a5 ("m68k: common PCI support definitions and code") introducing this code states "Nothing specific to any PCI implementation in any m68k class CPU hardware yet". Replace the resource enable loop with a call to pci_enable_resources() and adjust the Command Register afterwards as it's unclear if that is necessary or not so keep it for now. Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-2-ilpo.jarvinen@linux.intel.com --- arch/m68k/kernel/pcibios.c | 39 +++++++++++---------------------------- 1 file changed, 11 insertions(+), 28 deletions(-) diff --git a/arch/m68k/kernel/pcibios.c b/arch/m68k/kernel/pcibios.c index 9504eb19d73a..e6ab3f9ff5d8 100644 --- a/arch/m68k/kernel/pcibios.c +++ b/arch/m68k/kernel/pcibios.c @@ -44,41 +44,24 @@ resource_size_t pcibios_align_resource(void *data, const struct resource *res, */ int pcibios_enable_device(struct pci_dev *dev, int mask) { - struct resource *r; u16 cmd, newcmd; - int idx; + int ret; - pci_read_config_word(dev, PCI_COMMAND, &cmd); - newcmd = cmd; - - for (idx = 0; idx < 6; idx++) { - /* Only set up the requested stuff */ - if (!(mask & (1 << idx))) - continue; - - r = dev->resource + idx; - if (!r->start && r->end) { - pr_err("PCI: Device %s not available because of resource collisions\n", - pci_name(dev)); - return -EINVAL; - } - if (r->flags & IORESOURCE_IO) - newcmd |= PCI_COMMAND_IO; - if (r->flags & IORESOURCE_MEM) - newcmd |= PCI_COMMAND_MEMORY; - } + ret = pci_enable_resources(dev, mask); + if (ret < 0) + return ret; /* * Bridges (eg, cardbus bridges) need to be fully enabled */ - if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE) + if ((dev->class >> 16) == PCI_BASE_CLASS_BRIDGE) { + pci_read_config_word(dev, PCI_COMMAND, &cmd); newcmd |= PCI_COMMAND_IO | PCI_COMMAND_MEMORY; - - - if (newcmd != cmd) { - pr_info("PCI: enabling device %s (0x%04x -> 0x%04x)\n", - pci_name(dev), cmd, newcmd); - pci_write_config_word(dev, PCI_COMMAND, newcmd); + if (newcmd != cmd) { + pr_info("PCI: enabling bridge %s (0x%04x -> 0x%04x)\n", + pci_name(dev), cmd, newcmd); + pci_write_config_word(dev, PCI_COMMAND, newcmd); + } } return 0; } -- cgit v1.2.3 From 754babaaf33349d9ef27bb1ac6f5d9d5a503a2a6 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:51 +0300 Subject: sparc/PCI: Remove pcibios_enable_device() as they do nothing extra MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Under arch/sparc/ there are multiple copies of pcibios_enable_device() but none of those seem to do anything extra beyond what pci_enable_resources() is supposed to do. These functions could lead to inconsistencies in behavior, especially now as pci_enable_resources() and the bridge window resource flags behavior are going to be altered by upcoming changes. Remove all pcibios_enable_device() from arch/sparc/ so that PCI core can simply call into pci_enable_resources() instead using its __weak version of pcibios_enable_device(). Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-3-ilpo.jarvinen@linux.intel.com --- arch/sparc/kernel/leon_pci.c | 27 --------------------------- arch/sparc/kernel/pci.c | 27 --------------------------- arch/sparc/kernel/pcic.c | 27 --------------------------- 3 files changed, 81 deletions(-) diff --git a/arch/sparc/kernel/leon_pci.c b/arch/sparc/kernel/leon_pci.c index 8de6646e9ce8..10934dfa987a 100644 --- a/arch/sparc/kernel/leon_pci.c +++ b/arch/sparc/kernel/leon_pci.c @@ -60,30 +60,3 @@ void leon_pci_init(struct platform_device *ofdev, struct leon_pci_info *info) pci_assign_unassigned_resources(); pci_bus_add_devices(root_bus); } - -int pcibios_enable_device(struct pci_dev *dev, int mask) -{ - struct resource *res; - u16 cmd, oldcmd; - int i; - - pci_read_config_word(dev, PCI_COMMAND, &cmd); - oldcmd = cmd; - - pci_dev_for_each_resource(dev, res, i) { - /* Only set up the requested stuff */ - if (!(mask & (1<flags & IORESOURCE_IO) - cmd |= PCI_COMMAND_IO; - if (res->flags & IORESOURCE_MEM) - cmd |= PCI_COMMAND_MEMORY; - } - - if (cmd != oldcmd) { - pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd); - pci_write_config_word(dev, PCI_COMMAND, cmd); - } - return 0; -} diff --git a/arch/sparc/kernel/pci.c b/arch/sparc/kernel/pci.c index ddac216a2aff..a9448088e762 100644 --- a/arch/sparc/kernel/pci.c +++ b/arch/sparc/kernel/pci.c @@ -722,33 +722,6 @@ struct pci_bus *pci_scan_one_pbm(struct pci_pbm_info *pbm, return bus; } -int pcibios_enable_device(struct pci_dev *dev, int mask) -{ - struct resource *res; - u16 cmd, oldcmd; - int i; - - pci_read_config_word(dev, PCI_COMMAND, &cmd); - oldcmd = cmd; - - pci_dev_for_each_resource(dev, res, i) { - /* Only set up the requested stuff */ - if (!(mask & (1<flags & IORESOURCE_IO) - cmd |= PCI_COMMAND_IO; - if (res->flags & IORESOURCE_MEM) - cmd |= PCI_COMMAND_MEMORY; - } - - if (cmd != oldcmd) { - pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd); - pci_write_config_word(dev, PCI_COMMAND, cmd); - } - return 0; -} - /* Platform support for /proc/bus/pci/X/Y mmap()s. */ int pci_iobar_pfn(struct pci_dev *pdev, int bar, struct vm_area_struct *vma) { diff --git a/arch/sparc/kernel/pcic.c b/arch/sparc/kernel/pcic.c index 25fe0a061732..3d54ad5656a4 100644 --- a/arch/sparc/kernel/pcic.c +++ b/arch/sparc/kernel/pcic.c @@ -641,33 +641,6 @@ void pcibios_fixup_bus(struct pci_bus *bus) } } -int pcibios_enable_device(struct pci_dev *dev, int mask) -{ - struct resource *res; - u16 cmd, oldcmd; - int i; - - pci_read_config_word(dev, PCI_COMMAND, &cmd); - oldcmd = cmd; - - pci_dev_for_each_resource(dev, res, i) { - /* Only set up the requested stuff */ - if (!(mask & (1<flags & IORESOURCE_IO) - cmd |= PCI_COMMAND_IO; - if (res->flags & IORESOURCE_MEM) - cmd |= PCI_COMMAND_MEMORY; - } - - if (cmd != oldcmd) { - pci_info(dev, "enabling device (%04x -> %04x)\n", oldcmd, cmd); - pci_write_config_word(dev, PCI_COMMAND, cmd); - } - return 0; -} - /* Makes compiler happy */ static volatile int pcic_timer_dummy; -- cgit v1.2.3 From ae81aad5c2e17fd1fafd930e75b81aedc837f705 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:52 +0300 Subject: MIPS: PCI: Use pci_enable_resources() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit pci-legacy.c under MIPS has a copy of pci_enable_resources() named as pcibios_enable_resources(). Having own copy of same functionality could lead to inconsistencies in behavior, especially now as pci_enable_resources() and the bridge window resource flags behavior are going to be altered by upcoming changes. The check for !r->start && r->end is already covered by the more generic checks done in pci_enable_resources(). Call pci_enable_resources() from MIPS's pcibios_enable_device() and remove pcibios_enable_resources(). Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Acked-by: Thomas Bogendoerfer Link: https://patch.msgid.link/20250829131113.36754-4-ilpo.jarvinen@linux.intel.com --- arch/mips/pci/pci-legacy.c | 38 ++------------------------------------ 1 file changed, 2 insertions(+), 36 deletions(-) diff --git a/arch/mips/pci/pci-legacy.c b/arch/mips/pci/pci-legacy.c index 66898fd182dc..d04b7c1294b6 100644 --- a/arch/mips/pci/pci-legacy.c +++ b/arch/mips/pci/pci-legacy.c @@ -249,45 +249,11 @@ static int __init pcibios_init(void) subsys_initcall(pcibios_init); -static int pcibios_enable_resources(struct pci_dev *dev, int mask) -{ - u16 cmd, old_cmd; - int idx; - struct resource *r; - - pci_read_config_word(dev, PCI_COMMAND, &cmd); - old_cmd = cmd; - pci_dev_for_each_resource(dev, r, idx) { - /* Only set up the requested stuff */ - if (!(mask & (1<flags & (IORESOURCE_IO | IORESOURCE_MEM))) - continue; - if ((idx == PCI_ROM_RESOURCE) && - (!(r->flags & IORESOURCE_ROM_ENABLE))) - continue; - if (!r->start && r->end) { - pci_err(dev, - "can't enable device: resource collisions\n"); - return -EINVAL; - } - if (r->flags & IORESOURCE_IO) - cmd |= PCI_COMMAND_IO; - if (r->flags & IORESOURCE_MEM) - cmd |= PCI_COMMAND_MEMORY; - } - if (cmd != old_cmd) { - pci_info(dev, "enabling device (%04x -> %04x)\n", old_cmd, cmd); - pci_write_config_word(dev, PCI_COMMAND, cmd); - } - return 0; -} - int pcibios_enable_device(struct pci_dev *dev, int mask) { - int err = pcibios_enable_resources(dev, mask); + int err; + err = pci_enable_resources(dev, mask); if (err < 0) return err; -- cgit v1.2.3 From e240edffd04fe179536f7b5c22daae1e3b509b46 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:53 +0300 Subject: PCI: Move find_bus_resource_of_type() earlier MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Move find_bus_resource_of_type() earlier in setup-bus.c to be able to call it in upcoming changes. Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-5-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 56 ++++++++++++++++++++++++------------------------- 1 file changed, 28 insertions(+), 28 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index def29506700e..4097d8703b8f 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -140,6 +140,34 @@ static void restore_dev_resource(struct pci_dev_resource *dev_res) res->flags = dev_res->flags; } +/* + * Helper function for sizing routines. Assigned resources have non-NULL + * parent resource. + * + * Return first unassigned resource of the correct type. If there is none, + * return first assigned resource of the correct type. If none of the + * above, return NULL. + * + * Returning an assigned resource of the correct type allows the caller to + * distinguish between already assigned and no resource of the correct type. + */ +static struct resource *find_bus_resource_of_type(struct pci_bus *bus, + unsigned long type_mask, + unsigned long type) +{ + struct resource *r, *r_assigned = NULL; + + pci_bus_for_each_resource(bus, r) { + if (r == &ioport_resource || r == &iomem_resource) + continue; + if (r && (r->flags & type_mask) == type && !r->parent) + return r; + if (r && (r->flags & type_mask) == type && !r_assigned) + r_assigned = r; + } + return r_assigned; +} + static bool pdev_resources_assignable(struct pci_dev *dev) { u16 class = dev->class >> 8, command; @@ -876,34 +904,6 @@ static void pci_bridge_check_ranges(struct pci_bus *bus) } } -/* - * Helper function for sizing routines. Assigned resources have non-NULL - * parent resource. - * - * Return first unassigned resource of the correct type. If there is none, - * return first assigned resource of the correct type. If none of the - * above, return NULL. - * - * Returning an assigned resource of the correct type allows the caller to - * distinguish between already assigned and no resource of the correct type. - */ -static struct resource *find_bus_resource_of_type(struct pci_bus *bus, - unsigned long type_mask, - unsigned long type) -{ - struct resource *r, *r_assigned = NULL; - - pci_bus_for_each_resource(bus, r) { - if (r == &ioport_resource || r == &iomem_resource) - continue; - if (r && (r->flags & type_mask) == type && !r->parent) - return r; - if (r && (r->flags & type_mask) == type && !r_assigned) - r_assigned = r; - } - return r_assigned; -} - static resource_size_t calculate_iosize(resource_size_t size, resource_size_t min_size, resource_size_t size1, -- cgit v1.2.3 From 1ce76bc0497b9289d6f6195258d8bdc1c42eb91a Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:54 +0300 Subject: PCI: Refactor find_bus_resource_of_type() logic checks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Reorder the logic checks in find_bus_resource_of_type() to simplify them. Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-6-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 4097d8703b8f..c5fc4e2825be 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -158,11 +158,15 @@ static struct resource *find_bus_resource_of_type(struct pci_bus *bus, struct resource *r, *r_assigned = NULL; pci_bus_for_each_resource(bus, r) { - if (r == &ioport_resource || r == &iomem_resource) + if (!r || r == &ioport_resource || r == &iomem_resource) continue; - if (r && (r->flags & type_mask) == type && !r->parent) + + if ((r->flags & type_mask) != type) + continue; + + if (!r->parent) return r; - if (r && (r->flags & type_mask) == type && !r_assigned) + if (!r_assigned) r_assigned = r; } return r_assigned; -- cgit v1.2.3 From 2ee33aa14d3f2e92ba8ae80443f2cd9b575f08cb Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:55 +0300 Subject: PCI: Always claim bridge window before its setup MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When the claim of a resource fails for the full range in pci_claim_bridge_resource(), clipping the resource to a smaller size is attempted. If clipping is successful, the new bridge window is programmed and only as the last step the code attempts to claim the resource again. The order of the last two steps is slightly illogical and inconsistent with the assignment call chains. If claiming the bridge window after clipping fails, the bridge window that was set up is left in place. Rework the logic such that the bridge window is claimed before calling the relevant bridge setup function. This make the behavior consistent with resource fitting call chains that always assign the bridge window before programming it. If claiming the bridge window fails, the clipped bridge window is no longer set up but pci_claim_bridge_resource() returns without writing the bridge window at all. Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-7-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index c5fc4e2825be..b477f68b236c 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -857,9 +857,16 @@ int pci_claim_bridge_resource(struct pci_dev *bridge, int i) if ((bridge->class >> 8) != PCI_CLASS_BRIDGE_PCI) return 0; + if (i > PCI_BRIDGE_PREF_MEM_WINDOW) + return -EINVAL; + + /* Try to clip the resource and claim the smaller window */ if (!pci_bus_clip_resource(bridge, i)) return -EINVAL; /* Clipping didn't change anything */ + if (!pci_claim_resource(bridge, i)) + return -EINVAL; + switch (i) { case PCI_BRIDGE_IO_WINDOW: pci_setup_bridge_io(bridge); @@ -874,10 +881,7 @@ int pci_claim_bridge_resource(struct pci_dev *bridge, int i) return -EINVAL; } - if (pci_claim_resource(bridge, i) == 0) - return 0; /* Claimed a smaller window */ - - return -EINVAL; + return 0; } /* -- cgit v1.2.3 From b15f45ab65e2ce04339fbd54387a9209529d315b Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:56 +0300 Subject: PCI: Disable non-claimed bridge window MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If clipping or claiming the bridge window fails, the bridge window is left in a state that does not match the kernel's view on what the bridge window is. Disable the bridge window by writing the magic disable value into the Base and Limit Registers if clipping or claiming failed. To detect if claiming the resource was successful, add res->parent checks into the bridge setup functions. Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-8-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 25 ++++++++++++------------- 1 file changed, 12 insertions(+), 13 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index b477f68b236c..6bdc1af887da 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -660,7 +660,7 @@ void pci_setup_cardbus(struct pci_bus *bus) res = bus->resource[0]; pcibios_resource_to_bus(bridge->bus, ®ion, res); - if (res->flags & IORESOURCE_IO) { + if (res->parent && res->flags & IORESOURCE_IO) { /* * The IO resource is allocated a range twice as large as it * would normally need. This allows us to set both IO regs. @@ -674,7 +674,7 @@ void pci_setup_cardbus(struct pci_bus *bus) res = bus->resource[1]; pcibios_resource_to_bus(bridge->bus, ®ion, res); - if (res->flags & IORESOURCE_IO) { + if (res->parent && res->flags & IORESOURCE_IO) { pci_info(bridge, " bridge window %pR\n", res); pci_write_config_dword(bridge, PCI_CB_IO_BASE_1, region.start); @@ -684,7 +684,7 @@ void pci_setup_cardbus(struct pci_bus *bus) res = bus->resource[2]; pcibios_resource_to_bus(bridge->bus, ®ion, res); - if (res->flags & IORESOURCE_MEM) { + if (res->parent && res->flags & IORESOURCE_MEM) { pci_info(bridge, " bridge window %pR\n", res); pci_write_config_dword(bridge, PCI_CB_MEMORY_BASE_0, region.start); @@ -694,7 +694,7 @@ void pci_setup_cardbus(struct pci_bus *bus) res = bus->resource[3]; pcibios_resource_to_bus(bridge->bus, ®ion, res); - if (res->flags & IORESOURCE_MEM) { + if (res->parent && res->flags & IORESOURCE_MEM) { pci_info(bridge, " bridge window %pR\n", res); pci_write_config_dword(bridge, PCI_CB_MEMORY_BASE_1, region.start); @@ -735,7 +735,7 @@ static void pci_setup_bridge_io(struct pci_dev *bridge) res = &bridge->resource[PCI_BRIDGE_IO_WINDOW]; res_name = pci_resource_name(bridge, PCI_BRIDGE_IO_WINDOW); pcibios_resource_to_bus(bridge->bus, ®ion, res); - if (res->flags & IORESOURCE_IO) { + if (res->parent && res->flags & IORESOURCE_IO) { pci_read_config_word(bridge, PCI_IO_BASE, &l); io_base_lo = (region.start >> 8) & io_mask; io_limit_lo = (region.end >> 8) & io_mask; @@ -767,7 +767,7 @@ static void pci_setup_bridge_mmio(struct pci_dev *bridge) res = &bridge->resource[PCI_BRIDGE_MEM_WINDOW]; res_name = pci_resource_name(bridge, PCI_BRIDGE_MEM_WINDOW); pcibios_resource_to_bus(bridge->bus, ®ion, res); - if (res->flags & IORESOURCE_MEM) { + if (res->parent && res->flags & IORESOURCE_MEM) { l = (region.start >> 16) & 0xfff0; l |= region.end & 0xfff00000; pci_info(bridge, " %s %pR\n", res_name, res); @@ -796,7 +796,7 @@ static void pci_setup_bridge_mmio_pref(struct pci_dev *bridge) res = &bridge->resource[PCI_BRIDGE_PREF_MEM_WINDOW]; res_name = pci_resource_name(bridge, PCI_BRIDGE_PREF_MEM_WINDOW); pcibios_resource_to_bus(bridge->bus, ®ion, res); - if (res->flags & IORESOURCE_PREFETCH) { + if (res->parent && res->flags & IORESOURCE_PREFETCH) { l = (region.start >> 16) & 0xfff0; l |= region.end & 0xfff00000; if (res->flags & IORESOURCE_MEM_64) { @@ -848,6 +848,8 @@ static void pci_setup_bridge(struct pci_bus *bus) int pci_claim_bridge_resource(struct pci_dev *bridge, int i) { + int ret = -EINVAL; + if (i < PCI_BRIDGE_RESOURCES || i > PCI_BRIDGE_RESOURCE_END) return 0; @@ -861,11 +863,8 @@ int pci_claim_bridge_resource(struct pci_dev *bridge, int i) return -EINVAL; /* Try to clip the resource and claim the smaller window */ - if (!pci_bus_clip_resource(bridge, i)) - return -EINVAL; /* Clipping didn't change anything */ - - if (!pci_claim_resource(bridge, i)) - return -EINVAL; + if (pci_bus_clip_resource(bridge, i)) + ret = pci_claim_resource(bridge, i); switch (i) { case PCI_BRIDGE_IO_WINDOW: @@ -881,7 +880,7 @@ int pci_claim_bridge_resource(struct pci_dev *bridge, int i) return -EINVAL; } - return 0; + return ret; } /* -- cgit v1.2.3 From 3baeae36039afc233d4a42d6ff4aa7019892619f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:57 +0300 Subject: PCI: Use pci_release_resource() instead of release_resource() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A few places in setup-bus.c call release_resource() directly and end up duplicating functionality from pci_release_resource() such as parent check, logging, and clearing the resource. Worse yet, the way the resource is cleared is inconsistent between different sites. Convert release_resource() calls into pci_release_resource() to remove code duplication. This will also make the resource start, end, and flags behavior consistent, i.e., start address is cleared, and only IORESOURCE_UNSET is asserted for the resource. While at it, eliminate the unnecessary initialization of idx variable in pci_bridge_release_resources(). Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-9-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-bus.c | 46 ++++++++++++++-------------------------------- drivers/pci/setup-res.c | 11 ++++++++--- include/linux/pci.h | 2 +- 3 files changed, 23 insertions(+), 36 deletions(-) diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 6bdc1af887da..b62465665abc 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -473,8 +473,6 @@ static void __assign_resources_sorted(struct list_head *head, struct pci_dev_resource *dev_res, *tmp_res, *dev_res2; struct resource *res; struct pci_dev *dev; - const char *res_name; - int idx; unsigned long fail_type; resource_size_t add_align, align; @@ -582,14 +580,7 @@ assign: res = dev_res->res; dev = dev_res->dev; - if (!res->parent) - continue; - - idx = pci_resource_num(dev, res); - res_name = pci_resource_name(dev, idx); - pci_dbg(dev, "%s %pR: releasing\n", res_name, res); - - release_resource(res); + pci_release_resource(dev, pci_resource_num(dev, res)); restore_dev_resource(dev_res); } /* Restore start/end/flags from saved list */ @@ -1732,7 +1723,7 @@ static void pci_bridge_release_resources(struct pci_bus *bus, struct resource *r; unsigned int old_flags; struct resource *b_res; - int idx = 1; + int idx, ret; b_res = &dev->resource[PCI_BRIDGE_RESOURCES]; @@ -1766,21 +1757,18 @@ static void pci_bridge_release_resources(struct pci_bus *bus, /* If there are children, release them all */ release_child_resources(r); - if (!release_resource(r)) { - type = old_flags = r->flags & PCI_RES_TYPE_MASK; - pci_info(dev, "resource %d %pR released\n", - PCI_BRIDGE_RESOURCES + idx, r); - /* Keep the old size */ - resource_set_range(r, 0, resource_size(r)); - r->flags = 0; - /* Avoiding touch the one without PREF */ - if (type & IORESOURCE_PREFETCH) - type = IORESOURCE_PREFETCH; - __pci_setup_bridge(bus, type); - /* For next child res under same bridge */ - r->flags = old_flags; - } + type = old_flags = r->flags & PCI_RES_TYPE_MASK; + ret = pci_release_resource(dev, PCI_BRIDGE_RESOURCES + idx); + if (ret) + return; + + /* Avoiding touch the one without PREF */ + if (type & IORESOURCE_PREFETCH) + type = IORESOURCE_PREFETCH; + __pci_setup_bridge(bus, type); + /* For next child res under same bridge */ + r->flags = old_flags; } enum release_type { @@ -2425,7 +2413,6 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type) for (i = PCI_BRIDGE_RESOURCES; i < PCI_BRIDGE_RESOURCE_END; i++) { struct resource *res = &bridge->resource[i]; - const char *res_name = pci_resource_name(bridge, i); if ((res->flags ^ type) & PCI_RES_TYPE_MASK) continue; @@ -2438,12 +2425,7 @@ int pci_reassign_bridge_resources(struct pci_dev *bridge, unsigned long type) if (ret) goto cleanup; - pci_info(bridge, "%s %pR: releasing\n", res_name, res); - - if (res->parent) - release_resource(res); - res->start = 0; - res->end = 0; + pci_release_resource(bridge, i); break; } if (i == PCI_BRIDGE_RESOURCE_END) diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index d2b3ed51e880..0468c058b598 100644 --- a/drivers/pci/setup-res.c +++ b/drivers/pci/setup-res.c @@ -406,20 +406,25 @@ int pci_reassign_resource(struct pci_dev *dev, int resno, return 0; } -void pci_release_resource(struct pci_dev *dev, int resno) +int pci_release_resource(struct pci_dev *dev, int resno) { struct resource *res = pci_resource_n(dev, resno); const char *res_name = pci_resource_name(dev, resno); + int ret; if (!res->parent) - return; + return 0; pci_info(dev, "%s %pR: releasing\n", res_name, res); - release_resource(res); + ret = release_resource(res); + if (ret) + return ret; res->end = resource_size(res) - 1; res->start = 0; res->flags |= IORESOURCE_UNSET; + + return 0; } EXPORT_SYMBOL(pci_release_resource); diff --git a/include/linux/pci.h b/include/linux/pci.h index 59876de13860..275df4058767 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1417,7 +1417,7 @@ void pci_reset_secondary_bus(struct pci_dev *dev); void pcibios_reset_secondary_bus(struct pci_dev *dev); void pci_update_resource(struct pci_dev *dev, int resno); int __must_check pci_assign_resource(struct pci_dev *dev, int i); -void pci_release_resource(struct pci_dev *dev, int resno); +int pci_release_resource(struct pci_dev *dev, int resno); static inline int pci_rebar_bytes_to_size(u64 bytes) { bytes = roundup_pow_of_two(bytes); -- cgit v1.2.3 From 1cdffa51ecc4ee02c46160bafa2e5d25d09e97ec Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:58 +0300 Subject: PCI: Enable bridge even if bridge window fails to assign MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit A normal PCI bridge has multiple bridge windows and not all of them are always required by devices underneath the bridge. If a Root Port or bridge does not have a device underneath, no bridge windows get assigned. Yet, pci_enable_resources() is set to fail indiscriminantly on any resource assignment failure if the resource is not known to be optional. In practice, the code in pci_enable_resources() is currently largely dormant. The kernel sets resource flags to zero for any unused bridge window and resets flags to zero in case of an resource assignment failure, which short-circuits pci_enable_resources() because of this check: if (!(r->flags & (IORESOURCE_IO | IORESOURCE_MEM))) continue; However, an upcoming change to resource flags will alter how bridge window resource flags behave activating these long dormants checks in pci_enable_resources(). While complex logic could be built to selectively enable a bridge only under some conditions, a few versions of such logic were tried during development of this change and none of them worked satisfactorily. Thus, I just gave up and decided to enable any bridge regardless of the bridge windows as there seems to be no clear benefit from not enabling it, but a major downside as pcieport will not be probed for the bridge if it's not enabled. Therefore, change pci_enable_resources() to not check if bridge window resources remain unassigned. Resource assignment failures are pretty noisy already so there is no need to log that for bridge windows in pci_enable_resources(). Ignoring bridge window failures hopefully prevents an obvious source of regressions when the upcoming change that no longer clears resource flags for bridge windows is enacted. I've hit this problem even during my own testing on multiple occasions so I expect it to be a quite common problem. This can always be revisited later if somebody thinks the enable check for bridges is not strict enough, but expect a mind-boggling number of regressions from such a change. Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-10-ilpo.jarvinen@linux.intel.com --- drivers/pci/setup-res.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index 0468c058b598..4e0e60256f04 100644 --- a/drivers/pci/setup-res.c +++ b/drivers/pci/setup-res.c @@ -527,22 +527,26 @@ int pci_enable_resources(struct pci_dev *dev, int mask) if (pci_resource_is_optional(dev, i)) continue; - if (r->flags & IORESOURCE_UNSET) { - pci_err(dev, "%s %pR: not assigned; can't enable device\n", - r_name, r); - return -EINVAL; + if (i < PCI_BRIDGE_RESOURCES) { + if (r->flags & IORESOURCE_UNSET) { + pci_err(dev, "%s %pR: not assigned; can't enable device\n", + r_name, r); + return -EINVAL; + } + + if (!r->parent) { + pci_err(dev, "%s %pR: not claimed; can't enable device\n", + r_name, r); + return -EINVAL; + } } - if (!r->parent) { - pci_err(dev, "%s %pR: not claimed; can't enable device\n", - r_name, r); - return -EINVAL; + if (r->parent) { + if (r->flags & IORESOURCE_IO) + cmd |= PCI_COMMAND_IO; + if (r->flags & IORESOURCE_MEM) + cmd |= PCI_COMMAND_MEMORY; } - - if (r->flags & IORESOURCE_IO) - cmd |= PCI_COMMAND_IO; - if (r->flags & IORESOURCE_MEM) - cmd |= PCI_COMMAND_MEMORY; } if (cmd != old_cmd) { -- cgit v1.2.3 From 8278c6914306f35f32d73bdf2a918950919a0051 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:10:59 +0300 Subject: PCI: Preserve bridge window resource type flags MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When a bridge window is found unused or fails to assign, the flags of the associated resource are cleared. Clearing flags is problematic as it also removes the type information of the resource which is needed later. Thus, always preserve the bridge window type flags and use IORESOURCE_UNSET and IORESOURCE_DISABLED to indicate the status of the bridge window. Also, when initializing resources, make sure all valid bridge windows do get their type flags set. Change various places that relied on resource flags being cleared to check for IORESOURCE_UNSET and IORESOURCE_DISABLED to allow bridge window resource to retain their type flags. Add pdev_resource_assignable() and pdev_resource_should_fit() helpers to filter out disabled bridge windows during resource fitting; the latter combines more common checks into the helper. When reading the bridge windows from the registers, instead of leaving the resource flags cleared for bridge windows that are not enabled, always set up the flags and set IORESOURCE_UNSET | IORESOURCE_DISABLED as needed. When resource fitting or assignment fails for a bridge window resource, or the bridge window is not needed, mark the resource with IORESOURCE_UNSET or IORESOURCE_DISABLED, respectively. Use dummy zero resource in resource_show() for backwards compatibility as lspci will otherwise misrepresent disabled bridge windows. This change fixes an issue which highlights the importance of keeping the resource type flags intact: At the end of __assign_resources_sorted(), reset_resource() is called, previously clearing the flags. Later, pci_prepare_next_assign_round() attempted to release bridge resources using pci_bus_release_bridge_resources() that calls into pci_bridge_release_resources() that assumes type flags are still present. As type flags were cleared, IORESOURCE_MEM_64 was not set leading to resources under an incorrect bridge window to be released (idx = 1 instead of idx = 2). While the assignments performed later covered this problem so that the wrongly released resources got assigned in the end, it was still causing extra release+assign pairs. There are other reasons why the resource flags should be retained in upcoming changes too. Removing the flag reset for non-bridge window resource is left as future work, in part because it has a much higher regression potential due to pci_enable_resources() that will start to work also for those resources then and due to what endpoint drivers might assume about resources. Despite the Fixes tag, backporting this (at least any time soon) is highly discouraged. The issue fixed is borderline cosmetic as the later assignments normally cover the problem entirely. Also there might be non-obvious dependencies. Fixes: 5b28541552ef ("PCI: Restrict 64-bit prefetchable bridge windows to 64-bit resources") Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-11-ilpo.jarvinen@linux.intel.com --- drivers/pci/bus.c | 3 ++ drivers/pci/pci-sysfs.c | 7 ++++ drivers/pci/probe.c | 25 ++++++++++---- drivers/pci/setup-bus.c | 89 ++++++++++++++++++++++++++++++++----------------- drivers/pci/setup-res.c | 3 ++ 5 files changed, 90 insertions(+), 37 deletions(-) diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index b77fd30bbfd9..58b5388423ee 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -204,6 +204,9 @@ static int pci_bus_alloc_from_region(struct pci_bus *bus, struct resource *res, if (!r) continue; + if (r->flags & (IORESOURCE_UNSET|IORESOURCE_DISABLED)) + continue; + /* type_mask must match */ if ((res->flags ^ r->flags) & type_mask) continue; diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 5eea14c1f7f5..162a5241c7f7 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -177,6 +177,13 @@ static ssize_t resource_show(struct device *dev, struct device_attribute *attr, for (i = 0; i < max; i++) { struct resource *res = &pci_dev->resource[i]; + struct resource zerores = {}; + + /* For backwards compatibility */ + if (i >= PCI_BRIDGE_RESOURCES && i <= PCI_BRIDGE_RESOURCE_END && + res->flags & (IORESOURCE_UNSET | IORESOURCE_DISABLED)) + res = &zerores; + pci_resource_to_user(pci_dev, i, res, &start, &end); len += sysfs_emit_at(buf, len, "0x%016llx 0x%016llx 0x%016llx\n", (unsigned long long)start, diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index f41128f91ca7..f31d27c7708a 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -419,13 +419,17 @@ static void pci_read_bridge_io(struct pci_dev *dev, struct resource *res, limit |= ((unsigned long) io_limit_hi << 16); } + res->flags = (io_base_lo & PCI_IO_RANGE_TYPE_MASK) | IORESOURCE_IO; + if (base <= limit) { - res->flags = (io_base_lo & PCI_IO_RANGE_TYPE_MASK) | IORESOURCE_IO; region.start = base; region.end = limit + io_granularity - 1; pcibios_bus_to_resource(dev->bus, res, ®ion); if (log) pci_info(dev, " bridge window %pR\n", res); + } else { + resource_set_range(res, 0, 0); + res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED; } } @@ -440,13 +444,18 @@ static void pci_read_bridge_mmio(struct pci_dev *dev, struct resource *res, pci_read_config_word(dev, PCI_MEMORY_LIMIT, &mem_limit_lo); base = ((unsigned long) mem_base_lo & PCI_MEMORY_RANGE_MASK) << 16; limit = ((unsigned long) mem_limit_lo & PCI_MEMORY_RANGE_MASK) << 16; + + res->flags = (mem_base_lo & PCI_MEMORY_RANGE_TYPE_MASK) | IORESOURCE_MEM; + if (base <= limit) { - res->flags = (mem_base_lo & PCI_MEMORY_RANGE_TYPE_MASK) | IORESOURCE_MEM; region.start = base; region.end = limit + 0xfffff; pcibios_bus_to_resource(dev->bus, res, ®ion); if (log) pci_info(dev, " bridge window %pR\n", res); + } else { + resource_set_range(res, 0, 0); + res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED; } } @@ -489,16 +498,20 @@ static void pci_read_bridge_mmio_pref(struct pci_dev *dev, struct resource *res, return; } + res->flags = (mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) | IORESOURCE_MEM | + IORESOURCE_PREFETCH; + if (res->flags & PCI_PREF_RANGE_TYPE_64) + res->flags |= IORESOURCE_MEM_64; + if (base <= limit) { - res->flags = (mem_base_lo & PCI_PREF_RANGE_TYPE_MASK) | - IORESOURCE_MEM | IORESOURCE_PREFETCH; - if (res->flags & PCI_PREF_RANGE_TYPE_64) - res->flags |= IORESOURCE_MEM_64; region.start = base; region.end = limit + 0xfffff; pcibios_bus_to_resource(dev->bus, res, ®ion); if (log) pci_info(dev, " bridge window %pR\n", res); + } else { + resource_set_range(res, 0, 0); + res->flags |= IORESOURCE_UNSET | IORESOURCE_DISABLED; } } diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index b62465665abc..70b210ed200d 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -190,6 +190,31 @@ static bool pdev_resources_assignable(struct pci_dev *dev) return true; } +static bool pdev_resource_assignable(struct pci_dev *dev, struct resource *res) +{ + int idx = pci_resource_num(dev, res); + + if (!res->flags) + return false; + + if (idx >= PCI_BRIDGE_RESOURCES && idx <= PCI_BRIDGE_RESOURCE_END && + res->flags & IORESOURCE_DISABLED) + return false; + + return true; +} + +static bool pdev_resource_should_fit(struct pci_dev *dev, struct resource *res) +{ + if (res->parent) + return false; + + if (res->flags & IORESOURCE_PCI_FIXED) + return false; + + return pdev_resource_assignable(dev, res); +} + /* Sort resources by alignment */ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head) { @@ -205,10 +230,7 @@ static void pdev_sort_resources(struct pci_dev *dev, struct list_head *head) resource_size_t r_align; struct list_head *n; - if (r->flags & IORESOURCE_PCI_FIXED) - continue; - - if (!(r->flags) || r->parent) + if (!pdev_resource_should_fit(dev, r)) continue; r_align = pci_resource_alignment(dev, r); @@ -257,8 +279,15 @@ bool pci_resource_is_optional(const struct pci_dev *dev, int resno) return false; } -static inline void reset_resource(struct resource *res) +static inline void reset_resource(struct pci_dev *dev, struct resource *res) { + int idx = pci_resource_num(dev, res); + + if (idx >= PCI_BRIDGE_RESOURCES && idx <= PCI_BRIDGE_RESOURCE_END) { + res->flags |= IORESOURCE_UNSET; + return; + } + res->start = 0; res->end = 0; res->flags = 0; @@ -610,7 +639,7 @@ out: 0 /* don't care */); } - reset_resource(res); + reset_resource(dev, res); } free_list(head); @@ -1014,8 +1043,11 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, if (r->parent || !(r->flags & IORESOURCE_IO)) continue; - r_size = resource_size(r); + if (!pdev_resource_assignable(dev, r)) + continue; + + r_size = resource_size(r); if (r_size < SZ_1K) /* Might be re-aligned for ISA */ size += r_size; @@ -1034,6 +1066,9 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, size0 = calculate_iosize(size, min_size, size1, 0, 0, resource_size(b_res), min_align); + if (size0) + b_res->flags &= ~IORESOURCE_DISABLED; + size1 = size0; if (realloc_head && (add_size > 0 || children_add_size > 0)) { size1 = calculate_iosize(size, min_size, size1, add_size, @@ -1045,13 +1080,14 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, if (bus->self && (b_res->start || b_res->end)) pci_info(bus->self, "disabling bridge window %pR to %pR (unused)\n", b_res, &bus->busn_res); - b_res->flags = 0; + b_res->flags |= IORESOURCE_DISABLED; return; } resource_set_range(b_res, min_align, size0); b_res->flags |= IORESOURCE_STARTALIGN; if (bus->self && size1 > size0 && realloc_head) { + b_res->flags &= ~IORESOURCE_DISABLED; add_to_list(realloc_head, bus->self, b_res, size1-size0, min_align); pci_info(bus->self, "bridge window %pR to %pR add_size %llx\n", @@ -1198,11 +1234,13 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, const char *r_name = pci_resource_name(dev, i); resource_size_t r_size; - if (r->parent || (r->flags & IORESOURCE_PCI_FIXED) || - !pdev_resources_assignable(dev) || - ((r->flags & mask) != type && - (r->flags & mask) != type2 && - (r->flags & mask) != type3)) + if (!pdev_resources_assignable(dev) || + !pdev_resource_should_fit(dev, r)) + continue; + + if ((r->flags & mask) != type && + (r->flags & mask) != type2 && + (r->flags & mask) != type3) continue; r_size = resource_size(r); @@ -1253,6 +1291,9 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, min_align = max(min_align, win_align); size0 = calculate_memsize(size, min_size, 0, 0, resource_size(b_res), min_align); + if (size0) + b_res->flags &= ~IORESOURCE_DISABLED; + if (bus->self && size0 && !pbus_upstream_space_available(bus, mask | IORESOURCE_PREFETCH, type, size0, min_align)) { @@ -1287,13 +1328,14 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, if (bus->self && (b_res->start || b_res->end)) pci_info(bus->self, "disabling bridge window %pR to %pR (unused)\n", b_res, &bus->busn_res); - b_res->flags = 0; + b_res->flags |= IORESOURCE_DISABLED; return 0; } resource_set_range(b_res, min_align, size0); b_res->flags |= IORESOURCE_STARTALIGN; if (bus->self && size1 > size0 && realloc_head) { + b_res->flags &= ~IORESOURCE_DISABLED; add_to_list(realloc_head, bus->self, b_res, size1-size0, add_align); pci_info(bus->self, "bridge window %pR to %pR add_size %llx add_align %llx\n", b_res, &bus->busn_res, @@ -1721,7 +1763,6 @@ static void pci_bridge_release_resources(struct pci_bus *bus, { struct pci_dev *dev = bus->self; struct resource *r; - unsigned int old_flags; struct resource *b_res; int idx, ret; @@ -1758,17 +1799,15 @@ static void pci_bridge_release_resources(struct pci_bus *bus, /* If there are children, release them all */ release_child_resources(r); - type = old_flags = r->flags & PCI_RES_TYPE_MASK; ret = pci_release_resource(dev, PCI_BRIDGE_RESOURCES + idx); if (ret) return; + type = r->flags & PCI_RES_TYPE_MASK; /* Avoiding touch the one without PREF */ if (type & IORESOURCE_PREFETCH) type = IORESOURCE_PREFETCH; __pci_setup_bridge(bus, type); - /* For next child res under same bridge */ - r->flags = old_flags; } enum release_type { @@ -2246,21 +2285,9 @@ static void pci_prepare_next_assign_round(struct list_head *fail_head, } /* Restore size and flags */ - list_for_each_entry(fail_res, fail_head, list) { - struct resource *res = fail_res->res; - struct pci_dev *dev = fail_res->dev; - int idx = pci_resource_num(dev, res); - + list_for_each_entry(fail_res, fail_head, list) restore_dev_resource(fail_res); - if (!pci_is_bridge(dev)) - continue; - - if (idx >= PCI_BRIDGE_RESOURCES && - idx <= PCI_BRIDGE_RESOURCE_END) - res->flags = 0; - } - free_list(fail_head); } diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c index 4e0e60256f04..21f77e5c647c 100644 --- a/drivers/pci/setup-res.c +++ b/drivers/pci/setup-res.c @@ -359,6 +359,9 @@ int pci_assign_resource(struct pci_dev *dev, int resno) res->flags &= ~IORESOURCE_UNSET; res->flags &= ~IORESOURCE_STARTALIGN; + if (resno >= PCI_BRIDGE_RESOURCES && resno <= PCI_BRIDGE_RESOURCE_END) + res->flags &= ~IORESOURCE_DISABLED; + pci_info(dev, "%s %pR: assigned\n", res_name, res); if (resno < PCI_BRIDGE_RESOURCES) pci_update_resource(dev, resno); -- cgit v1.2.3 From e4934832c588f72bcc139d3ca0acc490c63a821c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:11:00 +0300 Subject: PCI: Add defines for bridge window indexing MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit include/linux/pci.h provides PCI_BRIDGE_{IO,MEM,PREF_MEM}_WINDOW defines, however, they're based on the resource array indexing in the pci_dev struct. The struct pci_bus also has pointers to those same resources but they start from zeroth index. Add PCI_BUS_BRIDGE_{IO,MEM,PREF_MEM}_WINDOW defines to get rid of literal indexing. Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-12-ilpo.jarvinen@linux.intel.com --- drivers/pci/pci.h | 4 ++++ drivers/pci/probe.c | 10 +++++++--- 2 files changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 34f65d69662e..1dc8a8066761 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -81,6 +81,10 @@ struct pcie_tlp_log; #define PCIE_MSG_CODE_DEASSERT_INTC 0x26 #define PCIE_MSG_CODE_DEASSERT_INTD 0x27 +#define PCI_BUS_BRIDGE_IO_WINDOW 0 +#define PCI_BUS_BRIDGE_MEM_WINDOW 1 +#define PCI_BUS_BRIDGE_PREF_MEM_WINDOW 2 + extern const unsigned char pcie_link_speed[]; extern bool pci_early_dump; diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index f31d27c7708a..eaeb66bec433 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -598,9 +598,13 @@ void pci_read_bridge_bases(struct pci_bus *child) for (i = 0; i < PCI_BRIDGE_RESOURCE_NUM; i++) child->resource[i] = &dev->resource[PCI_BRIDGE_RESOURCES+i]; - pci_read_bridge_io(child->self, child->resource[0], false); - pci_read_bridge_mmio(child->self, child->resource[1], false); - pci_read_bridge_mmio_pref(child->self, child->resource[2], false); + pci_read_bridge_io(child->self, + child->resource[PCI_BUS_BRIDGE_IO_WINDOW], false); + pci_read_bridge_mmio(child->self, + child->resource[PCI_BUS_BRIDGE_MEM_WINDOW], false); + pci_read_bridge_mmio_pref(child->self, + child->resource[PCI_BUS_BRIDGE_PREF_MEM_WINDOW], + false); if (!dev->transparent) return; -- cgit v1.2.3 From 74afce3dfcba117064c0eb7eb4d075836aa1370f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= Date: Fri, 29 Aug 2025 16:11:01 +0300 Subject: PCI: Add bridge window selection functions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Various places in the PCI core code independently decide into which bridge window a child resource should be placed. It is hard to see whether these decisions always end up in agreement, especially in the corner cases, and in some places it requires complex logic to pass multiple resource types and/or bridge windows around. Add pbus_select_window() and pbus_select_window_for_type() for cases where the former cannot be used so that eventually the same helper can be used to select the bridge window everywhere. Using the same function ensures the selected bridge window remains always the same and it can be easily recalculated in-situ allowing simplifying the interfaces between internal functions in upcoming changes. Signed-off-by: Ilpo Järvinen Signed-off-by: Bjorn Helgaas Link: https://patch.msgid.link/20250829131113.36754-13-ilpo.jarvinen@linux.intel.com --- drivers/pci/pci.h | 2 + drivers/pci/setup-bus.c | 101 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 103 insertions(+) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 1dc8a8066761..cbd40f05c39c 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -385,6 +385,8 @@ static inline int pci_resource_num(const struct pci_dev *dev, return resno; } +struct resource *pbus_select_window(struct pci_bus *bus, + const struct resource *res); void pci_reassigndev_resource_alignment(struct pci_dev *dev); void pci_disable_bridge_window(struct pci_dev *dev); struct pci_bus *pci_bus_get(struct pci_bus *bus); diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c index 70b210ed200d..913fd41e1d0d 100644 --- a/drivers/pci/setup-bus.c +++ b/drivers/pci/setup-bus.c @@ -172,6 +172,107 @@ static struct resource *find_bus_resource_of_type(struct pci_bus *bus, return r_assigned; } +/** + * pbus_select_window_for_type - Select bridge window for a resource type + * @bus: PCI bus + * @type: Resource type (resource flags can be passed as is) + * + * Select the bridge window based on a resource @type. + * + * For memory resources, the selection is done as follows: + * + * Any non-prefetchable resource is put into the non-prefetchable window. + * + * If there is no prefetchable MMIO window, put all memory resources into the + * non-prefetchable window. + * + * If there's a 64-bit prefetchable MMIO window, put all 64-bit prefetchable + * resources into it and place 32-bit prefetchable memory into the + * non-prefetchable window. + * + * Otherwise, put all prefetchable resources into the prefetchable window. + * + * Return: the bridge window resource or NULL if no bridge window is found. + */ +static struct resource *pbus_select_window_for_type(struct pci_bus *bus, + unsigned long type) +{ + int iores_type = type & IORESOURCE_TYPE_BITS; /* w/o 64bit & pref */ + struct resource *mmio, *mmio_pref, *win; + + type &= PCI_RES_TYPE_MASK; /* with 64bit & pref */ + + if ((iores_type != IORESOURCE_IO) && (iores_type != IORESOURCE_MEM)) + return NULL; + + if (pci_is_root_bus(bus)) { + win = find_bus_resource_of_type(bus, type, type); + if (win) + return win; + + type &= ~IORESOURCE_MEM_64; + win = find_bus_resource_of_type(bus, type, type); + if (win) + return win; + + type &= ~IORESOURCE_PREFETCH; + return find_bus_resource_of_type(bus, type, type); + } + + switch (iores_type) { + case IORESOURCE_IO: + return pci_bus_resource_n(bus, PCI_BUS_BRIDGE_IO_WINDOW); + + case IORESOURCE_MEM: + mmio = pci_bus_resource_n(bus, PCI_BUS_BRIDGE_MEM_WINDOW); + mmio_pref = pci_bus_resource_n(bus, PCI_BUS_BRIDGE_PREF_MEM_WINDOW); + + if (!(type & IORESOURCE_PREFETCH) || + !(mmio_pref->flags & IORESOURCE_MEM)) + return mmio; + + if ((type & IORESOURCE_MEM_64) || + !(mmio_pref->flags & IORESOURCE_MEM_64)) + return mmio_pref; + + return mmio; + default: + return NULL; + } +} + +/** + * pbus_select_window - Select bridge window for a resource + * @bus: PCI bus + * @res: Resource + * + * Select the bridge window for @res. If the resource is already assigned, + * return the current bridge window. + * + * For memory resources, the selection is done as follows: + * + * Any non-prefetchable resource is put into the non-prefetchable window. + * + * If there is no prefetchable MMIO window, put all memory resources into the + * non-prefetchable window. + * + * If there's a 64-bit prefetchable MMIO window, put all 64-bit prefetchable + * resources into it and place 32-bit prefetchable memory into the + * non-prefetchable window. + * + * Otherwise, put all prefetchable resources into the prefetchable window. + * + * Return: the bridge window resource or NULL if no bridge window is found. + */ +struct resource *pbus_select_window(struct pci_bus *bus, + const struct resource *res) +{ + if (res->parent) + return res->parent; + + return pbus_select_window_for_type(bus,