Messages in this thread Patch in this message | | | Date | Thu, 17 Jun 2010 11:40:39 -0700 | From | Yinghai Lu <> | Subject | Re: [Bug 16228] BUG/boot failure on Dell Precision T3500 (pci/ahci_stop_engine) |
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On 06/17/2010 09:37 AM, bugzilla-daemon@bugzilla.kernel.org wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=16228 > > > Bjorn Helgaas <bjorn.helgaas@hp.com> changed: > > What |Removed |Added > ---------------------------------------------------------------------------- > CC| |yinghai@kernel.org > > > > > --- Comment #8 from Bjorn Helgaas <bjorn.helgaas@hp.com> 2010-06-17 16:37:42 --- > That's perfect, thanks! > > The E820 memory map from BIOS reports a range that overlaps the first > megabyte (0xbff00000-0xbfffffff) of that host bridge window: > > BIOS-e820: 0000000000100000 - 00000000bfdf9c00 (usable) > BIOS-e820: 00000000bfdf9c00 - 00000000bfe4bc00 (ACPI NVS) > BIOS-e820: 00000000bfe4bc00 - 00000000bfe4dc00 (ACPI data) > BIOS-e820: 00000000bfe4dc00 - 00000000c0000000 (reserved) > pci_root PNP0A03:00: host bridge window [mem 0xbff00000-0xdfffffff] > > The 0x100000-0xbfdf9c00 range is system RAM, and I would expect that > the ACPI NVS and data area is also RAM, and the last reserved piece is > probably RAM, too, because RAM tends to end at nicely aligned boundaries. > > Table 14-1 in the ACPI 4.0 spec says "reserved" ranges from the E820 > table are "unsuitable for a standard device to use as a device memory > space." > > I think maybe Linux should regard those reserved ranges as unavailable > for allocation to PCI devices, even if they happen to be included in a > host bridge window. What do you think, Yinghai?
for above 1M area, current kernel will honor setting from HW register and later will use insert_resource_expand_to_fit() with e820 reserved entries. so in this case will have one big 0xbfe4dc00 - 0xe000000 reserved entry in /proc/iomem as parent of 0xbff00000 - 0xe0000000
Sane BIOS should not put allocated range to PCI bridge/device into e820 table as reserved entries.
But there IS some BIOS doing that. So Linus decided to trust setting from PCI bar at first.
later for pci_assign_unsigned, We should avoid those range.
one solution is expanding my one of old version for below 1M handling to: use reserve_region_with_split instead. will get /proc/iomem bfe4dc00 - bfefffff reserved bff00000 - dfffffff PCI BUS #00 bff00000 - bfffffff reserved ...
so will use bff0000 - bfffffff reserved as holder to prevent those range to be allocated to unassigned devices. reserve_region_with_split need to need be updated a little bit to make sure it will not put holder on range with children already.
something like this
Subject: [PATCH] x86, resource: Add reserve_region_with_split_check_child()
It will cover the whole region to BUSY, except that some regions that have children under them.
those children normally is PCI bar but it is falling into E820_RESERVED. We can not put BUSY on them, otherwise driver can not use pci_request_region() later
/proc/iomem will have 00010000-00094fff : System RAM 00095000-0009ffff : reserved 000a0000-000bffff : PCI Bus 0000:00 000a0000-000bffff : reserved 000c0000-000cffff : reserved 000d0000-000dffff : PCI Bus 0000:00 000d0000-000dffff : reserved 000e0000-000fffff : reserved
-v2: Add function pointer to put string comparing with caller -v3: expand to use it above 1M resources.
Tested-by: Guenter Roeck <guenter.roeck@ericsson.com> Tested-by: Andy Isaacson <adi@hexapodia.org> Signed-off-by: Yinghai Lu <yinghai@kernel.org>
--- arch/x86/kernel/e820.c | 15 ++++++++++++--- include/linux/ioport.h | 3 +++ kernel/resource.c | 29 ++++++++++++++++++++++++----- 3 files changed, 39 insertions(+), 8 deletions(-)
Index: linux-2.6/arch/x86/kernel/e820.c =================================================================== --- linux-2.6.orig/arch/x86/kernel/e820.c +++ linux-2.6/arch/x86/kernel/e820.c @@ -1094,7 +1094,7 @@ void __init e820_reserve_resources(void) * pci device BAR resource and insert them later in * pcibios_resource_survey() */ - if (e820.map[i].type != E820_RESERVED || res->start < (1ULL<<20)) { + if (e820.map[i].type != E820_RESERVED) { res->flags |= IORESOURCE_BUSY; insert_resource(&iomem_resource, res); } @@ -1128,6 +1128,14 @@ static unsigned long ram_alignment(resou #define MAX_RESOURCE_SIZE ((resource_size_t)-1) +static int __init check_func(struct resource *cf) +{ + if (strstr(cf->name, "PCI Bus")) + return 1; + + return 0; +} + void __init e820_reserve_resources_late(void) { int i; @@ -1135,8 +1143,9 @@ void __init e820_reserve_resources_late( res = e820_res; for (i = 0; i < e820.nr_map; i++) { - if (!res->parent && res->end) - insert_resource_expand_to_fit(&iomem_resource, res); + if (!res->parent && res->end) { + reserve_region_with_split_check_child(&iomem_resource, res->start, res->end, res->name, check_func); + } res++; } Index: linux-2.6/include/linux/ioport.h =================================================================== --- linux-2.6.orig/include/linux/ioport.h +++ linux-2.6/include/linux/ioport.h @@ -120,6 +120,9 @@ void release_child_resources(struct reso extern void reserve_region_with_split(struct resource *root, resource_size_t start, resource_size_t end, const char *name); +void reserve_region_with_split_check_child(struct resource *root, + resource_size_t start, resource_size_t end, + const char *name, int (*check_func)(struct resource *cf)); extern struct resource *insert_resource_conflict(struct resource *parent, struct resource *new); extern int insert_resource(struct resource *parent, struct resource *new); extern void insert_resource_expand_to_fit(struct resource *root, struct resource *new); Index: linux-2.6/kernel/resource.c =================================================================== --- linux-2.6.orig/kernel/resource.c +++ linux-2.6/kernel/resource.c @@ -607,9 +607,14 @@ int adjust_resource(struct resource *res return result; } +static int __init check_func_nop(struct resource *cf) +{ + return 1; +} + static void __init __reserve_region_with_split(struct resource *root, resource_size_t start, resource_size_t end, - const char *name) + const char *name, bool check_child, int (*check_func)(struct resource *cf)) { struct resource *parent = root; struct resource *conflict; @@ -631,13 +636,18 @@ static void __init __reserve_region_with kfree(res); /* conflict covered whole area */ - if (conflict->start <= start && conflict->end >= end) + if (conflict->start <= start && conflict->end >= end) { + if (check_child && !conflict->child && check_func(conflict)) + __reserve_region_with_split(conflict, start, end, name, false, check_func_nop); return; + } if (conflict->start > start) - __reserve_region_with_split(root, start, conflict->start-1, name); + __reserve_region_with_split(root, start, conflict->start-1, name, check_child, check_func); if (conflict->end < end) - __reserve_region_with_split(root, conflict->end+1, end, name); + __reserve_region_with_split(root, conflict->end+1, end, name, check_child, check_func); + if (check_child && !conflict->child && check_func(conflict)) + __reserve_region_with_split(conflict, conflict->start, conflict->end, name, false, check_func_nop); } void __init reserve_region_with_split(struct resource *root, @@ -645,7 +655,16 @@ void __init reserve_region_with_split(st const char *name) { write_lock(&resource_lock); - __reserve_region_with_split(root, start, end, name); + __reserve_region_with_split(root, start, end, name, false, check_func_nop); + write_unlock(&resource_lock); +} + +void __init reserve_region_with_split_check_child(struct resource *root, + resource_size_t start, resource_size_t end, + const char *name, int (*check_func)(struct resource *cf)) +{ + write_lock(&resource_lock); + __reserve_region_with_split(root, start, end, name, true, check_func); write_unlock(&resource_lock); }
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