| Message ID | 20160819012651.GE20080@linaro.org |
|---|---|
| State | New |
| Headers | show |
James, On Fri, Aug 19, 2016 at 02:28:06PM +0100, James Morse wrote: > On 19/08/16 02:26, AKASHI Takahiro wrote: > > Can you try the following change? > > If it fixes your problem, I will post it as a patch. > > Almost! This causes booting with acpi=on to fail for the familiar > alignment-fault reasons[2], > details and a suggested fix below. Thank you for the fix. I will merge your hunk to the patch. -Takahiro AKASHI > I think we should have this change as it matches x86's use of acpi, and means we > don't rely on re-parsing the efi memory map to learn which areas of memory > shouldn't be in the vmcore. > > > > ===8<=== > > From 740563e4a437f0d6ecf6e421c91433f9b8f19041 Mon Sep 17 00:00:00 2001 > > From: AKASHI Takahiro <takahiro.akashi@linaro.org> > > Date: Fri, 19 Aug 2016 09:57:52 +0900 > > Subject: [PATCH] arm64: mark reserved memblock regions explicitly > > > > --- > > arch/arm64/kernel/setup.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > > index 38eda13..38589b5 100644 > > --- a/arch/arm64/kernel/setup.c > > +++ b/arch/arm64/kernel/setup.c > > @@ -205,10 +205,15 @@ static void __init request_standard_resources(void) > > > > for_each_memblock(memory, region) { > > res = alloc_bootmem_low(sizeof(*res)); > > - res->name = "System RAM"; > > + if (memblock_is_nomap(region)) { > > + res->name = "reserved"; > > > + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; > > This causes acpica to choke. arch/arm64/include/asm/acpi.h:acpi_os_ioremap() > calls page_is_ram(), which expects IORESOURCE_SYSTEM_RAM. From kernel/resource.c: > > /* > > * This generic page_is_ram() returns true if specified address is > > * registered as System RAM in iomem_resource list. > > */ > > int __weak page_is_ram(unsigned long pfn) > > We are trying to infer information about the EFI memory map by looking through > iomem_resource list generated from memblock. > drivers/firmware/efi/arm-init.c:reserve_regions() adds memory with the WB > attribute to memblock via early_init_dt_add_memory_arch(), so changing > page_is_ram() for memblock_is_memory() is one step closer to checking the > attributes in the efi memory map (which turns out to tricky). > > With your v24 on v4.8-rc1 and 'mark reserved memblock regions explicitly', and > this extra hack [0], I can boot, kdump, extract the vmcore (with read() and > mmap()), and pull things out of it with crash. > > > Thanks, > > James > > > > + } else { > > + res->name = "System RAM"; > > + res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > > + } > > res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region)); > > res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1; > > - res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > > > > request_resource(&iomem_resource, res); > > [0] whitespace damaged hack for acpi_os_ioremap(). > ------------------------------------%<------------------------------------ > +++ b/arch/arm64/include/asm/acpi.h > @@ -12,6 +12,7 @@ > #ifndef _ASM_ACPI_H > #define _ASM_ACPI_H > > +#include <linux/memblock.h> > #include <linux/mm.h> > #include <linux/psci.h> > > @@ -32,7 +33,11 @@ > static inline void __iomem *acpi_os_ioremap(acpi_physical_address phys, > acpi_size size) > { > - if (!page_is_ram(phys >> PAGE_SHIFT)) > + /* > + * EFI's reserve_regions() call adds memory with the WB attribute > + * to memblock via early_init_dt_add_memory_arch(). > + */ > + if (!memblock_is_memory(phys)) > return ioremap(phys, size); > > return ioremap_cache(phys, size); > ------------------------------------%<------------------------------------ > > [1] cat /proc/iomem | tail -n 9 > 8000000000-8001e7ffff : reserved > 8001e80000-83ff17ffff : System RAM > 8002080000-8002b0ffff : Kernel code > 8002d90000-8002f6ffff : Kernel data > 80dfe00000-80ffdfffff : Crash kernel > 83ff180000-83ff1cffff : reserved > 83ff1d0000-83ff21ffff : System RAM > 83ff220000-83ffe4ffff : reserved > 83ffe50000-83ffffffff : System RAM > > [2] Panic on boot without [0] > [ 0.037098] ACPI: Core revision 20160422 > [ 0.041174] Unable to handle kernel paging request at virtual address > fffffc0008f831e7 > [ 0.049155] pgd = fffffc0008f50000 > [ 0.052576] [fffffc0008f831e7] *pgd=00000083fffe0003, *pud=00000083fffe0003, > *pmd=00000083fffe0003, *pte=00e80083ff1c0707 > [ 0.063632] Internal error: Oops: 96000021 [#1] PREEMPT SMP > [ 0.069245] Modules linked in: > [ 0.072317] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.8.0-rc1+ #4892 > [ 0.078891] Hardware name: AMD Seattle (Rev.B0) Development Board (Overdrive) > (DT) > [ 0.086518] task: fffffc0008dc8a80 task.stack: fffffc0008d90000 > [ 0.092486] PC is at acpi_ns_lookup+0x238/0x378 > [ 0.097049] LR is at acpi_ds_load1_begin_op+0x88/0x260 > [ 0.102290] pc : [<fffffc000840fed8>] lr : [<fffffc0008405dcc>] pstate: 60000045 > [ 0.109740] sp : fffffc0008d93bb0 > [ 0.113071] x29: fffffc0008d93bb0 x28: 0000000000000001 > [ 0.118420] x27: 0000000000000000 x26: 000000000000001b > [ 0.123768] x25: fffffc0008a813b7 x24: 000000000000001b > [ 0.129119] x23: 000000000000001b x22: 0000000000000001 > [ 0.134466] x21: fffffc0008d93cb8 x20: 0000000000000001 > [ 0.139814] x19: fffffc0008f831e7 x18: 0000000000000023 > [ 0.145163] x17: ffffffffffffffff x16: 0000000000000000 > [ 0.150511] x15: 000000000000038e x14: 0000000000007fff > [ 0.155859] x13: ffffffffffffff00 x12: 0000000000000008 > [ 0.161208] x11: 0000000000000028 x10: 00000000ffffff76 > [ 0.166556] x9 : 0000000000000000 x8 : fffffe03c00b0140 > [ 0.171907] x7 : 0000000000000003 x6 : fffffc0008d93cb8 > [ 0.177255] x5 : fffffe03c0060800 x4 : fffffc0008ee7fe8 > [ 0.182603] x3 : fffffc0008ee8000 x2 : fffffc0008ee7fe8 > [ 0.187951] x1 : fffffc0008f831e7 x0 : 0000000000000000 > [ 0.193296] > [ 0.194789] Process swapper/0 (pid: 0, stack limit = 0xfffffc0008d90020) > [ 0.483605] Call trace: > [ 0.486062] Exception stack(0xfffffc0008d939e0 to 0xfffffc0008d93b10) > [ 0.568522] [<fffffc000840fed8>] acpi_ns_lookup+0x238/0x378 > [ 0.574134] [<fffffc0008405dcc>] acpi_ds_load1_begin_op+0x88/0x260 > [ 0.580358] [<fffffc0008415e3c>] acpi_ps_build_named_op+0xa8/0x170 > [ 0.586582] [<fffffc0008416034>] acpi_ps_create_op+0x130/0x230 > [ 0.592455] [<fffffc0008415988>] acpi_ps_parse_loop+0x174/0x580 > [ 0.598419] [<fffffc00084168b4>] acpi_ps_parse_aml+0xa8/0x278 > [ 0.604208] [<fffffc0008411efc>] acpi_ns_one_complete_parse+0x130/0x158 > [ 0.610871] [<fffffc0008411f48>] acpi_ns_parse_table+0x24/0x44 > [ 0.616745] [<fffffc00084116fc>] acpi_ns_load_table+0x50/0xe0 > [ 0.622535] [<fffffc000841ad80>] acpi_tb_load_namespace+0xdc/0x25c > [ 0.628764] [<fffffc0008b383f4>] acpi_load_tables+0x3c/0xa8 > [ 0.634377] [<fffffc0008b37548>] acpi_early_init+0x88/0xbc > [ 0.639903] [<fffffc0008b10b30>] start_kernel+0x330/0x394 > [ 0.645340] [<fffffc0008b10210>] __primary_switched+0x7c/0x8c > [ 0.651127] Code: 2a1a03f7 2a0002d6 36380054 321902d6 (b9400260) > [ 0.657270] ---[ end trace 0000000000000000 ]--- > [ 0.661922] Kernel panic - not syncing: Attempted to kill the idle task! > [ 0.668673] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Fri, Aug 19, 2016 at 04:52:17PM +0530, Pratyush Anand wrote: > On 19/08/2016:10:26:52 AM, AKASHI Takahiro wrote: > > >From 740563e4a437f0d6ecf6e421c91433f9b8f19041 Mon Sep 17 00:00:00 2001 > > From: AKASHI Takahiro <takahiro.akashi@linaro.org> > > Date: Fri, 19 Aug 2016 09:57:52 +0900 > > Subject: [PATCH] arm64: mark reserved memblock regions explicitly > > > > --- > > arch/arm64/kernel/setup.c | 9 +++++++-- > > 1 file changed, 7 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > > index 38eda13..38589b5 100644 > > --- a/arch/arm64/kernel/setup.c > > +++ b/arch/arm64/kernel/setup.c > > @@ -205,10 +205,15 @@ static void __init request_standard_resources(void) > > > > for_each_memblock(memory, region) { > > res = alloc_bootmem_low(sizeof(*res)); > > - res->name = "System RAM"; > > + if (memblock_is_nomap(region)) { > > + res->name = "reserved"; > > + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; > > + } else { > > + res->name = "System RAM"; > > + res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > > + } > > res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region)); > > res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1; > > - res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; > > > > request_resource(&iomem_resource, res); > > > It will help kexec-tools to prevent copying of any unnecessary data. I > think, then you also need to change phys_offset calculation in kexec-tools. That > should be start of either of first "reserved" or "System RAM" block. Good point, but I'm not sure this is always true. Is there any system whose ACPI memory is *not* part of DRAM (so not part of linear mapping)? Thanks, -Takahiro AKASHI > ~Pratyush _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
On Mon, Aug 22, 2016 at 02:47:30PM +0100, James Morse wrote: > On 22/08/16 02:29, AKASHI Takahiro wrote: > > On Fri, Aug 19, 2016 at 04:52:17PM +0530, Pratyush Anand wrote: > >> It will help kexec-tools to prevent copying of any unnecessary data. I > >> think, then you also need to change phys_offset calculation in kexec-tools. That > >> should be start of either of first "reserved" or "System RAM" block. > > > > Good point, but I'm not sure this is always true. > > > Is there any system whose ACPI memory is *not* part of DRAM > > From the spec, it looks like this is allowed. > > What do you mean by 'DRAM'? Any ACPI region will be in the UEFI memory map, so > the question is what is its type and memory attributes? Yes. > The UEFI spec[0] says ACPI regions can have a type of EfiACPIReclaimMemory or > EfiACPIMemoryNVS, the memory attributes aren't specified, so are chosen by the > firmware. > > It is possible these regions have to be mapped non-cacheable, page 40 has a > couple of: > > If no information about the table location exists in the UEFI memory map or > ACPI memory > > descriptors, the table is assumed to be non-cached. > > reserve_regions() in drivers/firmware/efi/arm-init.c will add any entry in the > memory map that has a 'WB' attribute to the memblock.memory list (via > early_init_dt_add_memory_arch()), it will also mark as no-map regions that have > this attribute and aren't in the is_reserve_region() list. > > If these ACPI regions have the 'WB' attribute, we add them as memory and mark > them nomap. These show up as either a hole, or 'reserved' in /proc/iomem. > If they don't have the 'WB' attribute, then then they are left out of memblock > and aren't part of DRAM, I don't think these will show up in /proc/iomem at all. Let's say, 0x1000-0x1fff: reserved (SRAM for UEFI, WB) 0x80000000-0xffffffff: System RAM (DRAM) If, as Pratyush suggested, "reserved" resources are added to phys_offset calculation, the kernel linear mapping area starts at PAGE_OFFSET, but there is no actual mapping around PAGE_OFFSET. It won't hurt anything, but looks funny. So we'd better not include "reserved" in phys_offset calculation anyway. -> Pratyush Thanks, -Takahiro AKASHI > > > Thanks, > > James > > [0] '2.3.6 AArch64 Platforms' of version 2.6 of the UEFI spec at > http://uefi.org/specifications _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
===8<=== From 740563e4a437f0d6ecf6e421c91433f9b8f19041 Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro <takahiro.akashi@linaro.org> Date: Fri, 19 Aug 2016 09:57:52 +0900 Subject: [PATCH] arm64: mark reserved memblock regions explicitly --- arch/arm64/kernel/setup.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c index 38eda13..38589b5 100644 --- a/arch/arm64/kernel/setup.c +++ b/arch/arm64/kernel/setup.c @@ -205,10 +205,15 @@ static void __init request_standard_resources(void) for_each_memblock(memory, region) { res = alloc_bootmem_low(sizeof(*res)); - res->name = "System RAM"; + if (memblock_is_nomap(region)) { + res->name = "reserved"; + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY; + } else { + res->name = "System RAM"; + res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; + } res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region)); res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1; - res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY; request_resource(&iomem_resource, res);