(+ James) Hello Akashi, On 6 March 2018 at 09:00, AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> wrote: > Tyler, Jeffrey, > > On Fri, Mar 02, 2018 at 08:27:11AM -0500, Tyler Baicar wrote: >> On 3/2/2018 12:53 AM, AKASHI Takahiro wrote: >> >Tyler, Jeffrey, >> > >> >[Note: This issue takes place in kexec, not kdump. So to be precise, >> >it is not the same phenomenon as what I addressed in [1],[2]: >> > [1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-February/557254.html >> > [2] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-January/553098.html >> >] >> > >> >On Thu, Mar 01, 2018 at 12:56:38PM -0500, Tyler Baicar wrote: >> >>Hello, >> >> >> >>On 2/28/2018 9:50 PM, AKASHI Takahiro wrote: >> >>>Hi, >> >>> >> >>>On Wed, Feb 28, 2018 at 08:39:42AM -0700, Jeffrey Hugo wrote: >> >>>>On 2/27/2018 11:19 PM, AKASHI Takahiro wrote: >> >>>>>Tyler, >> >>>>> >> >>>>># I missed catching your patch as its subject doesn't contain arm64. >> >>>>> >> >>>>>On Fri, Feb 23, 2018 at 12:42:31PM -0700, Tyler Baicar wrote: >> >>>>>>Currently on arm64 ESRT memory does not appear to be properly blocked off. >> >>>>>>Upon successful initialization, ESRT prints out the memory region that it >> >>>>>>exists in like: >> >>>>>> >> >>>>>>esrt: Reserving ESRT space from 0x000000000a4c1c18 to 0x000000000a4c1cf0. >> >>>>>> >> >>>>>>But then by dumping /proc/iomem this region appears as part of System RAM >> >>>>>>rather than being reserved: >> >>>>>> >> >>>>>>08f10000-0deeffff : System RAM >> >>>>>> >> >>>>>>This causes issues when trying to kexec if the kernel is relocatable. When >> >>>>>>kexec tries to execute, this memory can be selected to relocate the kernel to >> >>>>>>which then overwrites all the ESRT information. Then when the kexec'd kernel >> >>>>>>tries to initialize ESRT, it doesn't recognize the ESRT version number and >> >>>>>>just returns from efi_esrt_init(). >> >>>>>I'm not sure what is the root cause of your problem. >> >>>>>Do you have good confidence that the kernel (2nd kernel image in this case?) >> >>>>>really overwrite ESRT region? >> >>>>According to my debug, yes. >> >>>>Using JTAG, I was able to determine that the ESRT memory region was getting >> >>>>overwritten by the secondary kernel in >> >>>>kernel/arch/arm64/kernel/relocate_kernel.S - specifically the "copy_page" >> >>>>line of arm64_relocate_new_kernel() >> >>>> >> >>>>>To my best knowledge, kexec is carefully designed not to do such a thing >> >>>>>as it allocates a temporary buffer for kernel image and copies it to the >> >>>>>final destination at the very end of the 1st kernel. >> >>>>> >> >>>>>My guess is that kexec, or rather kexec-tools, tries to load the kernel image >> >>>>>at 0x8f80000 (or 0x9080000?, not sure) in your case. It may or may not be >> >>>>>overlapped with ESRT. >> >>>>>(Try "-d" option when executing kexec command for confirmation.) >> >>>>With -d, I see >> >>>> >> >>>>get_memory_ranges_iomem_cb: 0000000009611000 - 000000000e5fffff : System RAM >> >>>> >> >>>>That overlaps the ESRT reservation - >> >>>>[ 0.000000] esrt: Reserving ESRT space from 0x000000000b708718 to >> >>>>0x000000000b7087f0 >> >>>> >> >>>>>Are you using initrd with kexec? >> >>>>Yes >> >>>To make the things clear, can you show me, if possible, the followings: >> >>I have attached all of these: >> >Many thanks. >> >According to the data, ESRT was overwritten by initrd, not the kernel image. >> >It doesn't matter to you though :) >> > >> >The solution would be, as Ard suggested, that more information be >> >added to /proc/iomem. >> >I'm going to fix the issue as quickly as possible. >> Great, thank you!! Please add us to the fix and we will gladly test it out. > > I have created a workaround patch, attached below, as a kind of PoC. > Can you give it a go, please? > You need another patch for kexec-tools, too. See > https:/git.linaro.org/people/takahiro.akashi/kexecl-tools.git arm64/resv_mem > Thanks for putting this together. Some questions below. > With this patch, extra entries for firmware-reserved memory resources, > which means any regions that are already reserved before arm64_memblock_init(), > or specifically efi/acpi tables in this case, are added to /proc/iomem. > > $ cat /proc/iomem (on my qemu+edk2 execution) > ... > 40000000-5871ffff : System RAM > 40080000-40f1ffff : Kernel code > 41040000-411e9fff : Kernel data > 54400000-583fffff : Crash kernel > 58590000-585effff : reserved > 58700000-5871ffff : reserved > 58720000-58b5ffff : reserved > 58b60000-5be3ffff : System RAM > 58b61000-58b61fff : reserved > 59a7b118-59a7b667 : reserved > 5be40000-5becffff : reserved > 5bed0000-5bedffff : System RAM > 5bee0000-5bffffff : reserved > 5c000000-5fffffff : System RAM > 5ec00000-5edfffff : reserved > 8000000000-ffffffffff : PCI Bus 0000:00 > 8000000000-8000003fff : 0000:00:01.0 > 8000000000-8000003fff : virtio-pci-modern > > While all the entries are currently marked as just "reserved," we'd better > give them more specific names for general/extensive use. > (Then it will require modifying respective fw/drivers.) > > Kexec-tools will allocate spaces for kernel, initrd and dtb so that > they will not be overlapped with "reserved" memory. > > As I haven't run extensive tests, please let me know if you find > any problems. > > Thanks, > -Takahiro AKASHI > >> >> Thanks, >> Tyler >> >> -- >> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. >> Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, >> a Linux Foundation Collaborative Project. >> > ===8<=== > From 57d93b89d16b967c913f3949601a5559ddf4aa57 Mon Sep 17 00:00:00 2001 > From: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> > Date: Fri, 2 Mar 2018 16:39:18 +0900 > Subject: [PATCH] arm64: kexec: set asdie firmware-reserved memory regions > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx> > --- > arch/arm64/kernel/setup.c | 24 ++++++++++++++++++++---- > arch/arm64/mm/init.c | 21 +++++++++++++++++++++ > 2 files changed, 41 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > index 30ad2f085d1f..997f07e86243 100644 > --- a/arch/arm64/kernel/setup.c > +++ b/arch/arm64/kernel/setup.c > @@ -87,6 +87,9 @@ static struct resource mem_res[] = { > #define kernel_code mem_res[0] > #define kernel_data mem_res[1] > > +/* TODO: Firmware-reserved memory resources */ > +extern struct memblock_type fw_mem; > + Why do you need this intermediate data structure? can't you iterate over the memblock_reserve'd regions directly? > /* > * The recorded values of x0 .. x3 upon kernel entry. > */ > @@ -206,7 +209,20 @@ static void __init request_standard_resources(void) > { > struct memblock_region *region; > struct resource *res; > + int i; > + > + /* add firmware-reserved memory first */ > + for (i = 1; i < fw_mem.cnt; i++) { > + res = alloc_bootmem_low(sizeof(*res)); > + res->name = "reserved"; > + res->flags = IORESOURCE_MEM; > + res->start = fw_mem.regions[i].base; > + res->end = fw_mem.regions[i].base + fw_mem.regions[i].size - 1; > > + request_resource(&iomem_resource, res); > + } > + > + /* add standard resources */ > kernel_code.start = __pa_symbol(_text); > kernel_code.end = __pa_symbol(__init_begin - 1); > kernel_data.start = __pa_symbol(_sdata); > @@ -224,19 +240,19 @@ static void __init request_standard_resources(void) > res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region)); > res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1; > > - request_resource(&iomem_resource, res); > + insert_resource(&iomem_resource, res); > I see why you need to switch from request_resource() to insert_resource(). Could we ever run into the situation where a memblock_reserved region overlaps the boundary between System RAM and a NOMAP region? I don't /think/ this is the case, but I am not sure, and if that happens, this will fail. (I think it should never be needed to memblock_reserve() NOMAP regions but I am not 100% sure) > if (kernel_code.start >= res->start && > kernel_code.end <= res->end) > - request_resource(res, &kernel_code); > + insert_resource(res, &kernel_code); > if (kernel_data.start >= res->start && > kernel_data.end <= res->end) > - request_resource(res, &kernel_data); > + insert_resource(res, &kernel_data); > #ifdef CONFIG_KEXEC_CORE > /* Userspace will find "Crash kernel" region in /proc/iomem. */ > if (crashk_res.end && crashk_res.start >= res->start && > crashk_res.end <= res->end) > - request_resource(res, &crashk_res); > + insert_resource(res, &crashk_res); > #endif > } > } > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 9f3c47acf8ff..b6f86a7bbfb7 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -62,6 +62,14 @@ > s64 memstart_addr __ro_after_init = -1; > phys_addr_t arm64_dma_phys_limit __ro_after_init; > > +static struct memblock_region fw_mem_regions[INIT_MEMBLOCK_REGIONS]; > +struct memblock_type fw_mem = { > + .regions = fw_mem_regions, > + .cnt = 1, /* empty dummy entry */ > + .max = INIT_MEMBLOCK_REGIONS, > + .name = "firmware-reserved memory", > +}; > + > #ifdef CONFIG_BLK_DEV_INITRD > static int __init early_initrd(char *p) > { > @@ -362,6 +370,19 @@ static void __init fdt_enforce_memory_region(void) > void __init arm64_memblock_init(void) > { > const s64 linear_region_size = -(s64)PAGE_OFFSET; > + struct memblock_region *region; > + > + /* > + * Export firmware-reserved memory regions > + * TODO: via more generic interface > + */ > + for_each_memblock(reserved, region) { > + if (WARN_ON(fw_mem.cnt >= fw_mem.max)) > + break; > + fw_mem.regions[fw_mem.cnt].base = region->base; > + fw_mem.regions[fw_mem.cnt].size = region->size; > + fw_mem.cnt++; > + } > > /* Handle linux,usable-memory-range property */ > fdt_enforce_memory_region(); > -- > 2.16.2 > -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
