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SubjectRe: [RFC] [Patch] calgary iommu: Use the first kernel's tce tables in kdump
Date
ACK (as a JAFO, though). I feel this patch was a long time coming!  
Thanks!

Sincerely -- Mark Salyzyn

On Jun 21, 2008, at 8:11 AM, Chandru wrote:

> kdump kernel fails to boot with calgary iommu and aacraid driver on
> a x366
> box. The ongoing dma's of aacraid from the first kernel continue to
> exist
> until the driver is loaded in the kdump kernel. Calgary is
> initialized prior
> to aacraid and creation of new tce tables causes wrong dma's to
> occur. Here
> we try to get the tce tables of the first kernel in kdump kernel and
> use
> them. While in the kdump kernel we do not allocate new tce tables
> but instead
> read the base address register contents of calgary iommu and use the
> tables
> that the registers point to. With these changes the kdump kernel and
> hence
> aacraid now boots normally.
>
> Signed-off-by: Chandru Siddalingappa <chandru@in.ibm.com>
> ---
>
> arch/x86/kernel/pci-calgary_64.c | 91 ++++++++++++++++++++++++++---
> include/linux/crash_dump.h | 8 ++
> 2 files changed, 92 insertions(+), 7 deletions(-)
>
>>> Hello Andrew,
>>>
>>> Could you pls consider the attached patch for inclusion in mainline.
>>
>> I can sort-of work out what the patch does from the above quote,
>> but it
>> would be nice to have a proper changelog description from yourself
>> rather
>> than having me try to write it, please.
>> The patch was badly wordwrapped. Please fix your email client for
>> the next
>> version.
> Sorry for the much delayed response on this mail. The patch was
> tested with
> linux-2.6.26-rc6. Pls consider it for inclusion.
> Thanks,
>
>
>
> diff -Naurp linux-2.6.26-rc6-orig/arch/x86/kernel/pci-calgary_64.c
> linux-2.6.26-rc6/arch/x86/kernel/pci-calgary_64.c
> --- linux-2.6.26-rc6-orig/arch/x86/kernel/pci-calgary_64.c
> 2008-06-21
> 13:59:08.000000000 +0530
> +++ linux-2.6.26-rc6/arch/x86/kernel/pci-calgary_64.c 2008-06-21
> 13:59:45.000000000 +0530
> @@ -36,6 +36,7 @@
> #include <linux/delay.h>
> #include <linux/scatterlist.h>
> #include <linux/iommu-helper.h>
> +#include <linux/crash_dump.h>
> #include <asm/gart.h>
> #include <asm/calgary.h>
> #include <asm/tce.h>
> @@ -167,6 +168,8 @@ static void calgary_dump_error_regs(stru
> static void calioc2_handle_quirks(struct iommu_table *tbl, struct
> pci_dev
> *dev);
> static void calioc2_tce_cache_blast(struct iommu_table *tbl);
> static void calioc2_dump_error_regs(struct iommu_table *tbl);
> +static void calgary_init_bitmap_from_tce_table(struct iommu_table
> *tbl);
> +static void get_tce_space_from_tar(void);
>
> static struct cal_chipset_ops calgary_chip_ops = {
> .handle_quirks = calgary_handle_quirks,
> @@ -830,7 +833,11 @@ static int __init calgary_setup_tar(stru
>
> tbl = pci_iommu(dev->bus);
> tbl->it_base = (unsigned long)bus_info[dev->bus-
> >number].tce_space;
> - tce_free(tbl, 0, tbl->it_size);
> +
> + if (is_kdump_kernel())
> + calgary_init_bitmap_from_tce_table(tbl);
> + else
> + tce_free(tbl, 0, tbl->it_size);
>
> if (is_calgary(dev->device))
> tbl->chip_ops = &calgary_chip_ops;
> @@ -1206,9 +1213,14 @@ static int __init calgary_init(void)
> struct calgary_bus_info *info;
>
> ret = calgary_locate_bbars();
> +
> if (ret)
> return ret;
>
> + /* Purely for kdump kernel case */
> + if (is_kdump_kernel())
> + get_tce_space_from_tar();
> +
> do {
> dev = pci_get_device(PCI_VENDOR_ID_IBM, PCI_ANY_ID,
> dev);
> if (!dev)
> @@ -1256,6 +1268,24 @@ error:
> return ret;
> }
>
> +
> +/*
> + * calgary_init_bitmap_from_tce_table():
> + * Funtion for kdump case. In the second/kdump kernel initialize
> + * the bitmap based on the tce table entries obtained from first
> kernel
> + */
> +static void calgary_init_bitmap_from_tce_table(struct iommu_table
> *tbl)
> +{
> + u64 *tp;
> + unsigned int index;
> + tp = ((u64 *)tbl->it_base);
> + for (index = 0 ; index < tbl->it_size; index++) {
> + if (*tp != 0x0)
> + set_bit(index, tbl->it_map);
> + tp++;
> + }
> +}
> +
> static inline int __init determine_tce_table_size(u64 ram)
> {
> int ret;
> @@ -1318,6 +1348,8 @@ static int __init build_detail_arrays(vo
> return 0;
> }
>
> +
> +
> static int __init calgary_bus_has_devices(int bus, unsigned short
> pci_dev)
> {
> int dev;
> @@ -1339,12 +1371,50 @@ static int __init calgary_bus_has_device
> return (val != 0xffffffff);
> }
>
> +/*
> + * get_tce_space_from_tar():
> + * Function for kdump case. Get the tce tables from first kernel
> + * by reading the contents of the base adress register of calgary
> iommu
> + */
> +static void get_tce_space_from_tar()
> +{
> + int bus;
> + void __iomem *target;
> + unsigned long tce_space;
> +
> + for (bus = 0; bus < MAX_PHB_BUS_NUM; bus++) {
> + struct calgary_bus_info *info = &bus_info[bus];
> + unsigned short pci_device;
> + u32 val;
> +
> + val = read_pci_config(bus, 0, 0, 0);
> + pci_device = (val & 0xFFFF0000) >> 16;
> +
> + if (!is_cal_pci_dev(pci_device))
> + continue;
> + if (info->translation_disabled)
> + continue;
> +
> + if (calgary_bus_has_devices(bus, pci_device) ||
> + translate_empty_slots) {
> + target = calgary_reg(bus_info[bus].bbar,
> + tar_offset(bus));
> + tce_space = be64_to_cpu(readq(target));
> + tce_space = tce_space & TAR_SW_BITS;
> +
> + tce_space = tce_space &
> (~specified_table_size);
> + info->tce_space = (u64 *)__va(tce_space);
> + }
> + }
> + return;
> +}
> +
> void __init detect_calgary(void)
> {
> int bus;
> void *tbl;
> int calgary_found = 0;
> - unsigned long ptr;
> + unsigned long ptr, max_pfn;
> unsigned int offset, prev_offset;
> int ret;
>
> @@ -1394,7 +1464,8 @@ void __init detect_calgary(void)
> return;
> }
>
> - specified_table_size = determine_tce_table_size(end_pfn *
> PAGE_SIZE);
> + max_pfn = is_kdump_kernel() ? saved_max_pfn : end_pfn ;
> + specified_table_size = determine_tce_table_size(max_pfn *
> PAGE_SIZE);
>
> for (bus = 0; bus < MAX_PHB_BUS_NUM; bus++) {
> struct calgary_bus_info *info = &bus_info[bus];
> @@ -1412,10 +1483,16 @@ void __init detect_calgary(void)
>
> if (calgary_bus_has_devices(bus, pci_device) ||
> translate_empty_slots) {
> - tbl = alloc_tce_table();
> - if (!tbl)
> - goto cleanup;
> - info->tce_space = tbl;
> + /*
> + * If it is kdump kernel, find and use tce
> tables
> + * from first kernel, else allocate tce
> tables here
> + */
> + if (!is_kdump_kernel()) {
> + tbl = alloc_tce_table();
> + if (!tbl)
> + goto cleanup;
> + info->tce_space = tbl;
> + }
> calgary_found = 1;
> }
> }
> diff -Naurp linux-2.6.26-rc6-orig/include/linux/crash_dump.h
> linux-2.6.26-rc6/include/linux/crash_dump.h
> --- linux-2.6.26-rc6-orig/include/linux/crash_dump.h 2008-06-21
> 13:59:18.000000000 +0530
> +++ linux-2.6.26-rc6/include/linux/crash_dump.h 2008-06-21
> 14:00:42.000000000
> +0530
> @@ -22,5 +22,13 @@ extern struct proc_dir_entry *proc_vmcor
>
> #define vmcore_elf_check_arch(x) (elf_check_arch(x) ||
> vmcore_elf_check_arch_cross(x))
>
> +static inline int is_kdump_kernel(void)
> +{
> + return (elfcorehdr_addr != ELFCORE_ADDR_MAX) ? 1 : 0 ;
> +}
> +#else /* !CONFIG_CRASH_DUMP */
> +static inline int is_kdump_kernel(void) { return 0; }
> #endif /* CONFIG_CRASH_DUMP */
> +
> +extern unsigned long saved_max_pfn;
> #endif /* LINUX_CRASHDUMP_H */
> --
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