Hi Dave Recently there were changes made to kexec tools to support 64K page size. With those changes vmcore file obtained from a kernel which supports 64K page size cannot be analyzed using crash on a machine running with kernel supporting 4K page size. The following changes in crash tool resolves the problem. Look if the symbol __hash_page_64k exists. This symbol is defined only for kernels with 64K PAGE SIZE support. If yes then the dump was taken with a kernel supporting 64k page size. So use the vmcore page size[64K] instead of getpagesize(). Thanks -Sachin ------------------------------------------------------------------------------------------------------------------------ * Recently there were changes made to kexec tools to support 64K page size. With those changes vmcore file obtained from a kernel which supports 64K page size cannot be analyzed using crash on a machine running with kernel supporting 4K page size. The following change were made in crash tool to solve the problem. Look if the symbol __hash_page_64k exists. If yes then the dump was taken with a kernel supporting 64k page size. So change the page size accordingly. Signed-Off-By: Sachin Sant <sachinp(a)in.ibm.com&gt; -- diff -Naurp crash-4.0/defs.h crash-4.0-new/defs.h --- crash-4.0/defs.h 2006-09-14 21:41:50.000000000 -0400 +++ crash-4.0-new/defs.h 2006-09-14 21:48:37.000000000 -0400 @@ -2297,6 +2297,7 @@ struct efi_memory_desc_t { #define _64BIT_ #define MACHINE_TYPE "PPC64" +#define PPC64_64K_PAGE_SIZE 65536 #define PAGEBASE(X) (((ulong)(X)) & (ulong)machdep->pagemask) #define PTOV(X) ((unsigned long)(X)+(machdep->kvbase)) diff -Naurp crash-4.0/ppc64.c crash-4.0-new/ppc64.c --- crash-4.0/ppc64.c 2006-09-14 21:41:50.000000000 -0400 +++ crash-4.0-new/ppc64.c 2006-09-14 21:50:26.000000000 -0400 @@ -67,19 +67,6 @@ ppc64_init(int when) machdep->verify_symbol = ppc64_verify_symbol; if (pc->flags & KERNEL_DEBUG_QUERY) return; - machdep->pagesize = memory_page_size(); - machdep->pageshift = ffs(machdep->pagesize) - 1; - machdep->pageoffset = machdep->pagesize - 1; - machdep->pagemask = ~((ulonglong)machdep->pageoffset); - machdep->stacksize = 4 * machdep->pagesize; - if ((machdep->pgd = (char *)malloc(PAGESIZE())) == NULL) - error(FATAL, "cannot malloc pgd space."); - if ((machdep->pmd = (char *)malloc(PAGESIZE())) == NULL) - error(FATAL, "cannot malloc pmd space."); - if ((machdep->ptbl = (char *)malloc(PAGESIZE())) == NULL) - error(FATAL, "cannot malloc ptbl space."); - if ((machdep->machspec->level4 = (char *)malloc(PAGESIZE())) == NULL) - error(FATAL, "cannot malloc level4 space."); machdep->last_pgd_read = 0; machdep->last_pmd_read = 0; machdep->last_ptbl_read = 0; @@ -93,6 +80,40 @@ ppc64_init(int when) break; case PRE_GDB: + /* + * Recently there were changes made to kexec tools + * to support 64K page size. With those changes + * vmcore file obtained from a kernel which supports + * 64K page size cannot be analyzed using crash on a + * machine running with kernel supporting 4K page size + * + * The following modifications are required in crash + * tool to be in sync with kexec tools. + * + * Look if the following symbol exists. If yes then + * the dump was taken with a kernel supporting 64k + * page size. So change the page size accordingly. + * + * Also moved the following code block from + * PRE_SYMTAB case here. + */ + if (symbol_exists("__hash_page_64K")) + machdep->pagesize = PPC64_64K_PAGE_SIZE; + else + machdep->pagesize = memory_page_size(); + machdep->pageshift = ffs(machdep->pagesize) - 1; + machdep->pageoffset = machdep->pagesize - 1; + machdep->pagemask = ~((ulonglong)machdep->pageoffset); + machdep->stacksize = 4 * machdep->pagesize; + if ((machdep->pgd = (char *)malloc(PAGESIZE())) == NULL) + error(FATAL, "cannot malloc pgd space."); + if ((machdep->pmd = (char *)malloc(PAGESIZE())) == NULL) + error(FATAL, "cannot malloc pmd space."); + if ((machdep->ptbl = (char *)malloc(PAGESIZE())) == NULL) + error(FATAL, "cannot malloc ptbl space."); + if ((machdep->machspec->level4 = (char *)malloc(PAGESIZE())) == NULL) + error(FATAL, "cannot malloc level4 space."); + machdep->kvbase = symbol_value("_stext"); machdep->identity_map_base = machdep->kvbase; machdep->is_kvaddr = generic_is_kvaddr;

Dave Anderson wrote: > "Sachin P. Sant" wrote: > > > Hi Dave > > Recently there were changes made to kexec tools to support 64K page > size. > > With those changes vmcore file obtained from a kernel which > supports 64K > > page size cannot be analyzed using crash on a machine running with > kernel > > supporting 4K page size. > > > > The following changes in crash tool resolves the problem. > > Look if the symbol __hash_page_64k exists. This symbol is defined only > > for kernels with 64K PAGE SIZE support. If yes then the dump was taken > > with a kernel supporting 64k page size. So use the vmcore page > size[64K] > > instead of getpagesize(). > > > > Thanks > > -Sachin > > > > > ------------------------------------------------------------------------------------------------------------------------ > > > * Recently there were changes made to kexec tools to support 64K > page size. > > With those changes vmcore file obtained from a kernel which > supports 64K > > page size cannot be analyzed using crash on a machine running > with kernel > > supporting 4K page size. > > The following change were made in crash tool to solve the problem. > > Look if the symbol __hash_page_64k exists. If yes then the dump > was taken > > with a kernel supporting 64k page size. So change the page size > accordingly. > > > > Signed-Off-By: Sachin Sant <sachinp(a)in.ibm.com&gt; > > -- > > > > diff -Naurp crash-4.0/defs.h crash-4.0-new/defs.h > > --- crash-4.0/defs.h 2006-09-14 21:41:50.000000000 -0400 > > +++ crash-4.0-new/defs.h 2006-09-14 21:48:37.000000000 -0400 > > @@ -2297,6 +2297,7 @@ struct efi_memory_desc_t { > > #define _64BIT_ > > #define MACHINE_TYPE "PPC64" > > > > +#define PPC64_64K_PAGE_SIZE 65536 > > #define PAGEBASE(X) (((ulong)(X)) & (ulong)machdep->pagemask) > > > > #define PTOV(X) ((unsigned long)(X)+(machdep->kvbase)) > > diff -Naurp crash-4.0/ppc64.c crash-4.0-new/ppc64.c > > --- crash-4.0/ppc64.c 2006-09-14 21:41:50.000000000 -0400 > > +++ crash-4.0-new/ppc64.c 2006-09-14 21:50:26.000000000 -0400 > > @@ -67,19 +67,6 @@ ppc64_init(int when) > > machdep->verify_symbol = ppc64_verify_symbol; > > if (pc->flags & KERNEL_DEBUG_QUERY) > > return; > > - machdep->pagesize = memory_page_size(); > > - machdep->pageshift = ffs(machdep->pagesize) - 1; > > - machdep->pageoffset = machdep->pagesize - 1; > > - machdep->pagemask = ~((ulonglong)machdep->pageoffset); > > - machdep->stacksize = 4 * machdep->pagesize; > > - if ((machdep->pgd = (char *)malloc(PAGESIZE())) == > NULL) > > - error(FATAL, "cannot malloc pgd space."); > > - if ((machdep->pmd = (char *)malloc(PAGESIZE())) == > NULL) > > - error(FATAL, "cannot malloc pmd space."); > > - if ((machdep->ptbl = (char *)malloc(PAGESIZE())) == > NULL) > > - error(FATAL, "cannot malloc ptbl space."); > > - if ((machdep->machspec->level4 = (char > *)malloc(PAGESIZE())) == NULL) > > - error(FATAL, "cannot malloc level4 space."); > > machdep->last_pgd_read = 0; > > machdep->last_pmd_read = 0; > > machdep->last_ptbl_read = 0; > > @@ -93,6 +80,40 @@ ppc64_init(int when) > > break; > > > > case PRE_GDB: > > + /* > > + * Recently there were changes made to kexec tools > > + * to support 64K page size. With those changes > > + * vmcore file obtained from a kernel which supports > > + * 64K page size cannot be analyzed using crash on a > > + * machine running with kernel supporting 4K page size > > + * > > + * The following modifications are required in crash > > + * tool to be in sync with kexec tools. > > + * > > + * Look if the following symbol exists. If yes then > > + * the dump was taken with a kernel supporting 64k > > + * page size. So change the page size accordingly. > > + * > > + * Also moved the following code block from > > + * PRE_SYMTAB case here. > > + */ > > + if (symbol_exists("__hash_page_64K")) > > + machdep->pagesize = PPC64_64K_PAGE_SIZE; > > + else > > + machdep->pagesize = memory_page_size(); > > + machdep->pageshift = ffs(machdep->pagesize) - 1; > > + machdep->pageoffset = machdep->pagesize - 1; > > + machdep->pagemask = ~((ulonglong)machdep->pageoffset); > > + machdep->stacksize = 4 * machdep->pagesize; > > + if ((machdep->pgd = (char *)malloc(PAGESIZE())) == > NULL) > > + error(FATAL, "cannot malloc pgd space."); > > + if ((machdep->pmd = (char *)malloc(PAGESIZE())) == > NULL) > > + error(FATAL, "cannot malloc pmd space."); > > + if ((machdep->ptbl = (char *)malloc(PAGESIZE())) == > NULL) > > + error(FATAL, "cannot malloc ptbl space."); > > + if ((machdep->machspec->level4 = (char > *)malloc(PAGESIZE())) == NULL) > > + error(FATAL, "cannot malloc level4 space."); > > + > > machdep->kvbase = symbol_value("_stext"); > > machdep->identity_map_base = machdep->kvbase; > > machdep->is_kvaddr = generic_is_kvaddr; > > The patch looks safe enough. > > A couple things I just noticed though... > > Is it true that the process stack size will be 256K? And the > ppc64 hardware interrupt stack would be 512K? Based upon > the machdep->pagesize value, these inititializations get done > later: > > machdep->stacksize = 4 * machdep->pagesize; > > machdep->machspec->hwstacksize = 8 * machdep->pagesize; > > If they have not increased, won't the backtrace code get confused? > > Thanks, > Dave > The kernel's asm-powerpc/thread_info.h file doesn't show any change in stack size, which I didn't expect it would anyway: #ifdef __KERNEL__ /* We have 8k stacks on ppc32 and 16k on ppc64 */ #ifdef CONFIG_PPC64 #define THREAD_SHIFT 14 #else #define THREAD_SHIFT 13 #endif #define THREAD_SIZE (1 << THREAD_SHIFT) and the hardware interrupt stack seems to only be in the paca_struct in 2.4 kernels. I think we can safely hardwire those two values anyway, right?

Dave ------------------------------------------------------------------------ -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility

Haren Myneni wrote: > Dave Anderson wrote: > > >> Dave Anderson wrote: >> >> >>> "Sachin P. Sant" wrote: >>> >>> >>>> Hi Dave >>>> Recently there were changes made to kexec tools to support 64K page >>>> >>> size. >>> >>>> With those changes vmcore file obtained from a kernel which >>>> >>> supports 64K >>> >>>> page size cannot be analyzed using crash on a machine running with >>>> >>> kernel >>> >>>> supporting 4K page size. >>>> >>>> The following changes in crash tool resolves the problem. >>>> Look if the symbol __hash_page_64k exists. This symbol is defined only >>>> for kernels with 64K PAGE SIZE support. If yes then the dump was taken >>>> with a kernel supporting 64k page size. So use the vmcore page >>>> >>> size[64K] >>> >>>> instead of getpagesize(). >>>> >>>> Thanks >>>> -Sachin >>>> >>>> >>>> >>> ------------------------------------------------------------------------------------------------------------------------ >>> >>> >>>> * Recently there were changes made to kexec tools to support 64K >>>> >>> page size. >>> >>>> With those changes vmcore file obtained from a kernel which >>>> >>> supports 64K >>> >>>> page size cannot be analyzed using crash on a machine running >>>> >>> with kernel >>> >>>> supporting 4K page size. >>>> The following change were made in crash tool to solve the problem. >>>> Look if the symbol __hash_page_64k exists. If yes then the dump >>>> >>> was taken >>> >>>> with a kernel supporting 64k page size. So change the page size >>>> >>> accordingly. >>> >>>> Signed-Off-By: Sachin Sant <sachinp(a)in.ibm.com&gt; >>>> -- >>>> >>>> diff -Naurp crash-4.0/defs.h crash-4.0-new/defs.h >>>> --- crash-4.0/defs.h 2006-09-14 21:41:50.000000000 -0400 >>>> +++ crash-4.0-new/defs.h 2006-09-14 21:48:37.000000000 -0400 >>>> @@ -2297,6 +2297,7 @@ struct efi_memory_desc_t { >>>> #define _64BIT_ >>>> #define MACHINE_TYPE "PPC64" >>>> >>>> +#define PPC64_64K_PAGE_SIZE 65536 >>>> #define PAGEBASE(X) (((ulong)(X)) & (ulong)machdep->pagemask) >>>> >>>> #define PTOV(X) ((unsigned long)(X)+(machdep->kvbase)) >>>> diff -Naurp crash-4.0/ppc64.c crash-4.0-new/ppc64.c >>>> --- crash-4.0/ppc64.c 2006-09-14 21:41:50.000000000 -0400 >>>> +++ crash-4.0-new/ppc64.c 2006-09-14 21:50:26.000000000 -0400 >>>> @@ -67,19 +67,6 @@ ppc64_init(int when) >>>> machdep->verify_symbol = ppc64_verify_symbol; >>>> if (pc->flags & KERNEL_DEBUG_QUERY) >>>> return; >>>> - machdep->pagesize = memory_page_size(); >>>> - machdep->pageshift = ffs(machdep->pagesize) - 1; >>>> - machdep->pageoffset = machdep->pagesize - 1; >>>> - machdep->pagemask = ~((ulonglong)machdep->pageoffset); >>>> - machdep->stacksize = 4 * machdep->pagesize; >>>> - if ((machdep->pgd = (char *)malloc(PAGESIZE())) == >>>> >>> NULL) >>> >>>> - error(FATAL, "cannot malloc pgd space."); >>>> - if ((machdep->pmd = (char *)malloc(PAGESIZE())) == >>>> >>> NULL) >>> >>>> - error(FATAL, "cannot malloc pmd space."); >>>> - if ((machdep->ptbl = (char *)malloc(PAGESIZE())) == >>>> >>> NULL) >>> >>>> - error(FATAL, "cannot malloc ptbl space."); >>>> - if ((machdep->machspec->level4 = (char >>>> >>> *)malloc(PAGESIZE())) == NULL) >>> >>>> - error(FATAL, "cannot malloc level4 space."); >>>> machdep->last_pgd_read = 0; >>>> machdep->last_pmd_read = 0; >>>> machdep->last_ptbl_read = 0; >>>> @@ -93,6 +80,40 @@ ppc64_init(int when) >>>> break; >>>> >>>> case PRE_GDB: >>>> + /* >>>> + * Recently there were changes made to kexec tools >>>> + * to support 64K page size. With those changes >>>> + * vmcore file obtained from a kernel which supports >>>> + * 64K page size cannot be analyzed using crash on a >>>> + * machine running with kernel supporting 4K page size >>>> + * >>>> + * The following modifications are required in crash >>>> + * tool to be in sync with kexec tools. >>>> + * >>>> + * Look if the following symbol exists. If yes then >>>> + * the dump was taken with a kernel supporting 64k >>>> + * page size. So change the page size accordingly. >>>> + * >>>> + * Also moved the following code block from >>>> + * PRE_SYMTAB case here. >>>> + */ >>>> + if (symbol_exists("__hash_page_64K")) >>>> + machdep->pagesize = PPC64_64K_PAGE_SIZE; >>>> + else >>>> + machdep->pagesize = memory_page_size(); >>>> + machdep->pageshift = ffs(machdep->pagesize) - 1; >>>> + machdep->pageoffset = machdep->pagesize - 1; >>>> + machdep->pagemask = ~((ulonglong)machdep->pageoffset); >>>> + machdep->stacksize = 4 * machdep->pagesize; >>>> + if ((machdep->pgd = (char *)malloc(PAGESIZE())) == >>>> >>> NULL) >>> >>>> + error(FATAL, "cannot malloc pgd space."); >>>> + if ((machdep->pmd = (char *)malloc(PAGESIZE())) == >>>> >>> NULL) >>> >>>> + error(FATAL, "cannot malloc pmd space."); >>>> + if ((machdep->ptbl = (char *)malloc(PAGESIZE())) == >>>> >>> NULL) >>> >>>> + error(FATAL, "cannot malloc ptbl space."); >>>> + if ((machdep->machspec->level4 = (char >>>> >>> *)malloc(PAGESIZE())) == NULL) >>> >>>> + error(FATAL, "cannot malloc level4 space."); >>>> + >>>> machdep->kvbase = symbol_value("_stext"); >>>> machdep->identity_map_base = machdep->kvbase; >>>> machdep->is_kvaddr = generic_is_kvaddr; >>>> >>> The patch looks safe enough. >>> >>> A couple things I just noticed though... >>> >>> Is it true that the process stack size will be 256K? And the >>> ppc64 hardware interrupt stack would be 512K? Based upon >>> the machdep->pagesize value, these inititializations get done >>> later: >>> >>> machdep->stacksize = 4 * machdep->pagesize; >>> >>> machdep->machspec->hwstacksize = 8 * machdep->pagesize; >>> >>> If they have not increased, won't the backtrace code get confused? >>> >>> Thanks, >>> Dave >>> >>> >> The kernel's asm-powerpc/thread_info.h file doesn't >> show any change in stack size, which I didn't expect >> it would anyway: >> >> #ifdef __KERNEL__ >> >> /* We have 8k stacks on ppc32 and 16k on ppc64 */ >> >> #ifdef CONFIG_PPC64 >> #define THREAD_SHIFT 14 >> #else >> #define THREAD_SHIFT 13 >> #endif >> >> #define THREAD_SIZE (1 << THREAD_SHIFT) >> >> and the hardware interrupt stack seems to only be in >> the paca_struct in 2.4 kernels. >> >> I think we can safely hardwire those two values anyway, >> right? >> >> > Sachin, Yes, we should be hardcoding the stack size value (16K). It does > not matter for hardware intr stack which is used only for 2.4 kernel and > supports only 4K page. Uses soft IRQ and hard IRQ stacks in 2.6 kernel > for interrupt context and their sizes are the same as THREAD_SIZE. > > This patch should also support backward compatibility since the symbol > __hash_page_64K does not exist and thus the page size is always 4K. > > Thanks, Haren. Sachin is probably blissfully asleep and not aware of this discussion, so I will go ahead and modify his patch to: (1) hardwire the process stack size, and (2) as you state, it doesn't really make a difference for the 2.4 kernel since it won't ever see the larger pagesize.

Thanks, Dave -- Crash-utility mailing list Crash-utility(a)redhat.com https://www.redhat.com/mailman/listinfo/crash-utility