-----Original Message----- From: Hatayama, Daisuke Sent: Friday, January 26, 2018 3:56 PM To: Indoh, Takao/印藤 隆夫 <indou.takao(a)jp.fujitsu.com>; crash-utility(a)redhat.com Subject: RE: [PATCH] sadump: Fix a problem of PTI enabled kernel > -----Original Message----- > From: Takao Indoh [mailto:indou.takao@jp.fujitsu.com] > Sent: Friday, January 26, 2018 9:26 AM > To: crash-utility(a)redhat.com; Hatayama, Daisuke > <d.hatayama(a)jp.fujitsu.com&gt; > Subject: [PATCH] sadump: Fix a problem of PTI enabled kernel > > This patch fixes a problem that a dumpfile of sadump cannot be opened > by crash when Page Table Isolation(PTI) is enabled. > > When PTI is enabled, bit 12 of CR3 register is used to split user > space and kernel space. Also bit 11:0 is used for Process Context > IDentifiers(PCID). To open a dump file of sadump, a value of CR3 is > used to calculate KASLR offset and phys_base, therefore this patch > fixes to mask CR3 register value collectly for PTI enabled kernel. > > This patch also includes code cleanup. > > Signed-off-by: Takao Indoh <indou.takao(a)jp.fujitsu.com&gt; > --- > defs.h | 2 ++ > sadump.c | 33 +++++++++++++++++++++------------ > symbols.c | 9 +++++++++ > 3 files changed, 32 insertions(+), 12 deletions(-) > > diff --git a/defs.h b/defs.h > index dcd6c26..a19f280 100644 > --- a/defs.h > +++ b/defs.h > @@ -2605,6 +2605,8 @@ struct symbol_table_data { > ulong divide_error_vmlinux; > ulong idt_table_vmlinux; > ulong saved_command_line_vmlinux; > + ulong pti_init_vmlinux; > + ulong kaiser_init_vmlinux; > }; > > /* flags for st */ > diff --git a/sadump.c b/sadump.c > index 6b912d4..25cefe9 100644 > --- a/sadump.c > +++ b/sadump.c > @@ -1749,7 +1749,7 @@ static ulong memparse(char *ptr, char **retptr) > * of elfcorehdr. > */ > static ulong > -get_elfcorehdr(ulong cr3, ulong kaslr_offset) > +get_elfcorehdr(ulong kaslr_offset) > { > char cmdline[BUFSIZE], *ptr; > ulong cmdline_vaddr; > @@ -1906,7 +1906,7 @@ get_vmcoreinfo(ulong elfcorehdr, ulong *addr, int *len) > * using "elfcorehdr=" and retrieve kaslr_offset/phys_base from > vmcoreinfo. > */ > static int > -get_kaslr_offset_from_vmcoreinfo(ulong cr3, ulong orig_kaslr_offset, > +get_kaslr_offset_from_vmcoreinfo(ulong orig_kaslr_offset, > ulong *kaslr_offset, ulong *phys_base) > { > ulong elfcorehdr_addr = 0; > @@ -1916,7 +1916,7 @@ get_kaslr_offset_from_vmcoreinfo(ulong cr3, ulong > orig_kaslr_offset, > int ret = FALSE; > > /* Find "elfcorehdr=" in the kernel boot parameter */ > - elfcorehdr_addr = get_elfcorehdr(cr3, orig_kaslr_offset); > + elfcorehdr_addr = get_elfcorehdr(orig_kaslr_offset); > if (!elfcorehdr_addr) > return FALSE; > > @@ -1973,8 +1973,8 @@ quit: > * 1) Get IDTR and CR3 value from the dump header. > * 2) Get a virtual address of IDT from IDTR value > * --- (A) > - * 3) Translate (A) to physical address using CR3, which points a top of > - * page table. > + * 3) Translate (A) to physical address using CR3, the upper 52 bits > + * of which points a top of page table. > * --- (B) > * 4) Get an address of vector0 (Devide Error) interrupt handler from > * IDT, which are pointed by (B). > @@ -2023,12 +2023,15 @@ quit: > * kernel. Retrieve vmcoreinfo from address of "elfcorehdr=" and > * get kaslr_offset and phys_base from vmcoreinfo. > */ > +#define PTI_USER_PGTABLE_BIT PAGE_SHIFT > +#define PTI_USER_PGTABLE_MASK (1 << PTI_USER_PGTABLE_BIT) > +#define CR3_PCID_MASK 0xFFFull > int > sadump_calc_kaslr_offset(ulong *kaslr_offset) > { > ulong phys_base = 0; > struct sadump_smram_cpu_state scs; > - uint64_t idtr = 0, cr3 = 0, idtr_paddr; > + uint64_t idtr = 0, pgd = 0, idtr_paddr; > ulong divide_error_vmcore; > ulong kaslr_offset_kdump, phys_base_kdump; > int ret = FALSE; > @@ -2039,7 +2042,10 @@ sadump_calc_kaslr_offset(ulong *kaslr_offset) > > memset(&scs, 0, sizeof(scs)); > get_sadump_smram_cpu_state_any(&scs); > - cr3 = scs.Cr3; > + if (st->pti_init_vmlinux || st->kaiser_init_vmlinux) > + pgd = scs.Cr3 & ~(CR3_PCID_MASK|PTI_USER_PGTABLE_MASK); > + else > + pgd = scs.Cr3 & ~CR3_PCID_MASK; > idtr = ((uint64_t)scs.IdtUpper)<<32 | (uint64_t)scs.IdtLower; > > /* > @@ -2050,12 +2056,12 @@ sadump_calc_kaslr_offset(ulong *kaslr_offset) > * > * TODO: XEN and 5-level is not supported > */ > - vt->kernel_pgd[0] = cr3; > + vt->kernel_pgd[0] = pgd; > machdep->machspec->last_pml4_read = vt->kernel_pgd[0]; > machdep->machspec->physical_mask_shift = > __PHYSICAL_MASK_SHIFT_2_6; > machdep->machspec->pgdir_shift = PGDIR_SHIFT; > - if (!readmem(cr3, PHYSADDR, machdep->machspec->pml4, PAGESIZE(), > - "cr3", RETURN_ON_ERROR)) > + if (!readmem(pgd, PHYSADDR, machdep->machspec->pml4, PAGESIZE(), > + "pgd", RETURN_ON_ERROR)) > goto quit; > > /* Convert virtual address of IDT table to physical address */ > @@ -2070,7 +2076,7 @@ sadump_calc_kaslr_offset(ulong *kaslr_offset) > > if (CRASHDEBUG(1)) { > fprintf(fp, "calc_kaslr_offset: idtr=%lx\n", idtr); > - fprintf(fp, "calc_kaslr_offset: cr3=%lx\n", cr3); > + fprintf(fp, "calc_kaslr_offset: pgd=%lx\n", pgd); > fprintf(fp, "calc_kaslr_offset: idtr(phys)=%lx\n", > idtr_paddr); > fprintf(fp, "calc_kaslr_offset: > divide_error(vmlinux): %lx\n", > st->divide_error_vmlinux); > @@ -2084,9 +2090,12 @@ sadump_calc_kaslr_offset(ulong *kaslr_offset) > * from vmcoreinfo > */ > if (get_kaslr_offset_from_vmcoreinfo( > - cr3, *kaslr_offset, &kaslr_offset_kdump, > &phys_base_kdump)) { > + *kaslr_offset, &kaslr_offset_kdump, &phys_base_kdump)) { > *kaslr_offset = kaslr_offset_kdump; > phys_base = phys_base_kdump; > + } else if (CRASHDEBUG(1)) { > + fprintf(fp, "sadump: failed to determine which kernel was > running at crash,\n"); > + fprintf(fp, "sadump: asssuming the kdump 1st kernel.\n"); > } > > if (CRASHDEBUG(1)) { > diff --git a/symbols.c b/symbols.c > index 2372887..26b319a 100644 > --- a/symbols.c > +++ b/symbols.c > @@ -3072,10 +3072,14 @@ dump_symbol_table(void) > fprintf(fp, "divide_error_vmlinux: %lx\n", > st->divide_error_vmlinux); > fprintf(fp, " idt_table_vmlinux: %lx\n", > st->idt_table_vmlinux); > fprintf(fp, "saved_command_line_vmlinux: %lx\n", > st->saved_command_line_vmlinux); > + fprintf(fp, " pti_init_vmlinux: %lx\n", > st->pti_init_vmlinux); > + fprintf(fp, " kaiser_init_vmlinux: %lx\n", > st->kaiser_init_vmlinux); > } else { > fprintf(fp, "divide_error_vmlinux: (unused)\n"); > fprintf(fp, " idt_table_vmlinux: (unused)\n"); > fprintf(fp, "saved_command_line_vmlinux: (unused)\n"); > + fprintf(fp, " pti_init_vmlinux: (unused)\n"); > + fprintf(fp, " kaiser_init_vmlinux: (unused)\n"); > } > > fprintf(fp, " symval_hash[%d]: %lx\n", SYMVAL_HASH, > @@ -12306,6 +12310,11 @@ numeric_forward(const void *P_x, const void *P_y) > st->saved_command_line_vmlinux = valueof(x); > else if (STREQ(y->name, "saved_command_line")) > st->saved_command_line_vmlinux = valueof(y); > + > + if (STREQ(x->name, "pti_init")) > + st->pti_init_vmlinux = valueof(x); > + else if (STREQ(y->name, "kaiser_init")) > + st->kaiser_init_vmlinux = valueof(y); > } > > xs = bfd_get_section(x); > -- > 1.8.3.1 It looks good to me. Thanks. Dave, could you merge this patch? Thanks. HATAYAMA, Daisuke