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Update for the recognition of the new x86_64 CPU_ENTRY_AREA virtual

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address range introduced in Linux 4.15.  The memory range exists
above the vmemmap range and below the mapped kernel static text/data
region, and where all of the x86_64 exception stacks have been moved.
Without the patch, reads from the new memory region fail because the
address range is not recognized as a legitimate virtual address.
Most notable is the failure of "bt" on tasks whose backtraces
originate from any of the exception stacks, which fail with the two
error messages "bt: seek error: kernel virtual address: <address>
type: stack contents" followed by "bt: read of stack at <address>
failed".
(anderson@redhat.com)
This commit is contained in:
Dave Anderson 2018-06-01 10:58:00 -04:00
parent a6cd8408d1
commit da49e2010b
2 changed files with 40 additions and 12 deletions
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5
defs.h
View File

@ -3391,6 +3391,9 @@ struct arm64_stackframe {
#define VSYSCALL_START 0xffffffffff600000
#define VSYSCALL_END 0xffffffffff601000
#define CPU_ENTRY_AREA_START 0xfffffe0000000000
#define CPU_ENTRY_AREA_END 0xfffffe7fffffffff
#define PTOV(X) ((unsigned long)(X)+(machdep->kvbase))
#define VTOP(X) x86_64_VTOP((ulong)(X))
#define IS_VMALLOC_ADDR(X) x86_64_IS_VMALLOC_ADDR((ulong)(X))
@ -5829,6 +5832,8 @@ struct machine_specific {
ulong kpti_entry_stack;
ulong kpti_entry_stack_size;
ulong ptrs_per_pgd;
ulong cpu_entry_area_start;
ulong cpu_entry_area_end;
};
#define KSYMS_START (0x1)

47
x86_64.c
View File

@ -407,6 +407,11 @@ x86_64_init(int when)
machdep->machspec->modules_end = MODULES_END_2_6_31;
}
}
if (STRUCT_EXISTS("cpu_entry_area")) {
machdep->machspec->cpu_entry_area_start = CPU_ENTRY_AREA_START;
machdep->machspec->cpu_entry_area_end = CPU_ENTRY_AREA_END;
}
STRUCT_SIZE_INIT(cpuinfo_x86, "cpuinfo_x86");
/*
* Before 2.6.25 the structure was called gate_struct
@ -879,20 +884,21 @@ x86_64_dump_machdep_table(ulong arg)
/* pml4 and upml is legacy for extension modules */
if (ms->pml4) {
fprintf(fp, " pml4: %lx\n", (ulong)ms->pml4);
fprintf(fp, " last_pml4_read: %lx\n", (ulong)ms->last_pml4_read);
fprintf(fp, " pml4: %lx\n", (ulong)ms->pml4);
fprintf(fp, " last_pml4_read: %lx\n", (ulong)ms->last_pml4_read);
} else {
fprintf(fp, " pml4: (unused)\n");
fprintf(fp, " last_pml4_read: (unused)\n");
fprintf(fp, " pml4: (unused)\n");
fprintf(fp, " last_pml4_read: (unused)\n");
}
if (ms->upml) {
fprintf(fp, " upml: %lx\n", (ulong)ms->upml);
fprintf(fp, " last_upml_read: %lx\n", (ulong)ms->last_upml_read);
fprintf(fp, " upml: %lx\n", (ulong)ms->upml);
fprintf(fp, " last_upml_read: %lx\n", (ulong)ms->last_upml_read);
} else {
fprintf(fp, " upml: (unused)\n");
fprintf(fp, " last_upml_read: (unused)\n");
fprintf(fp, " GART_end: %lx\n", ms->GART_end);
fprintf(fp, " upml: (unused)\n");
fprintf(fp, " last_upml_read: (unused)\n");
}
if (ms->p4d) {
@ -1016,10 +1022,14 @@ x86_64_dump_machdep_table(ulong arg)
fprintf(fp, "\n ");
fprintf(fp, "%016lx ", ms->stkinfo.ibase[c]);
}
fprintf(fp, "\n kpti_entry_stack_size: %ld", ms->kpti_entry_stack_size);
fprintf(fp, "\n kpti_entry_stack: ");
fprintf(fp, "\n kpti_entry_stack_size: ");
if (ms->kpti_entry_stack_size)
fprintf(fp, "%ld", ms->kpti_entry_stack_size);
else
fprintf(fp, "(unused)");
fprintf(fp, "\n kpti_entry_stack: ");
if (machdep->flags & KPTI) {
fprintf(fp, "%lx\n ", ms->kpti_entry_stack);
fprintf(fp, "(percpu: %lx):\n ", ms->kpti_entry_stack);
for (c = 0; c < cpus; c++) {
if (c && !(c%4))
fprintf(fp, "\n ");
@ -1028,6 +1038,16 @@ x86_64_dump_machdep_table(ulong arg)
fprintf(fp, "\n");
} else
fprintf(fp, "(unused)\n");
fprintf(fp, " cpu_entry_area_start: ");
if (ms->cpu_entry_area_start)
fprintf(fp, "%016lx\n", (ulong)ms->cpu_entry_area_start);
else
fprintf(fp, "(unused)\n");
fprintf(fp, " cpu_entry_area_end: ");
if (ms->cpu_entry_area_end)
fprintf(fp, "%016lx\n", (ulong)ms->cpu_entry_area_end);
else
fprintf(fp, "(unused)\n");
}
/*
@ -1586,7 +1606,10 @@ x86_64_IS_VMALLOC_ADDR(ulong vaddr)
((machdep->flags & VMEMMAP) &&
(vaddr >= VMEMMAP_VADDR && vaddr <= VMEMMAP_END)) ||
(vaddr >= MODULES_VADDR && vaddr <= MODULES_END) ||
(vaddr >= VSYSCALL_START && vaddr < VSYSCALL_END));
(vaddr >= VSYSCALL_START && vaddr < VSYSCALL_END) ||
(machdep->machspec->cpu_entry_area_start &&
vaddr >= machdep->machspec->cpu_entry_area_start &&
vaddr <= machdep->machspec->cpu_entry_area_end));
}
static int