linux/arch/um/kernel/dyn.lds.S
Patricia Alfonso 5b301409e8 UML: add support for KASAN under x86_64
Make KASAN run on User Mode Linux on x86_64.

The UML-specific KASAN initializer uses mmap to map the ~16TB of shadow
memory to the location defined by KASAN_SHADOW_OFFSET.  kasan_init()
utilizes constructors to initialize KASAN before main().

The location of the KASAN shadow memory, starting at
KASAN_SHADOW_OFFSET, can be configured using the KASAN_SHADOW_OFFSET
option. The default location of this offset is 0x100000000000, which
keeps it out-of-the-way even on UML setups with more "physical" memory.

For low-memory setups, 0x7fff8000 can be used instead, which fits in an
immediate and is therefore faster, as suggested by Dmitry Vyukov. There
is usually enough free space at this location; however, it is a config
option so that it can be easily changed if needed.

Note that, unlike KASAN on other architectures, vmalloc allocations
still use the shadow memory allocated upfront, rather than allocating
and free-ing it per-vmalloc allocation.

If another architecture chooses to go down the same path, we should
replace the checks for CONFIG_UML with something more generic, such
as:
- A CONFIG_KASAN_NO_SHADOW_ALLOC option, which architectures could set
- or, a way of having architecture-specific versions of these vmalloc
  and module shadow memory allocation options.

Also note that, while UML supports both KASAN in inline mode
(CONFIG_KASAN_INLINE) and static linking (CONFIG_STATIC_LINK), it does
not support both at the same time.

Signed-off-by: Patricia Alfonso <trishalfonso@google.com>
Co-developed-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Johannes Berg <johannes@sipsolutions.net>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
2022-07-17 23:35:22 +02:00

182 lines
5.3 KiB
ArmAsm

#include <asm/vmlinux.lds.h>
#include <asm/page.h>
OUTPUT_FORMAT(ELF_FORMAT)
OUTPUT_ARCH(ELF_ARCH)
ENTRY(_start)
jiffies = jiffies_64;
VERSION {
{
local: *;
};
}
SECTIONS
{
PROVIDE (__executable_start = START);
. = START + SIZEOF_HEADERS;
.interp : { *(.interp) }
__binary_start = .;
. = ALIGN(4096); /* Init code and data */
_text = .;
INIT_TEXT_SECTION(PAGE_SIZE)
. = ALIGN(PAGE_SIZE);
/* Read-only sections, merged into text segment: */
.hash : { *(.hash) }
.gnu.hash : { *(.gnu.hash) }
.dynsym : { *(.dynsym) }
.dynstr : { *(.dynstr) }
.gnu.version : { *(.gnu.version) }
.gnu.version_d : { *(.gnu.version_d) }
.gnu.version_r : { *(.gnu.version_r) }
.rel.init : { *(.rel.init) }
.rela.init : { *(.rela.init) }
.rel.text : { *(.rel.text .rel.text.* .rel.gnu.linkonce.t.*) }
.rela.text : { *(.rela.text .rela.text.* .rela.gnu.linkonce.t.*) }
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.rela.fini : { *(.rela.fini) }
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.rela.tbss : { *(.rela.tbss .rela.tbss.* .rela.gnu.linkonce.tb.*) }
.rel.ctors : { *(.rel.ctors) }
.rela.ctors : { *(.rela.ctors) }
.rel.dtors : { *(.rel.dtors) }
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.rel.plt : {
*(.rel.plt)
PROVIDE_HIDDEN(__rel_iplt_start = .);
*(.rel.iplt)
PROVIDE_HIDDEN(__rel_iplt_end = .);
}
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*(.rela.plt)
PROVIDE_HIDDEN(__rela_iplt_start = .);
*(.rela.iplt)
PROVIDE_HIDDEN(__rela_iplt_end = .);
}
.init : {
KEEP (*(.init))
} =0x90909090
.plt : { *(.plt) }
.text : {
_stext = .;
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
IRQENTRY_TEXT
SOFTIRQENTRY_TEXT
*(.fixup)
*(.stub .text.* .gnu.linkonce.t.*)
/* .gnu.warning sections are handled specially by elf32.em. */
*(.gnu.warning)
. = ALIGN(PAGE_SIZE);
} =0x90909090
. = ALIGN(PAGE_SIZE);
.syscall_stub : {
__syscall_stub_start = .;
*(.__syscall_stub*)
__syscall_stub_end = .;
}
.fini : {
KEEP (*(.fini))
} =0x90909090
.kstrtab : { *(.kstrtab) }
#include <asm/common.lds.S>
__init_begin = .;
init.data : { INIT_DATA }
__init_end = .;
/* Ensure the __preinit_array_start label is properly aligned. We
could instead move the label definition inside the section, but
the linker would then create the section even if it turns out to
be empty, which isn't pretty. */
. = ALIGN(32 / 8);
.preinit_array : { *(.preinit_array) }
.init_array : {
*(.kasan_init)
*(.init_array.*)
*(.init_array)
}
.fini_array : { *(.fini_array) }
.data : {
INIT_TASK_DATA(KERNEL_STACK_SIZE)
. = ALIGN(KERNEL_STACK_SIZE);
*(.data..init_irqstack)
DATA_DATA
*(.data.* .gnu.linkonce.d.*)
SORT(CONSTRUCTORS)
}
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.eh_frame : { KEEP (*(.eh_frame)) }
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.dynamic : { *(.dynamic) }
.ctors : {
/* gcc uses crtbegin.o to find the start of
the constructors, so we make sure it is
first. Because this is a wildcard, it
doesn't matter if the user does not
actually link against crtbegin.o; the
linker won't look for a file to match a
wildcard. The wildcard also means that it
doesn't matter which directory crtbegin.o
is in. */
KEEP (*crtbegin.o(.ctors))
/* We don't want to include the .ctor section from
from the crtend.o file until after the sorted ctors.
The .ctor section from the crtend file contains the
end of ctors marker and it must be last */
KEEP (*(EXCLUDE_FILE (*crtend.o ) .ctors))
KEEP (*(SORT(.ctors.*)))
KEEP (*(.ctors))
}
.dtors : {
KEEP (*crtbegin.o(.dtors))
KEEP (*(EXCLUDE_FILE (*crtend.o ) .dtors))
KEEP (*(SORT(.dtors.*)))
KEEP (*(.dtors))
}
.jcr : { KEEP (*(.jcr)) }
.got : { *(.got.plt) *(.got) }
_edata = .;
PROVIDE (edata = .);
.bss : {
__bss_start = .;
*(.dynbss)
*(.bss .bss.* .gnu.linkonce.b.*)
*(COMMON)
/* Align here to ensure that the .bss section occupies space up to
_end. Align after .bss to ensure correct alignment even if the
.bss section disappears because there are no input sections. */
. = ALIGN(32 / 8);
. = ALIGN(32 / 8);
}
__bss_stop = .;
_end = .;
PROVIDE (end = .);
STABS_DEBUG
DWARF_DEBUG
ELF_DETAILS
DISCARDS
}