d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
kq
freebsd-skq/sys/conf/ldscript.amd64
markj 436ad09030 Tighten mapping protections on preloaded files on amd64. 
- We load the kernel at 0x200000.  Memory below that address need not
  be executable, so do not map it as such.
- Remove references to .ldata and related sections in the kernel linker
  script.  They come from ld.bfd's default linker script, but are not
  used, and we now use ld.lld to link the amd64 kernel.  lld does not
  contain a default linker script.
- Pad the .bss to a 2MB as we do between .text and .data.  This
  forces the loader to load additional files starting in the following
  2MB page, preserving the use of superpage mappings for kernel data.
- Map memory above the kernel image with NX.  The kernel linker now
  upgrades protections as needed, and other preloaded file types
  (e.g., entropy, microcode) need not be mapped with execute permissions
  in the first place.

Reviewed by:	kib
MFC after:	1 month
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D21859
2019-10-18 14:05:13 +00:00

221 lines
7.8 KiB
Plaintext
Raw Permalink Blame History

/* $FreeBSD$ */
OUTPUT_FORMAT("elf64-x86-64-freebsd", "elf64-x86-64-freebsd", "elf64-x86-64-freebsd")
OUTPUT_ARCH(i386:x86-64)
ENTRY(btext)
SEARCH_DIR("/usr/lib");
SECTIONS
{
/* Read-only sections, merged into text segment: */
kernphys = 0x200000; /* 2MB superpage size */
. = kernbase + kernphys + SIZEOF_HEADERS;
/*
* Use the AT keyword in order to set the right LMA that contains
* the physical address where the section should be loaded. This is
* needed for the Xen loader which honours the LMA.
*/
.interp : AT (kernphys + SIZEOF_HEADERS) { *(.interp) }
.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.*) }
.rel.fini : { *(.rel.fini) }
.rela.fini : { *(.rela.fini) }
.rel.rodata : { *(.rel.rodata .rel.rodata.* .rel.gnu.linkonce.r.*) }
.rela.rodata : { *(.rela.rodata .rela.rodata.* .rela.gnu.linkonce.r.*) }
.rel.data.rel.ro : { *(.rel.data.rel.ro* .rel.gnu.linkonce.d.rel.ro.*) }
.rela.data.rel.ro : { *(.rela.data.rel.ro* .rela.gnu.linkonce.d.rel.ro.*) }
.rel.data : { *(.rel.data .rel.data.* .rel.gnu.linkonce.d.*) }
.rela.data : { *(.rela.data .rela.data.* .rela.gnu.linkonce.d.*) }
.rel.tdata : { *(.rel.tdata .rel.tdata.* .rel.gnu.linkonce.td.*) }
.rela.tdata : { *(.rela.tdata .rela.tdata.* .rela.gnu.linkonce.td.*) }
.rel.tbss : { *(.rel.tbss .rel.tbss.* .rel.gnu.linkonce.tb.*) }
.rela.tbss : { *(.rela.tbss .rela.tbss.* .rela.gnu.linkonce.tb.*) }
.rel.ctors : { *(.rel.ctors) }
.rela.ctors : { *(.rela.ctors) }
.rel.dtors : { *(.rel.dtors) }
.rela.dtors : { *(.rela.dtors) }
.rel.got : { *(.rel.got) }
.rela.got : { *(.rela.got) }
.rel.bss : { *(.rel.bss .rel.bss.* .rel.gnu.linkonce.b.*) }
.rela.bss : { *(.rela.bss .rela.bss.* .rela.gnu.linkonce.b.*) }
.rel.plt : { *(.rel.plt) }
.rela.plt : { *(.rela.plt) }
.init :
{
KEEP (*(.init))
} =0xCCCCCCCC
.plt : { *(.plt) }
.text :
{
*(.text .stub .text.* .gnu.linkonce.t.*)
KEEP (*(.text.*personality*))
/* .gnu.warning sections are handled specially by elf32.em. */
*(.gnu.warning)
} =0xCCCCCCCC
.fini :
{
KEEP (*(.fini))
} =0xCCCCCCCC
PROVIDE (__etext = .);
PROVIDE (_etext = .);
PROVIDE (etext = .);
.rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) }
.rodata1 : { *(.rodata1) }
.note.gnu.build-id : {
PROVIDE (__build_id_start = .);
*(.note.gnu.build-id)
PROVIDE (__build_id_end = .);
}
.eh_frame_hdr : { *(.eh_frame_hdr) }
.eh_frame : ONLY_IF_RO { KEEP (*(.eh_frame)) }
.gcc_except_table : ONLY_IF_RO { *(.gcc_except_table .gcc_except_table.*) }
/* Adjust the address for the data segment. We want to adjust up to
the same address within the page on the next page up. */
. = ALIGN (CONSTANT (MAXPAGESIZE)) - ((CONSTANT (MAXPAGESIZE) - .) & (CONSTANT (MAXPAGESIZE) - 1)); . = DATA_SEGMENT_ALIGN (CONSTANT (MAXPAGESIZE), CONSTANT (COMMONPAGESIZE));
PROVIDE (brwsection = .);
/* Exception handling */
.eh_frame : ONLY_IF_RW { KEEP (*(.eh_frame)) }
.gcc_except_table : ONLY_IF_RW { *(.gcc_except_table .gcc_except_table.*) }
/* Thread Local Storage sections */
.tdata : { *(.tdata .tdata.* .gnu.linkonce.td.*) }
.tbss : { *(.tbss .tbss.* .gnu.linkonce.tb.*) *(.tcommon) }
.preinit_array :
{
PROVIDE_HIDDEN (__preinit_array_start = .);
KEEP (*(.preinit_array))
PROVIDE_HIDDEN (__preinit_array_end = .);
}
.init_array :
{
PROVIDE_HIDDEN (__init_array_start = .);
KEEP (*(SORT(.init_array.*)))
KEEP (*(.init_array))
PROVIDE_HIDDEN (__init_array_end = .);
}
.fini_array :
{
PROVIDE_HIDDEN (__fini_array_start = .);
KEEP (*(.fini_array))
KEEP (*(SORT(.fini_array.*)))
PROVIDE_HIDDEN (__fini_array_end = .);
}
_start_ctors = .;
PROVIDE (start_ctors = .);
.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))
KEEP (*crtbegin?.o(.ctors))
/* We don't want to include the .ctor section 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 *crtend?.o ) .ctors))
KEEP (*(SORT(.ctors.*)))
KEEP (*(.ctors))
}
_stop_ctors = .;
PROVIDE (stop_ctors = .);
.dtors :
{
KEEP (*crtbegin.o(.dtors))
KEEP (*crtbegin?.o(.dtors))
KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o ) .dtors))
KEEP (*(SORT(.dtors.*)))
KEEP (*(.dtors))
}
.jcr : { KEEP (*(.jcr)) }
.data.rel.ro : { *(.data.rel.ro.local* .gnu.linkonce.d.rel.ro.local.*) *(.data.rel.ro* .gnu.linkonce.d.rel.ro.*) }
.dynamic : { *(.dynamic) }
.got : { *(.got) }
. = DATA_SEGMENT_RELRO_END (24, .);
.got.plt : { *(.got.plt) }
. = ALIGN(128);
.data.read_frequently :
{
*(SORT_BY_ALIGNMENT(.data.read_frequently))
}
.data.read_mostly :
{
*(.data.read_mostly)
}
. = ALIGN(128);
.data.exclusive_cache_line :
{
*(.data.exclusive_cache_line)
}
. = ALIGN(128);
.data :
{
*(.data .data.* .gnu.linkonce.d.*)
KEEP (*(.gnu.linkonce.d.*personality*))
}
.data1 : { *(.data1) }
_edata = .; PROVIDE (edata = .);
__bss_start = .;
.bss :
{
*(.dynbss)
*(.bss .bss.* .gnu.linkonce.b.*)
*(COMMON)
/* Ensure that the .bss section ends at a superpage boundary.
This way it can be mapped using non-executable large pages. */
. = ALIGN(0x200000);
}
_end = .; PROVIDE (end = .);
. = DATA_SEGMENT_END (.);
/* Stabs debugging sections. */
.stab 0 : { *(.stab) }
.stabstr 0 : { *(.stabstr) }
.stab.excl 0 : { *(.stab.excl) }
.stab.exclstr 0 : { *(.stab.exclstr) }
.stab.index 0 : { *(.stab.index) }
.stab.indexstr 0 : { *(.stab.indexstr) }
.comment 0 : { *(.comment) }
/* DWARF debug sections.
Symbols in the DWARF debugging sections are relative to the beginning
of the section so we begin them at 0. */
/* DWARF 1 */
.debug 0 : { *(.debug) }
.line 0 : { *(.line) }
/* GNU DWARF 1 extensions */
.debug_srcinfo 0 : { *(.debug_srcinfo) }
.debug_sfnames 0 : { *(.debug_sfnames) }
/* DWARF 1.1 and DWARF 2 */
.debug_aranges 0 : { *(.debug_aranges) }
.debug_pubnames 0 : { *(.debug_pubnames) }
/* DWARF 2 */
.debug_info 0 : { *(.debug_info .gnu.linkonce.wi.*) }
.debug_abbrev 0 : { *(.debug_abbrev) }
.debug_line 0 : { *(.debug_line) }
.debug_frame 0 : { *(.debug_frame) }
.debug_str 0 : { *(.debug_str) }
.debug_loc 0 : { *(.debug_loc) }
.debug_macinfo 0 : { *(.debug_macinfo) }
/* SGI/MIPS DWARF 2 extensions */
.debug_weaknames 0 : { *(.debug_weaknames) }
.debug_funcnames 0 : { *(.debug_funcnames) }
.debug_typenames 0 : { *(.debug_typenames) }
.debug_varnames 0 : { *(.debug_varnames) }
/* DWARF 3 */
.debug_pubtypes 0 : { *(.debug_pubtypes) }
.debug_ranges 0 : { *(.debug_ranges) }
.gnu.attributes 0 : { KEEP (*(.gnu.attributes)) }
/DISCARD/ : { *(.note.GNU-stack) }
}
Reference in New Issue View Git Blame Copy Permalink