freebsd-dev/stand/i386/boot.ldscript

/* $FreeBSD$ */
/* Simplified linker script for the boot loaders. */
OUTPUT_FORMAT("elf32-i386-freebsd")
OUTPUT_ARCH(i386)
ENTRY(_start)
SECTIONS {
  . = ORG;
  .text : { *(.text .text.*) } =0xcccccccc	/* Pad with int3, if needed */
  .rodata : { *(.rodata .rodata.*) }
  .got : { *(.got) *(.igot) }
  .got.plt : { *(.got.plt) *(.igot.plt) }
  .data : { *(.data .data.*) }
  _edata = .; PROVIDE (edata = .);
  .bss : { *(.bss .bss.*) }
  _end = .; PROVIDE (end = .);
  /DISCARD/ : { *(.interp) }
}
Don't use -N to set the OMAGIC with data and text writeable and data not page aligned. To do this, use the ld script gnu ld installs on my system. This is imperfect: LDFLAGS_BIN and LD_FLAGS_BIN describe different things. The loader script could be better named and take into account other architectures. And having two different mechanisms to do basically the same thing needs study. However, it's blocking forward progress on lld, so I'll work in parallel to sort these out. Differential Revision: https://reviews.freebsd.org/D7409 Reviewed by: emaste 2016-09-03 15:26:28 +00:00			`/* $FreeBSD$ */`
Link stand/i386 components using a linker script LLD 10.0.0 changed the behavior of the -Ttext option, so that using -Ttext=0x0 now causes linking of the loaders to fail with: ld: error: output file too large: 18446744073707016908 bytes I reported this in https://bugs.llvm.org/show_bug.cgi?id=44715, and initially reverted the upstream change in r357259 to work around it. However, after some discussion with Fangrui Song in the upstream ticket, I think we can classify this as an unfortunate interaction between using -Ttext=0 in combination with --no-rosegment. (We added the latter in r332090, because btxld does not correctly handle input with more than 2 PT_LOAD segments.) Fangrui suggested to use a linker script instead, and Warner was already attempting this in r305353, but had to revert it due to "crypto-using boot problems" (not sure what those were :). This review updates the stand/i386/boot.ldscript to handle more sections, inserts some symbols like _edata and such that we use in libsa, and also discards any .interp section. It uses ORG which is defined on the linker command line using --defsym ORG=value to set the start of all the sections. Reviewed by: imp MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D23952 2020-03-04 21:01:22 +00:00			`/* Simplified linker script for the boot loaders. */`
Don't use -N to set the OMAGIC with data and text writeable and data not page aligned. To do this, use the ld script gnu ld installs on my system. This is imperfect: LDFLAGS_BIN and LD_FLAGS_BIN describe different things. The loader script could be better named and take into account other architectures. And having two different mechanisms to do basically the same thing needs study. However, it's blocking forward progress on lld, so I'll work in parallel to sort these out. Differential Revision: https://reviews.freebsd.org/D7409 Reviewed by: emaste 2016-09-03 15:26:28 +00:00			`OUTPUT_FORMAT("elf32-i386-freebsd")`
			`OUTPUT_ARCH(i386)`
			`ENTRY(_start)`
			`SECTIONS {`
Link stand/i386 components using a linker script LLD 10.0.0 changed the behavior of the -Ttext option, so that using -Ttext=0x0 now causes linking of the loaders to fail with: ld: error: output file too large: 18446744073707016908 bytes I reported this in https://bugs.llvm.org/show_bug.cgi?id=44715, and initially reverted the upstream change in r357259 to work around it. However, after some discussion with Fangrui Song in the upstream ticket, I think we can classify this as an unfortunate interaction between using -Ttext=0 in combination with --no-rosegment. (We added the latter in r332090, because btxld does not correctly handle input with more than 2 PT_LOAD segments.) Fangrui suggested to use a linker script instead, and Warner was already attempting this in r305353, but had to revert it due to "crypto-using boot problems" (not sure what those were :). This review updates the stand/i386/boot.ldscript to handle more sections, inserts some symbols like _edata and such that we use in libsa, and also discards any .interp section. It uses ORG which is defined on the linker command line using --defsym ORG=value to set the start of all the sections. Reviewed by: imp MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D23952 2020-03-04 21:01:22 +00:00			`. = ORG;`
			`.text : { (.text .text.) } =0xcccccccc /* Pad with int3, if needed */`
			`.rodata : { (.rodata .rodata.) }`
			`.got : { (.got) (.igot) }`
			`.got.plt : { (.got.plt) (.igot.plt) }`
			`.data : { (.data .data.) }`
			`_edata = .; PROVIDE (edata = .);`
			`.bss : { (.bss .bss.) }`
			`_end = .; PROVIDE (end = .);`
			`/DISCARD/ : { *(.interp) }`
Don't use -N to set the OMAGIC with data and text writeable and data not page aligned. To do this, use the ld script gnu ld installs on my system. This is imperfect: LDFLAGS_BIN and LD_FLAGS_BIN describe different things. The loader script could be better named and take into account other architectures. And having two different mechanisms to do basically the same thing needs study. However, it's blocking forward progress on lld, so I'll work in parallel to sort these out. Differential Revision: https://reviews.freebsd.org/D7409 Reviewed by: emaste 2016-09-03 15:26:28 +00:00			`}`