3ddee7b2ee
Merge module sections only when using Clang LTO. With ld.bfd, merging
sections does not appear to update the symbol tables for the module,
e.g. 'readelf -s' shows the value that a symbol would have had, if
sections were not merged. ld.lld does not show this problem.
The stale symbol table breaks gdb's function disassembler, and presumably
other things, e.g.
gdb -batch -ex "file arch/x86/kvm/kvm.ko" -ex "disassemble kvm_init"
reads the wrong bytes and dumps garbage.
Fixes: dd2776222abb ("kbuild: lto: merge module sections")
Cc: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210322234438.502582-1-seanjc@google.com
(cherry picked from commit 6a3193cdd5e5b96ac65f04ee42555c216da332af)
Bug: 187129171
Signed-off-by: Connor O'Brien <connoro@google.com>
Change-Id: I295d9a6b71a41fd1585059d0f48a2a2c13eb2361
75 lines
1.9 KiB
ArmAsm
75 lines
1.9 KiB
ArmAsm
/*
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* Common module linker script, always used when linking a module.
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* Archs are free to supply their own linker scripts. ld will
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* combine them automatically.
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*/
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#include <asm/page.h>
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SECTIONS {
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/DISCARD/ : {
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*(.discard)
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*(.discard.*)
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/*
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* LLD may emit .eh_frame with CONFIG_CFI_CLANG despite
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* -fno-asynchronous-unwind-tables. Discard the section.
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*/
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*(.eh_frame)
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}
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__ksymtab 0 : { *(SORT(___ksymtab+*)) }
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__ksymtab_gpl 0 : { *(SORT(___ksymtab_gpl+*)) }
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__ksymtab_unused 0 : { *(SORT(___ksymtab_unused+*)) }
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__ksymtab_unused_gpl 0 : { *(SORT(___ksymtab_unused_gpl+*)) }
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__ksymtab_gpl_future 0 : { *(SORT(___ksymtab_gpl_future+*)) }
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__kcrctab 0 : { *(SORT(___kcrctab+*)) }
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__kcrctab_gpl 0 : { *(SORT(___kcrctab_gpl+*)) }
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__kcrctab_unused 0 : { *(SORT(___kcrctab_unused+*)) }
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__kcrctab_unused_gpl 0 : { *(SORT(___kcrctab_unused_gpl+*)) }
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__kcrctab_gpl_future 0 : { *(SORT(___kcrctab_gpl_future+*)) }
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.init_array 0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }
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__jump_table 0 : ALIGN(8) { KEEP(*(__jump_table)) }
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__patchable_function_entries : { *(__patchable_function_entries) }
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#ifdef CONFIG_LTO_CLANG
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/*
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* With CONFIG_LTO_CLANG, LLD always enables -fdata-sections and
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* -ffunction-sections, which increases the size of the final module.
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* Merge the split sections in the final binary.
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*/
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.bss : {
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*(.bss .bss.[0-9a-zA-Z_]*)
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*(.bss..L*)
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}
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.data : {
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*(.data .data.[0-9a-zA-Z_]*)
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*(.data..L*)
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}
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.rodata : {
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*(.rodata .rodata.[0-9a-zA-Z_]*)
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*(.rodata..L*)
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}
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#ifdef CONFIG_CFI_CLANG
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/*
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* With CFI_CLANG, ensure __cfi_check is at the beginning of the
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* .text section, and that the section is aligned to page size.
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*/
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.text : ALIGN(PAGE_SIZE) {
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*(.text.__cfi_check)
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*(.text .text.[0-9a-zA-Z_]*)
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__cfi_jt_start = .;
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*(.text..L.cfi.jumptable .text..L.cfi.jumptable.*)
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__cfi_jt_end = .;
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}
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#endif
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#endif
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}
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/* bring in arch-specific sections */
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#include <asm/module.lds.h>
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