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6a3193cdd5
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: dd2776222a ("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
50 lines
1.1 KiB
ArmAsm
50 lines
1.1 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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SECTIONS {
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/DISCARD/ : {
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*(.discard)
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*(.discard.*)
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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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__kcrctab 0 : { *(SORT(___kcrctab+*)) }
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__kcrctab_gpl 0 : { *(SORT(___kcrctab_gpl+*)) }
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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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.text : { *(.text .text.[0-9a-zA-Z_]*) }
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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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