Date: Fri, 7 Jul 2023 16:56:21 GMT From: Dmitry Chagin <dchagin@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: ac7759f54574 - main - rtld: Annotate .rtld_start on aarch64 Message-ID: <202307071656.367GuLEI013861@gitrepo.freebsd.org>
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The branch main has been updated by dchagin: URL: https://cgit.FreeBSD.org/src/commit/?id=ac7759f54574ceb9da48829fd09ea6545404bdc0 commit ac7759f54574ceb9da48829fd09ea6545404bdc0 Author: Dmitry Chagin <dchagin@FreeBSD.org> AuthorDate: 2023-07-07 16:55:28 +0000 Commit: Dmitry Chagin <dchagin@FreeBSD.org> CommitDate: 2023-07-07 16:55:28 +0000 rtld: Annotate .rtld_start on aarch64 1. Add a stop indicator to rtld_start to satisfy unwinders on aarch64: The right unwinding stop indicator should be CFI-undefined PC. https://dwarfstd.org/doc/Dwarf3.pdf - page 118: If a Return Address register is defined in the virtual unwind table, and its rule is undefined (for example, by DW_CFA_undefined), then there is no return address and no call address, and the virtual unwind of stack activations is complete. 2. Add a proper annotations for CFA. That is allows gdb and libunwind successfully stop when unwinding stack from global constructors and destructors. Reviewed by: Differential Revision: https://reviews.freebsd.org/D40844 --- libexec/rtld-elf/aarch64/rtld_start.S | 3 +++ 1 file changed, 3 insertions(+) diff --git a/libexec/rtld-elf/aarch64/rtld_start.S b/libexec/rtld-elf/aarch64/rtld_start.S index 4f0bef0233b0..107920548432 100644 --- a/libexec/rtld-elf/aarch64/rtld_start.S +++ b/libexec/rtld-elf/aarch64/rtld_start.S @@ -31,15 +31,18 @@ __FBSDID("$FreeBSD$"); ENTRY(.rtld_start) + .cfi_undefined x30 mov x19, x0 /* Put ps_strings in a callee-saved register */ sub sp, sp, #16 /* Make room for obj_main & exit proc */ + .cfi_adjust_cfa_offset 16 mov x1, sp /* exit_proc */ add x2, x1, #8 /* obj_main */ bl _rtld /* Call the loader */ mov x8, x0 /* Backup the entry point */ ldp x2, x1, [sp], #16 /* Load cleanup, obj_main */ + .cfi_adjust_cfa_offset 0 mov x0, x19 /* Restore ps_strings */ br x8 /* Jump to the entry point */
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