kernel/linux.git/tools/objtool/check.c, branch v5.18.2

Merge tag 'x86_urgent_for_v5.18_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-05-01T17:03:36+00:00

Pull x86 fixes from Borislav Petkov: - A fix to disable PCI/MSI[-X] masking for XEN_HVM guests as that is solely controlled by the hypervisor - A build fix to make the function prototype (__warn()) as visible as the definition itself - A bunch of objtool annotation fixes which have accumulated over time - An ORC unwinder fix to handle bad input gracefully - Well, we thought the microcode gets loaded in time in order to restore the microcode-emulated MSRs but we thought wrong. So there's a fix for that to have the ordering done properly - Add new Intel model numbers - A spelling fix * tag 'x86_urgent_for_v5.18_rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/pci/xen: Disable PCI/MSI[-X] masking for XEN_HVM guests bug: Have __warn() prototype defined unconditionally x86/Kconfig: fix the spelling of 'becoming' in X86_KERNEL_IBT config objtool: Use offstr() to print address of missing ENDBR objtool: Print data address for "!ENDBR" data warnings x86/xen: Add ANNOTATE_NOENDBR to startup_xen() x86/uaccess: Add ENDBR to __put_user_nocheck*() x86/retpoline: Add ANNOTATE_NOENDBR for retpolines x86/static_call: Add ANNOTATE_NOENDBR to static call trampoline objtool: Enable unreachable warnings for CLANG LTO x86,objtool: Explicitly mark idtentry_body()s tail REACHABLE x86,objtool: Mark cpu_startup_entry() __noreturn x86,xen,objtool: Add UNWIND hint lib/strn*,objtool: Enforce user_access_begin() rules MAINTAINERS: Add x86 unwinding entry x86/unwind/orc: Recheck address range after stack info was updated x86/cpu: Load microcode during restore_processor_state() x86/cpu: Add new Alderlake and Raptorlake CPU model numbers

objtool: Fix type of reloc::addend

2022-04-22T10:13:55+00:00

Elf{32,64}_Rela::r_addend is of type: Elf{32,64}_Sword, that means that our reloc::addend needs to be long or face tuncation issues when we do elf_rebuild_reloc_section(): - 107: 48 b8 00 00 00 00 00 00 00 00 movabs $0x0,%rax 109: R_X86_64_64 level4_kernel_pgt+0x80000067 + 107: 48 b8 00 00 00 00 00 00 00 00 movabs $0x0,%rax 109: R_X86_64_64 level4_kernel_pgt-0x7fffff99 Fixes: 627fce14809b ("objtool: Add ORC unwind table generation") Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20220419203807.596871927@infradead.org

objtool: Fix function fallthrough detection for vmlinux

2022-04-19T19:58:53+00:00

Objtool's function fallthrough detection only works on C objects. The distinction between C and assembly objects no longer makes sense with objtool running on vmlinux.o. Now that copy_user_64.S has been fixed up, and an objtool sibling call detection bug has been fixed, the asm code is in "compliance" and this hack is no longer needed. Remove it. Fixes: ed53a0d97192 ("x86/alternative: Use .ibt_endbr_seal to seal indirect calls") Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/b434cff98eca3a60dcc64c620d7d5d405a0f441c.1649718562.git.jpoimboe@redhat.com

objtool: Fix sibling call detection in alternatives

2022-04-19T19:58:53+00:00

In add_jump_destinations(), sibling call detection requires 'insn->func' to be valid. But alternative instructions get their 'func' set in handle_group_alt(), which runs *after* add_jump_destinations(). So sibling calls in alternatives code don't get properly detected. Fix that by changing the initialization order: call add_special_section_alts() *before* add_jump_destinations(). This also means the special case for a missing 'jump_dest' in add_jump_destinations() can be removed, as it has already been dealt with. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/c02e0a0a2a4286b5f848d17c77fdcb7e0caf709c.1649718562.git.jpoimboe@redhat.com

objtool: Don't set 'jump_dest' for sibling calls

2022-04-19T19:58:53+00:00

For most sibling calls, 'jump_dest' is NULL because objtool treats the jump like a call and sets 'call_dest'. But there are a few edge cases where that's not true. Make it consistent to avoid unexpected behavior. Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/8737d6b9d1691831aed73375f444f0f42da3e2c9.1649718562.git.jpoimboe@redhat.com

objtool: Use offstr() to print address of missing ENDBR

2022-04-19T19:58:50+00:00

Fixes: 89bc853eae4a ("objtool: Find unused ENDBR instructions") Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/95d12e800c736a3f7d08d61dabb760b2d5251a8e.1650300597.git.jpoimboe@redhat.com

objtool: Print data address for "!ENDBR" data warnings

2022-04-19T19:58:50+00:00

When a "!ENDBR" warning is reported for a data section, objtool just prints the text address of the relocation target twice, without giving any clues about the location of the original data reference: vmlinux.o: warning: objtool: dcbnl_netdevice_event()+0x0: .text+0xb64680: data relocation to !ENDBR: dcbnl_netdevice_event+0x0 Instead, print the address of the data reference, in addition to the address of the relocation target. vmlinux.o: warning: objtool: dcbnl_nb+0x0: .data..read_mostly+0xe260: data relocation to !ENDBR: dcbnl_netdevice_event+0x0 Fixes: 89bc853eae4a ("objtool: Find unused ENDBR instructions") Signed-off-by: Josh Poimboeuf Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/762e88d51300e8eaf0f933a5b0feae20ac033bea.1650300597.git.jpoimboe@redhat.com

x86,objtool: Mark cpu_startup_entry() __noreturn

2022-04-19T19:58:48+00:00

GCC-8 isn't clever enough to figure out that cpu_start_entry() is a noreturn while objtool is. This results in code after the call in start_secondary(). Give GCC a hand so that they all agree on things. vmlinux.o: warning: objtool: start_secondary()+0x10e: unreachable Reported-by: Rick Edgecombe Signed-off-by: Peter Zijlstra (Intel) Acked-by: Josh Poimboeuf Link: https://lore.kernel.org/r/20220408094718.383658532@infradead.org

objtool: Fix SLS validation for kcov tail-call replacement

2022-04-05T08:24:40+00:00

Since not all compilers have a function attribute to disable KCOV instrumentation, objtool can rewrite KCOV instrumentation in noinstr functions as per commit: f56dae88a81f ("objtool: Handle __sanitize_cov*() tail calls") However, this has subtle interaction with the SLS validation from commit: 1cc1e4c8aab4 ("objtool: Add straight-line-speculation validation") In that when a tail-call instrucion is replaced with a RET an additional INT3 instruction is also written, but is not represented in the decoded instruction stream. This then leads to false positive missing INT3 objtool warnings in noinstr code. Instead of adding additional struct instruction objects, mark the RET instruction with retpoline_safe to suppress the warning (since we know there really is an INT3). Fixes: 1cc1e4c8aab4 ("objtool: Add straight-line-speculation validation") Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220323230712.GA8939@worktop.programming.kicks-ass.net

objtool: Fix IBT tail-call detection

2022-04-05T08:24:40+00:00

Objtool reports: arch/x86/crypto/poly1305-x86_64.o: warning: objtool: poly1305_blocks_avx() falls through to next function poly1305_blocks_x86_64() arch/x86/crypto/poly1305-x86_64.o: warning: objtool: poly1305_emit_avx() falls through to next function poly1305_emit_x86_64() arch/x86/crypto/poly1305-x86_64.o: warning: objtool: poly1305_blocks_avx2() falls through to next function poly1305_blocks_x86_64() Which reads like: 0000000000000040 : 40: f3 0f 1e fa endbr64 ... 0000000000000400 : 400: f3 0f 1e fa endbr64 404: 44 8b 47 14 mov 0x14(%rdi),%r8d 408: 48 81 fa 80 00 00 00 cmp $0x80,%rdx 40f: 73 09 jae 41a 411: 45 85 c0 test %r8d,%r8d 414: 0f 84 2a fc ff ff je 44 ... These are simple conditional tail-calls and *should* be recognised as such by objtool, however due to a mistake in commit 08f87a93c8ec ("objtool: Validate IBT assumptions") this is failing. Specifically, the jump_dest is +4, this means the instruction pointed at will not be ENDBR and as such it will fail the second clause of is_first_func_insn() that was supposed to capture this exact case. Instead, have is_first_func_insn() look at the previous instruction. Fixes: 08f87a93c8ec ("objtool: Validate IBT assumptions") Reported-by: Stephen Rothwell Signed-off-by: Peter Zijlstra (Intel) Link: https://lkml.kernel.org/r/20220322115125.811582125@infradead.org