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2020-04-30objtool: UNWIND_HINT_RET_OFFSET should not check registersAlexandre Chartre1-0/+8
UNWIND_HINT_RET_OFFSET will adjust a modified stack. However if a callee-saved register was pushed on the stack then the stack frame will still appear modified. So stop checking registers when UNWIND_HINT_RET_OFFSET is used. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200407073142.20659-3-alexandre.chartre@oracle.com
2020-04-30objtool: is_fentry_call() crashes if call has no destinationAlexandre Chartre1-1/+1
Fix is_fentry_call() so that it works if a call has no destination set (call_dest). This needs to be done in order to support intra- function calls. Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200414103618.12657-2-alexandre.chartre@oracle.com
2020-04-30objtool: Fix ORC vs alternativesPeter Zijlstra2-1/+40
Jann reported that (for instance) entry_64.o:general_protection has very odd ORC data: 0000000000000f40 <general_protection>: #######sp:sp+8 bp:(und) type:iret end:0 f40: 90 nop #######sp:(und) bp:(und) type:call end:0 f41: 90 nop f42: 90 nop #######sp:sp+8 bp:(und) type:iret end:0 f43: e8 a8 01 00 00 callq 10f0 <error_entry> #######sp:sp+0 bp:(und) type:regs end:0 f48: f6 84 24 88 00 00 00 testb $0x3,0x88(%rsp) f4f: 03 f50: 74 00 je f52 <general_protection+0x12> f52: 48 89 e7 mov %rsp,%rdi f55: 48 8b 74 24 78 mov 0x78(%rsp),%rsi f5a: 48 c7 44 24 78 ff ff movq $0xffffffffffffffff,0x78(%rsp) f61: ff ff f63: e8 00 00 00 00 callq f68 <general_protection+0x28> f68: e9 73 02 00 00 jmpq 11e0 <error_exit> #######sp:(und) bp:(und) type:call end:0 f6d: 0f 1f 00 nopl (%rax) Note the entry at 0xf41. Josh found this was the result of commit: 764eef4b109a ("objtool: Rewrite alt->skip_orig") Due to the early return in validate_branch() we no longer set insn->cfi of the original instruction stream (the NOPs at 0xf41 and 0xf42) and we'll end up with the above weirdness. In other discussions we realized alternatives should be ORC invariant; that is, due to there being only a single ORC table, it must be valid for all alternatives. The easiest way to ensure this is to not allow any stack modifications in alternatives. When we enforce this latter observation, we get the property that the whole alternative must have the same CFI, which we can employ to fix the former report. Fixes: 764eef4b109a ("objtool: Rewrite alt->skip_orig") Reported-by: Jann Horn <jannh@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200428191659.499074346@infradead.org
2020-04-30objtool: Uniquely identify alternative instruction groupsAlexandre Chartre2-2/+7
Assign a unique identifier to every alternative instruction group in order to be able to tell which instructions belong to what alternative. [peterz: extracted from a larger patch] Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz>
2020-04-30objtool: Remove check preventing branches within alternativeJulien Thierry1-6/+0
While jumping from outside an alternative region to the middle of an alternative region is very likely wrong, jumping from an alternative region into the same region is valid. It is a common pattern on arm64. The first pattern is unlikely to happen in practice and checking only for this adds a lot of complexity. Just remove the current check. Suggested-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Link: https://lkml.kernel.org/r/20200327152847.15294-6-jthierry@redhat.com
2020-04-26objtool: Fix infinite loop in for_offset_range()Josh Poimboeuf1-3/+4
Randy reported that objtool got stuck in an infinite loop when processing drivers/i2c/busses/i2c-parport.o. It was caused by the following code: 00000000000001fd <line_set>: 1fd: 48 b8 00 00 00 00 00 movabs $0x0,%rax 204: 00 00 00 1ff: R_X86_64_64 .rodata-0x8 207: 41 55 push %r13 209: 41 89 f5 mov %esi,%r13d 20c: 41 54 push %r12 20e: 49 89 fc mov %rdi,%r12 211: 55 push %rbp 212: 48 89 d5 mov %rdx,%rbp 215: 53 push %rbx 216: 0f b6 5a 01 movzbl 0x1(%rdx),%ebx 21a: 48 8d 34 dd 00 00 00 lea 0x0(,%rbx,8),%rsi 221: 00 21e: R_X86_64_32S .rodata 222: 48 89 f1 mov %rsi,%rcx 225: 48 29 c1 sub %rax,%rcx find_jump_table() saw the .rodata reference and tried to find a jump table associated with it (though there wasn't one). The -0x8 rela addend is unusual. It caused find_jump_table() to send a negative table_offset (unsigned 0xfffffffffffffff8) to find_rela_by_dest(). The negative offset should have been harmless, but it actually threw for_offset_range() for a loop... literally. When the mask value got incremented past the end value, it also wrapped to zero, causing the loop exit condition to remain true forever. Prevent this scenario from happening by ensuring the incremented value is always >= the starting value. Fixes: 74b873e49d92 ("objtool: Optimize find_rela_by_dest_range()") Reported-by: Randy Dunlap <rdunlap@infradead.org> Tested-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Julien Thierry <jthierry@redhat.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/02b719674b031800b61e33c30b2e823183627c19.1587842122.git.jpoimboe@redhat.com
2020-04-25objtool: Fix stack offset tracking for indirect CFAsJosh Poimboeuf1-1/+1
When the current frame address (CFA) is stored on the stack (i.e., cfa->base == CFI_SP_INDIRECT), objtool neglects to adjust the stack offset when there are subsequent pushes or pops. This results in bad ORC data at the end of the ENTER_IRQ_STACK macro, when it puts the previous stack pointer on the stack and does a subsequent push. This fixes the following unwinder warning: WARNING: can't dereference registers at 00000000f0a6bdba for ip interrupt_entry+0x9f/0xa0 Fixes: 627fce14809b ("objtool: Add ORC unwind table generation") Reported-by: Vince Weaver <vincent.weaver@maine.edu> Reported-by: Dave Jones <dsj@fb.com> Reported-by: Steven Rostedt <rostedt@goodmis.org> Reported-by: Vegard Nossum <vegard.nossum@oracle.com> Reported-by: Joe Mario <jmario@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Jann Horn <jannh@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/853d5d691b29e250333332f09b8e27410b2d9924.1587808742.git.jpoimboe@redhat.com
2020-04-23objtool: Constify arch_decode_instruction()Ingo Molnar2-4/+4
Mostly straightforward constification, except that WARN_FUNC() needs a writable pointer while we have read-only pointers, so deflect this to WARN(). Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200422103205.61900-4-mingo@kernel.org
2020-04-23objtool: Rename elf_read() to elf_open_read()Ingo Molnar3-3/+3
'struct elf *' handling is an open/close paradigm, make sure the naming matches that: elf_open_read() elf_write() elf_close() Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200422103205.61900-3-mingo@kernel.org
2020-04-23objtool: Constify 'struct elf *' parametersIngo Molnar2-15/+15
In preparation to parallelize certain parts of objtool, map out which uses of various data structures are read-only vs. read-write. As a first step constify 'struct elf' pointer passing, most of the secondary uses of it in find_symbol_*() methods are read-only. Also, while at it, better group the 'struct elf' handling methods in elf.h. Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20200422103205.61900-2-mingo@kernel.org
2020-04-23objtool: Fix off-by-one in symbol_by_offset()Julien Thierry1-1/+1
Sometimes, WARN_FUNC() and other users of symbol_by_offset() will associate the first instruction of a symbol with the symbol preceding it. This is because symbol->offset + symbol->len is already outside of the symbol's range. Fixes: 2a362ecc3ec9 ("objtool: Optimize find_symbol_*() and read_symbols()") Signed-off-by: Julien Thierry <jthierry@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
2020-04-23objtool: Fix 32bit cross buildsPeter Zijlstra1-1/+1
Apparently there's people doing 64bit builds on 32bit machines. Fixes: 74b873e49d92 ("objtool: Optimize find_rela_by_dest_range()") Reported-by: youling257@gmail.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2020-04-22objtool: Also consider .entry.text as noinstrThomas Gleixner1-6/+12
Consider all of .entry.text as noinstr. This gets us coverage across the PTI boundary. While we could add everything .noinstr.text into .entry.text that would bloat the amount of code in the user mapping. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115119.525037514@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Add STT_NOTYPE noinstr validationPeter Zijlstra1-16/+30
Make sure to also check STT_NOTYPE symbols for noinstr violations. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115119.465335884@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Rearrange validate_section()Peter Zijlstra1-22/+29
In preparation of further changes, once again break out the loop body. No functional changes intended. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115119.405863817@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Avoid iterating !text section symbolsPeter Zijlstra1-1/+5
validate_functions() iterates all sections their symbols; this is pointless to do for !text sections as they won't have instructions anyway. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115119.346582716@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Use sec_offset_hash() for insn_hashPeter Zijlstra1-2/+3
In preparation for find_insn_containing(), change insn_hash to use sec_offset_hash(). This actually reduces runtime; probably because mixing in the section index reduces the collisions due to text sections all starting their instructions at offset 0. Runtime on vmlinux.o from 3.1 to 2.5 seconds. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115119.227240432@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Optimize !vmlinux.o againPeter Zijlstra3-26/+52
When doing kbuild tests to see if the objtool changes affected those I found that there was a measurable regression: pre post real 1m13.594 1m16.488s user 34m58.246s 35m23.947s sys 4m0.393s 4m27.312s Perf showed that for small files the increased hash-table sizes were a measurable difference. Since we already have -l "vmlinux" to distinguish between the modes, make it also use a smaller portion of the hash-tables. This flips it into a small win: real 1m14.143s user 34m49.292s sys 3m44.746s Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115119.167588731@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Implement noinstr validationPeter Zijlstra5-4/+112
Validate that any call out of .noinstr.text is in between instr_begin() and instr_end() annotations. This annotation is useful to ensure correct behaviour wrt tracing sensitive code like entry/exit and idle code. When we run code in a sensitive context we want a guarantee no unknown code is ran. Since this validation relies on knowing the section of call destination symbols, we must run it on vmlinux.o instead of on individual object files. Add two options: -d/--duplicate "duplicate validation for vmlinux" -l/--vmlinux "vmlinux.o validation" Where the latter auto-detects when objname ends with "vmlinux.o" and the former will force all validations, also those already done on !vmlinux object files. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115119.106268040@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Fix !CFI insn_state propagationPeter Zijlstra4-140/+157
Objtool keeps per instruction CFI state in struct insn_state and will save/restore this where required. However, insn_state has grown some !CFI state, and this must not be saved/restored (that would loose/destroy state). Fix this by moving the CFI specific parts of insn_state into struct cfi_state. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115119.045821071@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Rename struct cfi_statePeter Zijlstra4-4/+4
There's going to be a new struct cfi_state, rename this one to make place. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115118.986441913@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Remove SAVE/RESTORE hintsPeter Zijlstra2-40/+4
The SAVE/RESTORE hints are now unused; remove them. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115118.926738768@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Introduce HINT_RET_OFFSETPeter Zijlstra2-9/+19
Normally objtool ensures a function keeps the stack layout invariant. But there is a useful exception, it is possible to stuff the return stack in order to 'inject' a 'call': push $fun ret In this case the invariant mentioned above is violated. Add an objtool HINT to annotate this and allow a function exit with a modified stack frame. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115118.690601403@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Better handle IRETPeter Zijlstra3-15/+29
Teach objtool a little more about IRET so that we can avoid using the SAVE/RESTORE annotation. In particular, make the weird corner case in insn->restore go away. The purpose of that corner case is to deal with the fact that UNWIND_HINT_RESTORE lands on the instruction after IRET, but that instruction can end up being outside the basic block, consider: if (cond) sync_core() foo(); Then the hint will land on foo(), and we'll encounter the restore hint without ever having seen the save hint. By teaching objtool about the arch specific exception frame size, and assuming that any IRET in an STT_FUNC symbol is an exception frame sized POP, we can remove the use of save/restore hints for this code. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200416115118.631224674@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Support multiple stack_op per instructionJulien Thierry4-31/+62
Instruction sets can include more or less complex operations which might not fit the currently defined set of stack_ops. Combining more than one stack_op provides more flexibility to describe the behaviour of an instruction. This also reduces the need to define new stack_ops specific to a single instruction set. Allow instruction decoders to generate multiple stack_op per instruction. Signed-off-by: Julien Thierry <jthierry@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200327152847.15294-11-jthierry@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Remove redundant .rodata section name comparisonMuchun Song1-2/+2
If the prefix of section name is not '.rodata', the following function call can never return 0. strcmp(sec->name, C_JUMP_TABLE_SECTION) So the name comparison is pointless, just remove it. Signed-off-by: Muchun Song <songmuchun@bytedance.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Documentation: document UACCESS warningsNick Desaulniers1-0/+26
Compiling with Clang and CONFIG_KASAN=y was exposing a few warnings: call to memset() with UACCESS enabled Document how to fix these for future travelers. Link: https://github.com/ClangBuiltLinux/linux/issues/876 Suggested-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Suggested-by: Matt Helsley <mhelsley@vmware.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Split out arch-specific CFI definitionsJulien Thierry3-20/+29
Some CFI definitions used by generic objtool code have no reason to vary from one architecture to another. Keep those definitions in generic code and move the arch-specific ones to a new arch-specific header. Signed-off-by: Julien Thierry <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Add abstraction for destination offsetsRaphael Gault3-8/+27
The jump and call destination relocation offsets are x86-specific. Abstract them by calling arch-specific implementations. [ jthierry: Remove superfluous comment; replace other addend offsets with arch_dest_rela_offset() ] Signed-off-by: Raphael Gault <raphael.gault@arm.com> Signed-off-by: Julien Thierry <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Use arch specific values in restore_reg()Julien Thierry1-2/+2
The initial register state is set up by arch specific code. Use the value the arch code has set when restoring registers from the stack. Suggested-by: Raphael Gault <raphael.gault@arm.com> Signed-off-by: Julien Thierry <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Ignore empty alternativesJulien Thierry1-0/+6
The .alternatives section can contain entries with no original instructions. Objtool will currently crash when handling such an entry. Just skip that entry, but still give a warning to discourage useless entries. Signed-off-by: Julien Thierry <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Clean instruction state before each function validationJulien Thierry1-7/+6
When a function fails its validation, it might leave a stale state that will be used for the validation of other functions. That would cause false warnings on potentially valid functions. Reset the instruction state before the validation of each individual function. Signed-off-by: Julien Thierry <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Remove redundant checks on operand typeJulien Thierry1-3/+1
POP operations are already in the code path where the destination operand is OP_DEST_REG. There is no need to check the operand type again. Signed-off-by: Julien Thierry <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Always do header sync checkJulien Thierry1-1/+1
Currently, the check of tools files against kernel equivalent is only done after every object file has been built. This means one might fix build issues against outdated headers without seeing a warning about this. Check headers before any object is built. Also, make it part of a FORCE'd recipe so every attempt to build objtool will report the outdated headers (if any). Signed-off-by: Julien Thierry <jthierry@redhat.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Fix off-by-one in symbol_by_offset()Julien Thierry1-1/+1
Sometimes, WARN_FUNC() and other users of symbol_by_offset() will associate the first instruction of a symbol with the symbol preceding it. This is because symbol->offset + symbol->len is already outside of the symbol's range. Fixes: 2a362ecc3ec9 ("objtool: Optimize find_symbol_*() and read_symbols()") Signed-off-by: Julien Thierry <jthierry@redhat.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-22objtool: Fix 32bit cross buildsPeter Zijlstra1-1/+1
Apparently there's people doing 64bit builds on 32bit machines. Fixes: 74b873e49d92 ("objtool: Optimize find_rela_by_dest_range()") Reported-by: youling257@gmail.com Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-14objtool: Make BP scratch register warning more robustJosh Poimboeuf1-2/+2
If func is NULL, a seg fault can result. This is a theoretical issue which was found by Coverity, ID: 1492002 ("Dereference after null check"). Fixes: c705cecc8431 ("objtool: Track original function across branches") Reported-by: Gustavo A. R. Silva <gustavo@embeddedor.com> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/afc628693a37acd287e843bcc5c0430263d93c74.1585761021.git.jpoimboe@redhat.com
2020-04-14objtool: Fix switch table detection in .text.unlikelyJosh Poimboeuf1-4/+1
If a switch jump table's indirect branch is in a ".cold" subfunction in .text.unlikely, objtool doesn't detect it, and instead prints a false warning: drivers/media/v4l2-core/v4l2-ioctl.o: warning: objtool: v4l_print_format.cold()+0xd6: sibling call from callable instruction with modified stack frame drivers/hwmon/max6650.o: warning: objtool: max6650_probe.cold()+0xa5: sibling call from callable instruction with modified stack frame drivers/media/dvb-frontends/drxk_hard.o: warning: objtool: init_drxk.cold()+0x16f: sibling call from callable instruction with modified stack frame Fix it by comparing the function, instead of the section and offset. Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions") Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/157c35d42ca9b6354bbb1604fe9ad7d1153ccb21.1585761021.git.jpoimboe@redhat.com
2020-04-14objtool: Support Clang non-section symbols in ORC generationJosh Poimboeuf1-7/+26
When compiling the kernel with AS=clang, objtool produces a lot of warnings: warning: objtool: missing symbol for section .text warning: objtool: missing symbol for section .init.text warning: objtool: missing symbol for section .ref.text It then fails to generate the ORC table. The problem is that objtool assumes text section symbols always exist. But the Clang assembler is aggressive about removing them. When generating relocations for the ORC table, objtool always tries to reference instructions by their section symbol offset. If the section symbol doesn't exist, it bails. Do a fallback: when a section symbol isn't available, reference a function symbol instead. Reported-by: Dmitry Golovin <dima@golovin.in> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Tested-by: Nathan Chancellor <natechancellor@gmail.com> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://github.com/ClangBuiltLinux/linux/issues/669 Link: https://lkml.kernel.org/r/9a9cae7fcf628843aabe5a086b1a3c5bf50f42e8.1585761021.git.jpoimboe@redhat.com
2020-04-14objtool: Support Clang non-section symbols in ORC dumpJosh Poimboeuf1-17/+27
Historically, the relocation symbols for ORC entries have only been section symbols: .text+0: sp:sp+8 bp:(und) type:call end:0 However, the Clang assembler is aggressive about stripping section symbols. In that case we will need to use function symbols: freezing_slow_path+0: sp:sp+8 bp:(und) type:call end:0 In preparation for the generation of such entries in "objtool orc generate", add support for reading them in "objtool orc dump". Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/b811b5eb1a42602c3b523576dc5efab9ad1c174d.1585761021.git.jpoimboe@redhat.com
2020-04-14objtool: Fix CONFIG_UBSAN_TRAP unreachable warningsJosh Poimboeuf1-2/+15
CONFIG_UBSAN_TRAP causes GCC to emit a UD2 whenever it encounters an unreachable code path. This includes __builtin_unreachable(). Because the BUG() macro uses __builtin_unreachable() after it emits its own UD2, this results in a double UD2. In this case objtool rightfully detects that the second UD2 is unreachable: init/main.o: warning: objtool: repair_env_string()+0x1c8: unreachable instruction We weren't able to figure out a way to get rid of the double UD2s, so just silence the warning. Reported-by: Randy Dunlap <rdunlap@infradead.org> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/6653ad73c6b59c049211bd7c11ed3809c20ee9f5.1585761021.git.jpoimboe@redhat.com
2020-04-14objtool, kcsan: Add explicit check functions to uaccess whitelistMarco Elver1-0/+2
Add explicitly invoked KCSAN check functions to objtool's uaccess whitelist. This is needed in order to permit calling into kcsan_check_scoped_accesses() from the fast-path, which in turn calls __kcsan_check_access(). __kcsan_check_access() is the generic variant of the already whitelisted specializations __tsan_{read,write}N. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2020-04-13Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refreshIngo Molnar12-206/+429
Resolve these conflicts: arch/x86/Kconfig arch/x86/kernel/Makefile Do a minor "evil merge" to move the KCSAN entry up a bit by a few lines in the Kconfig to reduce the probability of future conflicts. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2020-04-08kbuild: support LLVM=1 to switch the default tools to Clang/LLVMMasahiro Yamada1-0/+6
As Documentation/kbuild/llvm.rst implies, building the kernel with a full set of LLVM tools gets very verbose and unwieldy. Provide a single switch LLVM=1 to use Clang and LLVM tools instead of GCC and Binutils. You can pass it from the command line or as an environment variable. Please note LLVM=1 does not turn on the integrated assembler. You need to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the integrated assembler, I think we can make it default. We discussed what we need, and we agreed to go with a simple boolean flag that switches both target and host tools: https://lkml.org/lkml/2020/3/28/494 https://lkml.org/lkml/2020/4/3/43 Some items discussed, but not adopted: - LLVM_DIR When multiple versions of LLVM are installed, I just thought supporting LLVM_DIR=/path/to/my/llvm/bin/ might be useful. CC = $(LLVM_DIR)clang LD = $(LLVM_DIR)ld.lld ... However, we can handle this by modifying PATH. So, we decided to not do this. - LLVM_SUFFIX Some distributions (e.g. Debian) package specific versions of LLVM with naming conventions that use the version as a suffix. CC = clang$(LLVM_SUFFIX) LD = ld.lld(LLVM_SUFFIX) ... will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc., but the suffixed versions in /usr/bin/ are symlinks to binaries in /usr/lib/llvm-#/bin/, so this can also be handled by PATH. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-04-03Merge tag 'spdx-5.7-rc1' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx Pull SPDX updates from Greg KH: "Here are three SPDX patches for 5.7-rc1. One fixes up the SPDX tag for a single driver, while the other two go through the tree and add SPDX tags for all of the .gitignore files as needed. Nothing too complex, but you will get a merge conflict with your current tree, that should be trivial to handle (one file modified by two things, one file deleted.) All three of these have been in linux-next for a while, with no reported issues other than the merge conflict" * tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx: ASoC: MT6660: make spdxcheck.py happy .gitignore: add SPDX License Identifier .gitignore: remove too obvious comments
2020-03-31Merge branch 'locking-core-for-linus' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking updates from Ingo Molnar: "The main changes in this cycle were: - Continued user-access cleanups in the futex code. - percpu-rwsem rewrite that uses its own waitqueue and atomic_t instead of an embedded rwsem. This addresses a couple of weaknesses, but the primary motivation was complications on the -rt kernel. - Introduce raw lock nesting detection on lockdep (CONFIG_PROVE_RAW_LOCK_NESTING=y), document the raw_lock vs. normal lock differences. This too originates from -rt. - Reuse lockdep zapped chain_hlocks entries, to conserve RAM footprint on distro-ish kernels running into the "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" depletion of the lockdep chain-entries pool. - Misc cleanups, smaller fixes and enhancements - see the changelog for details" * 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (55 commits) fs/buffer: Make BH_Uptodate_Lock bit_spin_lock a regular spinlock_t thermal/x86_pkg_temp: Make pkg_temp_lock a raw_spinlock_t Documentation/locking/locktypes: Minor copy editor fixes Documentation/locking/locktypes: Further clarifications and wordsmithing m68knommu: Remove mm.h include from uaccess_no.h x86: get rid of user_atomic_cmpxchg_inatomic() generic arch_futex_atomic_op_inuser() doesn't need access_ok() x86: don't reload after cmpxchg in unsafe_atomic_op2() loop x86: convert arch_futex_atomic_op_inuser() to user_access_begin/user_access_end() objtool: whitelist __sanitizer_cov_trace_switch() [parisc, s390, sparc64] no need for access_ok() in futex handling sh: no need of access_ok() in arch_futex_atomic_op_inuser() futex: arch_futex_atomic_op_inuser() calling conventions change completion: Use lockdep_assert_RT_in_threaded_ctx() in complete_all() lockdep: Add posixtimer context tracing bits lockdep: Annotate irq_work lockdep: Add hrtimer context tracing bits lockdep: Introduce wait-type checks completion: Use simple wait queues sched/swait: Prepare usage in completions ...
2020-03-28objtool: whitelist __sanitizer_cov_trace_switch()Al Viro1-0/+1
it's not really different from e.g. __sanitizer_cov_trace_cmp4(); as it is, the switches that generate an array of labels get rejected by objtool, while slightly different set of cases that gets compiled into a series of comparisons is accepted. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-03-25objtool: Re-arrange validate_functions()Peter Zijlstra1-22/+30
In preparation to adding a vmlinux.o specific pass, rearrange some code. No functional changes intended. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200324160924.924304616@infradead.org
2020-03-25objtool: Optimize find_rela_by_dest_range()Peter Zijlstra2-5/+26
Perf shows there is significant time in find_rela_by_dest(); this is because we have to iterate the address space per byte, looking for relocation entries. Optimize this by reducing the address space granularity. This reduces objtool on vmlinux.o runtime from 4.8 to 4.4 seconds. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200324160924.861321325@infradead.org
2020-03-25objtool: Delete cleanup()Peter Zijlstra1-19/+0
Perf shows we spend a measurable amount of time spend cleaning up right before we exit anyway. Avoid the needsless work and just terminate. This reduces objtool on vmlinux.o runtime from 5.4s to 4.8s Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Miroslav Benes <mbenes@suse.cz> Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Link: https://lkml.kernel.org/r/20200324160924.800720170@infradead.org
generated by cgit v1.2.3 (git 2.39.0) at 2025-09-23 19:26:15 +0300