c6cfcbd8ca
The following warning is reported when frame pointers and kernel IBT are enabled: vmlinux.o: warning: objtool: ibt_selftest+0x11: sibling call from callable instruction with modified stack frame The problem is that objtool interprets the indirect branch in ibt_selftest() as a sibling call, and GCC inserts a (partial) frame pointer prologue before it: 0000 000000000003f550 <ibt_selftest>: 0000 3f550: f3 0f 1e fa endbr64 0004 3f554: e8 00 00 00 00 call 3f559 <ibt_selftest+0x9> 3f555: R_X86_64_PLT32 __fentry__-0x4 0009 3f559: 55 push %rbp 000a 3f55a: 48 8d 05 02 00 00 00 lea 0x2(%rip),%rax # 3f563 <ibt_selftest_ip> 0011 3f561: ff e0 jmp *%rax Note the inline asm is missing ASM_CALL_CONSTRAINT, so the 'push %rbp' happens before the indirect branch and the 'mov %rsp, %rbp' happens afterwards. Simplify the generated code and make it easier to understand for both tools and humans by moving the selftest to proper asm. Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/99a7e16b97bda97bf0a04aa141d6241cd8a839a2.1680912949.git.jpoimboe@kernel.org
63 lines
1.5 KiB
C
63 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_TRAPS_H
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#define _ASM_X86_TRAPS_H
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#include <linux/context_tracking_state.h>
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#include <linux/kprobes.h>
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#include <asm/debugreg.h>
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#include <asm/idtentry.h>
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#include <asm/siginfo.h> /* TRAP_TRACE, ... */
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#include <asm/trap_pf.h>
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#ifdef CONFIG_X86_64
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asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs);
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asmlinkage __visible notrace
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struct pt_regs *fixup_bad_iret(struct pt_regs *bad_regs);
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void __init trap_init(void);
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asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs);
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#endif
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extern int ibt_selftest(void);
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extern int ibt_selftest_noendbr(void);
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#ifdef CONFIG_X86_F00F_BUG
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/* For handling the FOOF bug */
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void handle_invalid_op(struct pt_regs *regs);
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#endif
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static inline int get_si_code(unsigned long condition)
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{
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if (condition & DR_STEP)
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return TRAP_TRACE;
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else if (condition & (DR_TRAP0|DR_TRAP1|DR_TRAP2|DR_TRAP3))
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return TRAP_HWBKPT;
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else
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return TRAP_BRKPT;
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}
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extern int panic_on_unrecovered_nmi;
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void math_emulate(struct math_emu_info *);
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bool fault_in_kernel_space(unsigned long address);
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#ifdef CONFIG_VMAP_STACK
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void __noreturn handle_stack_overflow(struct pt_regs *regs,
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unsigned long fault_address,
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struct stack_info *info);
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#endif
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static inline void cond_local_irq_enable(struct pt_regs *regs)
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{
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if (regs->flags & X86_EFLAGS_IF)
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local_irq_enable();
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}
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static inline void cond_local_irq_disable(struct pt_regs *regs)
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{
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if (regs->flags & X86_EFLAGS_IF)
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local_irq_disable();
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}
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#endif /* _ASM_X86_TRAPS_H */
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