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a13644f3a5
The #VC handler needs special entry code because: 1. It runs on an IST stack 2. It needs to be able to handle nested #VC exceptions To make this work, the entry code is implemented to pretend it doesn't use an IST stack. When entered from user-mode or early SYSCALL entry path it switches to the task stack. If entered from kernel-mode it tries to switch back to the previous stack in the IRET frame. The stack found in the IRET frame is validated first, and if it is not safe to use it for the #VC handler, the code will switch to a fall-back stack (the #VC2 IST stack). From there, it can cause nested exceptions again. Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20200907131613.12703-46-joro@8bytes.org
42 lines
990 B
C
42 lines
990 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_PROTO_H
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#define _ASM_X86_PROTO_H
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#include <asm/ldt.h>
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/* misc architecture specific prototypes */
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void syscall_init(void);
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#ifdef CONFIG_X86_64
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void entry_SYSCALL_64(void);
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void entry_SYSCALL_64_safe_stack(void);
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long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2);
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#endif
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#ifdef CONFIG_X86_32
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void entry_INT80_32(void);
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void entry_SYSENTER_32(void);
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void __begin_SYSENTER_singlestep_region(void);
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void __end_SYSENTER_singlestep_region(void);
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#endif
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#ifdef CONFIG_IA32_EMULATION
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void entry_SYSENTER_compat(void);
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void __end_entry_SYSENTER_compat(void);
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void entry_SYSCALL_compat(void);
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void entry_INT80_compat(void);
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#ifdef CONFIG_XEN_PV
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void xen_entry_INT80_compat(void);
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#endif
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#endif
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void x86_configure_nx(void);
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void x86_report_nx(void);
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extern int reboot_force;
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long do_arch_prctl_common(struct task_struct *task, int option,
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unsigned long cpuid_enabled);
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#endif /* _ASM_X86_PROTO_H */
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