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| author |   Joerg Roedel <jroedel@suse.de> | 2020-09-07 15:15:46 +0200 |
|---|---|---|
| committer |   Borislav Petkov <bp@suse.de> | 2020-09-09 11:33:19 +0200 |
| commit | a13644f3a53de4e95a7bce6459f834e832ea44c5 (patch) | |
| tree | 9c5cb65710578399714129dd0482ee18e7ae1238 /arch/x86/include/asm/traps.h | |
| parent | x86/dumpstack/64: Add noinstr version of get_stack_info() (diff) | |
| download | wireguard-linux-a13644f3a53de4e95a7bce6459f834e832ea44c5.tar.xz wireguard-linux-a13644f3a53de4e95a7bce6459f834e832ea44c5.zip | |
x86/entry/64: Add entry code for #VC handler
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
Diffstat (limited to 'arch/x86/include/asm/traps.h')
| -rw-r--r-- | arch/x86/include/asm/traps.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/traps.h b/arch/x86/include/asm/traps.h index 6a308355ea29..1b86bb3abc56 100644 --- a/arch/x86/include/asm/traps.h +++ b/arch/x86/include/asm/traps.h @@ -15,6 +15,7 @@ asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs); asmlinkage __visible notrace struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s); void __init trap_init(void); +asmlinkage __visible noinstr struct pt_regs *vc_switch_off_ist(struct pt_regs *eregs); #endif #ifdef CONFIG_X86_F00F_BUG |