diff options
author | Joerg Roedel <jroedel@suse.de> | 2018-07-18 12:40:44 +0300 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2018-07-20 02:11:37 +0300 |
commit | 45d7b255747c21fc4b1f5043bee0754d39c3bdbf (patch) | |
tree | 3326c9a21730ae5de0a5902802cd43b861d34714 /arch/x86/include/asm/switch_to.h | |
parent | 0d2eb73b29996684d5bbb72f85c74b47b4c359f7 (diff) | |
download | linux-45d7b255747c21fc4b1f5043bee0754d39c3bdbf.tar.xz |
x86/entry/32: Enter the kernel via trampoline stack
Use the entry-stack as a trampoline to enter the kernel. The entry-stack is
already in the cpu_entry_area and will be mapped to userspace when PTI is
enabled.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Pavel Machek <pavel@ucw.cz>
Cc: "H . Peter Anvin" <hpa@zytor.com>
Cc: linux-mm@kvack.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Waiman Long <llong@redhat.com>
Cc: "David H . Gutteridge" <dhgutteridge@sympatico.ca>
Cc: joro@8bytes.org
Link: https://lkml.kernel.org/r/1531906876-13451-8-git-send-email-joro@8bytes.org
Diffstat (limited to 'arch/x86/include/asm/switch_to.h')
-rw-r--r-- | arch/x86/include/asm/switch_to.h | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h index eb5f7999a893..8bc2f70b452e 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -89,13 +89,23 @@ static inline void refresh_sysenter_cs(struct thread_struct *thread) /* This is used when switching tasks or entering/exiting vm86 mode. */ static inline void update_sp0(struct task_struct *task) { - /* On x86_64, sp0 always points to the entry trampoline stack, which is constant: */ + /* sp0 always points to the entry trampoline stack, which is constant: */ #ifdef CONFIG_X86_32 - load_sp0(task->thread.sp0); + if (static_cpu_has(X86_FEATURE_XENPV)) + load_sp0(task->thread.sp0); + else + this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0); #else + /* + * x86-64 updates x86_tss.sp1 via cpu_current_top_of_stack. That + * doesn't work on x86-32 because sp1 and + * cpu_current_top_of_stack have different values (because of + * the non-zero stack-padding on 32bit). + */ if (static_cpu_has(X86_FEATURE_XENPV)) load_sp0(task_top_of_stack(task)); #endif + } #endif /* _ASM_X86_SWITCH_TO_H */ |