lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Sun, 26 Sep 2021 23:08:15 +0800 From: Lai Jiangshan <jiangshanlai@...il.com> To: linux-kernel@...r.kernel.org Cc: Lai Jiangshan <laijs@...ux.alibaba.com>, Andy Lutomirski <luto@...nel.org>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, x86@...nel.org, "H. Peter Anvin" <hpa@...or.com> Subject: [PATCH V2 18/41] x86/entry: Call paranoid_exit() in asm_exc_nmi() From: Lai Jiangshan <laijs@...ux.alibaba.com> The code between "call exc_nmi" and nmi_restore is as the same as paranoid_exit(), so we can just use paranoid_exit() instead of the open duplicated code. No functional change intended. Signed-off-by: Lai Jiangshan <laijs@...ux.alibaba.com> --- arch/x86/entry/entry_64.S | 34 +++++----------------------------- 1 file changed, 5 insertions(+), 29 deletions(-) diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index 202253c9a4f2..a0d73dc0d2f3 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -922,8 +922,7 @@ SYM_CODE_END(paranoid_entry) /* * "Paranoid" exit path from exception stack. This is invoked - * only on return from non-NMI IST interrupts that came - * from kernel space. + * only on return from IST interrupts that came from kernel space. * * We may be returning to very strange contexts (e.g. very early * in syscall entry), so checking for preemption here would @@ -1271,11 +1270,7 @@ end_repeat_nmi: pushq $-1 /* ORIG_RAX: no syscall to restart */ /* - * Use paranoid_entry to handle SWAPGS, but no need to use paranoid_exit - * as we should not be calling schedule in NMI context. - * Even with normal interrupts enabled. An NMI should not be - * setting NEED_RESCHED or anything that normal interrupts and - * exceptions might do. + * Use paranoid_entry to handle SWAPGS and CR3. */ call paranoid_entry UNWIND_HINT_REGS @@ -1284,31 +1279,12 @@ end_repeat_nmi: movq $-1, %rsi call exc_nmi - /* Always restore stashed CR3 value (see paranoid_entry) */ - RESTORE_CR3 scratch_reg=%r15 save_reg=%r14 - /* - * The above invocation of paranoid_entry stored the GSBASE - * related information in R/EBX depending on the availability - * of FSGSBASE. - * - * If FSGSBASE is enabled, restore the saved GSBASE value - * unconditionally, otherwise take the conditional SWAPGS path. + * Use paranoid_exit to handle SWAPGS and CR3, but no need to use + * restore_regs_and_return_to_kernel as we must handle nested NMI. */ - ALTERNATIVE "jmp nmi_no_fsgsbase", "", X86_FEATURE_FSGSBASE - - wrgsbase %rbx - jmp nmi_restore - -nmi_no_fsgsbase: - /* EBX == 0 -> invoke SWAPGS */ - testl %ebx, %ebx - jnz nmi_restore - -nmi_swapgs: - swapgs + call paranoid_exit -nmi_restore: POP_REGS /* -- 2.19.1.6.gb485710b
Powered by blists - more mailing lists