diff options
| author | Dominik Brodowski <linux@dominikbrodowski.net> | 2018-02-11 11:49:46 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-22 15:42:21 +0100 |
| commit | bd25388691c041903c084c68dc7da0fc45265d98 (patch) | |
| tree | 7056d713dc0d6b9d8a69be311c2b37a59ceafded | |
| parent | 3ce4863a44ff4e7e8d48d480853eea79cfd27bf6 (diff) | |
x86/entry/64: Use PUSH_AND_CLEAN_REGS in more cases
commit 30907fd13bb593202574bb20af58d67c70a1ee14 upstream.
entry_SYSCALL_64_after_hwframe() and nmi() can be converted to use
PUSH_AND_CLEAN_REGS instead of opencoded variants thereof. Due to
the interleaving, the additional XOR-based clearing of R8 and R9
in entry_SYSCALL_64_after_hwframe() should not have any noticeable
negative implications.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dan.j.williams@intel.com
Link: http://lkml.kernel.org/r/20180211104949.12992-6-linux@dominikbrodowski.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/entry/calling.h | 6 | ||||
| -rw-r--r-- | arch/x86/entry/entry_64.S | 65 |
2 files changed, 6 insertions, 65 deletions
diff --git a/arch/x86/entry/calling.h b/arch/x86/entry/calling.h index 57b1b87a04f0..d6a97e2945ee 100644 --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -137,7 +137,7 @@ For 32-bit we have the following conventions - kernel is built with UNWIND_HINT_REGS offset=\offset .endm - .macro PUSH_AND_CLEAR_REGS + .macro PUSH_AND_CLEAR_REGS rdx=%rdx rax=%rax /* * Push registers and sanitize registers of values that a * speculation attack might otherwise want to exploit. The @@ -147,9 +147,9 @@ For 32-bit we have the following conventions - kernel is built with */ pushq %rdi /* pt_regs->di */ pushq %rsi /* pt_regs->si */ - pushq %rdx /* pt_regs->dx */ + pushq \rdx /* pt_regs->dx */ pushq %rcx /* pt_regs->cx */ - pushq %rax /* pt_regs->ax */ + pushq \rax /* pt_regs->ax */ pushq %r8 /* pt_regs->r8 */ xorq %r8, %r8 /* nospec r8 */ pushq %r9 /* pt_regs->r9 */ diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index cf8119c46c2a..02c9b54203b6 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -223,35 +223,8 @@ ENTRY(entry_SYSCALL_64) pushq %rcx /* pt_regs->ip */ GLOBAL(entry_SYSCALL_64_after_hwframe) pushq %rax /* pt_regs->orig_ax */ - pushq %rdi /* pt_regs->di */ - pushq %rsi /* pt_regs->si */ - pushq %rdx /* pt_regs->dx */ - pushq %rcx /* pt_regs->cx */ - pushq $-ENOSYS /* pt_regs->ax */ - pushq %r8 /* pt_regs->r8 */ - pushq %r9 /* pt_regs->r9 */ - pushq %r10 /* pt_regs->r10 */ - /* - * Clear extra registers that a speculation attack might - * otherwise want to exploit. Interleave XOR with PUSH - * for better uop scheduling: - */ - xorq %r10, %r10 /* nospec r10 */ - pushq %r11 /* pt_regs->r11 */ - xorq %r11, %r11 /* nospec r11 */ - pushq %rbx /* pt_regs->rbx */ - xorl %ebx, %ebx /* nospec rbx */ - pushq %rbp /* pt_regs->rbp */ - xorl %ebp, %ebp /* nospec rbp */ - pushq %r12 /* pt_regs->r12 */ - xorq %r12, %r12 /* nospec r12 */ - pushq %r13 /* pt_regs->r13 */ - xorq %r13, %r13 /* nospec r13 */ - pushq %r14 /* pt_regs->r14 */ - xorq %r14, %r14 /* nospec r14 */ - pushq %r15 /* pt_regs->r15 */ - xorq %r15, %r15 /* nospec r15 */ - UNWIND_HINT_REGS + + PUSH_AND_CLEAR_REGS rax=$-ENOSYS TRACE_IRQS_OFF @@ -1382,39 +1355,7 @@ ENTRY(nmi) pushq 1*8(%rdx) /* pt_regs->rip */ UNWIND_HINT_IRET_REGS pushq $-1 /* pt_regs->orig_ax */ - pushq %rdi /* pt_regs->di */ - pushq %rsi /* pt_regs->si */ - pushq (%rdx) /* pt_regs->dx */ - pushq %rcx /* pt_regs->cx */ - pushq %rax /* pt_regs->ax */ - /* - * Sanitize registers of values that a speculation attack - * might otherwise want to exploit. The lower registers are - * likely clobbered well before they could be put to use in - * a speculative execution gadget. Interleave XOR with PUSH - * for better uop scheduling: - */ - pushq %r8 /* pt_regs->r8 */ - xorq %r8, %r8 /* nospec r8 */ - pushq %r9 /* pt_regs->r9 */ - xorq %r9, %r9 /* nospec r9 */ - pushq %r10 /* pt_regs->r10 */ - xorq %r10, %r10 /* nospec r10 */ - pushq %r11 /* pt_regs->r11 */ - xorq %r11, %r11 /* nospec r11*/ - pushq %rbx /* pt_regs->rbx */ - xorl %ebx, %ebx /* nospec rbx*/ - pushq %rbp /* pt_regs->rbp */ - xorl %ebp, %ebp /* nospec rbp*/ - pushq %r12 /* pt_regs->r12 */ - xorq %r12, %r12 /* nospec r12*/ - pushq %r13 /* pt_regs->r13 */ - xorq %r13, %r13 /* nospec r13*/ - pushq %r14 /* pt_regs->r14 */ - xorq %r14, %r14 /* nospec r14*/ - pushq %r15 /* pt_regs->r15 */ - xorq %r15, %r15 /* nospec r15*/ - UNWIND_HINT_REGS + PUSH_AND_CLEAR_REGS rdx=(%rdx) ENCODE_FRAME_POINTER /* |