diff options
| author | sigsegv7 <ian@vegaa.systems> | 2023-09-25 05:28:54 -0400 |
|---|---|---|
| committer | sigsegv7 <ian@vegaa.systems> | 2023-09-25 05:30:19 -0400 |
| commit | b143f00b1605f588e02349914b6fcb0fd3bab55e (patch) | |
| tree | 893580beb5c9fe47ffbf58944616c44fb7ac6859 /sys/arch/amd64/spectre.S | |
| parent | b46ad8dbf5f8ec212a80a575f0d07e001f825fbf (diff) | |
kernel/amd64: Add spectre mitigation support
Add spectre mitigation support for AMD64 hosts which may be enabled via
the --enable-spectre-mitigation configure flag. This commit currently
only adds IBRS support but more techniques may be added later on.
Signed-off-by: sigsegv7 <ian@vegaa.systems>
Diffstat (limited to 'sys/arch/amd64/spectre.S')
| -rw-r--r-- | sys/arch/amd64/spectre.S | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/sys/arch/amd64/spectre.S b/sys/arch/amd64/spectre.S new file mode 100644 index 0000000..f91f744 --- /dev/null +++ b/sys/arch/amd64/spectre.S @@ -0,0 +1,49 @@ +/* + * Copyright (c) 2023 Ian Marco Moffett and the VegaOS team. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of VegaOS nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +.text +.globl __can_mitigate_spectre + +__can_mitigate_spectre: + xor %ecx, %ecx // NULL out ECX + mov $0x7, %eax // 0x7 (Check IBRS) + cpuid + + /* Check if supported (if EDX[26] == 1) */ + mov $1, %ebx + shl $26, %ebx + test %ebx, %edx + jnz supported +not_supported: + xor %rax, %rax + jmp 1f +supported: + mov $1, %rax +1: + ret |