Upstream commit:
238ec850b95a02dcdff3edc86781aa913549282f
Set X86_FEATURE_RETHUNK when enabling the SRSO mitigation so that
generated code (e.g., ftrace, static call, eBPF) generates "jmp
__x86_return_thunk" instead of RET.
[ bp: Add a comment. ]
Fixes:
fb3bd914b3ec ("x86/srso: Add a Speculative RAS Overflow mitigation")
Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
- if (cpu_feature_enabled(X86_FEATURE_RETHUNK) ||
- cpu_feature_enabled(X86_FEATURE_SRSO) ||
- cpu_feature_enabled(X86_FEATURE_SRSO_ALIAS))
+ if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
return -1;
bytes[i++] = RET_INSN_OPCODE;
return -1;
bytes[i++] = RET_INSN_OPCODE;
case SRSO_CMD_SAFE_RET:
if (IS_ENABLED(CONFIG_CPU_SRSO)) {
case SRSO_CMD_SAFE_RET:
if (IS_ENABLED(CONFIG_CPU_SRSO)) {
+ /*
+ * Enable the return thunk for generated code
+ * like ftrace, static_call, etc.
+ */
+ setup_force_cpu_cap(X86_FEATURE_RETHUNK);
+
if (boot_cpu_data.x86 == 0x19)
setup_force_cpu_cap(X86_FEATURE_SRSO_ALIAS);
else
if (boot_cpu_data.x86 == 0x19)
setup_force_cpu_cap(X86_FEATURE_SRSO_ALIAS);
else