This is a preparatory change which allows to drop most of SYSENTER machinery
and make SYSENTER reuse SYSCALL code: we will be deleting entire
SYSENTER code block, including auditsys_entry_common and
auditsys_exit macros.
Signed-off-by: Denys Vlasenko <dvlas...@redhat.com>
CC: Ingo Molnar <mi...@kernel.org>
CC: Linus Torvalds <torva...@linux-foundation.org>
CC: Krzysztof A. Sobiecki <sob...@gmail.com>
CC: Steven Rostedt <rost...@goodmis.org>
CC: Borislav Petkov <b...@alien8.de>
CC: "H. Peter Anvin" <h...@zytor.com>
CC: Andy Lutomirski <l...@amacapital.net>
CC: Oleg Nesterov <o...@redhat.com>
CC: Frederic Weisbecker <fweis...@gmail.com>
CC: Alexei Starovoitov <a...@plumgrid.com>
CC: Will Drewry <w...@chromium.org>
CC: Kees Cook <keesc...@chromium.org>
CC: x...@kernel.org
CC: linux-kernel@vger.kernel.org
---
arch/x86/entry/entry_64_compat.S | 57 +++++++++++++++++++++++++++++++++++++---
1 file changed, 53 insertions(+), 4 deletions(-)
diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S
index 9f9dfa5..df102e8 100644
--- a/arch/x86/entry/entry_64_compat.S
+++ b/arch/x86/entry/entry_64_compat.S
@@ -396,13 +396,62 @@ sysretl_from_sys_call:
#ifdef CONFIG_AUDITSYSCALL
cstar_auditsys:
- movl %r9d, R9(%rsp) /* register to be clobbered by call */
- auditsys_entry_common
- movl R9(%rsp), %r9d /* reload 6th syscall arg */
+ movl %r9d, R9(%rsp) /* R9 is callee-clobbered, save it */
+ /*
+ * At this point, registers hold syscall args in the 32-bit syscall ABI:
+ * EAX is syscall number, the 6 args are in EBX,ECX,EDX,ESI,EDI,
+ * 6th arg is in R9.
+ *
+ * We want to pass them to __audit_syscall_entry(), which is a 64-bit
+ * C function with 5 parameters, so shuffle them to match what
+ * the function expects: RDI,RSI,RDX,RCX,R8.
+ */
+ movl %esi, %r8d /* arg5 (R8 ) <= 4th syscall arg (ESI)
*/
+ xchg %ecx, %edx /* arg4 (RCX) <= 3rd syscall arg (EDX)
*/
+ /* arg3 (RDX) <= 2nd syscall arg (ECX)
*/
+ movl %ebx, %esi /* arg2 (RSI) <= 1st syscall arg (EBX)
*/
+ movl %eax, %edi /* arg1 (RDI) <= syscall number (EAX)
*/
+ call __audit_syscall_entry
+
+ /*
+ * We are going to jump back to the syscall dispatch code.
+ * Prepare syscall args as required by the 64-bit C ABI.
+ * Registers clobbered by __audit_syscall_entry() are
+ * loaded from pt_regs on stack:
+ */
+ movl ORIG_RAX(%rsp), %eax /* syscall number */
+ movl %ebx, %edi /* arg1 */
+ movl RCX(%rsp), %esi /* arg2 */
+ movl RDX(%rsp), %edx /* arg3 */
+ movl RSI(%rsp), %ecx /* arg4 */
+ movl RDI(%rsp), %r8d /* arg5 */
+ movl R9(%rsp), %r9d /* arg6 */
jmp cstar_dispatch
sysretl_audit:
- auditsys_exit sysretl_from_sys_call
+ TRACE_IRQS_ON
+ ENABLE_INTERRUPTS(CLBR_NONE)
+ testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),
ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jnz ia32_ret_from_sys_call
+ movl %eax, %esi /* second arg, syscall return value */
+ cmpl $-MAX_ERRNO, %eax /* is it an error ? */
+ jbe 1f
+ movslq %eax, %rsi /* if error sign extend to 64 bits */
+1: setbe %al /* 1 if error, 0 if not */
+ movzbl %al, %edi /* zero-extend that into %edi */
+ call __audit_syscall_exit
+ movq RAX(%rsp), %rax /* reload syscall return value */
+ movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT), %edi
+ DISABLE_INTERRUPTS(CLBR_NONE)
+ TRACE_IRQS_OFF
+ testl %edi, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
+ jz sysretl_from_sys_call
+ xorl %eax, %eax /* Do not leak kernel information */
+ movq %rax, R11(%rsp)
+ movq %rax, R10(%rsp)
+ movq %rax, R9(%rsp)
+ movq %rax, R8(%rsp)
+ jmp int_ret_from_sys_call_irqs_off
#endif
cstar_tracesys:
--
1.8.1.4
--
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