[PATCH] uml: skas0 stubs now check system call return values
Change syscall-stub's data to include a "expected retval".
Stub now checks syscalls retval and aborts execution of syscall list, if
retval != expected retval.
run_syscall_stub prints the data of the failed syscall, using the data pointer
and retval written by the stub to the beginning of the stack.
one_syscall_stub is removed, to simplify code, because only some instructions
are saved by one_syscall_stub, no host-syscall.
Using the stub with additional data (modify_ldt via stub)
is prepared also.
Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/sys-x86_64/stub.S b/arch/um/sys-x86_64/stub.S
index 957f2ef..03c2797 100644
--- a/arch/um/sys-x86_64/stub.S
+++ b/arch/um/sys-x86_64/stub.S
@@ -16,21 +16,51 @@
.globl batch_syscall_stub
batch_syscall_stub:
- movq $(UML_CONFIG_STUB_DATA >> 32), %rbx
- salq $32, %rbx
- movq $(UML_CONFIG_STUB_DATA & 0xffffffff), %rcx
- or %rcx, %rbx
- movq %rbx, %rsp
-again: pop %rax
- cmpq $0, %rax
-jz done
+ mov $(UML_CONFIG_STUB_DATA >> 32), %rbx
+ sal $32, %rbx
+ mov $(UML_CONFIG_STUB_DATA & 0xffffffff), %rax
+ or %rax, %rbx
+ /* load pointer to first operation */
+ mov %rbx, %rsp
+ add $0x10, %rsp
+again:
+ /* load length of additional data */
+ mov 0x0(%rsp), %rax
+
+ /* if(length == 0) : end of list */
+ /* write possible 0 to header */
+ mov %rax, 8(%rbx)
+ cmp $0, %rax
+ jz done
+
+ /* save current pointer */
+ mov %rsp, 8(%rbx)
+
+ /* skip additional data */
+ add %rax, %rsp
+
+ /* load syscall-# */
+ pop %rax
+
+ /* load syscall params */
pop %rdi
pop %rsi
pop %rdx
pop %r10
pop %r8
pop %r9
+
+ /* execute syscall */
syscall
+
+ /* check return value */
+ pop %rcx
+ cmp %rcx, %rax
+ je again
+
+done:
+ /* save return value */
mov %rax, (%rbx)
- jmp again
-done: int3
+
+ /* stop */
+ int3