D26406.id77305.diff
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D26406.id77305.diff
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	Index: sys/amd64/linux/linux_sysvec.c
	===================================================================
	--- sys/amd64/linux/linux_sysvec.c
	+++ sys/amd64/linux/linux_sysvec.c
	@@ -207,24 +207,48 @@
	static void
	linux_set_syscall_retval(struct thread *td, int error)
	{
	- struct trapframe *frame = td->td_frame;
	+ struct trapframe *frame;

	+ frame = td->td_frame;
	+
	/*
	* On Linux only %rcx and %r11 values are not preserved across
	* the syscall. So, do not clobber %rdx and %r10.
	*/
	td->td_retval[1] = frame->tf_rdx;
	- if (error != EJUSTRETURN)
	- frame->tf_r10 = frame->tf_rcx;

	- cpu_set_syscall_retval(td, error);
	+ switch (error) {
	+ case 0:
	+ frame->tf_rax = td->td_retval[0];
	+ frame->tf_r10 = frame->tf_rcx;
	+ break;

	- if (__predict_false(error != 0)) {
	- if (error != ERESTART && error != EJUSTRETURN)
	- frame->tf_rax = linux_to_bsd_errno(error);
	+ case ERESTART:
	+ /*
	+ * Reconstruct pc, we know that 'syscall' is 2 bytes,
	+ * lcall $X,y is 7 bytes, int 0x80 is 2 bytes.
	+ * We saved this in tf_err.
	+ *
	+ * Require full context restore to get the arguments
	+ * in the registers reloaded at return to usermode.
	+ */
	+ frame->tf_rip -= frame->tf_err;
	+ frame->tf_r10 = frame->tf_rcx;
	+ break;
	+
	+ case EJUSTRETURN:
	+ break;
	+
	+ default:
	+ frame->tf_rax = linux_to_bsd_errno(error);
	+ frame->tf_r10 = frame->tf_rcx;
	+ break;
	}

	- /* Restore all registers. */
	+ /*
	+ * XXX: Would be great to be able to avoid PCB_FULL_IRET at least
	+ * for the error == 0 case.
	+ */
	set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
	}