arch/tile: add Tilera's <arch/sim.h> header as an open-source header

This change adds one of the Tilera standard <arch> headers to the set
of headers shipped with Linux.  The <arch/sim.h> header provides
methods for programmatically interacting with the Tilera simulator.

The current <arch/sim.h> provides inline assembly for the _sim_syscall
function, so the declaration and definition previously provided
manually in Linux are no longer needed.  We now use the standard
sim_validate_lines_evicted() method from <arch/sim.h> rather than
rolling our own direct call to sim_syscall().
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

arch/tile/include/asm/system.h

@@ -217,13 +217,6 @@ int hardwall_deactivate(struct task_struct *task);
 } while (0)
 #endif
 
-/* Invoke the simulator "syscall" mechanism (see arch/tile/kernel/entry.S). */
-extern int _sim_syscall(int syscall_num, ...);
-#define sim_syscall(syscall_num, ...) \
-	_sim_syscall(SIM_CONTROL_SYSCALL + \
-		((syscall_num) << _SIM_CONTROL_OPERATOR_BITS), \
-		## __VA_ARGS__)
-
 /*
  * Kernel threads can check to see if they need to migrate their
  * stack whenever they return from a context switch; for user

arch/tile/kernel/entry.S

@@ -25,28 +25,6 @@ STD_ENTRY(current_text_addr)
 	{ move r0, lr; jrp lr }
 	STD_ENDPROC(current_text_addr)
 
-STD_ENTRY(_sim_syscall)
-	/*
-	 * Wait for r0-r9 to be ready (and lr on the off chance we
-	 * want the syscall to locate its caller), then make a magic
-	 * simulator syscall.
-	 *
-	 * We carefully stall until the registers are readable in case they
-	 * are the target of a slow load, etc. so that tile-sim will
-	 * definitely be able to read all of them inside the magic syscall.
-	 *
-	 * Technically this is wrong for r3-r9 and lr, since an interrupt
-	 * could come in and restore the registers with a slow load right
-	 * before executing the mtspr. We may need to modify tile-sim to
-	 * explicitly stall for this case, but we do not yet have
-	 * a way to implement such a stall.
-	 */
-	{ and zero, lr, r9 ; and zero, r8, r7 }
-	{ and zero, r6, r5 ; and zero, r4, r3 }
-	{ and zero, r2, r1 ; mtspr SIM_CONTROL, r0 }
-	{ jrp lr }
-	STD_ENDPROC(_sim_syscall)
-
 /*
  * Implement execve().  The i386 code has a note that forking from kernel
  * space results in no copy on write until the execve, so we should be

arch/tile/mm/homecache.c

@@ -37,6 +37,8 @@
 #include <asm/pgalloc.h>
 #include <asm/homecache.h>
 
+#include <arch/sim.h>
+
 #include "migrate.h"
 
 
@@ -217,13 +219,6 @@ static unsigned long cache_flush_length(unsigned long length)
 	return (length >= CHIP_L2_CACHE_SIZE()) ? HV_FLUSH_EVICT_L2 : length;
 }
 
-/* On the simulator, confirm lines have been evicted everywhere. */
-static void validate_lines_evicted(unsigned long pfn, size_t length)
-{
-	sim_syscall(SIM_SYSCALL_VALIDATE_LINES_EVICTED,
-		    (HV_PhysAddr)pfn << PAGE_SHIFT, length);
-}
-
 /* Flush a page out of whatever cache(s) it is in. */
 void homecache_flush_cache(struct page *page, int order)
 {
@@ -234,7 +229,7 @@ void homecache_flush_cache(struct page *page, int order)
 
 	homecache_mask(page, pages, &home_mask);
 	flush_remote(pfn, length, &home_mask, 0, 0, 0, NULL, NULL, 0);
-	validate_lines_evicted(pfn, pages * PAGE_SIZE);
+	sim_validate_lines_evicted(PFN_PHYS(pfn), pages * PAGE_SIZE);
 }