x86/platform/intel/quark: Drop IMR lock bit support

Isolated Memory Regions support a lock bit. The lock bit in an IMR prevents
modification of the IMR until the core goes through a warm or cold reset.
The lock bit feature is not useful in the context of the kernel API and is
not really necessary since modification of IMRs is possible only from
ring-zero anyway. This patch drops support for IMR locks bits, it
simplifies the kernel API and removes an unnecessary and needlessly complex
feature.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: andriy.shevchenko@linux.intel.com
Cc: boon.leong.ong@intel.com
Cc: paul.gortmaker@windriver.com
Link: http://lkml.kernel.org/r/1456190999-12685-3-git-send-email-pure.logic@nexus-software.ie
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/imr.h

@@ -53,7 +53,7 @@
 #define IMR_MASK		(IMR_ALIGN - 1)
 
 int imr_add_range(phys_addr_t base, size_t size,
-		  unsigned int rmask, unsigned int wmask, bool lock);
+		  unsigned int rmask, unsigned int wmask);
 
 int imr_remove_range(phys_addr_t base, size_t size);
 

arch/x86/platform/intel-quark/imr.c

@@ -134,11 +134,9 @@ static int imr_read(struct imr_device *idev, u32 imr_id, struct imr_regs *imr)
  * @idev:	pointer to imr_device structure.
  * @imr_id:	IMR entry to write.
  * @imr:	IMR structure representing address and access masks.
- * @lock:	indicates if the IMR lock bit should be applied.
  * @return:	0 on success or error code passed from mbi_iosf on failure.
  */
-static int imr_write(struct imr_device *idev, u32 imr_id,
-		     struct imr_regs *imr, bool lock)
+static int imr_write(struct imr_device *idev, u32 imr_id, struct imr_regs *imr)
 {
 	unsigned long flags;
 	u32 reg = imr_id * IMR_NUM_REGS + idev->reg_base;
@@ -162,15 +160,6 @@ static int imr_write(struct imr_device *idev, u32 imr_id,
 	if (ret)
 		goto failed;
 
-	/* Lock bit must be set separately to addr_lo address bits. */
-	if (lock) {
-		imr->addr_lo |= IMR_LOCK;
-		ret = iosf_mbi_write(QRK_MBI_UNIT_MM, MBI_REG_WRITE,
-				     reg - IMR_NUM_REGS, imr->addr_lo);
-		if (ret)
-			goto failed;
-	}
-
 	local_irq_restore(flags);
 	return 0;
 failed:
@@ -322,11 +311,10 @@ static inline int imr_address_overlap(phys_addr_t addr, struct imr_regs *imr)
  * @size:	physical size of region in bytes must be aligned to 1KiB.
  * @read_mask:	read access mask.
  * @write_mask:	write access mask.
- * @lock:	indicates whether or not to permanently lock this region.
  * @return:	zero on success or negative value indicating error.
  */
 int imr_add_range(phys_addr_t base, size_t size,
-		  unsigned int rmask, unsigned int wmask, bool lock)
+		  unsigned int rmask, unsigned int wmask)
 {
 	phys_addr_t end;
 	unsigned int i;
@@ -399,7 +387,7 @@ int imr_add_range(phys_addr_t base, size_t size,
 	imr.rmask = rmask;
 	imr.wmask = wmask;
 
-	ret = imr_write(idev, reg, &imr, lock);
+	ret = imr_write(idev, reg, &imr);
 	if (ret < 0) {
 		/*
 		 * In the highly unlikely event iosf_mbi_write failed
@@ -410,7 +398,7 @@ int imr_add_range(phys_addr_t base, size_t size,
 		imr.addr_hi = 0;
 		imr.rmask = IMR_READ_ACCESS_ALL;
 		imr.wmask = IMR_WRITE_ACCESS_ALL;
-		imr_write(idev, reg, &imr, false);
+		imr_write(idev, reg, &imr);
 	}
 failed:
 	mutex_unlock(&idev->lock);
@@ -506,7 +494,7 @@ static int __imr_remove_range(int reg, phys_addr_t base, size_t size)
 	imr.rmask = IMR_READ_ACCESS_ALL;
 	imr.wmask = IMR_WRITE_ACCESS_ALL;
 
-	ret = imr_write(idev, reg, &imr, false);
+	ret = imr_write(idev, reg, &imr);
 
 failed:
 	mutex_unlock(&idev->lock);
@@ -587,7 +575,7 @@ static void __init imr_fixup_memmap(struct imr_device *idev)
 	 * We don't round up @size since it is already PAGE_SIZE aligned.
 	 * See vmlinux.lds.S for details.
 	 */
-	ret = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
+	ret = imr_add_range(base, size, IMR_CPU, IMR_CPU);
 	if (ret < 0) {
 		pr_err("unable to setup IMR for kernel: %zu KiB (%lx - %lx)\n",
 			size / 1024, start, end);

arch/x86/platform/intel-quark/imr_selftest.c

@@ -60,30 +60,30 @@ static void __init imr_self_test(void)
 	int ret;
 
 	/* Test zero zero. */
-	ret = imr_add_range(0, 0, 0, 0, false);
+	ret = imr_add_range(0, 0, 0, 0);
 	imr_self_test_result(ret < 0, "zero sized IMR\n");
 
 	/* Test exact overlap. */
-	ret = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
+	ret = imr_add_range(base, size, IMR_CPU, IMR_CPU);
 	imr_self_test_result(ret < 0, fmt_over, __va(base), __va(base + size));
 
 	/* Test overlap with base inside of existing. */
 	base += size - IMR_ALIGN;
-	ret = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
+	ret = imr_add_range(base, size, IMR_CPU, IMR_CPU);
 	imr_self_test_result(ret < 0, fmt_over, __va(base), __va(base + size));
 
 	/* Test overlap with end inside of existing. */
 	base -= size + IMR_ALIGN * 2;
-	ret = imr_add_range(base, size, IMR_CPU, IMR_CPU, false);
+	ret = imr_add_range(base, size, IMR_CPU, IMR_CPU);
 	imr_self_test_result(ret < 0, fmt_over, __va(base), __va(base + size));
 
 	/* Test that a 1 KiB IMR @ zero with read/write all will bomb out. */
 	ret = imr_add_range(0, IMR_ALIGN, IMR_READ_ACCESS_ALL,
-			    IMR_WRITE_ACCESS_ALL, false);
+			    IMR_WRITE_ACCESS_ALL);
 	imr_self_test_result(ret < 0, "1KiB IMR @ 0x00000000 - access-all\n");
 
 	/* Test that a 1 KiB IMR @ zero with CPU only will work. */
-	ret = imr_add_range(0, IMR_ALIGN, IMR_CPU, IMR_CPU, false);
+	ret = imr_add_range(0, IMR_ALIGN, IMR_CPU, IMR_CPU);
 	imr_self_test_result(ret >= 0, "1KiB IMR @ 0x00000000 - cpu-access\n");
 	if (ret >= 0) {
 		ret = imr_remove_range(0, IMR_ALIGN);
@@ -92,8 +92,7 @@ static void __init imr_self_test(void)
 
 	/* Test 2 KiB works. */
 	size = IMR_ALIGN * 2;
-	ret = imr_add_range(0, size, IMR_READ_ACCESS_ALL,
-			    IMR_WRITE_ACCESS_ALL, false);
+	ret = imr_add_range(0, size, IMR_READ_ACCESS_ALL, IMR_WRITE_ACCESS_ALL);
 	imr_self_test_result(ret >= 0, "2KiB IMR @ 0x00000000\n");
 	if (ret >= 0) {
 		ret = imr_remove_range(0, size);