Merge branch 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm

torvalds · torvalds · commit 3f9c08f7ce2c · 2014-08-02T10:57:39.000-07:00
Pull ARM fixes from Russell King:
 "A few fixes for ARM.  Some of these are correctness issues:
   - TLBs must be flushed after the old mappings are removed by the DMA
     mapping code, but before the new mappings are established.
   - An off-by-one entry error in the Keystone LPAE setup code.

  Fixes include:
   - ensuring that the identity mapping for LPAE does not remove the
     kernel image from the identity map.
   - preventing userspace from trapping into kgdb.
   - fixing a preemption issue in the Intel iwmmxt code.
   - fixing a build error with nommu.

  Other changes include:
   - Adding a note about which areas of memory are expected to be
     accessible while the identity mapping tables are in place"

* 'fixes' of git://ftp.arm.linux.org.uk/~rmk/linux-arm:
  ARM: 8124/1: don't enter kgdb when userspace executes a kgdb break instruction
  ARM: idmap: add identity mapping usage note
  ARM: 8115/1: LPAE: reduce damage caused by idmap to virtual memory layout
  ARM: fix alignment of keystone page table fixup
  ARM: 8112/1: only select ARM_PATCH_PHYS_VIRT if MMU is enabled
  ARM: 8100/1: Fix preemption disable in iwmmxt_task_enable()
  ARM: DMA: ensure that old section mappings are flushed from the TLB
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
@@ -313,7 +313,7 @@ config ARCH_MULTIPLATFORM
 config ARCH_INTEGRATOR
 	bool "ARM Ltd. Integrator family"
 	select ARM_AMBA
-	select ARM_PATCH_PHYS_VIRT
+	select ARM_PATCH_PHYS_VIRT if MMU
 	select AUTO_ZRELADDR
 	select COMMON_CLK
 	select COMMON_CLK_VERSATILE
@@ -659,7 +659,7 @@ config ARCH_MSM
 config ARCH_SHMOBILE_LEGACY
 	bool "Renesas ARM SoCs (non-multiplatform)"
 	select ARCH_SHMOBILE
-	select ARM_PATCH_PHYS_VIRT
+	select ARM_PATCH_PHYS_VIRT if MMU
 	select CLKDEV_LOOKUP
 	select GENERIC_CLOCKEVENTS
 	select HAVE_ARM_SCU if SMP
diff --git a/arch/arm/kernel/iwmmxt.S b/arch/arm/kernel/iwmmxt.S
@@ -94,13 +94,19 @@ ENTRY(iwmmxt_task_enable)
 
 	mrc	p15, 0, r2, c2, c0, 0
 	mov	r2, r2				@ cpwait
+	bl	concan_save
 
-	teq	r1, #0				@ test for last ownership
-	mov	lr, r9				@ normal exit from exception
-	beq	concan_load			@ no owner, skip save
+#ifdef CONFIG_PREEMPT_COUNT
+	get_thread_info r10
+#endif
+4:	dec_preempt_count r10, r3
+	mov	pc, r9				@ normal exit from exception
 
 concan_save:
 
+	teq	r1, #0				@ test for last ownership
+	beq	concan_load			@ no owner, skip save
+
 	tmrc	r2, wCon
 
 	@ CUP? wCx
@@ -138,7 +144,7 @@ concan_dump:
 	wstrd	wR15, [r1, #MMX_WR15]
 
 2:	teq	r0, #0				@ anything to load?
-	beq	3f
+	moveq	pc, lr				@ if not, return
 
 concan_load:
 
@@ -171,14 +177,9 @@ concan_load:
 	@ clear CUP/MUP (only if r1 != 0)
 	teq	r1, #0
 	mov 	r2, #0
-	beq	3f
-	tmcr	wCon, r2
+	moveq	pc, lr
 
-3:
-#ifdef CONFIG_PREEMPT_COUNT
-	get_thread_info r10
-#endif
-4:	dec_preempt_count r10, r3
+	tmcr	wCon, r2
 	mov	pc, lr
 
 /*
diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
@@ -160,12 +160,16 @@ static int kgdb_compiled_brk_fn(struct pt_regs *regs, unsigned int instr)
 static struct undef_hook kgdb_brkpt_hook = {
 	.instr_mask		= 0xffffffff,
 	.instr_val		= KGDB_BREAKINST,
+	.cpsr_mask		= MODE_MASK,
+	.cpsr_val		= SVC_MODE,
 	.fn			= kgdb_brk_fn
 };
 
 static struct undef_hook kgdb_compiled_brkpt_hook = {
 	.instr_mask		= 0xffffffff,
 	.instr_val		= KGDB_COMPILED_BREAK,
+	.cpsr_mask		= MODE_MASK,
+	.cpsr_val		= SVC_MODE,
 	.fn			= kgdb_compiled_brk_fn
 };
 
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
@@ -461,12 +461,21 @@ void __init dma_contiguous_remap(void)
 		map.type = MT_MEMORY_DMA_READY;
 
 		/*
-		 * Clear previous low-memory mapping
+		 * Clear previous low-memory mapping to ensure that the
+		 * TLB does not see any conflicting entries, then flush
+		 * the TLB of the old entries before creating new mappings.
+		 *
+		 * This ensures that any speculatively loaded TLB entries
+		 * (even though they may be rare) can not cause any problems,
+		 * and ensures that this code is architecturally compliant.
 		 */
 		for (addr = __phys_to_virt(start); addr < __phys_to_virt(end);
 		     addr += PMD_SIZE)
 			pmd_clear(pmd_off_k(addr));
 
+		flush_tlb_kernel_range(__phys_to_virt(start),
+				       __phys_to_virt(end));
+
 		iotable_init(&map, 1);
 	}
 }
diff --git a/arch/arm/mm/idmap.c b/arch/arm/mm/idmap.c
@@ -9,6 +9,11 @@
 #include <asm/sections.h>
 #include <asm/system_info.h>
 
+/*
+ * Note: accesses outside of the kernel image and the identity map area
+ * are not supported on any CPU using the idmap tables as its current
+ * page tables.
+ */
 pgd_t *idmap_pgd;
 phys_addr_t (*arch_virt_to_idmap) (unsigned long x);
 
@@ -25,6 +30,13 @@ static void idmap_add_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 			pr_warning("Failed to allocate identity pmd.\n");
 			return;
 		}
+		/*
+		 * Copy the original PMD to ensure that the PMD entries for
+		 * the kernel image are preserved.
+		 */
+		if (!pud_none(*pud))
+			memcpy(pmd, pmd_offset(pud, 0),
+			       PTRS_PER_PMD * sizeof(pmd_t));
 		pud_populate(&init_mm, pud, pmd);
 		pmd += pmd_index(addr);
 	} else
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
@@ -1406,8 +1406,8 @@ void __init early_paging_init(const struct machine_desc *mdesc,
 		return;
 
 	/* remap kernel code and data */
-	map_start = init_mm.start_code;
-	map_end   = init_mm.brk;
+	map_start = init_mm.start_code & PMD_MASK;
+	map_end   = ALIGN(init_mm.brk, PMD_SIZE);
 
 	/* get a handle on things... */
 	pgd0 = pgd_offset_k(0);
@@ -1442,7 +1442,7 @@ void __init early_paging_init(const struct machine_desc *mdesc,
 	}
 
 	/* remap pmds for kernel mapping */
-	phys = __pa(map_start) & PMD_MASK;
+	phys = __pa(map_start);
 	do {
 		*pmdk++ = __pmd(phys | pmdprot);
 		phys += PMD_SIZE;
