ARM: earlier initialization of vectors page

Initialize the contents of the vectors page immediately after we
allocate the page, but before we map it.  This avoids any possible
aliases with other mappings which may need to be flushed after the
page has been mapped irrespective of the cache type.

We follow this later with a flush_cache_all() after all static memory
mappings have been initialized, which ensures that this is safe from
any cache effects.
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/include/asm/traps.h

@@ -46,7 +46,7 @@ static inline int in_exception_text(unsigned long ptr)
 	return in ? : __in_irqentry_text(ptr);
 }
 
-extern void __init early_trap_init(void);
+extern void __init early_trap_init(void *);
 extern void dump_backtrace_entry(unsigned long where, unsigned long from, unsigned long frame);
 extern void ptrace_break(struct task_struct *tsk, struct pt_regs *regs);
 

arch/arm/kernel/setup.c

@@ -961,7 +961,6 @@ void __init setup_arch(char **cmdline_p)
 	conswitchp = &dummy_con;
 #endif
 #endif
-	early_trap_init();
 
 	if (mdesc->init_early)
 		mdesc->init_early();

arch/arm/kernel/traps.c

@@ -781,18 +781,16 @@ static void __init kuser_get_tls_init(unsigned long vectors)
 		memcpy((void *)vectors + 0xfe0, (void *)vectors + 0xfe8, 4);
 }
 
-void __init early_trap_init(void)
+void __init early_trap_init(void *vectors_base)
 {
-#if defined(CONFIG_CPU_USE_DOMAINS)
-	unsigned long vectors = CONFIG_VECTORS_BASE;
-#else
-	unsigned long vectors = (unsigned long)vectors_page;
-#endif
+	unsigned long vectors = (unsigned long)vectors_base;
 	extern char __stubs_start[], __stubs_end[];
 	extern char __vectors_start[], __vectors_end[];
 	extern char __kuser_helper_start[], __kuser_helper_end[];
 	int kuser_sz = __kuser_helper_end - __kuser_helper_start;
 
+	vectors_page = vectors_base;
+
 	/*
 	 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
 	 * into the vector page, mapped at 0xffff0000, and ensure these

arch/arm/mm/mmu.c

@@ -997,11 +997,14 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
 {
 	struct map_desc map;
 	unsigned long addr;
+	void *vectors;
 
 	/*
 	 * Allocate the vector page early.
 	 */
-	vectors_page = early_alloc(PAGE_SIZE);
+	vectors = early_alloc(PAGE_SIZE);
+
+	early_trap_init(vectors);
 
 	for (addr = VMALLOC_START; addr; addr += PMD_SIZE)
 		pmd_clear(pmd_off_k(addr));
@@ -1041,7 +1044,7 @@ static void __init devicemaps_init(struct machine_desc *mdesc)
 	 * location (0xffff0000).  If we aren't using high-vectors, also
 	 * create a mapping at the low-vectors virtual address.
 	 */
-	map.pfn = __phys_to_pfn(virt_to_phys(vectors_page));
+	map.pfn = __phys_to_pfn(virt_to_phys(vectors));
 	map.virtual = 0xffff0000;
 	map.length = PAGE_SIZE;
 	map.type = MT_HIGH_VECTORS;