Merge tag 'ronx-next' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux into devel-stable

generic fixmaps
ARM support for CONFIG_DEBUG_RODATA

arch/arm/kernel/Makefile

@@ -67,7 +67,7 @@ test-kprobes-objs		+= kprobes-test-arm.o
 endif
 obj-$(CONFIG_OABI_COMPAT)	+= sys_oabi-compat.o
 obj-$(CONFIG_ARM_THUMBEE)	+= thumbee.o
-obj-$(CONFIG_KGDB)		+= kgdb.o
+obj-$(CONFIG_KGDB)		+= kgdb.o patch.o
 obj-$(CONFIG_ARM_UNWIND)	+= unwind.o
 obj-$(CONFIG_HAVE_TCM)		+= tcm.o
 obj-$(CONFIG_OF)		+= devtree.o

arch/arm/kernel/ftrace.c

@@ -15,6 +15,7 @@
 #include <linux/ftrace.h>
 #include <linux/uaccess.h>
 #include <linux/module.h>
+#include <linux/stop_machine.h>
 
 #include <asm/cacheflush.h>
 #include <asm/opcodes.h>
@@ -35,6 +36,22 @@
 
 #define	OLD_NOP		0xe1a00000	/* mov r0, r0 */
 
+static int __ftrace_modify_code(void *data)
+{
+	int *command = data;
+
+	set_kernel_text_rw();
+	ftrace_modify_all_code(*command);
+	set_kernel_text_ro();
+
+	return 0;
+}
+
+void arch_ftrace_update_code(int command)
+{
+	stop_machine(__ftrace_modify_code, &command, NULL);
+}
+
 static unsigned long ftrace_nop_replace(struct dyn_ftrace *rec)
 {
 	return rec->arch.old_mcount ? OLD_NOP : NOP;
@@ -73,6 +90,8 @@ int ftrace_arch_code_modify_prepare(void)
 int ftrace_arch_code_modify_post_process(void)
 {
 	set_all_modules_text_ro();
+	/* Make sure any TLB misses during machine stop are cleared. */
+	flush_tlb_all();
 	return 0;
 }
 

arch/arm/kernel/jump_label.c

@@ -19,7 +19,7 @@ static void __arch_jump_label_transform(struct jump_entry *entry,
 		insn = arm_gen_nop();
 
 	if (is_static)
-		__patch_text(addr, insn);
+		__patch_text_early(addr, insn);
 	else
 		patch_text(addr, insn);
 }

arch/arm/kernel/kgdb.c

@@ -12,8 +12,12 @@
 #include <linux/irq.h>
 #include <linux/kdebug.h>
 #include <linux/kgdb.h>
+#include <linux/uaccess.h>
+
 #include <asm/traps.h>
 
+#include "patch.h"
+
 struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
 {
 	{ "r0", 4, offsetof(struct pt_regs, ARM_r0)},
@@ -244,6 +248,31 @@ void kgdb_arch_exit(void)
 	unregister_die_notifier(&kgdb_notifier);
 }
 
+int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
+{
+	int err;
+
+	/* patch_text() only supports int-sized breakpoints */
+	BUILD_BUG_ON(sizeof(int) != BREAK_INSTR_SIZE);
+
+	err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+				BREAK_INSTR_SIZE);
+	if (err)
+		return err;
+
+	patch_text((void *)bpt->bpt_addr,
+		   *(unsigned int *)arch_kgdb_ops.gdb_bpt_instr);
+
+	return err;
+}
+
+int kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
+{
+	patch_text((void *)bpt->bpt_addr, *(unsigned int *)bpt->saved_instr);
+
+	return 0;
+}
+
 /*
  * Register our undef instruction hooks with ARM undef core.
  * We regsiter a hook specifically looking for the KGB break inst

arch/arm/kernel/machine_kexec.c

@@ -29,6 +29,7 @@ extern unsigned long kexec_boot_atags;
 
 static atomic_t waiting_for_crash_ipi;
 
+static unsigned long dt_mem;
 /*
  * Provide a dummy crash_notes definition while crash dump arrives to arm.
  * This prevents breakage of crash_notes attribute in kernel/ksysfs.c.
@@ -64,7 +65,7 @@ int machine_kexec_prepare(struct kimage *image)
 			return err;
 
 		if (be32_to_cpu(header) == OF_DT_HEADER)
-			kexec_boot_atags = current_segment->mem;
+			dt_mem = current_segment->mem;
 	}
 	return 0;
 }
@@ -163,12 +164,12 @@ void machine_kexec(struct kimage *image)
 	reboot_code_buffer = page_address(image->control_code_page);
 
 	/* Prepare parameters for reboot_code_buffer*/
+	set_kernel_text_rw();
 	kexec_start_address = image->start;
 	kexec_indirection_page = page_list;
 	kexec_mach_type = machine_arch_type;
-	if (!kexec_boot_atags)
-		kexec_boot_atags = image->start - KEXEC_ARM_ZIMAGE_OFFSET + KEXEC_ARM_ATAGS_OFFSET;
-
+	kexec_boot_atags = dt_mem ?: image->start - KEXEC_ARM_ZIMAGE_OFFSET
+				     + KEXEC_ARM_ATAGS_OFFSET;
 
 	/* copy our kernel relocation code to the control code page */
 	reboot_entry = fncpy(reboot_code_buffer,

arch/arm/kernel/patch.c

@@ -1,8 +1,11 @@
 #include <linux/kernel.h>
+#include <linux/spinlock.h>
 #include <linux/kprobes.h>
+#include <linux/mm.h>
 #include <linux/stop_machine.h>
 
 #include <asm/cacheflush.h>
+#include <asm/fixmap.h>
 #include <asm/smp_plat.h>
 #include <asm/opcodes.h>
 
@@ -13,21 +16,77 @@ struct patch {
 	unsigned int insn;
 };
 
-void __kprobes __patch_text(void *addr, unsigned int insn)
+static DEFINE_SPINLOCK(patch_lock);
+
+static void __kprobes *patch_map(void *addr, int fixmap, unsigned long *flags)
+	__acquires(&patch_lock)
+{
+	unsigned int uintaddr = (uintptr_t) addr;
+	bool module = !core_kernel_text(uintaddr);
+	struct page *page;
+
+	if (module && IS_ENABLED(CONFIG_DEBUG_SET_MODULE_RONX))
+		page = vmalloc_to_page(addr);
+	else if (!module && IS_ENABLED(CONFIG_DEBUG_RODATA))
+		page = virt_to_page(addr);
+	else
+		return addr;
+
+	if (flags)
+		spin_lock_irqsave(&patch_lock, *flags);
+	else
+		__acquire(&patch_lock);
+
+	set_fixmap(fixmap, page_to_phys(page));
+
+	return (void *) (__fix_to_virt(fixmap) + (uintaddr & ~PAGE_MASK));
+}
+
+static void __kprobes patch_unmap(int fixmap, unsigned long *flags)
+	__releases(&patch_lock)
+{
+	clear_fixmap(fixmap);
+
+	if (flags)
+		spin_unlock_irqrestore(&patch_lock, *flags);
+	else
+		__release(&patch_lock);
+}
+
+void __kprobes __patch_text_real(void *addr, unsigned int insn, bool remap)
 {
 	bool thumb2 = IS_ENABLED(CONFIG_THUMB2_KERNEL);
+	unsigned int uintaddr = (uintptr_t) addr;
+	bool twopage = false;
+	unsigned long flags;
+	void *waddr = addr;
 	int size;
 
+	if (remap)
+		waddr = patch_map(addr, FIX_TEXT_POKE0, &flags);
+	else
+		__acquire(&patch_lock);
+
 	if (thumb2 && __opcode_is_thumb16(insn)) {
-		*(u16 *)addr = __opcode_to_mem_thumb16(insn);
+		*(u16 *)waddr = __opcode_to_mem_thumb16(insn);
 		size = sizeof(u16);
-	} else if (thumb2 && ((uintptr_t)addr & 2)) {
+	} else if (thumb2 && (uintaddr & 2)) {
 		u16 first = __opcode_thumb32_first(insn);
 		u16 second = __opcode_thumb32_second(insn);
-		u16 *addrh = addr;
+		u16 *addrh0 = waddr;
+		u16 *addrh1 = waddr + 2;
 
-		addrh[0] = __opcode_to_mem_thumb16(first);
-		addrh[1] = __opcode_to_mem_thumb16(second);
+		twopage = (uintaddr & ~PAGE_MASK) == PAGE_SIZE - 2;
+		if (twopage && remap)
+			addrh1 = patch_map(addr + 2, FIX_TEXT_POKE1, NULL);
+
+		*addrh0 = __opcode_to_mem_thumb16(first);
+		*addrh1 = __opcode_to_mem_thumb16(second);
+
+		if (twopage && addrh1 != addr + 2) {
+			flush_kernel_vmap_range(addrh1, 2);
+			patch_unmap(FIX_TEXT_POKE1, NULL);
+		}
 
 		size = sizeof(u32);
 	} else {
@@ -36,10 +95,16 @@ void __kprobes __patch_text(void *addr, unsigned int insn)
 		else
 			insn = __opcode_to_mem_arm(insn);
 
-		*(u32 *)addr = insn;
+		*(u32 *)waddr = insn;
 		size = sizeof(u32);
 	}
 
+	if (waddr != addr) {
+		flush_kernel_vmap_range(waddr, twopage ? size / 2 : size);
+		patch_unmap(FIX_TEXT_POKE0, &flags);
+	} else
+		__release(&patch_lock);
+
 	flush_icache_range((uintptr_t)(addr),
 			   (uintptr_t)(addr) + size);
 }
@@ -60,16 +125,5 @@ void __kprobes patch_text(void *addr, unsigned int insn)
 		.insn = insn,
 	};
 
-	if (cache_ops_need_broadcast()) {
-		stop_machine(patch_text_stop_machine, &patch, cpu_online_mask);
-	} else {
-		bool straddles_word = IS_ENABLED(CONFIG_THUMB2_KERNEL)
-				      && __opcode_is_thumb32(insn)
-				      && ((uintptr_t)addr & 2);
-
-		if (straddles_word)
-			stop_machine(patch_text_stop_machine, &patch, NULL);
-		else
-			__patch_text(addr, insn);
-	}
+	stop_machine(patch_text_stop_machine, &patch, NULL);
 }

arch/arm/kernel/patch.h

@@ -2,6 +2,16 @@
 #define _ARM_KERNEL_PATCH_H
 
 void patch_text(void *addr, unsigned int insn);
-void __patch_text(void *addr, unsigned int insn);
+void __patch_text_real(void *addr, unsigned int insn, bool remap);
+
+static inline void __patch_text(void *addr, unsigned int insn)
+{
+	__patch_text_real(addr, insn, true);
+}
+
+static inline void __patch_text_early(void *addr, unsigned int insn)
+{
+	__patch_text_real(addr, insn, false);
+}
 
 #endif

arch/arm/kernel/vmlinux.lds.S

@@ -8,6 +8,9 @@
 #include <asm/thread_info.h>
 #include <asm/memory.h>
 #include <asm/page.h>
+#ifdef CONFIG_ARM_KERNMEM_PERMS
+#include <asm/pgtable.h>
+#endif
 	
 #define PROC_INFO							\
 	. = ALIGN(4);							\
@@ -90,6 +93,11 @@ SECTIONS
 		_text = .;
 		HEAD_TEXT
 	}
+
+#ifdef CONFIG_ARM_KERNMEM_PERMS
+	. = ALIGN(1<<SECTION_SHIFT);
+#endif
+
 	.text : {			/* Real text segment		*/
 		_stext = .;		/* Text and read-only data	*/
 			__exception_text_start = .;
@@ -112,6 +120,9 @@ SECTIONS
 			ARM_CPU_KEEP(PROC_INFO)
 	}
 
+#ifdef CONFIG_DEBUG_RODATA
+	. = ALIGN(1<<SECTION_SHIFT);
+#endif
 	RO_DATA(PAGE_SIZE)
 
 	. = ALIGN(4);
@@ -145,7 +156,11 @@ SECTIONS
 	_etext = .;			/* End of text and rodata section */
 
 #ifndef CONFIG_XIP_KERNEL
+# ifdef CONFIG_ARM_KERNMEM_PERMS
+	. = ALIGN(1<<SECTION_SHIFT);
+# else
 	. = ALIGN(PAGE_SIZE);
+# endif
 	__init_begin = .;
 #endif
 	/*
@@ -218,8 +233,12 @@ SECTIONS
 #ifdef CONFIG_XIP_KERNEL
 	__data_loc = ALIGN(4);		/* location in binary */
 	. = PAGE_OFFSET + TEXT_OFFSET;
+#else
+#ifdef CONFIG_ARM_KERNMEM_PERMS
+	. = ALIGN(1<<SECTION_SHIFT);
 #else
 	. = ALIGN(THREAD_SIZE);
+#endif
 	__init_end = .;
 	__data_loc = .;
 #endif