Commit ef06e682 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux 

Pull arm64 fixes from Catalin Marinas:

 - Revert the moving of the jump labels initialisation before
   setup_machine_fdt(). The bug was fixed in drivers/char/random.c.

 - Ftrace fixes: branch range check and consistent handling of PLTs.

 - Clean rather than invalidate FROM_DEVICE buffers at start of DMA
   transfer (safer if such buffer is mapped in user space). A cache
   invalidation is done already at the end of the transfer.

 - A couple of clean-ups (unexport symbol, remove unused label).

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: mm: Don't invalidate FROM_DEVICE buffers at start of DMA transfer
  arm64/cpufeature: Unexport set_cpu_feature()
  arm64: ftrace: remove redundant label
  arm64: ftrace: consistently handle PLTs.
  arm64: ftrace: fix branch range checks
  Revert "arm64: Initialize jump labels before setup_machine_fdt()"
parents cc2fb31d c50f11c6

arch/arm64/kernel/cpufeature.c

+0 −1
Original line number Diff line number Diff line
@@ -3101,7 +3101,6 @@ void cpu_set_feature(unsigned int num) 
	WARN_ON(num >= MAX_CPU_FEATURES);

	elf_hwcap |= BIT(num);

}

EXPORT_SYMBOL_GPL(cpu_set_feature);



bool cpu_have_feature(unsigned int num)

{

arch/arm64/kernel/entry-ftrace.S

+0 −1
Original line number Diff line number Diff line
@@ -102,7 +102,6 @@ SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) 
 * x19-x29 per the AAPCS, and we created frame records upon entry, so we need

 * to restore x0-x8, x29, and x30.

 */

ftrace_common_return:

	/* Restore function arguments */

	ldp	x0, x1, [sp]

	ldp	x2, x3, [sp, #S_X2]

arch/arm64/kernel/ftrace.c

+66 −71
Original line number Diff line number Diff line
@@ -78,47 +78,76 @@ static struct plt_entry *get_ftrace_plt(struct module *mod, unsigned long addr) 
}



/*

 * Turn on the call to ftrace_caller() in instrumented function

 * Find the address the callsite must branch to in order to reach '*addr'.

 *

 * Due to the limited range of 'BL' instructions, modules may be placed too far

 * away to branch directly and must use a PLT.

 *

 * Returns true when '*addr' contains a reachable target address, or has been

 * modified to contain a PLT address. Returns false otherwise.

 */

int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

static bool ftrace_find_callable_addr(struct dyn_ftrace *rec,

				      struct module *mod,

				      unsigned long *addr)

{

	unsigned long pc = rec->ip;

	u32 old, new;

	long offset = (long)pc - (long)addr;



	if (offset < -SZ_128M || offset >= SZ_128M) {

		struct module *mod;

	long offset = (long)*addr - (long)pc;

	struct plt_entry *plt;



	/*

	 * When the target is within range of the 'BL' instruction, use 'addr'

	 * as-is and branch to that directly.

	 */

	if (offset >= -SZ_128M && offset < SZ_128M)

		return true;



	/*

	 * When the target is outside of the range of a 'BL' instruction, we

	 * must use a PLT to reach it. We can only place PLTs for modules, and

	 * only when module PLT support is built-in.

	 */

	if (!IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))

			return -EINVAL;

		return false;



	/*

		 * On kernels that support module PLTs, the offset between the

		 * branch instruction and its target may legally exceed the

		 * range of an ordinary relative 'bl' opcode. In this case, we

		 * need to branch via a trampoline in the module.

	 * 'mod' is only set at module load time, but if we end up

	 * dealing with an out-of-range condition, we can assume it

	 * is due to a module being loaded far away from the kernel.

	 *

	 * NOTE: __module_text_address() must be called with preemption

	 * disabled, but we can rely on ftrace_lock to ensure that 'mod'

	 * retains its validity throughout the remainder of this code.

	 */

	if (!mod) {

		preempt_disable();

		mod = __module_text_address(pc);

		preempt_enable();

	}



	if (WARN_ON(!mod))

			return -EINVAL;

		return false;



		plt = get_ftrace_plt(mod, addr);

	plt = get_ftrace_plt(mod, *addr);

	if (!plt) {

			pr_err("ftrace: no module PLT for %ps\n", (void *)addr);

			return -EINVAL;

		pr_err("ftrace: no module PLT for %ps\n", (void *)*addr);

		return false;

	}



		addr = (unsigned long)plt;

	*addr = (unsigned long)plt;

	return true;

}



/*

 * Turn on the call to ftrace_caller() in instrumented function

 */

int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)

{

	unsigned long pc = rec->ip;

	u32 old, new;



	if (!ftrace_find_callable_addr(rec, NULL, &addr))

		return -EINVAL;



	old = aarch64_insn_gen_nop();

	new = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK);
@@ -132,6 +161,11 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, 
	unsigned long pc = rec->ip;

	u32 old, new;



	if (!ftrace_find_callable_addr(rec, NULL, &old_addr))

		return -EINVAL;

	if (!ftrace_find_callable_addr(rec, NULL, &addr))

		return -EINVAL;



	old = aarch64_insn_gen_branch_imm(pc, old_addr,

					  AARCH64_INSN_BRANCH_LINK);

	new = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK);
@@ -181,54 +215,15 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec, 
		    unsigned long addr)

{

	unsigned long pc = rec->ip;

	bool validate = true;

	u32 old = 0, new;

	long offset = (long)pc - (long)addr;



	if (offset < -SZ_128M || offset >= SZ_128M) {

		u32 replaced;



		if (!IS_ENABLED(CONFIG_ARM64_MODULE_PLTS))

			return -EINVAL;



		/*

		 * 'mod' is only set at module load time, but if we end up

		 * dealing with an out-of-range condition, we can assume it

		 * is due to a module being loaded far away from the kernel.

		 */

		if (!mod) {

			preempt_disable();

			mod = __module_text_address(pc);

			preempt_enable();



			if (WARN_ON(!mod))

	if (!ftrace_find_callable_addr(rec, mod, &addr))

		return -EINVAL;

		}



		/*

		 * The instruction we are about to patch may be a branch and

		 * link instruction that was redirected via a PLT entry. In

		 * this case, the normal validation will fail, but we can at

		 * least check that we are dealing with a branch and link

		 * instruction that points into the right module.

		 */

		if (aarch64_insn_read((void *)pc, &replaced))

			return -EFAULT;



		if (!aarch64_insn_is_bl(replaced) ||

		    !within_module(pc + aarch64_get_branch_offset(replaced),

				   mod))

			return -EINVAL;



		validate = false;

	} else {

		old = aarch64_insn_gen_branch_imm(pc, addr,

						  AARCH64_INSN_BRANCH_LINK);

	}



	old = aarch64_insn_gen_branch_imm(pc, addr, AARCH64_INSN_BRANCH_LINK);

	new = aarch64_insn_gen_nop();



	return ftrace_modify_code(pc, old, new, validate);

	return ftrace_modify_code(pc, old, new, true);

}



void arch_ftrace_update_code(int command)

arch/arm64/kernel/setup.c

+3 −4
Original line number Diff line number Diff line
@@ -303,14 +303,13 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p) 
	early_fixmap_init();

	early_ioremap_init();



	setup_machine_fdt(__fdt_pointer);



	/*

	 * Initialise the static keys early as they may be enabled by the

	 * cpufeature code, early parameters, and DT setup.

	 * cpufeature code and early parameters.

	 */

	jump_label_init();



	setup_machine_fdt(__fdt_pointer);



	parse_early_param();



	/*

arch/arm64/mm/cache.S

+0 −2
Original line number Diff line number Diff line
@@ -218,8 +218,6 @@ SYM_FUNC_ALIAS(__dma_flush_area, __pi___dma_flush_area) 
 */

SYM_FUNC_START(__pi___dma_map_area)

	add	x1, x0, x1

	cmp	w2, #DMA_FROM_DEVICE

	b.eq	__pi_dcache_inval_poc

	b	__pi_dcache_clean_poc

SYM_FUNC_END(__pi___dma_map_area)

SYM_FUNC_ALIAS(__dma_map_area, __pi___dma_map_area)