s390/jump label: use different nop instruction (d5caa4db) · Commits · 戴 / test

arch/s390/include/asm/jump_label.h

+6 −1

Original line number	Diff line number	Diff line
		@@ -4,6 +4,7 @@
		#include <linux/types.h>

		#define JUMP_LABEL_NOP_SIZE 6
		#define JUMP_LABEL_NOP_OFFSET 2

		#ifdef CONFIG_64BIT
		#define ASM_PTR ".quad"
		@@ -13,9 +14,13 @@
		#define ASM_ALIGN ".balign 4"
		#endif

		/*
		* We use a brcl 0,2 instruction for jump labels at compile time so it
		* can be easily distinguished from a hotpatch generated instruction.
		*/
		static __always_inline bool arch_static_branch(struct static_key *key)
		{
		asm_volatile_goto("0: brcl 0,0\n"
		asm_volatile_goto("0: brcl 0,"__stringify(JUMP_LABEL_NOP_OFFSET)"\n"
		".pushsection __jump_table, \"aw\"\n"
		ASM_ALIGN "\n"
		ASM_PTR " 0b, %l[label], %0\n"

+13 −6

Original line number	Diff line number	Diff line
		@@ -49,6 +49,11 @@ static void jump_label_bug(struct jump_entry entry, struct insn insn)
		panic("Corrupted kernel text");
		}

		static struct insn orignop = {
		.opcode = 0xc004,
		.offset = JUMP_LABEL_NOP_OFFSET >> 1,
		};

		static void __jump_label_transform(struct jump_entry *entry,
		enum jump_label_type type,
		int init)
		@@ -59,14 +64,16 @@ static void __jump_label_transform(struct jump_entry *entry,
		jump_label_make_nop(entry, &old);
		jump_label_make_branch(entry, &new);
		} else {
		if (init)
		jump_label_make_nop(entry, &old);
		else
		jump_label_make_branch(entry, &old);
		jump_label_make_nop(entry, &new);
		}
		if (init) {
		if (memcmp((void *)entry->code, &orignop, sizeof(orignop)))
		jump_label_bug(entry, &old);
		} else {
		if (memcmp((void *)entry->code, &old, sizeof(old)))
		jump_label_bug(entry, &old);
		}
		probe_kernel_write((void *)entry->code, &new, sizeof(new));
		}