Commit fa5e5dc3 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

jump_label, x86: Introduce jump_entry_size() 



This allows architectures to have variable sized jumps.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210506194157.786777050@infradead.org
parent f9510fa9

arch/x86/include/asm/jump_label.h

+2 −2
Original line number Diff line number Diff line
@@ -4,8 +4,6 @@ 


#define HAVE_JUMP_LABEL_BATCH



#define JUMP_LABEL_NOP_SIZE 5



#include <asm/asm.h>

#include <asm/nops.h>
@@ -47,6 +45,8 @@ static __always_inline bool arch_static_branch_jump(struct static_key * const ke 
	return true;

}



extern int arch_jump_entry_size(struct jump_entry *entry);



#endif	/* __ASSEMBLY__ */



#endif

arch/x86/kernel/jump_label.c

+7 −0
Original line number Diff line number Diff line
@@ -16,6 +16,13 @@ 
#include <asm/alternative.h>

#include <asm/text-patching.h>



#define JUMP_LABEL_NOP_SIZE	JMP32_INSN_SIZE



int arch_jump_entry_size(struct jump_entry *entry)

{

	return JMP32_INSN_SIZE;

}



static const void *

__jump_label_set_jump_code(struct jump_entry *entry, enum jump_label_type type)

{

include/linux/jump_label.h

+9 −0
Original line number Diff line number Diff line
@@ -176,6 +176,15 @@ static inline void jump_entry_set_init(struct jump_entry *entry) 
	entry->key |= 2;

}



static inline int jump_entry_size(struct jump_entry *entry)

{

#ifdef JUMP_LABEL_NOP_SIZE

	return JUMP_LABEL_NOP_SIZE;

#else

	return arch_jump_entry_size(entry);

#endif

}



#endif

#endif

kernel/jump_label.c

+1 −1
Original line number Diff line number Diff line
@@ -309,7 +309,7 @@ EXPORT_SYMBOL_GPL(jump_label_rate_limit); 
static int addr_conflict(struct jump_entry *entry, void *start, void *end)

{

	if (jump_entry_code(entry) <= (unsigned long)end &&

	    jump_entry_code(entry) + JUMP_LABEL_NOP_SIZE > (unsigned long)start)

	    jump_entry_code(entry) + jump_entry_size(entry) > (unsigned long)start)

		return 1;



	return 0;