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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_ARC_JUMP_LABEL_H
#define _ASM_ARC_JUMP_LABEL_H
#ifndef __ASSEMBLY__
#include <linux/stringify.h>
#include <linux/types.h>
#define JUMP_LABEL_NOP_SIZE 4
/*
* NOTE about '.balign 4':
*
* To make atomic update of patched instruction available we need to guarantee
* that this instruction doesn't cross L1 cache line boundary.
*
* As of today we simply align instruction which can be patched by 4 byte using
* ".balign 4" directive. In that case patched instruction is aligned with one
* 16-bit NOP_S if this is required.
* However 'align by 4' directive is much stricter than it actually required.
* It's enough that our 32-bit instruction don't cross L1 cache line boundary /
* L1 I$ fetch block boundary which can be achieved by using
* ".bundle_align_mode" assembler directive. That will save us from adding
* useless NOP_S padding in most of the cases.
*
* TODO: switch to ".bundle_align_mode" directive using whin it will be
* supported by ARC toolchain.
*/
static __always_inline bool arch_static_branch(struct static_key *key,
bool branch)
{
asm goto(".balign "__stringify(JUMP_LABEL_NOP_SIZE)" \n"
"1: \n"
"nop \n"
".pushsection __jump_table, \"aw\" \n"
".word 1b, %l[l_yes], %c0 \n"
".popsection \n"
: : "i" (&((char *)key)[branch]) : : l_yes);
return false;
l_yes:
return true;
}
static __always_inline bool arch_static_branch_jump(struct static_key *key,
bool branch)
{
asm goto(".balign "__stringify(JUMP_LABEL_NOP_SIZE)" \n"
"1: \n"
"b %l[l_yes] \n"
".pushsection __jump_table, \"aw\" \n"
".word 1b, %l[l_yes], %c0 \n"
".popsection \n"
: : "i" (&((char *)key)[branch]) : : l_yes);
return false;
l_yes:
return true;
}
typedef u32 jump_label_t;
struct jump_entry {
jump_label_t code;
jump_label_t target;
jump_label_t key;
};
#endif /* __ASSEMBLY__ */
#endif
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