From: Jiang Liu <jiang....@huawei.com> Introduce aarch64_insn_gen_{nop|branch_imm}() helper functions, which will be used to implement jump label on ARM64.
Signed-off-by: Jiang Liu <jiang....@huawei.com> Cc: Jiang Liu <liu...@gmail.com> --- Fix a bug in comparing signed and unsigned value, it should be if (abs(offset) > BIT(25) || offset == BIT(25)) { instead of if (offset >= BIT(25) || abs(offset) > BIT(25)) { --- arch/arm64/include/asm/insn.h | 7 +++++++ arch/arm64/kernel/insn.c | 27 +++++++++++++++++++++++++++ 2 files changed, 34 insertions(+) diff --git a/arch/arm64/include/asm/insn.h b/arch/arm64/include/asm/insn.h index 8dc0a91..87c44b2 100644 --- a/arch/arm64/include/asm/insn.h +++ b/arch/arm64/include/asm/insn.h @@ -61,6 +61,13 @@ __AARCH64_INSN_FUNCS(nop, 0xFFFFFFFF, 0xD503201F) enum aarch64_insn_class aarch64_get_insn_class(u32 insn); u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, u32 insn, u64 imm); +u32 aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr, + bool link); +static __always_inline u32 aarch64_insn_gen_nop(void) +{ + return aarch64_insn_get_nop_value(); +} + u32 aarch64_insn_read(void *addr); void aarch64_insn_write(void *addr, u32 insn); bool aarch64_insn_hotpatch_safe(u32 old_insn, u32 new_insn); diff --git a/arch/arm64/kernel/insn.c b/arch/arm64/kernel/insn.c index a0f60cc..4d838cc 100644 --- a/arch/arm64/kernel/insn.c +++ b/arch/arm64/kernel/insn.c @@ -14,6 +14,7 @@ * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/bitops.h> #include <linux/kernel.h> #include <linux/stop_machine.h> #include <asm/cacheflush.h> @@ -261,3 +262,29 @@ u32 aarch64_insn_encode_immediate(enum aarch64_insn_imm_type type, return insn; } + +u32 aarch64_insn_gen_branch_imm(unsigned long pc, unsigned long addr, bool link) +{ + u32 insn; + long offset; + + /* + * PC: A 64-bit Program Counter holding the address of the current + * instruction. A64 instructions may be word-aligned. + */ + BUG_ON((pc & 0x3) || (addr & 0x3)); + + /* B/BR support [-128M, 128M) offset */ + offset = ((long)addr - (long)pc) >> 2; + if (abs(offset) > BIT(25) || offset == BIT(25)) { + WARN_ON_ONCE(1); + return 0; + } + + if (link) + insn = aarch64_insn_get_bl_value(); + else + insn = aarch64_insn_get_b_value(); + + return aarch64_insn_encode_immediate(AARCH64_INSN_IMM_26, insn, offset); +} -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/