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author | Tiezhu Yang <yangtiezhu@loongson.cn> | 2023-02-25 15:52:57 +0800 |
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committer | Huacai Chen <chenhuacai@loongson.cn> | 2023-02-25 22:12:17 +0800 |
commit | 9b3441a6b0e1ed4796e7f5a8586c4d6023c4e3ab (patch) | |
tree | 6797eb04b76a2228e91a75c5e83e6e7564d1e140 /arch/loongarch/kernel/inst.c | |
parent | 424421a7f34c1222d20a6c279f13b9caa71ecc83 (diff) | |
download | linux-stable-9b3441a6b0e1ed4796e7f5a8586c4d6023c4e3ab.tar.gz linux-stable-9b3441a6b0e1ed4796e7f5a8586c4d6023c4e3ab.tar.bz2 linux-stable-9b3441a6b0e1ed4796e7f5a8586c4d6023c4e3ab.zip |
LoongArch: Simulate branch and PC* instructions
According to LoongArch Reference Manual, simulate branch and PC*
instructions, this is preparation for later patch.
Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#branch-instructions
Link: https://loongson.github.io/LoongArch-Documentation/LoongArch-Vol1-EN.html#_pcaddi_pcaddu121_pcaddu18l_pcalau12i
Tested-by: Jeff Xie <xiehuan09@gmail.com>
Co-developed-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Jinyang He <hejinyang@loongson.cn>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Diffstat (limited to 'arch/loongarch/kernel/inst.c')
-rw-r--r-- | arch/loongarch/kernel/inst.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/inst.c b/arch/loongarch/kernel/inst.c index badc59087042..258ef267cd30 100644 --- a/arch/loongarch/kernel/inst.c +++ b/arch/loongarch/kernel/inst.c @@ -10,6 +10,129 @@ static DEFINE_RAW_SPINLOCK(patch_lock); +void simu_pc(struct pt_regs *regs, union loongarch_instruction insn) +{ + unsigned long pc = regs->csr_era; + unsigned int rd = insn.reg1i20_format.rd; + unsigned int imm = insn.reg1i20_format.immediate; + + if (pc & 3) { + pr_warn("%s: invalid pc 0x%lx\n", __func__, pc); + return; + } + + switch (insn.reg1i20_format.opcode) { + case pcaddi_op: + regs->regs[rd] = pc + sign_extend64(imm << 2, 21); + break; + case pcaddu12i_op: + regs->regs[rd] = pc + sign_extend64(imm << 12, 31); + break; + case pcaddu18i_op: + regs->regs[rd] = pc + sign_extend64(imm << 18, 37); + break; + case pcalau12i_op: + regs->regs[rd] = pc + sign_extend64(imm << 12, 31); + regs->regs[rd] &= ~((1 << 12) - 1); + break; + default: + pr_info("%s: unknown opcode\n", __func__); + return; + } + + regs->csr_era += LOONGARCH_INSN_SIZE; +} + +void simu_branch(struct pt_regs *regs, union loongarch_instruction insn) +{ + unsigned int imm, imm_l, imm_h, rd, rj; + unsigned long pc = regs->csr_era; + + if (pc & 3) { + pr_warn("%s: invalid pc 0x%lx\n", __func__, pc); + return; + } + + imm_l = insn.reg0i26_format.immediate_l; + imm_h = insn.reg0i26_format.immediate_h; + switch (insn.reg0i26_format.opcode) { + case b_op: + regs->csr_era = pc + sign_extend64((imm_h << 16 | imm_l) << 2, 27); + return; + case bl_op: + regs->csr_era = pc + sign_extend64((imm_h << 16 | imm_l) << 2, 27); + regs->regs[1] = pc + LOONGARCH_INSN_SIZE; + return; + } + + imm_l = insn.reg1i21_format.immediate_l; + imm_h = insn.reg1i21_format.immediate_h; + rj = insn.reg1i21_format.rj; + switch (insn.reg1i21_format.opcode) { + case beqz_op: + if (regs->regs[rj] == 0) + regs->csr_era = pc + sign_extend64((imm_h << 16 | imm_l) << 2, 22); + else + regs->csr_era = pc + LOONGARCH_INSN_SIZE; + return; + case bnez_op: + if (regs->regs[rj] != 0) + regs->csr_era = pc + sign_extend64((imm_h << 16 | imm_l) << 2, 22); + else + regs->csr_era = pc + LOONGARCH_INSN_SIZE; + return; + } + + imm = insn.reg2i16_format.immediate; + rj = insn.reg2i16_format.rj; + rd = insn.reg2i16_format.rd; + switch (insn.reg2i16_format.opcode) { + case beq_op: + if (regs->regs[rj] == regs->regs[rd]) + regs->csr_era = pc + sign_extend64(imm << 2, 17); + else + regs->csr_era = pc + LOONGARCH_INSN_SIZE; + break; + case bne_op: + if (regs->regs[rj] != regs->regs[rd]) + regs->csr_era = pc + sign_extend64(imm << 2, 17); + else + regs->csr_era = pc + LOONGARCH_INSN_SIZE; + break; + case blt_op: + if ((long)regs->regs[rj] < (long)regs->regs[rd]) + regs->csr_era = pc + sign_extend64(imm << 2, 17); + else + regs->csr_era = pc + LOONGARCH_INSN_SIZE; + break; + case bge_op: + if ((long)regs->regs[rj] >= (long)regs->regs[rd]) + regs->csr_era = pc + sign_extend64(imm << 2, 17); + else + regs->csr_era = pc + LOONGARCH_INSN_SIZE; + break; + case bltu_op: + if (regs->regs[rj] < regs->regs[rd]) + regs->csr_era = pc + sign_extend64(imm << 2, 17); + else + regs->csr_era = pc + LOONGARCH_INSN_SIZE; + break; + case bgeu_op: + if (regs->regs[rj] >= regs->regs[rd]) + regs->csr_era = pc + sign_extend64(imm << 2, 17); + else + regs->csr_era = pc + LOONGARCH_INSN_SIZE; + break; + case jirl_op: + regs->csr_era = regs->regs[rj] + sign_extend64(imm << 2, 17); + regs->regs[rd] = pc + LOONGARCH_INSN_SIZE; + break; + default: + pr_info("%s: unknown opcode\n", __func__); + return; + } +} + int larch_insn_read(void *addr, u32 *insnp) { int ret; |