[RFC PATCH V3 16/43] rv64ilp32_abi: riscv: Support physical addresses >= 0x80000000
From: guoren@kernel.org
Date: 2025-03-25 12:20:34
Also in:
bpf, kvm, kvm-riscv, linux-arch, linux-btrfs, linux-crypto, linux-fsdevel, linux-input, linux-media, linux-mm, linux-nfs, linux-perf-users, linux-riscv, linux-sctp, linux-serial, linux-usb, lkml, netdev, netfilter-devel
Subsystem:
risc-v architecture, the rest · Maintainers:
Paul Walmsley, Palmer Dabbelt, Albert Ou, Linus Torvalds
From: "Guo Ren (Alibaba DAMO Academy)" <guoren@kernel.org> The RV64ILP32 ABI has two independent 2GiB address space: - 0 ~ 0x7fffffff - 0xffffffff80000000 ~ 0xffffffffffffffff In the rv64ilp32 ABI, 0x80000000 is illegal; hence, use a temporary trap handler to zero-extend the address for jalr, load and store operations. Signed-off-by: Guo Ren (Alibaba DAMO Academy) <guoren@kernel.org> --- arch/riscv/kernel/head.S | 112 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 112 insertions(+)
diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index e55a92be12b1..bd2f30aa6d01 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S@@ -170,6 +170,118 @@ secondary_start_sbi: .align 2 .Lsecondary_park: +#ifdef CONFIG_ABI_RV64ILP32 +.option push +.option norelax +.option norvc + addiw sp, sp, -32 + + /* zext.w sp */ + slli sp, sp, 32 + srli sp, sp, 32 + + /* zext.w ra */ + slli ra, ra, 32 + srli ra, ra, 32 + + /* zext.w fp */ + slli fp, fp, 32 + srli fp, fp, 32 + + /* zext.w tp */ + slli tp, tp, 32 + srli tp, tp, 32 + + /* save tmp reg */ + REG_S ra, 24(sp) + REG_S fp, 16(sp) + REG_S tp, 8(sp) + REG_S gp, 0(sp) + + /* zext.w epc */ + csrr ra, CSR_EPC + slli ra, ra, 32 + srli ra, ra, 32 + csrw CSR_SEPC, ra + + csrr gp, CSR_CAUSE + + /* EXC_INST_ACCESS */ + addiw fp, gp, -1 + beqz fp, 6f + + /* EXC_LOAD_ACCESS */ + addiw fp, gp, -5 + beqz fp, 1f + + /* EXC_STORE_ACCESS */ + addiw fp, gp, -7 + beqz fp, 1f + + j 7f +1: + /* get inst */ + lw ra, 0(ra) + andi gp, ra, 0x3 + + /* c.(lw/sw/ld/sd)sp */ + addiw fp, gp, -2 + beqz fp, 6f + + /* lw/sw/ld/sd */ + addiw fp, gp, -3 + beqz fp, 2f + + /* c.(lw/sw/ld/sd) */ + li fp, 0x7 + slli fp, fp, 7 + and ra, fp, ra + slli ra, ra, 8 + j 3f + +2: + /* get rs1 */ + li fp, 0x1f + slli fp, fp, 15 + and ra, fp, ra + +3: + /* copy rs1 to rd */ + mv fp, ra + srli fp, fp, 8 + or ra, fp, ra + + /* modify slli */ + la fp, 4f + lw tp, 0(fp) + mv gp, tp + or tp, ra, tp + sw tp, 0(fp) + fence.i +4: slli x0, x0, 32 + sw gp, 0(fp) + + /* modify srli */ + la fp, 5f + lw tp, 0(fp) + mv gp, tp + or tp, ra, tp + sw tp, 0(fp) + fence.i +5: srli x0, x0, 32 + sw gp, 0(fp) + +6: + /* restore tmp reg */ + REG_L ra, 24(sp) + REG_L fp, 16(sp) + REG_L tp, 8(sp) + REG_L gp, 0(sp) + addi sp, sp, 32 + sret +.option pop +7: +#endif /* * Park this hart if we: * - have too many harts on CONFIG_RISCV_BOOT_SPINWAIT
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2.40.1