[PATCH v1 5/7] riscv: Use asm/insn.h to generate plt entries

Emil Renner Berthing kernel at esmil.dk
Mon Jan 31 10:21:43 PST 2022


This converts kernel/module-sections.c to use asm/insn.h to generate
the instructions in the plt entries.

Signed-off-by: Emil Renner Berthing <kernel at esmil.dk>
---
 arch/riscv/kernel/module-sections.c | 27 ++++-----------------------
 1 file changed, 4 insertions(+), 23 deletions(-)

diff --git a/arch/riscv/kernel/module-sections.c b/arch/riscv/kernel/module-sections.c
index 39d4ac681c2a..cb73399c3603 100644
--- a/arch/riscv/kernel/module-sections.c
+++ b/arch/riscv/kernel/module-sections.c
@@ -9,6 +9,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleloader.h>
+#include <asm/insn.h>
 
 struct got_entry {
 	unsigned long symbol_addr;	/* the real variable address */
@@ -61,36 +62,16 @@ struct plt_entry {
 	u32 insn_jr;		/* jr    t1                            */
 };
 
-#define OPC_AUIPC  0x0017
-#define OPC_LD     0x3003
-#define OPC_JALR   0x0067
-#define REG_T0     0x5
-#define REG_T1     0x6
-
 static struct plt_entry emit_plt_entry(unsigned long val,
 				       unsigned long plt,
 				       unsigned long got_plt)
 {
-	/*
-	 * U-Type encoding:
-	 * +------------+----------+----------+
-	 * | imm[31:12] | rd[11:7] | opc[6:0] |
-	 * +------------+----------+----------+
-	 *
-	 * I-Type encoding:
-	 * +------------+------------+--------+----------+----------+
-	 * | imm[31:20] | rs1[19:15] | funct3 | rd[11:7] | opc[6:0] |
-	 * +------------+------------+--------+----------+----------+
-	 *
-	 */
 	unsigned long offset = got_plt - plt;
-	u32 hi20 = (offset + 0x800) & 0xfffff000;
-	u32 lo12 = (offset - hi20);
 
 	return (struct plt_entry) {
-		OPC_AUIPC | (REG_T0 << 7) | hi20,
-		OPC_LD | (lo12 << 20) | (REG_T0 << 15) | (REG_T1 << 7),
-		OPC_JALR | (REG_T1 << 15)
+		RISCV_INSN_AUIPC | RISCV_INSN_RD_T0 | riscv_insn_u_imm(offset + 0x800),
+		RISCV_INSN_LD    | RISCV_INSN_RD_T1 | RISCV_INSN_RS1_T0 | riscv_insn_i_imm(offset),
+		RISCV_INSN_JALR  | RISCV_INSN_RS1_T1,
 	};
 }
 
-- 
2.35.1




More information about the linux-riscv mailing list