[PATCH 06/10] RISC-V: Refactor patch instructions

From: Charlie Jenkins
Date: Thu Aug 03 2023 - 22:12:30 EST

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Use shared instruction definitions in insn.h.

Signed-off-by: Charlie Jenkins <charlie@xxxxxxxxxxxx>
---
arch/riscv/kernel/patch.c | 3 +-
arch/riscv/kernel/probes/kprobes.c | 13 +++----
arch/riscv/kernel/probes/simulate-insn.c | 61 +++++++-------------------------
arch/riscv/kernel/probes/uprobes.c | 5 +--
4 files changed, 25 insertions(+), 57 deletions(-)

diff --git a/arch/riscv/kernel/patch.c b/arch/riscv/kernel/patch.c
index 575e71d6c8ae..df51f5155673 100644
--- a/arch/riscv/kernel/patch.c
+++ b/arch/riscv/kernel/patch.c
@@ -12,6 +12,7 @@
#include <asm/cacheflush.h>
#include <asm/fixmap.h>
#include <asm/ftrace.h>
+#include <asm/insn.h>
#include <asm/patch.h>

struct patch_insn {
@@ -118,7 +119,7 @@ static int patch_text_cb(void *data)

if (atomic_inc_return(&patch->cpu_count) == num_online_cpus()) {
for (i = 0; ret == 0 && i < patch->ninsns; i++) {
- len = GET_INSN_LENGTH(patch->insns[i]);
+ len = INSN_LEN(patch->insns[i]);
ret = patch_text_nosync(patch->addr + i * len,
&patch->insns[i], len);
}
diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index 2f08c14a933d..501c6ae4d803 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -12,6 +12,7 @@
#include <asm/cacheflush.h>
#include <asm/bug.h>
#include <asm/patch.h>
+#include <asm/insn.h>

#include "decode-insn.h"

@@ -24,7 +25,7 @@ post_kprobe_handler(struct kprobe *, struct kprobe_ctlblk *, struct pt_regs *);
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
{
u32 insn = __BUG_INSN_32;
- unsigned long offset = GET_INSN_LENGTH(p->opcode);
+ unsigned long offset = INSN_LEN(p->opcode);

p->ainsn.api.restore = (unsigned long)p->addr + offset;

@@ -58,7 +59,7 @@ static bool __kprobes arch_check_kprobe(struct kprobe *p)
if (tmp == addr)
return true;

- tmp += GET_INSN_LENGTH(*(u16 *)tmp);
+ tmp += INSN_LEN(*(u16 *)tmp);
}

return false;
@@ -76,7 +77,7 @@ int __kprobes arch_prepare_kprobe(struct kprobe *p)

/* copy instruction */
p->opcode = (kprobe_opcode_t)(*insn++);
- if (GET_INSN_LENGTH(p->opcode) == 4)
+ if (INSN_LEN(p->opcode) == 4)
p->opcode |= (kprobe_opcode_t)(*insn) << 16;

/* decode instruction */
@@ -117,8 +118,8 @@ void *alloc_insn_page(void)
/* install breakpoint in text */
void __kprobes arch_arm_kprobe(struct kprobe *p)
{
- u32 insn = (p->opcode & __INSN_LENGTH_MASK) == __INSN_LENGTH_32 ?
- __BUG_INSN_32 : __BUG_INSN_16;
+ u32 insn = INSN_IS_C(p->opcode) ?
+ __BUG_INSN_16 : __BUG_INSN_32;

patch_text(p->addr, &insn, 1);
}
@@ -344,7 +345,7 @@ kprobe_single_step_handler(struct pt_regs *regs)
struct kprobe *cur = kprobe_running();

if (cur && (kcb->kprobe_status & (KPROBE_HIT_SS | KPROBE_REENTER)) &&
- ((unsigned long)&cur->ainsn.api.insn[0] + GET_INSN_LENGTH(cur->opcode) == addr)) {
+ ((unsigned long)&cur->ainsn.api.insn[0] + INSN_LEN(cur->opcode) == addr)) {
kprobes_restore_local_irqflag(kcb, regs);
post_kprobe_handler(cur, kcb, regs);
return true;
diff --git a/arch/riscv/kernel/probes/simulate-insn.c b/arch/riscv/kernel/probes/simulate-insn.c
index 994edb4bd16a..f9671bb864a3 100644
--- a/arch/riscv/kernel/probes/simulate-insn.c
+++ b/arch/riscv/kernel/probes/simulate-insn.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0+

+#include <asm/insn.h>
#include <asm/reg.h>
#include <linux/bitops.h>
#include <linux/kernel.h>
@@ -16,19 +17,16 @@ bool __kprobes simulate_jal(u32 opcode, unsigned long addr, struct pt_regs *regs
* 1 10 1 8 5 JAL/J
*/
bool ret;
- u32 imm;
- u32 index = (opcode >> 7) & 0x1f;
+ s32 imm;
+ u32 index = riscv_insn_extract_rd(opcode);

ret = rv_insn_reg_set_val((unsigned long *)regs, index, addr + 4);
if (!ret)
return ret;

- imm = ((opcode >> 21) & 0x3ff) << 1;
- imm |= ((opcode >> 20) & 0x1) << 11;
- imm |= ((opcode >> 12) & 0xff) << 12;
- imm |= ((opcode >> 31) & 0x1) << 20;
+ imm = riscv_insn_extract_jtype_imm(opcode);

- instruction_pointer_set(regs, addr + sign_extend32((imm), 20));
+ instruction_pointer_set(regs, addr + imm);

return ret;
}
@@ -42,9 +40,9 @@ bool __kprobes simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *reg
*/
bool ret;
unsigned long base_addr;
- u32 imm = (opcode >> 20) & 0xfff;
- u32 rd_index = (opcode >> 7) & 0x1f;
- u32 rs1_index = (opcode >> 15) & 0x1f;
+ s32 imm = riscv_insn_extract_itype_imm(opcode);
+ u32 rd_index = riscv_insn_extract_rd(opcode);
+ u32 rs1_index = riscv_insn_extract_rs1(opcode);

ret = rv_insn_reg_get_val((unsigned long *)regs, rs1_index, &base_addr);
if (!ret)
@@ -54,25 +52,11 @@ bool __kprobes simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *reg
if (!ret)
return ret;

- instruction_pointer_set(regs, (base_addr + sign_extend32((imm), 11))&~1);
+ instruction_pointer_set(regs, (base_addr + imm) & ~1);

return ret;
}

-#define auipc_rd_idx(opcode) \
- ((opcode >> 7) & 0x1f)
-
-#define auipc_imm(opcode) \
- ((((opcode) >> 12) & 0xfffff) << 12)
-
-#if __riscv_xlen == 64
-#define auipc_offset(opcode) sign_extend64(auipc_imm(opcode), 31)
-#elif __riscv_xlen == 32
-#define auipc_offset(opcode) auipc_imm(opcode)
-#else
-#error "Unexpected __riscv_xlen"
-#endif
-
bool __kprobes simulate_auipc(u32 opcode, unsigned long addr, struct pt_regs *regs)
{
/*
@@ -82,35 +66,16 @@ bool __kprobes simulate_auipc(u32 opcode, unsigned long addr, struct pt_regs *re
* 20 5 7
*/

- u32 rd_idx = auipc_rd_idx(opcode);
- unsigned long rd_val = addr + auipc_offset(opcode);
+ u32 rd_idx = riscv_insn_extract_rd(opcode);
+ unsigned long rd_val = addr + riscv_insn_extract_utype_imm(opcode);

if (!rv_insn_reg_set_val((unsigned long *)regs, rd_idx, rd_val))
return false;

instruction_pointer_set(regs, addr + 4);
-
return true;
}

-#define branch_rs1_idx(opcode) \
- (((opcode) >> 15) & 0x1f)
-
-#define branch_rs2_idx(opcode) \
- (((opcode) >> 20) & 0x1f)
-
-#define branch_funct3(opcode) \
- (((opcode) >> 12) & 0x7)
-
-#define branch_imm(opcode) \
- (((((opcode) >> 8) & 0xf ) << 1) | \
- ((((opcode) >> 25) & 0x3f) << 5) | \
- ((((opcode) >> 7) & 0x1 ) << 11) | \
- ((((opcode) >> 31) & 0x1 ) << 12))
-
-#define branch_offset(opcode) \
- sign_extend32((branch_imm(opcode)), 12)
-
bool __kprobes simulate_branch(u32 opcode, unsigned long addr, struct pt_regs *regs)
{
/*
@@ -135,8 +100,8 @@ bool __kprobes simulate_branch(u32 opcode, unsigned long addr, struct pt_regs *r
!rv_insn_reg_get_val((unsigned long *)regs, riscv_insn_extract_rs2(opcode), &rs2_val))
return false;

- offset_tmp = branch_offset(opcode);
- switch (branch_funct3(opcode)) {
+ offset_tmp = riscv_insn_extract_btype_imm(opcode);
+ switch (riscv_insn_extract_funct3(opcode)) {
case RVG_FUNCT3_BEQ:
offset = (rs1_val == rs2_val) ? offset_tmp : 4;
break;
diff --git a/arch/riscv/kernel/probes/uprobes.c b/arch/riscv/kernel/probes/uprobes.c
index 194f166b2cc4..f2511cbaf931 100644
--- a/arch/riscv/kernel/probes/uprobes.c
+++ b/arch/riscv/kernel/probes/uprobes.c
@@ -1,5 +1,6 @@
// SPDX-License-Identifier: GPL-2.0-only

+#include <asm/insn.h>
#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/uprobes.h>
@@ -29,7 +30,7 @@ int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm,

opcode = *(probe_opcode_t *)(&auprobe->insn[0]);

- auprobe->insn_size = GET_INSN_LENGTH(opcode);
+ auprobe->insn_size = INSN_LEN(opcode);

switch (riscv_probe_decode_insn(&opcode, &auprobe->api)) {
case INSN_REJECTED:
@@ -166,7 +167,7 @@ void arch_uprobe_copy_ixol(struct page *page, unsigned long vaddr,

/* Add ebreak behind opcode to simulate singlestep */
if (vaddr) {
- dst += GET_INSN_LENGTH(*(probe_opcode_t *)src);
+ dst += INSN_LEN(*(probe_opcode_t *)src);
*(uprobe_opcode_t *)dst = __BUG_INSN_32;
}

--
2.34.1

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