[PATCH v6 23/28] powerpc: Add prefixed instructions to instruction data type
Jordan Niethe
jniethe5 at gmail.com
Tue Apr 28 11:58:09 AEST 2020
For powerpc64, redefine the ppc_inst type so both word and prefixed
instructions can be represented. On powerpc32 the type will remain the
same. Update places which had assumed instructions to be 4 bytes long.
Signed-off-by: Jordan Niethe <jniethe5 at gmail.com>
---
v4: New to series
v5: - Distinguish normal instructions from prefixed instructions with a
0xff marker for the suffix.
- __patch_instruction() using std for prefixed instructions
v6: - Return false instead of 0 in ppc_inst_prefixed()
- Fix up types for ppc32 so it compiles
- remove ppc_inst_write()
- __patching_instruction(): move flush out of condition
---
arch/powerpc/include/asm/inst.h | 68 +++++++++++++++++++++++++---
arch/powerpc/include/asm/kprobes.h | 2 +-
arch/powerpc/include/asm/uaccess.h | 32 ++++++++++++-
arch/powerpc/include/asm/uprobes.h | 2 +-
arch/powerpc/kernel/optprobes.c | 42 +++++++++--------
arch/powerpc/kernel/optprobes_head.S | 3 ++
arch/powerpc/lib/code-patching.c | 13 ++++--
arch/powerpc/lib/feature-fixups.c | 5 +-
arch/powerpc/lib/inst.c | 40 ++++++++++++++++
arch/powerpc/lib/sstep.c | 4 +-
arch/powerpc/xmon/xmon.c | 4 +-
arch/powerpc/xmon/xmon_bpts.S | 2 +
12 files changed, 180 insertions(+), 37 deletions(-)
diff --git a/arch/powerpc/include/asm/inst.h b/arch/powerpc/include/asm/inst.h
index 2f3c9d5bcf7c..1e743635c214 100644
--- a/arch/powerpc/include/asm/inst.h
+++ b/arch/powerpc/include/asm/inst.h
@@ -8,23 +8,72 @@
struct ppc_inst {
u32 val;
+#ifdef __powerpc64__
+ u32 suffix;
+#endif /* __powerpc64__ */
} __packed;
-#define ppc_inst(x) ((struct ppc_inst){ .val = x })
-
static inline u32 ppc_inst_val(struct ppc_inst x)
{
return x.val;
}
-static inline int ppc_inst_len(struct ppc_inst x)
+static inline int ppc_inst_primary_opcode(struct ppc_inst x)
{
- return sizeof(struct ppc_inst);
+ return ppc_inst_val(x) >> 26;
}
-static inline int ppc_inst_primary_opcode(struct ppc_inst x)
+#ifdef __powerpc64__
+#define ppc_inst(x) ((struct ppc_inst){ .val = (x), .suffix = 0xff })
+
+#define ppc_inst_prefix(x, y) ((struct ppc_inst){ .val = (x), .suffix = (y) })
+
+static inline u32 ppc_inst_suffix(struct ppc_inst x)
{
- return ppc_inst_val(x) >> 26;
+ return x.suffix;
+}
+
+static inline bool ppc_inst_prefixed(struct ppc_inst x)
+{
+ return (ppc_inst_primary_opcode(x) == 1) && ppc_inst_suffix(x) != 0xff;
+}
+
+static inline struct ppc_inst ppc_inst_swab(struct ppc_inst x)
+{
+ return ppc_inst_prefix(swab32(ppc_inst_val(x)),
+ swab32(ppc_inst_suffix(x)));
+}
+
+static inline struct ppc_inst ppc_inst_read(const struct ppc_inst *ptr)
+{
+ u32 val, suffix;
+
+ val = *(u32 *)ptr;
+ if ((val >> 26) == 1) {
+ suffix = *((u32 *)ptr + 1);
+ return ppc_inst_prefix(val, suffix);
+ } else {
+ return ppc_inst(val);
+ }
+}
+
+static inline bool ppc_inst_equal(struct ppc_inst x, struct ppc_inst y)
+{
+ return *(u64 *)&x == *(u64 *)&y;
+}
+
+#else
+
+#define ppc_inst(x) ((struct ppc_inst){ .val = x })
+
+static inline bool ppc_inst_prefixed(struct ppc_inst x)
+{
+ return false;
+}
+
+static inline u32 ppc_inst_suffix(struct ppc_inst x)
+{
+ return 0;
}
static inline struct ppc_inst ppc_inst_swab(struct ppc_inst x)
@@ -42,6 +91,13 @@ static inline bool ppc_inst_equal(struct ppc_inst x, struct ppc_inst y)
return ppc_inst_val(x) == ppc_inst_val(y);
}
+#endif /* __powerpc64__ */
+
+static inline int ppc_inst_len(struct ppc_inst x)
+{
+ return (ppc_inst_prefixed(x)) ? 8 : 4;
+}
+
int probe_user_read_inst(struct ppc_inst *inst,
struct ppc_inst *nip);
int probe_kernel_read_inst(struct ppc_inst *inst,
diff --git a/arch/powerpc/include/asm/kprobes.h b/arch/powerpc/include/asm/kprobes.h
index 66b3f2983b22..4fc0e15e23a5 100644
--- a/arch/powerpc/include/asm/kprobes.h
+++ b/arch/powerpc/include/asm/kprobes.h
@@ -43,7 +43,7 @@ extern kprobe_opcode_t optprobe_template_ret[];
extern kprobe_opcode_t optprobe_template_end[];
/* Fixed instruction size for powerpc */
-#define MAX_INSN_SIZE 1
+#define MAX_INSN_SIZE 2
#define MAX_OPTIMIZED_LENGTH sizeof(kprobe_opcode_t) /* 4 bytes */
#define MAX_OPTINSN_SIZE (optprobe_template_end - optprobe_template_entry)
#define RELATIVEJUMP_SIZE sizeof(kprobe_opcode_t) /* 4 bytes */
diff --git a/arch/powerpc/include/asm/uaccess.h b/arch/powerpc/include/asm/uaccess.h
index c0a35e4586a5..12e52aa179b6 100644
--- a/arch/powerpc/include/asm/uaccess.h
+++ b/arch/powerpc/include/asm/uaccess.h
@@ -105,11 +105,41 @@ static inline int __access_ok(unsigned long addr, unsigned long size,
#define __put_user_inatomic(x, ptr) \
__put_user_nosleep((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
+#ifdef __powerpc64__
+#define __get_user_instr(x, ptr) \
+({ \
+ long __gui_ret = 0; \
+ unsigned int prefix, suffix; \
+ __gui_ret = __get_user(prefix, (unsigned int __user *)ptr); \
+ if (!__gui_ret && (prefix >> 26) == 1) { \
+ __gui_ret = __get_user(suffix, (unsigned int __user *)ptr + 1); \
+ (x) = ppc_inst_prefix(prefix, suffix); \
+ } else { \
+ (x) = ppc_inst(prefix); \
+ } \
+ __gui_ret; \
+})
+
+#define __get_user_instr_inatomic(x, ptr) \
+({ \
+ long __gui_ret = 0; \
+ unsigned int prefix, suffix; \
+ __gui_ret = __get_user_inatomic(prefix, (unsigned int __user *)ptr); \
+ if (!__gui_ret && (prefix >> 26) == 1) { \
+ __gui_ret = __get_user_inatomic(suffix, (unsigned int __user *)ptr + 1); \
+ (x) = ppc_inst_prefix(prefix, suffix); \
+ } else { \
+ (x) = ppc_inst(prefix); \
+ } \
+ __gui_ret; \
+})
+#else
#define __get_user_instr(x, ptr) \
__get_user_nocheck((x).val, (u32 *)(ptr), sizeof(u32), true)
-
#define __get_user_instr_inatomic(x, ptr) \
__get_user_nosleep((x).val, (u32 *)(ptr), sizeof(u32))
+#endif
+
extern long __put_user_bad(void);
/*
diff --git a/arch/powerpc/include/asm/uprobes.h b/arch/powerpc/include/asm/uprobes.h
index 7e3b329ba2d3..5bf65f5d44a9 100644
--- a/arch/powerpc/include/asm/uprobes.h
+++ b/arch/powerpc/include/asm/uprobes.h
@@ -15,7 +15,7 @@
typedef ppc_opcode_t uprobe_opcode_t;
-#define MAX_UINSN_BYTES 4
+#define MAX_UINSN_BYTES 8
#define UPROBE_XOL_SLOT_BYTES (MAX_UINSN_BYTES)
/* The following alias is needed for reference from arch-agnostic code */
diff --git a/arch/powerpc/kernel/optprobes.c b/arch/powerpc/kernel/optprobes.c
index d704f9598f48..a67c5288cf50 100644
--- a/arch/powerpc/kernel/optprobes.c
+++ b/arch/powerpc/kernel/optprobes.c
@@ -159,38 +159,38 @@ void patch_imm32_load_insns(unsigned int val, kprobe_opcode_t *addr)
/*
* Generate instructions to load provided immediate 64-bit value
- * to register 'r3' and patch these instructions at 'addr'.
+ * to register 'reg' and patch these instructions at 'addr'.
*/
-void patch_imm64_load_insns(unsigned long val, kprobe_opcode_t *addr)
+void patch_imm64_load_insns(unsigned long val, int reg, kprobe_opcode_t *addr)
{
- /* lis r3,(op)@highest */
- patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ADDIS | ___PPC_RT(3) |
+ /* lis reg,(op)@highest */
+ patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ADDIS | ___PPC_RT(reg) |
((val >> 48) & 0xffff)));
addr++;
- /* ori r3,r3,(op)@higher */
- patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORI | ___PPC_RA(3) |
- ___PPC_RS(3) | ((val >> 32) & 0xffff)));
+ /* ori reg,reg,(op)@higher */
+ patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORI | ___PPC_RA(reg) |
+ ___PPC_RS(reg) | ((val >> 32) & 0xffff)));
addr++;
- /* rldicr r3,r3,32,31 */
- patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_RLDICR | ___PPC_RA(3) |
- ___PPC_RS(3) | __PPC_SH64(32) | __PPC_ME64(31)));
+ /* rldicr reg,reg,32,31 */
+ patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_RLDICR | ___PPC_RA(reg) |
+ ___PPC_RS(reg) | __PPC_SH64(32) | __PPC_ME64(31)));
addr++;
- /* oris r3,r3,(op)@h */
- patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORIS | ___PPC_RA(3) |
- ___PPC_RS(3) | ((val >> 16) & 0xffff)));
+ /* oris reg,reg,(op)@h */
+ patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORIS | ___PPC_RA(reg) |
+ ___PPC_RS(reg) | ((val >> 16) & 0xffff)));
addr++;
- /* ori r3,r3,(op)@l */
- patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORI | ___PPC_RA(3) |
- ___PPC_RS(3) | (val & 0xffff)));
+ /* ori reg,reg,(op)@l */
+ patch_instruction((struct ppc_inst *)addr, ppc_inst(PPC_INST_ORI | ___PPC_RA(reg) |
+ ___PPC_RS(reg) | (val & 0xffff)));
}
int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
{
- struct ppc_inst branch_op_callback, branch_emulate_step;
+ struct ppc_inst branch_op_callback, branch_emulate_step, temp;
kprobe_opcode_t *op_callback_addr, *emulate_step_addr, *buff;
long b_offset;
unsigned long nip, size;
@@ -240,7 +240,7 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
* Fixup the template with instructions to:
* 1. load the address of the actual probepoint
*/
- patch_imm64_load_insns((unsigned long)op, buff + TMPL_OP_IDX);
+ patch_imm64_load_insns((unsigned long)op, 3, buff + TMPL_OP_IDX);
/*
* 2. branch to optimized_callback() and emulate_step()
@@ -271,7 +271,11 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe *p)
/*
* 3. load instruction to be emulated into relevant register, and
*/
- patch_imm32_load_insns(*p->ainsn.insn, buff + TMPL_INSN_IDX);
+ temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
+ patch_imm64_load_insns(ppc_inst_val(temp) |
+ ((u64)ppc_inst_suffix(temp) << 32),
+ 4,
+ buff + TMPL_INSN_IDX);
/*
* 4. branch back from trampoline
diff --git a/arch/powerpc/kernel/optprobes_head.S b/arch/powerpc/kernel/optprobes_head.S
index cf383520843f..ff8ba4d3824d 100644
--- a/arch/powerpc/kernel/optprobes_head.S
+++ b/arch/powerpc/kernel/optprobes_head.S
@@ -94,6 +94,9 @@ optprobe_template_insn:
/* 2, Pass instruction to be emulated in r4 */
nop
nop
+ nop
+ nop
+ nop
.global optprobe_template_call_emulate
optprobe_template_call_emulate:
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 53b0d5cbc86a..dd2f982bb29e 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -24,13 +24,18 @@ static int __patch_instruction(struct ppc_inst *exec_addr, struct ppc_inst instr
{
int err = 0;
- __put_user_asm(ppc_inst_val(instr), patch_addr, err, "stw");
- if (err)
- return err;
+ if (!ppc_inst_prefixed(instr)) {
+ __put_user_asm(ppc_inst_val(instr), patch_addr, err, "stw");
+ if (err)
+ return err;
+ } else {
+ __put_user_asm((u64)ppc_inst_suffix(instr) << 32 | ppc_inst_val(instr), patch_addr, err, "std");
+ if (err)
+ return err;
+ }
asm ("dcbst 0, %0; sync; icbi 0,%1; sync; isync" :: "r" (patch_addr),
"r" (exec_addr));
-
return 0;
}
diff --git a/arch/powerpc/lib/feature-fixups.c b/arch/powerpc/lib/feature-fixups.c
index f4845e740338..243011f85287 100644
--- a/arch/powerpc/lib/feature-fixups.c
+++ b/arch/powerpc/lib/feature-fixups.c
@@ -84,12 +84,13 @@ static int patch_feature_section(unsigned long value, struct fixup_entry *fcur)
src = alt_start;
dest = start;
- for (; src < alt_end; src++, dest++) {
+ for (; src < alt_end; src = (void *)src + ppc_inst_len(ppc_inst_read(src)),
+ (dest = (void *)dest + ppc_inst_len(ppc_inst_read(dest)))) {
if (patch_alt_instruction(src, dest, alt_start, alt_end))
return 1;
}
- for (; dest < end; dest++)
+ for (; dest < end; dest = (void *)dest + ppc_inst_len(ppc_inst(PPC_INST_NOP)))
raw_patch_instruction(dest, ppc_inst(PPC_INST_NOP));
return 0;
diff --git a/arch/powerpc/lib/inst.c b/arch/powerpc/lib/inst.c
index 08dedd927268..71101791edcc 100644
--- a/arch/powerpc/lib/inst.c
+++ b/arch/powerpc/lib/inst.c
@@ -6,6 +6,45 @@
#include <linux/uaccess.h>
#include <asm/inst.h>
+#ifdef __powerpc64__
+int probe_user_read_inst(struct ppc_inst *inst,
+ struct ppc_inst *nip)
+{
+ unsigned int val, suffix;
+ int err;
+
+ err = probe_user_read(&val, nip, sizeof(val));
+ if (err)
+ return err;
+ if ((val >> 26) == 1) {
+ err = probe_user_read(&suffix, (void *)nip+4,
+ sizeof(unsigned int));
+ *inst = ppc_inst_prefix(val, suffix);
+ } else {
+ *inst = ppc_inst(val);
+ }
+ return err;
+}
+
+int probe_kernel_read_inst(struct ppc_inst *inst,
+ struct ppc_inst *src)
+{
+ unsigned int val, suffix;
+ int err;
+
+ err = probe_kernel_read(&val, src, sizeof(val));
+ if (err)
+ return err;
+ if ((val >> 26) == 1) {
+ err = probe_kernel_read(&suffix, (void *)src+4,
+ sizeof(unsigned int));
+ *inst = ppc_inst_prefix(val, suffix);
+ } else {
+ *inst = ppc_inst(val);
+ }
+ return err;
+}
+#else
int probe_user_read_inst(struct ppc_inst *inst,
struct ppc_inst *nip)
{
@@ -27,3 +66,4 @@ int probe_kernel_read_inst(struct ppc_inst *inst,
*inst = ppc_inst(val);
return err;
}
+#endif /* __powerpc64__ */
diff --git a/arch/powerpc/lib/sstep.c b/arch/powerpc/lib/sstep.c
index 13a81a55f58d..81c4c44262a6 100644
--- a/arch/powerpc/lib/sstep.c
+++ b/arch/powerpc/lib/sstep.c
@@ -1169,10 +1169,12 @@ int analyse_instr(struct instruction_op *op, const struct pt_regs *regs,
unsigned long int imm;
unsigned long int val, val2;
unsigned int mb, me, sh;
- unsigned int word;
+ unsigned int word, suffix;
long ival;
word = ppc_inst_val(instr);
+ suffix = ppc_inst_suffix(instr);
+
op->type = COMPUTE;
opcode = ppc_inst_primary_opcode(instr);
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index ce2a0150d43c..464f93b7037d 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -757,8 +757,8 @@ static int xmon_bpt(struct pt_regs *regs)
/* Are we at the trap at bp->instr[1] for some bp? */
bp = in_breakpoint_table(regs->nip, &offset);
- if (bp != NULL && offset == 4) {
- regs->nip = bp->address + 4;
+ if (bp != NULL && (offset == 4 || offset == 8)) {
+ regs->nip = bp->address + offset;
atomic_dec(&bp->ref_count);
return 1;
}
diff --git a/arch/powerpc/xmon/xmon_bpts.S b/arch/powerpc/xmon/xmon_bpts.S
index f3ad0ab50854..69726814cd27 100644
--- a/arch/powerpc/xmon/xmon_bpts.S
+++ b/arch/powerpc/xmon/xmon_bpts.S
@@ -4,6 +4,8 @@
#include <asm/asm-offsets.h>
#include "xmon_bpts.h"
+/* Prefixed instructions can not cross 64 byte boundaries */
+.align 6
.global bpt_table
bpt_table:
.space NBPTS * BPT_SIZE
--
2.17.1
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