[PATCH 3/3] uprobes/core: move insn to arch specific structure.

From: Srikar Dronamraju
Date: Wed Feb 22 2012 - 04:16:42 EST

From: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>

Few cleanups suggested by Ingo Molnar.

- Rename struct uprobe_arch_info to struct arch_uprobe.
- Move insn from struct uprobe to struct arch_uprobe.
- Make arch specific uprobe functions to accept struct arch_uprobe instead of
struct uprobe.
- Move struct uprobe to kernel/uprobes.c from include/linux/uprobes.h

Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/uprobes.h | 6 ++--
arch/x86/kernel/uprobes.c | 60 ++++++++++++++++++++--------------------
include/linux/uprobes.h | 23 +--------------
kernel/uprobes.c | 38 +++++++++++++++++--------
4 files changed, 61 insertions(+), 66 deletions(-)

diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
index 072df39..f7ce310 100644
--- a/arch/x86/include/asm/uprobes.h
+++ b/arch/x86/include/asm/uprobes.h
@@ -31,13 +31,13 @@ typedef u8 uprobe_opcode_t;
#define UPROBES_BKPT_INSN 0xcc
#define UPROBES_BKPT_INSN_SIZE 1

-struct uprobe_arch_info {
+struct arch_uprobe {
u16 fixups;
+ u8 insn[MAX_UINSN_BYTES];
#ifdef CONFIG_X86_64
unsigned long rip_rela_target_address;
#endif
};

-struct uprobe;
-extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe);
+extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct arch_uprobe *arch_uprobe);
#endif /* _ASM_UPROBES_H */
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 13d616d..04dfcef 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -200,9 +200,9 @@ static bool is_prefix_bad(struct insn *insn)
return false;
}

-static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn)
+static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn)
{
- insn_init(insn, uprobe->insn, false);
+ insn_init(insn, auprobe->insn, false);

/* Skip good instruction prefixes; reject "bad" ones. */
insn_get_opcode(insn);
@@ -222,11 +222,11 @@ static int validate_insn_32bits(struct uprobe *uprobe, struct insn *insn)

/*
* Figure out which fixups post_xol() will need to perform, and annotate
- * uprobe->arch_info.fixups accordingly. To start with,
- * uprobe->arch_info.fixups is either zero or it reflects rip-related
+ * arch_uprobe->fixups accordingly. To start with,
+ * arch_uprobe->fixups is either zero or it reflects rip-related
* fixups.
*/
-static void prepare_fixups(struct uprobe *uprobe, struct insn *insn)
+static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn)
{
bool fix_ip = true, fix_call = false; /* defaults */
int reg;
@@ -269,17 +269,17 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn)
break;
}
if (fix_ip)
- uprobe->arch_info.fixups |= UPROBES_FIX_IP;
+ auprobe->fixups |= UPROBES_FIX_IP;
if (fix_call)
- uprobe->arch_info.fixups |= UPROBES_FIX_CALL;
+ auprobe->fixups |= UPROBES_FIX_CALL;
}

#ifdef CONFIG_X86_64
/*
- * If uprobe->insn doesn't use rip-relative addressing, return
+ * If arch_uprobe->insn doesn't use rip-relative addressing, return
* immediately. Otherwise, rewrite the instruction so that it accesses
* its memory operand indirectly through a scratch register. Set
- * uprobe->arch_info.fixups and uprobe->arch_info.rip_rela_target_address
+ * arch_uprobe->fixups and arch_uprobe->rip_rela_target_address
* accordingly. (The contents of the scratch register will be saved
* before we single-step the modified instruction, and restored
* afterward.)
@@ -297,7 +297,7 @@ static void prepare_fixups(struct uprobe *uprobe, struct insn *insn)
* - There's never a SIB byte.
* - The displacement is always 4 bytes.
*/
-static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
+static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn)
{
u8 *cursor;
u8 reg;
@@ -305,7 +305,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
if (mm->context.ia32_compat)
return;

- uprobe->arch_info.rip_rela_target_address = 0x0;
+ auprobe->rip_rela_target_address = 0x0;
if (!insn_rip_relative(insn))
return;

@@ -315,7 +315,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
* we want to encode rax/rcx, not r8/r9.
*/
if (insn->rex_prefix.nbytes) {
- cursor = uprobe->insn + insn_offset_rex_prefix(insn);
+ cursor = auprobe->insn + insn_offset_rex_prefix(insn);
*cursor &= 0xfe; /* Clearing REX.B bit */
}

@@ -324,7 +324,7 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
* displacement. Beyond the displacement, for some instructions,
* is the immediate operand.
*/
- cursor = uprobe->insn + insn_offset_modrm(insn);
+ cursor = auprobe->insn + insn_offset_modrm(insn);
insn_get_length(insn);

/*
@@ -341,18 +341,18 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
* is NOT the register operand, so we use %rcx (register
* #1) for the scratch register.
*/
- uprobe->arch_info.fixups = UPROBES_FIX_RIP_CX;
+ auprobe->fixups = UPROBES_FIX_RIP_CX;
/* Change modrm from 00 000 101 to 00 000 001. */
*cursor = 0x1;
} else {
/* Use %rax (register #0) for the scratch register. */
- uprobe->arch_info.fixups = UPROBES_FIX_RIP_AX;
+ auprobe->fixups = UPROBES_FIX_RIP_AX;
/* Change modrm from 00 xxx 101 to 00 xxx 000 */
*cursor = (reg << 3);
}

/* Target address = address of next instruction + (signed) offset */
- uprobe->arch_info.rip_rela_target_address = (long)insn->length + insn->displacement.value;
+ auprobe->rip_rela_target_address = (long)insn->length + insn->displacement.value;

/* Displacement field is gone; slide immediate field (if any) over. */
if (insn->immediate.nbytes) {
@@ -362,9 +362,9 @@ static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, stru
return;
}

-static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn)
+static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn)
{
- insn_init(insn, uprobe->insn, true);
+ insn_init(insn, auprobe->insn, true);

/* Skip good instruction prefixes; reject "bad" ones. */
insn_get_opcode(insn);
@@ -381,42 +381,42 @@ static int validate_insn_64bits(struct uprobe *uprobe, struct insn *insn)
return -ENOTSUPP;
}

-static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
+static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn)
{
if (mm->context.ia32_compat)
- return validate_insn_32bits(uprobe, insn);
- return validate_insn_64bits(uprobe, insn);
+ return validate_insn_32bits(auprobe, insn);
+ return validate_insn_64bits(auprobe, insn);
}
#else /* 32-bit: */
-static void handle_riprel_insn(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
+static void handle_riprel_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn)
{
/* No RIP-relative addressing on 32-bit */
}

-static int validate_insn_bits(struct mm_struct *mm, struct uprobe *uprobe, struct insn *insn)
+static int validate_insn_bits(struct mm_struct *mm, struct arch_uprobe *auprobe, struct insn *insn)
{
- return validate_insn_32bits(uprobe, insn);
+ return validate_insn_32bits(auprobe, insn);
}
#endif /* CONFIG_X86_64 */

/**
* arch_uprobes_analyze_insn - instruction analysis including validity and fixups.
* @mm: the probed address space.
- * @uprobe: the probepoint information.
+ * @arch_uprobe: the probepoint information.
* Return 0 on success or a -ve number on error.
*/
-int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe)
+int arch_uprobes_analyze_insn(struct mm_struct *mm, struct arch_uprobe *auprobe)
{
int ret;
struct insn insn;

- uprobe->arch_info.fixups = 0;
- ret = validate_insn_bits(mm, uprobe, &insn);
+ auprobe->fixups = 0;
+ ret = validate_insn_bits(mm, auprobe, &insn);
if (ret != 0)
return ret;

- handle_riprel_insn(mm, uprobe, &insn);
- prepare_fixups(uprobe, &insn);
+ handle_riprel_insn(mm, auprobe, &insn);
+ prepare_fixups(auprobe, &insn);

return 0;
}
diff --git a/include/linux/uprobes.h b/include/linux/uprobes.h
index fd45b70..9c6be62 100644
--- a/include/linux/uprobes.h
+++ b/include/linux/uprobes.h
@@ -29,12 +29,6 @@
struct vm_area_struct;
#ifdef CONFIG_ARCH_SUPPORTS_UPROBES
#include <asm/uprobes.h>
-#else
-
-typedef u8 uprobe_opcode_t;
-struct uprobe_arch_info {};
-
-#define MAX_UINSN_BYTES 4
#endif

/* flags that denote/change uprobes behaviour */
@@ -56,22 +50,9 @@ struct uprobe_consumer {
struct uprobe_consumer *next;
};

-struct uprobe {
- struct rb_node rb_node; /* node in the rb tree */
- atomic_t ref;
- struct rw_semaphore consumer_rwsem;
- struct list_head pending_list;
- struct uprobe_arch_info arch_info;
- struct uprobe_consumer *consumers;
- struct inode *inode; /* Also hold a ref to inode */
- loff_t offset;
- int flags;
- u8 insn[MAX_UINSN_BYTES];
-};
-
#ifdef CONFIG_UPROBES
-extern int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr);
-extern int __weak set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify);
+extern int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr);
+extern int __weak set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify);
extern bool __weak is_bkpt_insn(uprobe_opcode_t *insn);
extern int uprobe_register(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer);
extern void uprobe_unregister(struct inode *inode, loff_t offset, struct uprobe_consumer *consumer);
diff --git a/kernel/uprobes.c b/kernel/uprobes.c
index ee496ad..0867302 100644
--- a/kernel/uprobes.c
+++ b/kernel/uprobes.c
@@ -65,6 +65,18 @@ struct vma_info {
loff_t vaddr;
};

+struct uprobe {
+ struct rb_node rb_node; /* node in the rb tree */
+ atomic_t ref;
+ struct rw_semaphore consumer_rwsem;
+ struct list_head pending_list;
+ struct uprobe_consumer *consumers;
+ struct inode *inode; /* Also hold a ref to inode */
+ loff_t offset;
+ int flags;
+ struct arch_uprobe arch;
+};
+
/*
* valid_vma: Verify if the specified vma is an executable vma
* Relax restrictions while unregistering: vm_flags might have
@@ -180,7 +192,7 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn)
/*
* write_opcode - write the opcode at a given virtual address.
* @mm: the probed process address space.
- * @uprobe: the breakpointing information.
+ * @arch_uprobe: the breakpointing information.
* @vaddr: the virtual address to store the opcode.
* @opcode: opcode to be written at @vaddr.
*
@@ -190,13 +202,14 @@ bool __weak is_bkpt_insn(uprobe_opcode_t *insn)
* For mm @mm, write the opcode at @vaddr.
* Return 0 (success) or a negative errno.
*/
-static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe,
+static int write_opcode(struct mm_struct *mm, struct arch_uprobe *auprobe,
unsigned long vaddr, uprobe_opcode_t opcode)
{
struct page *old_page, *new_page;
struct address_space *mapping;
void *vaddr_old, *vaddr_new;
struct vm_area_struct *vma;
+ struct uprobe *uprobe;
loff_t addr;
int ret;

@@ -216,6 +229,7 @@ static int write_opcode(struct mm_struct *mm, struct uprobe *uprobe,
if (!valid_vma(vma, is_bkpt_insn(&opcode)))
goto put_out;

+ uprobe = container_of(auprobe, struct uprobe, arch);
mapping = uprobe->inode->i_mapping;
if (mapping != vma->vm_file->f_mapping)
goto put_out;
@@ -326,7 +340,7 @@ static int is_bkpt_at_addr(struct mm_struct *mm, unsigned long vaddr)
* For mm @mm, store the breakpoint instruction at @vaddr.
* Return 0 (success) or a negative errno.
*/
-int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr)
+int __weak set_bkpt(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr)
{
int result;

@@ -337,7 +351,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long v
if (result)
return result;

- return write_opcode(mm, uprobe, vaddr, UPROBES_BKPT_INSN);
+ return write_opcode(mm, auprobe, vaddr, UPROBES_BKPT_INSN);
}

/**
@@ -351,7 +365,7 @@ int __weak set_bkpt(struct mm_struct *mm, struct uprobe *uprobe, unsigned long v
* Return 0 (success) or a negative errno.
*/
int __weak
-set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr, bool verify)
+set_orig_insn(struct mm_struct *mm, struct arch_uprobe *auprobe, unsigned long vaddr, bool verify)
{
if (verify) {
int result;
@@ -363,7 +377,7 @@ set_orig_insn(struct mm_struct *mm, struct uprobe *uprobe, unsigned long vaddr,
if (result != 1)
return result;
}
- return write_opcode(mm, uprobe, vaddr, *(uprobe_opcode_t *)uprobe->insn);
+ return write_opcode(mm, auprobe, vaddr, *(uprobe_opcode_t *)auprobe->insn);
}

static int match_uprobe(struct uprobe *l, struct uprobe *r)
@@ -593,13 +607,13 @@ static int copy_insn(struct uprobe *uprobe, struct vm_area_struct *vma, unsigned

/* Instruction at the page-boundary; copy bytes in second page */
if (nbytes < bytes) {
- if (__copy_insn(mapping, vma, uprobe->insn + nbytes,
+ if (__copy_insn(mapping, vma, uprobe->arch.insn + nbytes,
bytes - nbytes, uprobe->offset + nbytes))
return -ENOMEM;

bytes = nbytes;
}
- return __copy_insn(mapping, vma, uprobe->insn, bytes, uprobe->offset);
+ return __copy_insn(mapping, vma, uprobe->arch.insn, bytes, uprobe->offset);
}

static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
@@ -625,23 +639,23 @@ static int install_breakpoint(struct mm_struct *mm, struct uprobe *uprobe,
if (ret)
return ret;

- if (is_bkpt_insn((uprobe_opcode_t *)uprobe->insn))
+ if (is_bkpt_insn((uprobe_opcode_t *)uprobe->arch.insn))
return -EEXIST;

- ret = arch_uprobes_analyze_insn(mm, uprobe);
+ ret = arch_uprobes_analyze_insn(mm, &uprobe->arch);
if (ret)
return ret;

uprobe->flags |= UPROBES_COPY_INSN;
}
- ret = set_bkpt(mm, uprobe, addr);
+ ret = set_bkpt(mm, &uprobe->arch, addr);

return ret;
}

static void remove_breakpoint(struct mm_struct *mm, struct uprobe *uprobe, loff_t vaddr)
{
- set_orig_insn(mm, uprobe, (unsigned long)vaddr, true);
+ set_orig_insn(mm, &uprobe->arch, (unsigned long)vaddr, true);
}

static void delete_uprobe(struct uprobe *uprobe)


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