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Subject[PATCH 17/27] x86-64 ptrace debugreg cleanup
Date

This cleans up the 64-bit ptrace code to separate the guts of the
debug register access from the implementation of PTRACE_PEEKUSR and
PTRACE_POKEUSR. The new functions ptrace_[gs]et_debugreg are made
global so that the ia32 code can later be changed to call them too.

Signed-off-by: Roland McGrath <roland@redhat.com>
---
arch/x86/kernel/ptrace_64.c | 140 ++++++++++++++++++++-----------------------
include/asm-x86/ptrace.h | 3 +
2 files changed, 69 insertions(+), 74 deletions(-)
diff --git a/arch/x86/kernel/ptrace_64.c b/arch/x86/kernel/ptrace_64.c
index 8123ecb..bad8b3c 100644
--- a/arch/x86/kernel/ptrace_64.c
+++ b/arch/x86/kernel/ptrace_64.c
@@ -183,9 +183,63 @@ static unsigned long getreg(struct task_struct *child, unsigned long regno)

}

+unsigned long ptrace_get_debugreg(struct task_struct *child, int n)
+{
+ switch (n) {
+ case 0: return child->thread.debugreg0;
+ case 1: return child->thread.debugreg1;
+ case 2: return child->thread.debugreg2;
+ case 3: return child->thread.debugreg3;
+ case 6: return child->thread.debugreg6;
+ case 7: return child->thread.debugreg7;
+ }
+ return 0;
+}
+
+int ptrace_set_debugreg(struct task_struct *child, int n, unsigned long data)
+{
+ int i;
+
+ if (n < 4) {
+ int dsize = test_tsk_thread_flag(child, TIF_IA32) ? 3 : 7;
+ if (unlikely(data >= TASK_SIZE_OF(child) - dsize))
+ return -EIO;
+ }
+
+ switch (n) {
+ case 0: child->thread.debugreg0 = data; break;
+ case 1: child->thread.debugreg1 = data; break;
+ case 2: child->thread.debugreg2 = data; break;
+ case 3: child->thread.debugreg3 = data; break;
+
+ case 6:
+ if (data >> 32)
+ return -EIO;
+ child->thread.debugreg6 = data;
+ break;
+
+ case 7:
+ /*
+ * See ptrace_32.c for an explanation of this awkward check.
+ */
+ data &= ~DR_CONTROL_RESERVED;
+ for (i = 0; i < 4; i++)
+ if ((0x5554 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
+ return -EIO;
+ child->thread.debugreg7 = data;
+ if (data)
+ set_tsk_thread_flag(child, TIF_DEBUG);
+ else
+ clear_tsk_thread_flag(child, TIF_DEBUG);
+ break;
+ }
+
+ return 0;
+}
+
long arch_ptrace(struct task_struct *child, long request, long addr, long data)
{
- long i, ret;
+ long ret;
unsigned ui;

switch (request) {
@@ -204,32 +258,14 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
addr > sizeof(struct user) - 7)
break;

- switch (addr) {
- case 0 ... sizeof(struct user_regs_struct) - sizeof(long):
+ tmp = 0;
+ if (addr < sizeof(struct user_regs_struct))
tmp = getreg(child, addr);
- break;
- case offsetof(struct user, u_debugreg[0]):
- tmp = child->thread.debugreg0;
- break;
- case offsetof(struct user, u_debugreg[1]):
- tmp = child->thread.debugreg1;
- break;
- case offsetof(struct user, u_debugreg[2]):
- tmp = child->thread.debugreg2;
- break;
- case offsetof(struct user, u_debugreg[3]):
- tmp = child->thread.debugreg3;
- break;
- case offsetof(struct user, u_debugreg[6]):
- tmp = child->thread.debugreg6;
- break;
- case offsetof(struct user, u_debugreg[7]):
- tmp = child->thread.debugreg7;
- break;
- default:
- tmp = 0;
- break;
+ else if (addr >= offsetof(struct user, u_debugreg[0])) {
+ addr -= offsetof(struct user, u_debugreg[0]);
+ tmp = ptrace_get_debugreg(child, addr / sizeof(long));
}
+
ret = put_user(tmp,(unsigned long __user *) data);
break;
}
@@ -241,63 +277,19 @@ long arch_ptrace(struct task_struct *child, long request, long addr, long data)
break;

case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
- {
- int dsize = test_tsk_thread_flag(child, TIF_IA32) ? 3 : 7;
ret = -EIO;
if ((addr & 7) ||
addr > sizeof(struct user) - 7)
break;

- switch (addr) {
- case 0 ... sizeof(struct user_regs_struct) - sizeof(long):
+ if (addr < sizeof(struct user_regs_struct))
ret = putreg(child, addr, data);
- break;
- /* Disallows to set a breakpoint into the vsyscall */
- case offsetof(struct user, u_debugreg[0]):
- if (data >= TASK_SIZE_OF(child) - dsize) break;
- child->thread.debugreg0 = data;
- ret = 0;
- break;
- case offsetof(struct user, u_debugreg[1]):
- if (data >= TASK_SIZE_OF(child) - dsize) break;
- child->thread.debugreg1 = data;
- ret = 0;
- break;
- case offsetof(struct user, u_debugreg[2]):
- if (data >= TASK_SIZE_OF(child) - dsize) break;
- child->thread.debugreg2 = data;
- ret = 0;
- break;
- case offsetof(struct user, u_debugreg[3]):
- if (data >= TASK_SIZE_OF(child) - dsize) break;
- child->thread.debugreg3 = data;
- ret = 0;
- break;
- case offsetof(struct user, u_debugreg[6]):
- if (data >> 32)
- break;
- child->thread.debugreg6 = data;
- ret = 0;
- break;
- case offsetof(struct user, u_debugreg[7]):
- /* See arch/i386/kernel/ptrace.c for an explanation of
- * this awkward check.*/
- data &= ~DR_CONTROL_RESERVED;
- for(i=0; i<4; i++)
- if ((0x5554 >> ((data >> (16 + 4*i)) & 0xf)) & 1)
- break;
- if (i == 4) {
- child->thread.debugreg7 = data;
- if (data)
- set_tsk_thread_flag(child, TIF_DEBUG);
- else
- clear_tsk_thread_flag(child, TIF_DEBUG);
- ret = 0;
- }
- break;
+ else if (addr >= offsetof(struct user, u_debugreg[0])) {
+ addr -= offsetof(struct user, u_debugreg[0]);
+ ret = ptrace_set_debugreg(child,
+ addr / sizeof(long), data);
}
break;
- }

#ifdef CONFIG_IA32_EMULATION
/* This makes only sense with 32bit programs. Allow a
diff --git a/include/asm-x86/ptrace.h b/include/asm-x86/ptrace.h
index fe75422..d223dec 100644
--- a/include/asm-x86/ptrace.h
+++ b/include/asm-x86/ptrace.h
@@ -110,6 +110,9 @@ void signal_fault(struct pt_regs *regs, void __user *frame, char *where);

struct task_struct;

+extern unsigned long ptrace_get_debugreg(struct task_struct *child, int n);
+extern int ptrace_set_debugreg(struct task_struct *child, int n, unsigned long);
+
extern unsigned long
convert_rip_to_linear(struct task_struct *child, struct pt_regs *regs);

-
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