x86: single_step moved

This moves the single-step support code from ptrace_64.c into a new file
step.c, verbatim.  This paves the way for consolidating this code between
64-bit and 32-bit versions.

Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/Makefile_64 b/arch/x86/kernel/Makefile_64
index e1ba82e..d908f01 100644 (file)
--- a/arch/x86/kernel/Makefile_64
+++ b/arch/x86/kernel/Makefile_64
@@ -13,6 +13,8 @@ obj-y := process_64.o signal_64.o entry_64.o traps_64.o irq_64.o \
                pci-dma_64.o pci-nommu_64.o alternative.o hpet.o tsc_64.o bugs_64.o \
                i8253.o io_delay.o rtc.o
 
+obj-y                          += step.o
+
 obj-$(CONFIG_IA32_EMULATION)   += tls.o
 obj-$(CONFIG_STACKTRACE)       += stacktrace.o
 obj-y                          += cpu/

diff --git a/arch/x86/kernel/ptrace_64.c b/arch/x86/kernel/ptrace_64.c
index 7373a99..4abfbce 100644 (file)
--- a/arch/x86/kernel/ptrace_64.c
+++ b/arch/x86/kernel/ptrace_64.c
@@ -80,140 +80,6 @@ static inline long put_stack_long(struct task_struct *task, int offset,
        return 0;
 }
 
-#define LDT_SEGMENT 4
-
-unsigned long convert_rip_to_linear(struct task_struct *child, struct pt_regs *regs)
-{
-       unsigned long addr, seg;
-
-       addr = regs->rip;
-       seg = regs->cs & 0xffff;
-
-       /*
-        * We'll assume that the code segments in the GDT
-        * are all zero-based. That is largely true: the
-        * TLS segments are used for data, and the PNPBIOS
-        * and APM bios ones we just ignore here.
-        */
-       if (seg & LDT_SEGMENT) {
-               u32 *desc;
-               unsigned long base;
-
-               seg &= ~7UL;
-
-               mutex_lock(&child->mm->context.lock);
-               if (unlikely((seg >> 3) >= child->mm->context.size))
-                       addr = -1L; /* bogus selector, access would fault */
-               else {
-                       desc = child->mm->context.ldt + seg;
-                       base = ((desc[0] >> 16) |
-                               ((desc[1] & 0xff) << 16) |
-                               (desc[1] & 0xff000000));
-
-                       /* 16-bit code segment? */
-                       if (!((desc[1] >> 22) & 1))
-                               addr &= 0xffff;
-                       addr += base;
-               }
-               mutex_unlock(&child->mm->context.lock);
-       }
-
-       return addr;
-}
-
-static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs)
-{
-       int i, copied;
-       unsigned char opcode[15];
-       unsigned long addr = convert_rip_to_linear(child, regs);
-
-       copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
-       for (i = 0; i < copied; i++) {
-               switch (opcode[i]) {
-               /* popf and iret */
-               case 0x9d: case 0xcf:
-                       return 1;
-
-                       /* CHECKME: 64 65 */
-
-               /* opcode and address size prefixes */
-               case 0x66: case 0x67:
-                       continue;
-               /* irrelevant prefixes (segment overrides and repeats) */
-               case 0x26: case 0x2e:
-               case 0x36: case 0x3e:
-               case 0x64: case 0x65:
-               case 0xf2: case 0xf3:
-                       continue;
-
-               case 0x40 ... 0x4f:
-                       if (regs->cs != __USER_CS)
-                               /* 32-bit mode: register increment */
-                               return 0;
-                       /* 64-bit mode: REX prefix */
-                       continue;
-
-                       /* CHECKME: f2, f3 */
-
-               /*
-                * pushf: NOTE! We should probably not let
-                * the user see the TF bit being set. But
-                * it's more pain than it's worth to avoid
-                * it, and a debugger could emulate this
-                * all in user space if it _really_ cares.
-                */
-               case 0x9c:
-               default:
-                       return 0;
-               }
-       }
-       return 0;
-}
-
-void user_enable_single_step(struct task_struct *child)
-{
-       struct pt_regs *regs = task_pt_regs(child);
-
-       /*
-        * Always set TIF_SINGLESTEP - this guarantees that
-        * we single-step system calls etc..  This will also
-        * cause us to set TF when returning to user mode.
-        */
-       set_tsk_thread_flag(child, TIF_SINGLESTEP);
-
-       /*
-        * If TF was already set, don't do anything else
-        */
-       if (regs->eflags & X86_EFLAGS_TF)
-               return;
-
-       /* Set TF on the kernel stack.. */
-       regs->eflags |= X86_EFLAGS_TF;
-
-       /*
-        * ..but if TF is changed by the instruction we will trace,
-        * don't mark it as being "us" that set it, so that we
-        * won't clear it by hand later.
-        */
-       if (is_setting_trap_flag(child, regs))
-               return;
-
-       child->ptrace |= PT_DTRACE;
-}
-
-void user_disable_single_step(struct task_struct *child)
-{
-       /* Always clear TIF_SINGLESTEP... */
-       clear_tsk_thread_flag(child, TIF_SINGLESTEP);
-
-       /* But touch TF only if it was set by us.. */
-       if (child->ptrace & PT_DTRACE) {
-               struct pt_regs *regs = task_pt_regs(child);
-               regs->eflags &= ~X86_EFLAGS_TF;
-               child->ptrace &= ~PT_DTRACE;
-       }
-}
-
 /*
  * Called by kernel/ptrace.c when detaching..
  *

diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
new file mode 100644 (file)
index 0000000..cb3c8bc
--- /dev/null
+++ b/arch/x86/kernel/step.c
@@ -0,0 +1,140 @@
+/*
+ * x86 single-step support code, common to 32-bit and 64-bit.
+ */
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/ptrace.h>
+
+#define LDT_SEGMENT 4
+
+unsigned long convert_rip_to_linear(struct task_struct *child, struct pt_regs *regs)
+{
+       unsigned long addr, seg;
+
+       addr = regs->rip;
+       seg = regs->cs & 0xffff;
+
+       /*
+        * We'll assume that the code segments in the GDT
+        * are all zero-based. That is largely true: the
+        * TLS segments are used for data, and the PNPBIOS
+        * and APM bios ones we just ignore here.
+        */
+       if (seg & LDT_SEGMENT) {
+               u32 *desc;
+               unsigned long base;
+
+               seg &= ~7UL;
+
+               mutex_lock(&child->mm->context.lock);
+               if (unlikely((seg >> 3) >= child->mm->context.size))
+                       addr = -1L; /* bogus selector, access would fault */
+               else {
+                       desc = child->mm->context.ldt + seg;
+                       base = ((desc[0] >> 16) |
+                               ((desc[1] & 0xff) << 16) |
+                               (desc[1] & 0xff000000));
+
+                       /* 16-bit code segment? */
+                       if (!((desc[1] >> 22) & 1))
+                               addr &= 0xffff;
+                       addr += base;
+               }
+               mutex_unlock(&child->mm->context.lock);
+       }
+
+       return addr;
+}
+
+static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs)
+{
+       int i, copied;
+       unsigned char opcode[15];
+       unsigned long addr = convert_rip_to_linear(child, regs);
+
+       copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
+       for (i = 0; i < copied; i++) {
+               switch (opcode[i]) {
+               /* popf and iret */
+               case 0x9d: case 0xcf:
+                       return 1;
+
+                       /* CHECKME: 64 65 */
+
+               /* opcode and address size prefixes */
+               case 0x66: case 0x67:
+                       continue;
+               /* irrelevant prefixes (segment overrides and repeats) */
+               case 0x26: case 0x2e:
+               case 0x36: case 0x3e:
+               case 0x64: case 0x65:
+               case 0xf2: case 0xf3:
+                       continue;
+
+               case 0x40 ... 0x4f:
+                       if (regs->cs != __USER_CS)
+                               /* 32-bit mode: register increment */
+                               return 0;
+                       /* 64-bit mode: REX prefix */
+                       continue;
+
+                       /* CHECKME: f2, f3 */
+
+               /*
+                * pushf: NOTE! We should probably not let
+                * the user see the TF bit being set. But
+                * it's more pain than it's worth to avoid
+                * it, and a debugger could emulate this
+                * all in user space if it _really_ cares.
+                */
+               case 0x9c:
+               default:
+                       return 0;
+               }
+       }
+       return 0;
+}
+
+void user_enable_single_step(struct task_struct *child)
+{
+       struct pt_regs *regs = task_pt_regs(child);
+
+       /*
+        * Always set TIF_SINGLESTEP - this guarantees that
+        * we single-step system calls etc..  This will also
+        * cause us to set TF when returning to user mode.
+        */
+       set_tsk_thread_flag(child, TIF_SINGLESTEP);
+
+       /*
+        * If TF was already set, don't do anything else
+        */
+       if (regs->eflags & X86_EFLAGS_TF)
+               return;
+
+       /* Set TF on the kernel stack.. */
+       regs->eflags |= X86_EFLAGS_TF;
+
+       /*
+        * ..but if TF is changed by the instruction we will trace,
+        * don't mark it as being "us" that set it, so that we
+        * won't clear it by hand later.
+        */
+       if (is_setting_trap_flag(child, regs))
+               return;
+
+       child->ptrace |= PT_DTRACE;
+}
+
+void user_disable_single_step(struct task_struct *child)
+{
+       /* Always clear TIF_SINGLESTEP... */
+       clear_tsk_thread_flag(child, TIF_SINGLESTEP);
+
+       /* But touch TF only if it was set by us.. */
+       if (child->ptrace & PT_DTRACE) {
+               struct pt_regs *regs = task_pt_regs(child);
+               regs->eflags &= ~X86_EFLAGS_TF;
+               child->ptrace &= ~PT_DTRACE;
+       }
+}