x86: move get_segment_eip() to step.c

get_segment_eip has similarities to convert_rip_to_linear(),
and is used in a similar context.  Move get_segment_eip to
step.c to allow easier consolidation.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index 21ea22fda5fc3d4b023b0e7cb907a8e521837ba8..5884dd485db85d86b345a7f8bc665f65f47b77fb 100644 (file)
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -5,6 +5,87 @@
 #include <linux/mm.h>
 #include <linux/ptrace.h>
 
+#ifdef CONFIG_X86_32
+#include <linux/uaccess.h>
+
+#include <asm/desc.h>
+
+/*
+ * Return EIP plus the CS segment base.  The segment limit is also
+ * adjusted, clamped to the kernel/user address space (whichever is
+ * appropriate), and returned in *eip_limit.
+ *
+ * The segment is checked, because it might have been changed by another
+ * task between the original faulting instruction and here.
+ *
+ * If CS is no longer a valid code segment, or if EIP is beyond the
+ * limit, or if it is a kernel address when CS is not a kernel segment,
+ * then the returned value will be greater than *eip_limit.
+ *
+ * This is slow, but is very rarely executed.
+ */
+unsigned long get_segment_eip(struct pt_regs *regs,
+                                           unsigned long *eip_limit)
+{
+       unsigned long ip = regs->ip;
+       unsigned seg = regs->cs & 0xffff;
+       u32 seg_ar, seg_limit, base, *desc;
+
+       /* Unlikely, but must come before segment checks. */
+       if (unlikely(regs->flags & VM_MASK)) {
+               base = seg << 4;
+               *eip_limit = base + 0xffff;
+               return base + (ip & 0xffff);
+       }
+
+       /* The standard kernel/user address space limit. */
+       *eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg;
+
+       /* By far the most common cases. */
+       if (likely(SEGMENT_IS_FLAT_CODE(seg)))
+               return ip;
+
+       /* Check the segment exists, is within the current LDT/GDT size,
+          that kernel/user (ring 0..3) has the appropriate privilege,
+          that it's a code segment, and get the limit. */
+       __asm__("larl %3,%0; lsll %3,%1"
+                : "=&r" (seg_ar), "=r" (seg_limit) : "0" (0), "rm" (seg));
+       if ((~seg_ar & 0x9800) || ip > seg_limit) {
+               *eip_limit = 0;
+               return 1;        /* So that returned ip > *eip_limit. */
+       }
+
+       /* Get the GDT/LDT descriptor base.
+          When you look for races in this code remember that
+          LDT and other horrors are only used in user space. */
+       if (seg & (1<<2)) {
+               /* Must lock the LDT while reading it. */
+               mutex_lock(&current->mm->context.lock);
+               desc = current->mm->context.ldt;
+               desc = (void *)desc + (seg & ~7);
+       } else {
+               /* Must disable preemption while reading the GDT. */
+               desc = (u32 *)get_cpu_gdt_table(get_cpu());
+               desc = (void *)desc + (seg & ~7);
+       }
+
+       /* Decode the code segment base from the descriptor */
+       base = get_desc_base((struct desc_struct *)desc);
+
+       if (seg & (1<<2))
+               mutex_unlock(&current->mm->context.lock);
+       else
+               put_cpu();
+
+       /* Adjust EIP and segment limit, and clamp at the kernel limit.
+          It's legitimate for segments to wrap at 0xffffffff. */
+       seg_limit += base;
+       if (seg_limit < *eip_limit && seg_limit >= base)
+               *eip_limit = seg_limit;
+       return ip + base;
+}
+#endif
+
 #ifdef CONFIG_X86_32
 static
 #endif

diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c
index 421e276770ad3f27ba508d0ee2a1e0330e983222..b92922a1d65f4cf925d37ae8f343c6cbde3891c6 100644 (file)
--- a/arch/x86/mm/fault_32.c
+++ b/arch/x86/mm/fault_32.c
@@ -61,83 +61,6 @@ static inline int notify_page_fault(struct pt_regs *regs)
 #endif
 }
 
-#ifdef CONFIG_X86_32
-/*
- * Return EIP plus the CS segment base.  The segment limit is also
- * adjusted, clamped to the kernel/user address space (whichever is
- * appropriate), and returned in *eip_limit.
- *
- * The segment is checked, because it might have been changed by another
- * task between the original faulting instruction and here.
- *
- * If CS is no longer a valid code segment, or if EIP is beyond the
- * limit, or if it is a kernel address when CS is not a kernel segment,
- * then the returned value will be greater than *eip_limit.
- *
- * This is slow, but is very rarely executed.
- */
-static inline unsigned long get_segment_eip(struct pt_regs *regs,
-                                           unsigned long *eip_limit)
-{
-       unsigned long ip = regs->ip;
-       unsigned seg = regs->cs & 0xffff;
-       u32 seg_ar, seg_limit, base, *desc;
-
-       /* Unlikely, but must come before segment checks. */
-       if (unlikely(regs->flags & VM_MASK)) {
-               base = seg << 4;
-               *eip_limit = base + 0xffff;
-               return base + (ip & 0xffff);
-       }
-
-       /* The standard kernel/user address space limit. */
-       *eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg;
-
-       /* By far the most common cases. */
-       if (likely(SEGMENT_IS_FLAT_CODE(seg)))
-               return ip;
-
-       /* Check the segment exists, is within the current LDT/GDT size,
-          that kernel/user (ring 0..3) has the appropriate privilege,
-          that it's a code segment, and get the limit. */
-       __asm__ ("larl %3,%0; lsll %3,%1"
-                : "=&r" (seg_ar), "=r" (seg_limit) : "0" (0), "rm" (seg));
-       if ((~seg_ar & 0x9800) || ip > seg_limit) {
-               *eip_limit = 0;
-               return 1;        /* So that returned ip > *eip_limit. */
-       }
-
-       /* Get the GDT/LDT descriptor base.
-          When you look for races in this code remember that
-          LDT and other horrors are only used in user space. */
-       if (seg & (1<<2)) {
-               /* Must lock the LDT while reading it. */
-               mutex_lock(&current->mm->context.lock);
-               desc = current->mm->context.ldt;
-               desc = (void *)desc + (seg & ~7);
-       } else {
-               /* Must disable preemption while reading the GDT. */
-               desc = (u32 *)get_cpu_gdt_table(get_cpu());
-               desc = (void *)desc + (seg & ~7);
-       }
-
-       /* Decode the code segment base from the descriptor */
-       base = get_desc_base((struct desc_struct *)desc);
-
-       if (seg & (1<<2))
-               mutex_unlock(&current->mm->context.lock);
-       else
-               put_cpu();
-
-       /* Adjust EIP and segment limit, and clamp at the kernel limit.
-          It's legitimate for segments to wrap at 0xffffffff. */
-       seg_limit += base;
-       if (seg_limit < *eip_limit && seg_limit >= base)
-               *eip_limit = seg_limit;
-       return ip + base;
-}
-#endif
-
 /*
  * X86_32
  * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.

diff --git a/arch/x86/mm/fault_64.c b/arch/x86/mm/fault_64.c
index 95f142f5b5cc6053f2adeb694e0730450d7787f0..e82832961d7246519169ad706f2545f36e4478c6 100644 (file)
--- a/arch/x86/mm/fault_64.c
+++ b/arch/x86/mm/fault_64.c
@@ -64,83 +64,6 @@ static inline int notify_page_fault(struct pt_regs *regs)
 #endif
 }
 
-#ifdef CONFIG_X86_32
-/*
- * Return EIP plus the CS segment base.  The segment limit is also
- * adjusted, clamped to the kernel/user address space (whichever is
- * appropriate), and returned in *eip_limit.
- *
- * The segment is checked, because it might have been changed by another
- * task between the original faulting instruction and here.
- *
- * If CS is no longer a valid code segment, or if EIP is beyond the
- * limit, or if it is a kernel address when CS is not a kernel segment,
- * then the returned value will be greater than *eip_limit.
- *
- * This is slow, but is very rarely executed.
- */
-static inline unsigned long get_segment_eip(struct pt_regs *regs,
-                                           unsigned long *eip_limit)
-{
-       unsigned long ip = regs->ip;
-       unsigned seg = regs->cs & 0xffff;
-       u32 seg_ar, seg_limit, base, *desc;
-
-       /* Unlikely, but must come before segment checks. */
-       if (unlikely(regs->flags & VM_MASK)) {
-               base = seg << 4;
-               *eip_limit = base + 0xffff;
-               return base + (ip & 0xffff);
-       }
-
-       /* The standard kernel/user address space limit. */
-       *eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg;
-
-       /* By far the most common cases. */
-       if (likely(SEGMENT_IS_FLAT_CODE(seg)))
-               return ip;
-
-       /* Check the segment exists, is within the current LDT/GDT size,
-          that kernel/user (ring 0..3) has the appropriate privilege,
-          that it's a code segment, and get the limit. */
-       __asm__("larl %3,%0; lsll %3,%1"
-                : "=&r" (seg_ar), "=r" (seg_limit) : "0" (0), "rm" (seg));
-       if ((~seg_ar & 0x9800) || ip > seg_limit) {
-               *eip_limit = 0;
-               return 1;        /* So that returned ip > *eip_limit. */
-       }
-
-       /* Get the GDT/LDT descriptor base.
-          When you look for races in this code remember that
-          LDT and other horrors are only used in user space. */
-       if (seg & (1<<2)) {
-               /* Must lock the LDT while reading it. */
-               mutex_lock(&current->mm->context.lock);
-               desc = current->mm->context.ldt;
-               desc = (void *)desc + (seg & ~7);
-       } else {
-               /* Must disable preemption while reading the GDT. */
-               desc = (u32 *)get_cpu_gdt_table(get_cpu());
-               desc = (void *)desc + (seg & ~7);
-       }
-
-       /* Decode the code segment base from the descriptor */
-       base = get_desc_base((struct desc_struct *)desc);
-
-       if (seg & (1<<2))
-               mutex_unlock(&current->mm->context.lock);
-       else
-               put_cpu();
-
-       /* Adjust EIP and segment limit, and clamp at the kernel limit.
-          It's legitimate for segments to wrap at 0xffffffff. */
-       seg_limit += base;
-       if (seg_limit < *eip_limit && seg_limit >= base)
-               *eip_limit = seg_limit;
-       return ip + base;
-}
-#endif
-
 /*
  * X86_32
  * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch.

diff --git a/include/asm-x86/ptrace.h b/include/asm-x86/ptrace.h
index 61946fe8c0853295125d8ce16f2371e28ccf6b96..cc4456667d89547d75ed99af552a3f9fd229dc95 100644 (file)
--- a/include/asm-x86/ptrace.h
+++ b/include/asm-x86/ptrace.h
@@ -184,6 +184,8 @@ convert_rip_to_linear(struct task_struct *child, struct pt_regs *regs);
 
 #ifdef __KERNEL__
 
+unsigned long get_segment_eip(struct pt_regs *regs, unsigned long *eip_limit);
+
 /*
  * These are defined as per linux/ptrace.h, which see.
  */