diff options
author | Harvey Harrison <harvey.harrison@gmail.com> | 2008-01-30 07:33:00 -0500 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-01-30 07:33:00 -0500 |
commit | 1379a5ce3ffc549a7ff3daffc49c5e1c372717a3 (patch) | |
tree | 9138e94f173c6ce3bb267ca89888c72cf0a17614 /arch/x86/mm/fault_32.c | |
parent | 3d97775a80a03013abe1fd681620925f884ad18a (diff) |
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>
Diffstat (limited to 'arch/x86/mm/fault_32.c')
-rw-r--r-- | arch/x86/mm/fault_32.c | 77 |
1 files changed, 0 insertions, 77 deletions
diff --git a/arch/x86/mm/fault_32.c b/arch/x86/mm/fault_32.c index 421e276770ad..b92922a1d65f 100644 --- 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) | |||
61 | #endif | 61 | #endif |
62 | } | 62 | } |
63 | 63 | ||
64 | #ifdef CONFIG_X86_32 | ||
65 | /* | ||
66 | * Return EIP plus the CS segment base. The segment limit is also | ||
67 | * adjusted, clamped to the kernel/user address space (whichever is | ||
68 | * appropriate), and returned in *eip_limit. | ||
69 | * | ||
70 | * The segment is checked, because it might have been changed by another | ||
71 | * task between the original faulting instruction and here. | ||
72 | * | ||
73 | * If CS is no longer a valid code segment, or if EIP is beyond the | ||
74 | * limit, or if it is a kernel address when CS is not a kernel segment, | ||
75 | * then the returned value will be greater than *eip_limit. | ||
76 | * | ||
77 | * This is slow, but is very rarely executed. | ||
78 | */ | ||
79 | static inline unsigned long get_segment_eip(struct pt_regs *regs, | ||
80 | unsigned long *eip_limit) | ||
81 | { | ||
82 | unsigned long ip = regs->ip; | ||
83 | unsigned seg = regs->cs & 0xffff; | ||
84 | u32 seg_ar, seg_limit, base, *desc; | ||
85 | |||
86 | /* Unlikely, but must come before segment checks. */ | ||
87 | if (unlikely(regs->flags & VM_MASK)) { | ||
88 | base = seg << 4; | ||
89 | *eip_limit = base + 0xffff; | ||
90 | return base + (ip & 0xffff); | ||
91 | } | ||
92 | |||
93 | /* The standard kernel/user address space limit. */ | ||
94 | *eip_limit = user_mode(regs) ? USER_DS.seg : KERNEL_DS.seg; | ||
95 | |||
96 | /* By far the most common cases. */ | ||
97 | if (likely(SEGMENT_IS_FLAT_CODE(seg))) | ||
98 | return ip; | ||
99 | |||
100 | /* Check the segment exists, is within the current LDT/GDT size, | ||
101 | that kernel/user (ring 0..3) has the appropriate privilege, | ||
102 | that it's a code segment, and get the limit. */ | ||
103 | __asm__ ("larl %3,%0; lsll %3,%1" | ||
104 | : "=&r" (seg_ar), "=r" (seg_limit) : "0" (0), "rm" (seg)); | ||
105 | if ((~seg_ar & 0x9800) || ip > seg_limit) { | ||
106 | *eip_limit = 0; | ||
107 | return 1; /* So that returned ip > *eip_limit. */ | ||
108 | } | ||
109 | |||
110 | /* Get the GDT/LDT descriptor base. | ||
111 | When you look for races in this code remember that | ||
112 | LDT and other horrors are only used in user space. */ | ||
113 | if (seg & (1<<2)) { | ||
114 | /* Must lock the LDT while reading it. */ | ||
115 | mutex_lock(¤t->mm->context.lock); | ||
116 | desc = current->mm->context.ldt; | ||
117 | desc = (void *)desc + (seg & ~7); | ||
118 | } else { | ||
119 | /* Must disable preemption while reading the GDT. */ | ||
120 | desc = (u32 *)get_cpu_gdt_table(get_cpu()); | ||
121 | desc = (void *)desc + (seg & ~7); | ||
122 | } | ||
123 | |||
124 | /* Decode the code segment base from the descriptor */ | ||
125 | base = get_desc_base((struct desc_struct *)desc); | ||
126 | |||
127 | if (seg & (1<<2)) | ||
128 | mutex_unlock(¤t->mm->context.lock); | ||
129 | else | ||
130 | put_cpu(); | ||
131 | |||
132 | /* Adjust EIP and segment limit, and clamp at the kernel limit. | ||
133 | It's legitimate for segments to wrap at 0xffffffff. */ | ||
134 | seg_limit += base; | ||
135 | if (seg_limit < *eip_limit && seg_limit >= base) | ||
136 | *eip_limit = seg_limit; | ||
137 | return ip + base; | ||
138 | } | ||
139 | #endif | ||
140 | |||
141 | /* | 64 | /* |
142 | * X86_32 | 65 | * X86_32 |
143 | * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch. | 66 | * Sometimes AMD Athlon/Opteron CPUs report invalid exceptions on prefetch. |