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authorLinus Torvalds <torvalds@linux-foundation.org>2008-07-14 13:43:24 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-07-14 13:43:24 -0700
commita3da5bf84a97d48cfaf66c6842470fc403da5121 (patch)
treecdf66c0cff8c61eedd60601fc9dffdd1ed39b880 /arch/x86/lib/getuser.S
parent3b23e665b68387f5ee7b21f7b75ceea4d9acae4a (diff)
parentd59fdcf2ac501de99c3dfb452af5e254d4342886 (diff)
Merge branch 'x86/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86/for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (821 commits) x86: make 64bit hpet_set_mapping to use ioremap too, v2 x86: get x86_phys_bits early x86: max_low_pfn_mapped fix #4 x86: change _node_to_cpumask_ptr to return const ptr x86: I/O APIC: remove an IRQ2-mask hack x86: fix numaq_tsc_disable calling x86, e820: remove end_user_pfn x86: max_low_pfn_mapped fix, #3 x86: max_low_pfn_mapped fix, #2 x86: max_low_pfn_mapped fix, #1 x86_64: fix delayed signals x86: remove conflicting nx6325 and nx6125 quirks x86: Recover timer_ack lost in the merge of the NMI watchdog x86: I/O APIC: Never configure IRQ2 x86: L-APIC: Always fully configure IRQ0 x86: L-APIC: Set IRQ0 as edge-triggered x86: merge dwarf2 headers x86: use AS_CFI instead of UNWIND_INFO x86: use ignore macro instead of hash comment x86: use matching CFI_ENDPROC ...
Diffstat (limited to 'arch/x86/lib/getuser.S')
-rw-r--r--arch/x86/lib/getuser.S104
1 files changed, 104 insertions, 0 deletions
diff --git a/arch/x86/lib/getuser.S b/arch/x86/lib/getuser.S
new file mode 100644
index 000000000000..ad374003742f
--- /dev/null
+++ b/arch/x86/lib/getuser.S
@@ -0,0 +1,104 @@
+/*
+ * __get_user functions.
+ *
+ * (C) Copyright 1998 Linus Torvalds
+ * (C) Copyright 2005 Andi Kleen
+ * (C) Copyright 2008 Glauber Costa
+ *
+ * These functions have a non-standard call interface
+ * to make them more efficient, especially as they
+ * return an error value in addition to the "real"
+ * return value.
+ */
+
+/*
+ * __get_user_X
+ *
+ * Inputs: %[r|e]ax contains the address.
+ * The register is modified, but all changes are undone
+ * before returning because the C code doesn't know about it.
+ *
+ * Outputs: %[r|e]ax is error code (0 or -EFAULT)
+ * %[r|e]dx contains zero-extended value
+ *
+ *
+ * These functions should not modify any other registers,
+ * as they get called from within inline assembly.
+ */
+
+#include <linux/linkage.h>
+#include <asm/dwarf2.h>
+#include <asm/page.h>
+#include <asm/errno.h>
+#include <asm/asm-offsets.h>
+#include <asm/thread_info.h>
+#include <asm/asm.h>
+
+ .text
+ENTRY(__get_user_1)
+ CFI_STARTPROC
+ GET_THREAD_INFO(%_ASM_DX)
+ cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
+ jae bad_get_user
+1: movzb (%_ASM_AX),%edx
+ xor %eax,%eax
+ ret
+ CFI_ENDPROC
+ENDPROC(__get_user_1)
+
+ENTRY(__get_user_2)
+ CFI_STARTPROC
+ add $1,%_ASM_AX
+ jc bad_get_user
+ GET_THREAD_INFO(%_ASM_DX)
+ cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
+ jae bad_get_user
+2: movzwl -1(%_ASM_AX),%edx
+ xor %eax,%eax
+ ret
+ CFI_ENDPROC
+ENDPROC(__get_user_2)
+
+ENTRY(__get_user_4)
+ CFI_STARTPROC
+ add $3,%_ASM_AX
+ jc bad_get_user
+ GET_THREAD_INFO(%_ASM_DX)
+ cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
+ jae bad_get_user
+3: mov -3(%_ASM_AX),%edx
+ xor %eax,%eax
+ ret
+ CFI_ENDPROC
+ENDPROC(__get_user_4)
+
+#ifdef CONFIG_X86_64
+ENTRY(__get_user_8)
+ CFI_STARTPROC
+ add $7,%_ASM_AX
+ jc bad_get_user
+ GET_THREAD_INFO(%_ASM_DX)
+ cmp TI_addr_limit(%_ASM_DX),%_ASM_AX
+ jae bad_get_user
+4: movq -7(%_ASM_AX),%_ASM_DX
+ xor %eax,%eax
+ ret
+ CFI_ENDPROC
+ENDPROC(__get_user_8)
+#endif
+
+bad_get_user:
+ CFI_STARTPROC
+ xor %edx,%edx
+ mov $(-EFAULT),%_ASM_AX
+ ret
+ CFI_ENDPROC
+END(bad_get_user)
+
+.section __ex_table,"a"
+ _ASM_PTR 1b,bad_get_user
+ _ASM_PTR 2b,bad_get_user
+ _ASM_PTR 3b,bad_get_user
+#ifdef CONFIG_X86_64
+ _ASM_PTR 4b,bad_get_user
+#endif