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authorStas Sergeev <stsp@aknet.ru>2006-12-07 02:14:01 +0100
committerAndi Kleen <andi@basil.nowhere.org>2006-12-07 02:14:01 +0100
commitbe44d2aabce2d62f72d5751d1871b6212bf7a1c7 (patch)
tree3f190dd5b5747ee83b50c4596b4801ce6c6b551c /include/asm-i386/desc.h
parentbb81a09e55eaf7e5f798468ab971469b6f66a259 (diff)
[PATCH] i386: espfix cleanup
Clean up the espfix code: - Introduced PER_CPU() macro to be used from asm - Introduced GET_DESC_BASE() macro to be used from asm - Rewrote the fixup code in asm, as calling a C code with the altered %ss appeared to be unsafe - No longer altering the stack from a .fixup section - 16bit per-cpu stack is no longer used, instead the stack segment base is patched the way so that the high word of the kernel and user %esp are the same. - Added the limit-patching for the espfix segment. (Chuck Ebbert) [jeremy@goop.org: use the x86 scaling addressing mode rather than shifting] Signed-off-by: Stas Sergeev <stsp@aknet.ru> Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Zachary Amsden <zach@vmware.com> Acked-by: Chuck Ebbert <76306.1226@compuserve.com> Acked-by: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@osdl.org>
Diffstat (limited to 'include/asm-i386/desc.h')
-rw-r--r--include/asm-i386/desc.h27
1 files changed, 23 insertions, 4 deletions
diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h
index a0398f780ca..6cf2ac2bfde 100644
--- a/include/asm-i386/desc.h
+++ b/include/asm-i386/desc.h
@@ -4,8 +4,6 @@
#include <asm/ldt.h>
#include <asm/segment.h>
-#define CPU_16BIT_STACK_SIZE 1024
-
#ifndef __ASSEMBLY__
#include <linux/preempt.h>
@@ -16,8 +14,6 @@
extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
-DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
-
struct Xgt_desc_struct {
unsigned short size;
unsigned long address __attribute__((packed));
@@ -181,6 +177,29 @@ static inline unsigned long get_desc_base(unsigned long *desc)
return base;
}
+#else /* __ASSEMBLY__ */
+
+/*
+ * GET_DESC_BASE reads the descriptor base of the specified segment.
+ *
+ * Args:
+ * idx - descriptor index
+ * gdt - GDT pointer
+ * base - 32bit register to which the base will be written
+ * lo_w - lo word of the "base" register
+ * lo_b - lo byte of the "base" register
+ * hi_b - hi byte of the low word of the "base" register
+ *
+ * Example:
+ * GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah)
+ * Will read the base address of GDT_ENTRY_ESPFIX_SS and put it into %eax.
+ */
+#define GET_DESC_BASE(idx, gdt, base, lo_w, lo_b, hi_b) \
+ movb idx*8+4(gdt), lo_b; \
+ movb idx*8+7(gdt), hi_b; \
+ shll $16, base; \
+ movw idx*8+2(gdt), lo_w;
+
#endif /* !__ASSEMBLY__ */
#endif