diff options
| author | Stas Sergeev <stsp@aknet.ru> | 2006-12-07 01:14:01 (GMT) |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-12-07 01:14:01 (GMT) |
| commit | be44d2aabce2d62f72d5751d1871b6212bf7a1c7 (patch) | |
| tree | 3f190dd5b5747ee83b50c4596b4801ce6c6b551c /include/asm-i386/desc.h | |
| parent | bb81a09e55eaf7e5f798468ab971469b6f66a259 (diff) | |
| download | linux-be44d2aabce2d62f72d5751d1871b6212bf7a1c7.tar.xz | |
[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.h | 27 |
1 files changed, 23 insertions, 4 deletions
diff --git a/include/asm-i386/desc.h b/include/asm-i386/desc.h index a0398f7..6cf2ac2 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 |