From: Stas Sergeev <stsp@aknet.ru>
The previous discussion was started here:
http://www.uwsg.iu.edu/hypermail/linux/kernel/0211.0/0477.html but in 2.4
times this was kind of problematic.
Now, with the lazy bitmap allocation and per-CPU TSS, this will really not
drain any resources I think. 8K TSS increase and 8K per process *that does
ioperm()* - I think it is not very bad.
The reasons why I need that, are described in the URL above. Basically this
will allow to use full-screen VESA under dosemu (without LFB though), and this
may be also helpfull for the XFree project and some other projects:
http://www.uwsg.iu.edu/hypermail/linux/kernel/9807.1/1079.html
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/include/asm-i386/desc.h | 3 ++-
25-akpm/include/asm-i386/processor.h | 6 +++---
25-akpm/include/asm-mips/processor.h | 4 ++--
25-akpm/include/asm-x86_64/processor.h | 4 ++--
4 files changed, 9 insertions(+), 8 deletions(-)
diff -puN include/asm-i386/desc.h~larger-io-bitmap include/asm-i386/desc.h
--- 25/include/asm-i386/desc.h~larger-io-bitmap Fri Jun 18 15:40:31 2004
+++ 25-akpm/include/asm-i386/desc.h Fri Jun 18 15:40:31 2004
@@ -44,7 +44,8 @@ __asm__ __volatile__ ("movw %w3,0(%2)\n\
static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr)
{
- _set_tssldt_desc(&cpu_gdt_table[cpu][entry], (int)addr, 235, 0x89);
+ _set_tssldt_desc(&cpu_gdt_table[cpu][entry], (int)addr,
+ offsetof(struct tss_struct, __cacheline_filler) - 1, 0x89);
}
#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
diff -puN include/asm-i386/processor.h~larger-io-bitmap include/asm-i386/processor.h
--- 25/include/asm-i386/processor.h~larger-io-bitmap Fri Jun 18 15:40:31 2004
+++ 25-akpm/include/asm-i386/processor.h Fri Jun 18 15:40:31 2004
@@ -297,9 +297,9 @@ extern unsigned int mca_pentium_flag;
#define TASK_UNMAPPED_BASE (PAGE_ALIGN(TASK_SIZE / 3))
/*
- * Size of io_bitmap, covering ports 0 to 0x3ff.
+ * Size of io_bitmap.
*/
-#define IO_BITMAP_BITS 1024
+#define IO_BITMAP_BITS 65536
#define IO_BITMAP_BYTES (IO_BITMAP_BITS/8)
#define IO_BITMAP_LONGS (IO_BITMAP_BYTES/sizeof(long))
#define IO_BITMAP_OFFSET offsetof(struct tss_struct,io_bitmap)
@@ -391,7 +391,7 @@ struct tss_struct {
/*
* pads the TSS to be cacheline-aligned (size is 0x100)
*/
- unsigned long __cacheline_filler[5];
+ unsigned long __cacheline_filler[37];
/*
* .. and then another 0x100 bytes for emergency kernel stack
*/
diff -puN include/asm-mips/processor.h~larger-io-bitmap include/asm-mips/processor.h
--- 25/include/asm-mips/processor.h~larger-io-bitmap Fri Jun 18 15:40:31 2004
+++ 25-akpm/include/asm-mips/processor.h Fri Jun 18 15:40:31 2004
@@ -137,9 +137,9 @@ extern unsigned int vced_count, vcei_cou
#endif
/*
- * Size of io_bitmap in longwords: 32 is ports 0-0x3ff.
+ * Size of io_bitmap in longwords.
*/
-#define IO_BITMAP_SIZE 32
+#define IO_BITMAP_SIZE 2048
#define NUM_FPU_REGS 32
diff -puN include/asm-x86_64/processor.h~larger-io-bitmap include/asm-x86_64/processor.h
--- 25/include/asm-x86_64/processor.h~larger-io-bitmap Fri Jun 18 15:40:31 2004
+++ 25-akpm/include/asm-x86_64/processor.h Fri Jun 18 15:40:31 2004
@@ -178,9 +178,9 @@ static inline void clear_in_cr4 (unsigne
(test_thread_flag(TIF_IA32) ? TASK_UNMAPPED_32 : TASK_UNMAPPED_64)
/*
- * Size of io_bitmap, covering ports 0 to 0x3ff.
+ * Size of io_bitmap.
*/
-#define IO_BITMAP_BITS 1024
+#define IO_BITMAP_BITS 65536
#define IO_BITMAP_BYTES (IO_BITMAP_BITS/8)
#define IO_BITMAP_LONGS (IO_BITMAP_BYTES/sizeof(long))
#define IO_BITMAP_OFFSET offsetof(struct tss_struct,io_bitmap)
_