[PATCH 7/10] Fixed pnp bios limits

From: Zachary Amsden
Date: Wed Nov 09 2005 - 19:42:15 EST


PnP BIOS data, code, and 32-bit entry segments all have fixed limits
as well; set them in the GDT rather than adding more code. It would
be nice to add these fixups to the boot GDT rather than setting the
GDT for each CPU; perhaps I can wiggle this in later, but getting
it in before the subsys init looks tricky.

Also, make some progress on deprecating the ugly Q_SET_SEL macros.

Signed-off-by: Zachary Amsden <zach@xxxxxxxxxx>
Index: linux-2.6.14/arch/i386/kernel/head.S
===================================================================
--- linux-2.6.14.orig/arch/i386/kernel/head.S 2005-11-09 01:46:48.000000000 -0800
+++ linux-2.6.14/arch/i386/kernel/head.S 2005-11-09 06:11:35.000000000 -0800
@@ -504,10 +504,14 @@
.quad 0x0000000000000000 /* 0x80 TSS descriptor */
.quad 0x0000000000000000 /* 0x88 LDT descriptor */

- /* Segments used for calling PnP BIOS have byte granularity */
- .quad 0x00409a0000000000 /* 0x90 32-bit code */
- .quad 0x00009a0000000000 /* 0x98 16-bit code */
- .quad 0x0000920000000000 /* 0xa0 16-bit data */
+ /*
+ * Segments used for calling PnP BIOS have byte granularity.
+ * They code segments and data segments have fixed 64k limits,
+ * the transfer segment sizes are set at run time.
+ */
+ .quad 0x00409a000000ffff /* 0x90 32-bit code */
+ .quad 0x00009a000000ffff /* 0x98 16-bit code */
+ .quad 0x000092000000ffff /* 0xa0 16-bit data */
.quad 0x0000920000000000 /* 0xa8 16-bit data */
.quad 0x0000920000000000 /* 0xb0 16-bit data */

Index: linux-2.6.14/drivers/pnp/pnpbios/bioscalls.c
===================================================================
--- linux-2.6.14.orig/drivers/pnp/pnpbios/bioscalls.c 2005-11-09 05:30:24.000000000 -0800
+++ linux-2.6.14/drivers/pnp/pnpbios/bioscalls.c 2005-11-09 06:12:53.000000000 -0800
@@ -58,13 +58,6 @@
".previous \n"
);

-#define Q_SET_SEL(cpu, selname, address, size) \
-do { \
-struct desc_struct *gdt = get_cpu_gdt_table((cpu)); \
-set_base(gdt[(selname) >> 3], __va((u32)(address))); \
-set_limit(gdt[(selname) >> 3], size); \
-} while(0)
-
#define Q2_SET_SEL(cpu, selname, address, size) \
do { \
struct desc_struct *gdt = get_cpu_gdt_table((cpu)); \
@@ -534,8 +527,8 @@
struct desc_struct *gdt = get_cpu_gdt_table(i);
if (!gdt)
continue;
- Q2_SET_SEL(i, PNP_CS32, &pnp_bios_callfunc, 64 * 1024);
- Q_SET_SEL(i, PNP_CS16, header->fields.pm16cseg, 64 * 1024);
- Q_SET_SEL(i, PNP_DS, header->fields.pm16dseg, 64 * 1024);
- }
+ set_base(gdt[GDT_ENTRY_PNPBIOS_CS32], &pnp_bios_callfunc);
+ set_base(gdt[GDT_ENTRY_PNPBIOS_CS16], __va(header->fields.pm16cseg));
+ set_base(gdt[GDT_ENTRY_PNPBIOS_DS], __va(header->fields.pm16dseg));
+ }
}
-
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