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i386 Fixed pnp bios limits

PATCH In review Zachary Amsden 1 participant 1 message Nov 8, 2005 Pnp support

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Zachary Amsden

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PATCH 6/21 i386 Fixed pnp bios limits

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 <[email protected]>
arch/i386/kernel/head.S +8 -4
Index: linux-2.6.14-zach-work/arch/i386/kernel/head.S
===================================================================
@@ -504,10 +504,14 @@ ENTRY(cpu_gdt_table)
 	.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 */
drivers/pnp/pnpbios/bioscalls.c +5 -11
Index: linux-2.6.14-zach-work/drivers/pnp/pnpbios/bioscalls.c
===================================================================
@@ -58,12 +58,6 @@ __asm__(
 	".previous		\n"
 );
 
-#define Q_SET_SEL(cpu, selname, address, size) \
-do { \
-set_base(per_cpu(cpu_gdt_table,cpu)[(selname) >> 3], __va((u32)(address))); \
-set_limit(per_cpu(cpu_gdt_table,cpu)[(selname) >> 3], size); \
-} while(0)
-
 #define Q2_SET_SEL(cpu, selname, address, size) \
 do { \
 set_base(per_cpu(cpu_gdt_table,cpu)[(selname) >> 3], (u32)(address)); \

@@ -523,10 +517,10 @@ void pnpbios_calls_init(union pnp_bios_i
 	pnp_bios_callpoint.offset = header->fields.pm16offset;
 	pnp_bios_callpoint.segment = PNP_CS16;
 
-	for(i=0; i < NR_CPUS; i++)
-	{
-		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);
+	for(i=0; i < NR_CPUS; i++) {
+		struct desc_struct *gdt = get_cpu_gdt_table(i);
+		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));
 	}
 }