linux-kernel - [PATCH] avoid ifdefs in desc.h, getting rid of pack_ldt and pack

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Date:	Thu, 13 Dec 2007 12:29:31 -0200
From:	Glauber de Oliveira Costa <gcosta@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	akpm@...ux-foundation.org, glommer@...il.com, tglx@...utronix.de,
	mingo@...e.hu, ehabkost@...hat.com, jeremy@...p.org,
	avi@...ranet.com, anthony@...emonkey.ws,
	virtualization@...ts.linux-foundation.org, rusty@...tcorp.com.au,
	ak@...e.de, chrisw@...s-sol.org, rostedt@...dmis.org,
	hpa@...or.com, zach@...are.com, roland@...hat.com,
	Glauber de Oliveira Costa <gcosta@...hat.com>
Subject: [PATCH] avoid ifdefs in desc.h, getting rid of pack_ldt and pack_tss

By Andi Kleen's suggestion, this patch removes pack_ldt() and pack_tss()
wrappers in favour of a general wrapper. It saves us an ifdef and some lines
of code, but more importantly, it's more elegant.

No functional change is made.

Signed-off-by: Glauber de Oliveira Costa <gcosta@...hat.com>
---
 include/asm-x86/desc.h |   55 ++++++++++++++---------------------------------
 1 files changed, 17 insertions(+), 38 deletions(-)

diff --git a/include/asm-x86/desc.h b/include/asm-x86/desc.h
index 8849666..e302a02 100644
--- a/include/asm-x86/desc.h
+++ b/include/asm-x86/desc.h
@@ -125,21 +125,6 @@ static inline void native_write_gdt_entry(struct desc_struct *gdt, int entry,
 	memcpy(&gdt[entry], desc, size);
 }
 
-static inline void set_tssldt_descriptor(struct ldttss_desc64 *d,
-					 unsigned long tss, unsigned type,
-					 unsigned size)
-{
-	memset(d, 0, sizeof(*d));
-	d->limit0 = size & 0xFFFF;
-	d->base0 = PTR_LOW(tss);
-	d->base1 = PTR_MIDDLE(tss) & 0xFF;
-	d->type = type;
-	d->p = 1;
-	d->limit1 = (size >> 16) & 0xF;
-	d->base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF;
-	d->base3 = PTR_HIGH(tss);
-}
-
 static inline void pack_descriptor(struct desc_struct *desc, unsigned long base,
 				   unsigned long limit, unsigned char type,
 				   unsigned char flags)
@@ -151,30 +136,24 @@ static inline void pack_descriptor(struct desc_struct *desc, unsigned long base,
 	desc->p = 1;
 }
 
-static inline void pack_ldt(ldt_desc *ldt, unsigned long addr,
-			   unsigned size)
-{
 
-#ifdef CONFIG_X86_64
-		set_tssldt_descriptor(ldt,
-			     addr, DESC_LDT, size);
-#else
-		pack_descriptor(ldt, (unsigned long)addr,
-				size,
-				0x80 | DESC_LDT, 0);
-#endif
-}
-
-static inline void pack_tss(tss_desc *tss, unsigned long addr,
-			   unsigned size, unsigned entry)
+static inline void set_tssldt_descriptor(void *d, unsigned long addr,
+					 unsigned type, unsigned size)
 {
 #ifdef CONFIG_X86_64
-		set_tssldt_descriptor(tss,
-			     addr, entry, size);
+	struct ldttss_desc64 *desc = d;
+	memset(desc, 0, sizeof(*desc));
+	desc->limit0 = size & 0xFFFF;
+	desc->base0 = PTR_LOW(addr);
+	desc->base1 = PTR_MIDDLE(addr) & 0xFF;
+	desc->type = type;
+	desc->p = 1;
+	desc->limit1 = (size >> 16) & 0xF;
+	desc->base2 = (PTR_MIDDLE(addr) >> 8) & 0xFF;
+	desc->base3 = PTR_HIGH(addr);
 #else
-		pack_descriptor(tss, (unsigned long)addr,
-				size,
-				0x80 | entry, 0);
+
+	pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0);
 #endif
 }
 
@@ -190,7 +169,7 @@ static inline void __set_tss_desc(unsigned cpu, unsigned int entry, void *addr)
 	 * -1? seg base+limit should be pointing to the address of the
 	 * last valid byte
 	 */
-	pack_tss(&tss, (unsigned long)addr,
+	set_tssldt_descriptor(&tss, (unsigned long)addr,
 		IO_BITMAP_OFFSET + IO_BITMAP_BYTES + sizeof(unsigned long) - 1,
 		DESC_TSS);
 	write_gdt_entry(d, entry, &tss, DESC_TSS);
@@ -206,8 +185,8 @@ static inline void native_set_ldt(const void *addr, unsigned int entries)
 		unsigned cpu = smp_processor_id();
 		ldt_desc ldt;
 
-		pack_ldt(&ldt, (unsigned long)addr,
-				entries * sizeof(ldt) - 1);
+		set_tssldt_descriptor(&ldt, (unsigned long)addr,
+				      DESC_LDT, entries * sizeof(ldt) - 1);
 		write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT,
 				&ldt, DESC_LDT);
 		__asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
-- 
1.4.4.2

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