From: H. Peter Anvin <hpa@zytor.com>
Date: Sat, 23 May 2009 23:42:19 +0000 (-0700)
Subject: Merge branch 'x86/urgent' into x86/setup
X-Git-Tag: v2.6.31-rc1~413^2
X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=ee0736627d3347be0be2769fa7b26431f9726c9d;p=cascardo%2Flinux.git

Merge branch 'x86/urgent' into x86/setup

Resolved conflicts:
	arch/x86/boot/memory.c

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---

ee0736627d3347be0be2769fa7b26431f9726c9d
diff --cc arch/x86/boot/memory.c
index d989de810cac,74b3d2ba84e9..cae3feb1035e
--- a/arch/x86/boot/memory.c
+++ b/arch/x86/boot/memory.c
@@@ -20,30 -20,38 +20,33 @@@
  static int detect_memory_e820(void)
  {
  	int count = 0;
 -	u32 next = 0;
 -	u32 size, id, edi;
 -	u8 err;
 +	struct biosregs ireg, oreg;
  	struct e820entry *desc = boot_params.e820_map;
- 	static struct e820_ext_entry buf; /* static so it is zeroed */
+ 	static struct e820entry buf; /* static so it is zeroed */
  
 +	initregs(&ireg);
 +	ireg.ax  = 0xe820;
 +	ireg.cx  = sizeof buf;
 +	ireg.edx = SMAP;
 +	ireg.di  = (size_t)&buf;
 +
  	/*
- 	 * Set this here so that if the BIOS doesn't change this field
- 	 * but still doesn't change %ecx, we're still okay...
+ 	 * Note: at least one BIOS is known which assumes that the
+ 	 * buffer pointed to by one e820 call is the same one as
+ 	 * the previous call, and only changes modified fields.  Therefore,
+ 	 * we use a temporary buffer and copy the results entry by entry.
+ 	 *
+ 	 * This routine deliberately does not try to account for
+ 	 * ACPI 3+ extended attributes.  This is because there are
+ 	 * BIOSes in the field which report zero for the valid bit for
+ 	 * all ranges, and we don't currently make any use of the
+ 	 * other attribute bits.  Revisit this if we see the extended
+ 	 * attribute bits deployed in a meaningful way in the future.
  	 */
- 	buf.ext_flags = 1;
  
  	do {
 -		size = sizeof buf;
 -
 -		/* Important: %edx and %esi are clobbered by some BIOSes,
 -		   so they must be either used for the error output
 -		   or explicitly marked clobbered.  Given that, assume there
 -		   is something out there clobbering %ebp and %edi, too. */
 -		asm("pushl %%ebp; int $0x15; popl %%ebp; setc %0"
 -		    : "=d" (err), "+b" (next), "=a" (id), "+c" (size),
 -		      "=D" (edi), "+m" (buf)
 -		    : "D" (&buf), "d" (SMAP), "a" (0xe820)
 -		    : "esi");
 +		intcall(0x15, &ireg, &oreg);
 +		ireg.ebx = oreg.ebx; /* for next iteration... */
  
  		/* BIOSes which terminate the chain with CF = 1 as opposed
  		   to %ebx = 0 don't always report the SMAP signature on
@@@ -61,15 -69,9 +64,9 @@@
  			break;
  		}
  
- 		/* ACPI 3.0 added the extended flags support.  If bit 0
- 		   in the extended flags is zero, we're supposed to simply
- 		   ignore the entry -- a backwards incompatible change! */
- 		if (oreg.cx > 20 && !(buf.ext_flags & 1))
- 			continue;
- 
- 		*desc++ = buf.std;
+ 		*desc++ = buf;
  		count++;
 -	} while (next && count < ARRAY_SIZE(boot_params.e820_map));
 +	} while (ireg.ebx && count < ARRAY_SIZE(boot_params.e820_map));
  
  	return boot_params.e820_entries = count;
  }