amd64/178357: [patch] export CPU physical and virtual address sizes in sysctl oids using do_cpuid

[Sofian Brabez]

>Number:         178357
>Category:       amd64
>Synopsis:       [patch] export CPU physical and virtual address sizes in sysctl oids using do_cpuid
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-amd64
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          change-request
>Submitter-Id:   current-users
>Arrival-Date:   Sun May 05 22:50:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator:     Sofian Brabez
>Release:        FreeBSD 10.0-CURRENT amd64
>Organization:
>Environment:
System: FreeBSD ogoshi.lan 10.0-CURRENT FreeBSD 10.0-CURRENT #3 r250287M: Sun May 5 21:59:15 CEST 2013 root at ogoshi.lan:/usr/obj/usr/home/sbz/freebsd/svn/src/sys/GENERIC amd64

>Description:
This patch export CPU Physical and Virtual address sizes through the sysctl interface
using do_cpuid function.

It also patch the sys/modules/linprocfs module add this information in the
/usr/compat/linux/proc/cpuinfo output like it's done in Linux /proc/cpuinfo.

More details can be found here: http://people.freebsd.org/~sbz/cpu/
>How-To-Repeat:
>Fix:

Apply the given patch.

--- address_sizes.diff begins here ---
Index: amd64/amd64/identcpu.c
===================================================================
--- amd64/amd64/identcpu.c	(revision 250287)
+++ amd64/amd64/identcpu.c	(working copy)
@@ -109,6 +109,12 @@
 SYSCTL_INT(_hw, OID_AUTO, clockrate, CTLFLAG_RD, 
     &hw_clockrate, 0, "CPU instruction clock rate");
 
+SYSCTL_UINT(_machdep, OID_AUTO, cpu_physical_address_bits, CTLFLAG_RD,
+    &cpu_pma_bits, 0, "CPU physical address bits");
+
+SYSCTL_UINT(_machdep, OID_AUTO, cpu_virtual_address_bits, CTLFLAG_RD,
+    &cpu_vma_bits, 0, "CPU virtual address bits");
+
 static eventhandler_tag tsc_post_tag;
 
 static char cpu_brand[48];
@@ -516,6 +522,16 @@
 	cpu_feature = regs[3];
 	cpu_feature2 = regs[2];
 
+	/* Intel CPUID Specification chapter 5.2.7 
+	 * eax=0x80000008
+	 * */
+	do_cpuid(0x80000008, regs);
+
+	/* upper bits are virtual size */
+	cpu_vma_bits = ((regs[0] >> 8) & 0xFF);
+	/* lower bits are physical size */
+	cpu_pma_bits = (regs[0] & 0xFF);
+
 	/*
 	 * Clear "Limit CPUID Maxval" bit and get the largest standard CPUID
 	 * function number again if it is set from BIOS.  It is necessary
Index: amd64/amd64/initcpu.c
===================================================================
--- amd64/amd64/initcpu.c	(revision 250287)
+++ amd64/amd64/initcpu.c	(working copy)
@@ -66,10 +66,12 @@
 u_int	cpu_high;		/* Highest arg to CPUID */
 u_int	cpu_exthigh;		/* Highest arg to extended CPUID */
 u_int	cpu_id;			/* Stepping ID */
+u_int	cpu_pma_bits;		/* CPU physical address bits */
 u_int	cpu_procinfo;		/* HyperThreading Info / Brand Index / CLFUSH */
 u_int	cpu_procinfo2;		/* Multicore info */
 char	cpu_vendor[20];		/* CPU Origin code */
 u_int	cpu_vendor_id;		/* CPU vendor ID */
+u_int	cpu_vma_bits;		/* CPU virtual address bits */
 u_int	cpu_fxsr;		/* SSE enabled */
 u_int	cpu_mxcsr_mask;		/* Valid bits in mxcsr */
 u_int	cpu_clflush_line_size = 32;
Index: amd64/include/md_var.h
===================================================================
--- amd64/include/md_var.h	(revision 250287)
+++ amd64/include/md_var.h	(working copy)
@@ -54,10 +54,12 @@
 extern	u_int	cpu_id;
 extern	u_int	cpu_max_ext_state_size;
 extern	u_int	cpu_mxcsr_mask;
+extern u_int	cpu_pma_bits;
 extern	u_int	cpu_procinfo;
 extern	u_int	cpu_procinfo2;
 extern	char	cpu_vendor[];
 extern	u_int	cpu_vendor_id;
+extern u_int	cpu_vma_bits;
 extern	char	ctx_switch_xsave[];
 extern	char	kstack[];
 extern	char	sigcode[];
Index: compat/linprocfs/linprocfs.c
===================================================================
--- compat/linprocfs/linprocfs.c	(revision 250287)
+++ compat/linprocfs/linprocfs.c	(working copy)
@@ -310,6 +310,12 @@
 		    fqmhz, fqkhz, fqmhz, fqkhz);
 	}
 
+	if (cpu_vma_bits != 0 && cpu_vma_bits != 0) {
+		sbuf_printf(sb,
+		    "address sizes\t: %u bits physical, %u bits virtual\n",
+		    cpu_pma_bits, cpu_vma_bits);
+	}
+
 	return (0);
 }
 #endif /* __i386__ || __amd64__ */
--- address_sizes.diff ends here ---


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