RE: [PATCH] gdb, btrace: fix family and model computation

["Metzger, Markus T" <markus.t.metzger@intel.com>]

[-- Attachment #1: Type: text/plain, Size: 1193 bytes --]

Hello Tom,

>Markus>  	      cpu.family = (cpuid >> 8) & 0xf;
>Markus> -	      cpu.model = (cpuid >> 4) & 0xf;
>Markus> +	      if (cpu.family == 0xf)
>Markus> +		cpu.family += (cpuid >> 20) & 0xff;
>
>Markus> -	      if (cpu.family == 0x6)
>Markus> +	      cpu.model = (cpuid >> 4) & 0xf;
>Markus> +	      if ((cpu.family == 0x6) || ((cpu.family & 0xf) == 0xf))
>Markus>  		cpu.model += (cpuid >> 12) & 0xf0;
>
>I wonder if these magic numbers have #defines anywhere we could use.

In fact,

    bb368aad297 gprofng: a new GNU profiler

added the same functionality, so now we have two versions of it.  I tried
to unify them (attached) but wasn't able to pass gprofng tests on my box.
They already fail without my changes.

I could replace this patch with the attached two.  What do you think?

regards,
markus.

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[-- Attachment #2: 0001-make-gprofng-cpu-identification-available-to-others.patch --]
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From 606a3f58ae40d46d901703b64754a4789e9f2ae6 Mon Sep 17 00:00:00 2001
From: Markus Metzger <markus.t.metzger@intel.com>
Date: Mon, 24 Oct 2022 05:43:08 +0200
Subject: [PATCH 1/2] make gprofng cpu identification available to others

---
 gprofng/common/hwcdrv.c                      |  2 +-
 gprofng/common/cpuid.c => include/cpuident.h | 17 +++++++++++++----
 2 files changed, 14 insertions(+), 5 deletions(-)
 rename gprofng/common/cpuid.c => include/cpuident.h (96%)

diff --git a/gprofng/common/hwcdrv.c b/gprofng/common/hwcdrv.c
index 03c3a71c8e2..115638aa623 100644
--- a/gprofng/common/hwcdrv.c
+++ b/gprofng/common/hwcdrv.c
@@ -32,7 +32,7 @@
 /* macros */
 #define IS_GLOBAL /* Mark global symbols */
 
-#include "cpuid.c" /* ftns for identifying a chip */
+#include "cpuident.h" /* ftns for identifying a chip */
 
 static hdrv_pcbe_api_t hdrv_pcbe_core_api;
 static hdrv_pcbe_api_t hdrv_pcbe_opteron_api;
diff --git a/gprofng/common/cpuid.c b/include/cpuident.h
similarity index 96%
rename from gprofng/common/cpuid.c
rename to include/cpuident.h
index 211e09aa8ac..7ab6fc1f2b1 100644
--- a/gprofng/common/cpuid.c
+++ b/include/cpuident.h
@@ -18,6 +18,11 @@
    Foundation, 51 Franklin Street - Fifth Floor, Boston,
    MA 02110-1301, USA.  */
 
+#ifndef _CPUIDENT_H
+#define _CPUIDENT_H
+
+#include <stdint.h>
+
 #if defined(__i386__) || defined(__x86_64)
 #include <cpuid.h>  /* GCC-provided */
 #elif defined(__aarch64__)
@@ -85,7 +90,7 @@ typedef struct
 
 
 #if defined(__i386__) || defined(__x86_64)
-static uint_t
+static unsigned int
 cpuid_vendorstr_to_vendorcode (char *vendorstr)
 {
   if (strcmp (vendorstr, X86_VENDORSTR_Intel) == 0)
@@ -101,8 +106,10 @@ my_cpuid (unsigned int op, cpuid_regs_t *regs)
 {
   regs->eax = regs->ebx = regs->ecx = regs->edx = 0;
   int ret = __get_cpuid (op, &regs->eax, &regs->ebx, &regs->ecx, &regs->edx);
+#ifdef DBG_LT1
   TprintfT (DBG_LT1, "my_cpuid: __get_cpuid(0x%x, 0x%x, 0x%x, 0x%x, 0x%x) returns %d\n",
 	    op, regs->eax, regs->ebx, regs->ecx, regs->edx, ret);
+#endif
   return ret;
 }
 #endif
@@ -184,20 +191,22 @@ get_cpuid_info ()
   return cpi;
 }
 
-static inline uint_t
+static inline unsigned int
 cpuid_getvendor ()
 {
   return get_cpuid_info ()->cpi_vendor;
 }
 
-static inline uint_t
+static inline unsigned int
 cpuid_getfamily ()
 {
   return get_cpuid_info ()->cpi_family;
 }
 
-static inline uint_t
+static inline unsigned int
 cpuid_getmodel ()
 {
   return get_cpuid_info ()->cpi_model;
 }
+
+#endif /* _CPUIDENT_H */
-- 
2.37.3


[-- Attachment #3: 0002-use-cpuident.h-to-implement-btrace_this_cpu.patch --]
[-- Type: application/octet-stream, Size: 1943 bytes --]

From 82f8f0a44b22d494322ce592eccf0505d0abf608 Mon Sep 17 00:00:00 2001
From: Markus Metzger <markus.t.metzger@intel.com>
Date: Mon, 24 Oct 2022 07:39:42 +0200
Subject: [PATCH 2/2] use cpuident.h to implement btrace_this_cpu

---
 gdb/nat/linux-btrace.c | 37 ++++++++++++-------------------------
 1 file changed, 12 insertions(+), 25 deletions(-)

diff --git a/gdb/nat/linux-btrace.c b/gdb/nat/linux-btrace.c
index 4911630ba5c..108a4a10ecb 100644
--- a/gdb/nat/linux-btrace.c
+++ b/gdb/nat/linux-btrace.c
@@ -23,7 +23,7 @@
 #include "linux-btrace.h"
 #include "gdbsupport/common-regcache.h"
 #include "gdbsupport/gdb_wait.h"
-#include "x86-cpuid.h"
+#include "include/cpuident.h"
 #include "gdbsupport/filestuff.h"
 #include "gdbsupport/scoped_fd.h"
 #include "gdbsupport/scoped_mmap.h"
@@ -65,36 +65,23 @@ static struct btrace_cpu
 btrace_this_cpu (void)
 {
   struct btrace_cpu cpu;
-  unsigned int eax, ebx, ecx, edx;
-  int ok;
-
   memset (&cpu, 0, sizeof (cpu));
 
-  ok = x86_cpuid (0, &eax, &ebx, &ecx, &edx);
-  if (ok != 0)
+  unsigned int vendor = cpuid_getvendor ();
+  switch (vendor)
     {
-      if (ebx == signature_INTEL_ebx && ecx == signature_INTEL_ecx
-	  && edx == signature_INTEL_edx)
-	{
-	  unsigned int cpuid, ignore;
-
-	  ok = x86_cpuid (1, &cpuid, &ignore, &ignore, &ignore);
-	  if (ok != 0)
-	    {
-	      cpu.vendor = CV_INTEL;
-
-	      cpu.family = (cpuid >> 8) & 0xf;
-	      cpu.model = (cpuid >> 4) & 0xf;
+    case X86_VENDOR_Intel:
+      cpu.vendor = CV_INTEL;
+      break;
 
-	      if (cpu.family == 0x6)
-		cpu.model += (cpuid >> 12) & 0xf0;
-	    }
-	}
-      else if (ebx == signature_AMD_ebx && ecx == signature_AMD_ecx
-	       && edx == signature_AMD_edx)
-	cpu.vendor = CV_AMD;
+    case X86_VENDOR_AMD:
+      cpu.vendor = CV_AMD;
+      break;
     }
 
+  cpu.family = (unsigned short) cpuid_getfamily ();
+  cpu.model = (unsigned char) cpuid_getmodel ();
+
   return cpu;
 }
 
-- 
2.37.3