linux-kernel - [PATCH 12/17] x86/microcode/intel: Use *wrmsrl variants

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Date:	Wed,  3 Feb 2016 12:33:40 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	X86 ML <x86@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH 12/17] x86/microcode/intel: Use *wrmsrl variants

From: Borislav Petkov <bp@...e.de>

... and drop the 32-bit casting games which we had to do at the time
because wrmsr() was unforgiving then, see c3fd0bd5e19a from the
full history tree:

  commit c3fd0bd5e19aaff9cdd104edff136a2023db657e
  Author: Linus Torvalds <torvalds@...e.osdl.org>
  Date:   Tue Feb 17 23:23:41 2004 -0800

    Fix up the microcode update on regular 32-bit x86. Our wrmsr()
    is a bit unforgiving and really doesn't like 64-bit values.
    ...

Signed-off-by: Borislav Petkov <bp@...e.de>
---
 arch/x86/kernel/cpu/microcode/intel.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index 35186a0dd5fc..ff0b44951d12 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -370,7 +370,7 @@ static int collect_cpu_info_early(struct ucode_cpu_info *uci)
 		native_rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]);
 		csig.pf = 1 << ((val[1] >> 18) & 7);
 	}
-	native_wrmsr(MSR_IA32_UCODE_REV, 0, 0);
+	native_wrmsrl(MSR_IA32_UCODE_REV, 0);
 
 	/* As documented in the SDM: Do a CPUID 1 here */
 	sync_core();
@@ -648,10 +648,8 @@ static int apply_microcode_early(struct ucode_cpu_info *uci, bool early)
 		return 0;
 
 	/* write microcode via MSR 0x79 */
-	native_wrmsr(MSR_IA32_UCODE_WRITE,
-	      (unsigned long)mc->bits,
-	      (unsigned long)mc->bits >> 16 >> 16);
-	native_wrmsr(MSR_IA32_UCODE_REV, 0, 0);
+	native_wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);
+	native_wrmsrl(MSR_IA32_UCODE_REV, 0);
 
 	/* As documented in the SDM: Do a CPUID 1 here */
 	sync_core();
@@ -860,10 +858,8 @@ static int apply_microcode_intel(int cpu)
 		return 0;
 
 	/* write microcode via MSR 0x79 */
-	wrmsr(MSR_IA32_UCODE_WRITE,
-	      (unsigned long) mc->bits,
-	      (unsigned long) mc->bits >> 16 >> 16);
-	wrmsr(MSR_IA32_UCODE_REV, 0, 0);
+	wrmsrl(MSR_IA32_UCODE_WRITE, (unsigned long)mc->bits);
+	wrmsrl(MSR_IA32_UCODE_REV, 0);
 
 	/* As documented in the SDM: Do a CPUID 1 here */
 	sync_core();
-- 
2.3.5