[PATCH 4.4 082/107] x86/cpu: Make alternative_msr_write work for 32-bit code
From: Greg Kroah-Hartman
Date: Mon Jul 23 2018 - 08:46:58 EST
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jim Mattson <jmattson@xxxxxxxxxx>
commit 5f2b745f5e1304f438f9b2cd03ebc8120b6e0d3b upstream
Cast val and (val >> 32) to (u32), so that they fit in a
general-purpose register in both 32-bit and 64-bit code.
[ tglx: Made it u32 instead of uintptr_t ]
Fixes: c65732e4f721 ("x86/cpu: Restore CPUID_8000_0008_EBX reload")
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Srivatsa S. Bhat <srivatsa@xxxxxxxxxxxxx>
Reviewed-by: Matt Helsley (VMware) <matt.helsley@xxxxxxxxx>
Reviewed-by: Alexey Makhalov <amakhalov@xxxxxxxxxx>
Reviewed-by: Bo Gan <ganb@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/nospec-branch.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -219,8 +219,8 @@ void alternative_msr_write(unsigned int
{
asm volatile(ALTERNATIVE("", "wrmsr", %c[feature])
: : "c" (msr),
- "a" (val),
- "d" (val >> 32),
+ "a" ((u32)val),
+ "d" ((u32)(val >> 32)),
[feature] "i" (feature)
: "memory");
}