Re: [tip:x86/urgent] x86/CPU: Add native CPUID variants returning a single datum

From: hpa
Date: Mon Jan 09 2017 - 19:20:19 EST


On January 9, 2017 2:16:07 PM PST, tip-bot for Borislav Petkov <tipbot@xxxxxxxxx> wrote:
>Commit-ID: 5dedade6dfa243c130b85d1e4daba6f027805033
>Gitweb:
>http://git.kernel.org/tip/5dedade6dfa243c130b85d1e4daba6f027805033
>Author: Borislav Petkov <bp@xxxxxxx>
>AuthorDate: Mon, 9 Jan 2017 12:41:43 +0100
>Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>CommitDate: Mon, 9 Jan 2017 23:11:13 +0100
>
>x86/CPU: Add native CPUID variants returning a single datum
>
>... similarly to the cpuid_<reg>() variants.
>
>Signed-off-by: Borislav Petkov <bp@xxxxxxx>
>Link: http://lkml.kernel.org/r/20170109114147.5082-2-bp@xxxxxxxxx
>Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
>
>---
> arch/x86/include/asm/processor.h | 18 ++++++++++++++++++
> 1 file changed, 18 insertions(+)
>
>diff --git a/arch/x86/include/asm/processor.h
>b/arch/x86/include/asm/processor.h
>index eaf1005..1be64da 100644
>--- a/arch/x86/include/asm/processor.h
>+++ b/arch/x86/include/asm/processor.h
>@@ -219,6 +219,24 @@ static inline void native_cpuid(unsigned int *eax,
>unsigned int *ebx,
> : "memory");
> }
>
>+#define native_cpuid_reg(reg) \
>+static inline unsigned int native_cpuid_##reg(unsigned int op) \
>+{ \
>+ unsigned int eax = op, ebx, ecx = 0, edx; \
>+ \
>+ native_cpuid(&eax, &ebx, &ecx, &edx); \
>+ \
>+ return reg; \
>+}
>+
>+/*
>+ * Native CPUID functions returning a single datum.
>+ */
>+native_cpuid_reg(eax)
>+native_cpuid_reg(ebx)
>+native_cpuid_reg(ecx)
>+native_cpuid_reg(edx)
>+
> static inline void load_cr3(pgd_t *pgdir)
> {
> write_cr3(__pa(pgdir));

Any reason to not make these interfaces (leaf, subleaf) from the start?
--
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