Re: [PATCH v4] ELF: AT_PAGE_SHIFT_MASK -- supply userspace with available page shifts
From: Alexey Dobriyan <hidden>
Date: 2024-02-09 12:30:42
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linux-arch, linux-mm, lkml
On Mon, Feb 05, 2024 at 04:48:08AM -0800, Kees Cook wrote:
On Mon, Feb 05, 2024 at 12:51:43PM +0300, Alexey Dobriyan wrote:quoted
+#define ARCH_AT_PAGE_SHIFT_MASK \ + do { \ + u32 val = 1 << 12; \ + if (boot_cpu_has(X86_FEATURE_PSE)) { \ + val |= 1 << 21; \ + } \ + if (boot_cpu_has(X86_FEATURE_GBPAGES)) { \ + val |= 1 << 30; \ + } \Can we use something besides literal "12", "21", and "30" values here?
Ehh, no, why? Inside x86_64 the page shifts are very specific numbers, they won't change.