[PATCH v7 008/120] x86/cpu/transmeta: Rescan CPUID(0x1) after capability unhide

"Ahmed S. Darwish" <[email protected]> Thu, 28 May 2026 17:37:30 +0200
Newsgroups dev.linux.lists.x86-cpuid,org.kernel.vger.linux-kernel
Message-ID <[email protected]>
Transmeta CPUs allow masking CPUID(0x1).EDX feature flags via MSR writes.
If a bit is cleared in the 0x80860004 MSR, its corresponding feature flag
is not reported by CPUID.

Refresh the CPUID parser's CPUID(0x1) cache while all of that MSR bits are
unmasked.

Note, the MSR 0x80860004 semantics are documented at the "BIOS Programmer's
Guide: Transmeta Crusoe Processor", dated June 14, 2002.

Signed-off-by: Ahmed S. Darwish <[email protected]>
---
 arch/x86/kernel/cpu/transmeta.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/cpu/transmeta.c b/arch/x86/kernel/cpu/transmeta.c
index 1fdcd69c625c..d9e0edb379b8 100644
--- a/arch/x86/kernel/cpu/transmeta.c
+++ b/arch/x86/kernel/cpu/transmeta.c
@@ -88,6 +88,7 @@ static void init_transmeta(struct cpuinfo_x86 *c)
 	/* Unhide possibly hidden capability flags */
 	rdmsr(0x80860004, cap_mask, uk);
 	wrmsr(0x80860004, ~0, uk);
+	cpuid_refresh_leaf(c, 0x1);
 	c->x86_capability[CPUID_1_EDX] = cpuid_edx(0x00000001);
 	wrmsr(0x80860004, cap_mask, uk);
 
-- 
2.54.0