Eric Lee / linux-smarc-t335x-v3.2

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Commit 487472bc01fab0625996aad37836aad931e4eda9

Authored by Andi Kleen
Committed by Linus Torvalds
1 parent c818a18146
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

[PATCH] i386: Replace broken serialize_cpu in microcode driver with correct sync_core 

Passing random input values in eax to cpuid is not a good idea
because the CPU will GPF for unknown ones.
Use the correct x86-64 version that exists for a longer time too.
This also adds a memory barrier to prevent the optimizer from
reordering.

Cc: tigran@veritas.com

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Showing 2 changed files with 6 additions and 4 deletions Side-by-side Diff

arch/i386/kernel/microcode.c
Diff comments   View file @ 487472b
... ... @@ -166,7 +166,7 @@
166 166  
167 167 wrmsr(MSR_IA32_UCODE_REV, 0, 0);
168 168 /* see notes above for revision 1.07. Apparent chip bug */
169   - serialize_cpu();
  169 + sync_core();
170 170 /* get the current revision from MSR 0x8B */
171 171 rdmsr(MSR_IA32_UCODE_REV, val[0], uci->rev);
172 172 pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n",
... ... @@ -380,7 +380,7 @@
380 380 wrmsr(MSR_IA32_UCODE_REV, 0, 0);
381 381  
382 382 /* see notes above for revision 1.07. Apparent chip bug */
383   - serialize_cpu();
  383 + sync_core();
384 384  
385 385 /* get the current revision from MSR 0x8B */
386 386 rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]);
include/asm-i386/processor.h
Diff comments   View file @ 487472b
... ... @@ -281,9 +281,11 @@
281 281 outb((data), 0x23); \
282 282 } while (0)
283 283  
284   -static inline void serialize_cpu(void)
  284 +/* Stop speculative execution */
  285 +static inline void sync_core(void)
285 286 {
286   - __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx");
  287 + int tmp;
  288 + asm volatile("cpuid" : "=a" (tmp) : "0" (1) : "ebx","ecx","edx","memory");
287 289 }
288 290  
289 291 static inline void __monitor(const void *eax, unsigned long ecx,