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Subject[PATCH 3/4] x86, CPU: Add AMD TLB size detection
Date
From: Borislav Petkov <borislav.petkov@amd.com>

Read I- and DTLB entries count from CPUID on AMD. Handle all the
different family-specific cases.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
---
arch/x86/kernel/cpu/amd.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 9d92e19039f0..48e9d33245d9 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -737,6 +737,56 @@ static unsigned int __cpuinit amd_size_cache(struct cpuinfo_x86 *c,
}
#endif

+static void __cpuinit cpu_detect_tlb_amd(struct cpuinfo_x86 *c)
+{
+ u32 ebx, eax, ecx, edx;
+ u16 mask = 0xfff;
+
+ if (c->x86 < 0xf)
+ return;
+
+ cpuid(0x80000006, &eax, &ebx, &ecx, &edx);
+
+ tlb_lld_4k[ENTRIES] = (ebx >> 16) & mask;
+ tlb_lli_4k[ENTRIES] = ebx & mask;
+
+ /*
+ * K8 doesn't have 2M/4M entries in the L2 TLB so read out the L1 TLB
+ * characteristics from the CPUID function 0x80000005 instead.
+ */
+ if (c->x86 == 0xf) {
+ cpuid(0x80000005, &eax, &ebx, &ecx, &edx);
+ mask = 0xff;
+ }
+
+ /* Handle DTLB 2M and 4M sizes, fall back to L1 if L2 is disabled */
+ if (!((eax >> 16) & mask)) {
+ u32 a, b, c, d;
+
+ cpuid(0x80000005, &a, &b, &c, &d);
+ tlb_lld_2m[ENTRIES] = (a >> 16) & 0xff;
+ } else {
+ tlb_lld_2m[ENTRIES] = (eax >> 16) & mask;
+ }
+
+ /* a 4M entry uses two 2M entries */
+ tlb_lld_4m[ENTRIES] = tlb_lld_2m[ENTRIES] >> 1;
+
+ /* Handle ITLB 2M and 4M sizes, fall back to L1 if L2 is disabled */
+ if (!(eax & mask)) {
+ /* Erratum 658 */
+ if (c->x86 == 0x15 && c->x86_model <= 0x1f) {
+ tlb_lli_2m[ENTRIES] = 1024;
+ } else {
+ cpuid(0x80000005, &eax, &ebx, &ecx, &edx);
+ tlb_lli_2m[ENTRIES] = eax & 0xff;
+ }
+ } else
+ tlb_lli_2m[ENTRIES] = eax & mask;
+
+ tlb_lli_4m[ENTRIES] = tlb_lli_2m[ENTRIES] >> 1;
+}
+
static const struct cpu_dev __cpuinitconst amd_cpu_dev = {
.c_vendor = "AMD",
.c_ident = { "AuthenticAMD" },
@@ -756,6 +806,7 @@ static const struct cpu_dev __cpuinitconst amd_cpu_dev = {
.c_size_cache = amd_size_cache,
#endif
.c_early_init = early_init_amd,
+ .c_detect_tlb = cpu_detect_tlb_amd,
.c_bsp_init = bsp_init_amd,
.c_init = init_amd,
.c_x86_vendor = X86_VENDOR_AMD,
--
1.7.11.rc1


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