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-rw-r--r--arch/powerpc/kernel/prom.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 1cb69e8fb0b..9a07f97f071 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -885,6 +885,74 @@ void __init unflatten_device_tree(void)
885 DBG(" <- unflatten_device_tree()\n"); 885 DBG(" <- unflatten_device_tree()\n");
886} 886}
887 887
888/*
889 * ibm,pa-features is a per-cpu property that contains a string of
890 * attribute descriptors, each of which has a 2 byte header plus up
891 * to 254 bytes worth of processor attribute bits. First header
892 * byte specifies the number of bytes following the header.
893 * Second header byte is an "attribute-specifier" type, of which
894 * zero is the only currently-defined value.
895 * Implementation: Pass in the byte and bit offset for the feature
896 * that we are interested in. The function will return -1 if the
897 * pa-features property is missing, or a 1/0 to indicate if the feature
898 * is supported/not supported. Note that the bit numbers are
899 * big-endian to match the definition in PAPR.
900 */
901static struct ibm_pa_feature {
902 unsigned long cpu_features; /* CPU_FTR_xxx bit */
903 unsigned int cpu_user_ftrs; /* PPC_FEATURE_xxx bit */
904 unsigned char pabyte; /* byte number in ibm,pa-features */
905 unsigned char pabit; /* bit number (big-endian) */
906 unsigned char invert; /* if 1, pa bit set => clear feature */
907} ibm_pa_features[] __initdata = {
908 {0, PPC_FEATURE_HAS_MMU, 0, 0, 0},
909 {0, PPC_FEATURE_HAS_FPU, 0, 1, 0},
910 {CPU_FTR_SLB, 0, 0, 2, 0},
911 {CPU_FTR_CTRL, 0, 0, 3, 0},
912 {CPU_FTR_NOEXECUTE, 0, 0, 6, 0},
913 {CPU_FTR_NODSISRALIGN, 0, 1, 1, 1},
914 {CPU_FTR_CI_LARGE_PAGE, 0, 1, 2, 0},
915};
916
917static void __init check_cpu_pa_features(unsigned long node)
918{
919 unsigned char *pa_ftrs;
920 unsigned long len, tablelen, i, bit;
921
922 pa_ftrs = of_get_flat_dt_prop(node, "ibm,pa-features", &tablelen);
923 if (pa_ftrs == NULL)
924 return;
925
926 /* find descriptor with type == 0 */
927 for (;;) {
928 if (tablelen < 3)
929 return;
930 len = 2 + pa_ftrs[0];
931 if (tablelen < len)
932 return; /* descriptor 0 not found */
933 if (pa_ftrs[1] == 0)
934 break;
935 tablelen -= len;
936 pa_ftrs += len;
937 }
938
939 /* loop over bits we know about */
940 for (i = 0; i < ARRAY_SIZE(ibm_pa_features); ++i) {
941 struct ibm_pa_feature *fp = &ibm_pa_features[i];
942
943 if (fp->pabyte >= pa_ftrs[0])
944 continue;
945 bit = (pa_ftrs[2 + fp->pabyte] >> (7 - fp->pabit)) & 1;
946 if (bit ^ fp->invert) {
947 cur_cpu_spec->cpu_features |= fp->cpu_features;
948 cur_cpu_spec->cpu_user_features |= fp->cpu_user_ftrs;
949 } else {
950 cur_cpu_spec->cpu_features &= ~fp->cpu_features;
951 cur_cpu_spec->cpu_user_features &= ~fp->cpu_user_ftrs;
952 }
953 }
954}
955
888static int __init early_init_dt_scan_cpus(unsigned long node, 956static int __init early_init_dt_scan_cpus(unsigned long node,
889 const char *uname, int depth, 957 const char *uname, int depth,
890 void *data) 958 void *data)
@@ -969,6 +1037,8 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
969 } 1037 }
970#endif /* CONFIG_ALTIVEC */ 1038#endif /* CONFIG_ALTIVEC */
971 1039
1040 check_cpu_pa_features(node);
1041
972#ifdef CONFIG_PPC_PSERIES 1042#ifdef CONFIG_PPC_PSERIES
973 if (nthreads > 1) 1043 if (nthreads > 1)
974 cur_cpu_spec->cpu_features |= CPU_FTR_SMT; 1044 cur_cpu_spec->cpu_features |= CPU_FTR_SMT;