powerpc/64: Used named initialisers for ibm_pa_features

The ibm_pa_features array consists of structures that describe which bit
and byte in the ibm,pa-features property toggles one or more flags in
either the CPU, MMU, or user visible feature flags.

Each one consists of 7 values, which are all unsigned long, int or char,
meaning the compiler gives us no warning if we assign the wrong values
to the wrong elements. In fact we have had a bug here in the past, where
we were setting incorrect bits, see commit 6997e57d693b ("powerpc:
scan_features() updates incorrect bits for REAL_LE").

So switch to using named initialisers for the structure elements, to
reduce the likelihood of future bugs, and hopefully improve readability
also.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index b0245be..a7b87b6 100644 (file)
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -156,21 +156,22 @@ static struct ibm_pa_feature {
        unsigned char   pabit;          /* bit number (big-endian) */
        unsigned char   invert;         /* if 1, pa bit set => clear feature */
 } ibm_pa_features[] __initdata = {
-       {0, 0, PPC_FEATURE_HAS_MMU, 0,          0, 0, 0},
-       {0, 0, PPC_FEATURE_HAS_FPU, 0,          0, 1, 0},
-       {CPU_FTR_CTRL, 0, 0, 0,                 0, 3, 0},
-       {CPU_FTR_NOEXECUTE, 0, 0, 0,            0, 6, 0},
-       {CPU_FTR_NODSISRALIGN, 0, 0, 0,         1, 1, 1},
-       {0, MMU_FTR_CI_LARGE_PAGE, 0, 0,                1, 2, 0},
-       {CPU_FTR_REAL_LE, 0, PPC_FEATURE_TRUE_LE, 0, 5, 0, 0},
+       { .pabyte = 0,  .pabit = 0, .cpu_user_ftrs = PPC_FEATURE_HAS_MMU },
+       { .pabyte = 0,  .pabit = 1, .cpu_user_ftrs = PPC_FEATURE_HAS_FPU },
+       { .pabyte = 0,  .pabit = 3, .cpu_features  = CPU_FTR_CTRL },
+       { .pabyte = 0,  .pabit = 6, .cpu_features  = CPU_FTR_NOEXECUTE },
+       { .pabyte = 1,  .pabit = 2, .mmu_features  = MMU_FTR_CI_LARGE_PAGE },
+       { .pabyte = 40, .pabit = 0, .mmu_features  = MMU_FTR_TYPE_RADIX },
+       { .pabyte = 1,  .pabit = 1, .invert = 1, .cpu_features = CPU_FTR_NODSISRALIGN },
+       { .pabyte = 5,  .pabit = 0, .cpu_features  = CPU_FTR_REAL_LE,
+                                   .cpu_user_ftrs = PPC_FEATURE_TRUE_LE },
        /*
         * If the kernel doesn't support TM (ie CONFIG_PPC_TRANSACTIONAL_MEM=n),
         * we don't want to turn on TM here, so we use the *_COMP versions
         * which are 0 if the kernel doesn't support TM.
         */
-       {CPU_FTR_TM_COMP, 0, 0,
-        PPC_FEATURE2_HTM_COMP|PPC_FEATURE2_HTM_NOSC_COMP, 22, 0, 0},
-       {0, MMU_FTR_TYPE_RADIX, 0, 0,           40, 0, 0},
+       { .pabyte = 22, .pabit = 0, .cpu_features = CPU_FTR_TM_COMP,
+         .cpu_user_ftrs2 = PPC_FEATURE2_HTM_COMP | PPC_FEATURE2_HTM_NOSC_COMP },
 };
 
 static void __init scan_features(unsigned long node, const unsigned char *ftrs,