arm64/kernel: enable A53 erratum #8434319 handling at runtime

Omit patching of ADRP instruction at module load time if the current
CPUs are not susceptible to the erratum.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[will: Drop duplicate initialisation of .def_scope field]
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h
index bb26382..39134c4 100644 (file)
--- a/arch/arm64/include/asm/cpucaps.h
+++ b/arch/arm64/include/asm/cpucaps.h
@@ -45,7 +45,8 @@
 #define ARM64_HARDEN_BRANCH_PREDICTOR          24
 #define ARM64_HARDEN_BP_POST_GUEST_EXIT                25
 #define ARM64_HAS_RAS_EXTN                     26
+#define ARM64_WORKAROUND_843419                        27
 
-#define ARM64_NCAPS                            27
+#define ARM64_NCAPS                            28
 
 #endif /* __ASM_CPUCAPS_H */

diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index b161abd..186c0fc 100644 (file)
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -298,6 +298,15 @@ const struct arm64_cpu_capabilities arm64_errata[] = {
                           MIDR_CPU_VAR_REV(1, 2)),
        },
 #endif
+#ifdef CONFIG_ARM64_ERRATUM_843419
+       {
+       /* Cortex-A53 r0p[01234] */
+               .desc = "ARM erratum 843419",
+               .capability = ARM64_WORKAROUND_843419,
+               MIDR_RANGE(MIDR_CORTEX_A53, 0x00, 0x04),
+               MIDR_FIXED(0x4, BIT(8)),
+       },
+#endif
 #ifdef CONFIG_ARM64_ERRATUM_845719
        {
        /* Cortex-A53 r0p[01234] */

diff --git a/arch/arm64/kernel/module-plts.c b/arch/arm64/kernel/module-plts.c
index 271b773..fa36372 100644 (file)
--- a/arch/arm64/kernel/module-plts.c
+++ b/arch/arm64/kernel/module-plts.c
@@ -158,7 +158,8 @@ static unsigned int count_plts(Elf64_Sym *syms, Elf64_Rela *rela, int num,
                        break;
                case R_AARCH64_ADR_PREL_PG_HI21_NC:
                case R_AARCH64_ADR_PREL_PG_HI21:
-                       if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_843419))
+                       if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_843419) ||
+                           !cpus_have_const_cap(ARM64_WORKAROUND_843419))
                                break;
 
                        /*

diff --git a/arch/arm64/kernel/module.c b/arch/arm64/kernel/module.c
index f9d8249..719fde8 100644 (file)
--- a/arch/arm64/kernel/module.c
+++ b/arch/arm64/kernel/module.c
@@ -203,6 +203,7 @@ static int reloc_insn_adrp(struct module *mod, __le32 *place, u64 val)
        u32 insn;
 
        if (!IS_ENABLED(CONFIG_ARM64_ERRATUM_843419) ||
+           !cpus_have_const_cap(ARM64_WORKAROUND_843419) ||
            ((u64)place & 0xfff) < 0xff8)
                return reloc_insn_imm(RELOC_OP_PAGE, place, val, 12, 21,
                                      AARCH64_INSN_IMM_ADR);