Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Catalin Marinas:

 - Don't taint the kernel if CPUs have different sets of page sizes
   supported (other than the one in use).

 - Issue I-cache maintenance for module ftrace trampoline.

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: ftrace: Ensure module ftrace trampoline is coherent with I-side
  arm64: cpufeature: Don't treat granule sizes as strict

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index d19d14ba9ae401558e6e387bed2ef0b45aa211ce..b1fdc486aed8239c681acdcab1d98550bbdf60d9 100644 (file)
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -184,9 +184,17 @@ static const struct arm64_ftr_bits ftr_id_aa64zfr0[] = {
 };
 
 static const struct arm64_ftr_bits ftr_id_aa64mmfr0[] = {
-       S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN4_SHIFT, 4, ID_AA64MMFR0_TGRAN4_NI),
-       S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN64_SHIFT, 4, ID_AA64MMFR0_TGRAN64_NI),
-       ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN16_SHIFT, 4, ID_AA64MMFR0_TGRAN16_NI),
+       /*
+        * We already refuse to boot CPUs that don't support our configured
+        * page size, so we can only detect mismatches for a page size other
+        * than the one we're currently using. Unfortunately, SoCs like this
+        * exist in the wild so, even though we don't like it, we'll have to go
+        * along with it and treat them as non-strict.
+        */
+       S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN4_SHIFT, 4, ID_AA64MMFR0_TGRAN4_NI),
+       S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN64_SHIFT, 4, ID_AA64MMFR0_TGRAN64_NI),
+       ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_TGRAN16_SHIFT, 4, ID_AA64MMFR0_TGRAN16_NI),
+
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_BIGENDEL0_SHIFT, 4, 0),
        /* Linux shouldn't care about secure memory */
        ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_LOWER_SAFE, ID_AA64MMFR0_SNSMEM_SHIFT, 4, 0),

diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index 1285c7b2947fa74cf50e66b83ec163b2d7a21027..17177325797420cea45062f349f5dde71b72119b 100644 (file)
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -73,7 +73,7 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 
        if (offset < -SZ_128M || offset >= SZ_128M) {
 #ifdef CONFIG_ARM64_MODULE_PLTS
-               struct plt_entry trampoline;
+               struct plt_entry trampoline, *dst;
                struct module *mod;
 
                /*
@@ -106,23 +106,27 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
                 * to check if the actual opcodes are in fact identical,
                 * regardless of the offset in memory so use memcmp() instead.
                 */
-               trampoline = get_plt_entry(addr, mod->arch.ftrace_trampoline);
-               if (memcmp(mod->arch.ftrace_trampoline, &trampoline,
-                          sizeof(trampoline))) {
-                       if (plt_entry_is_initialized(mod->arch.ftrace_trampoline)) {
+               dst = mod->arch.ftrace_trampoline;
+               trampoline = get_plt_entry(addr, dst);
+               if (memcmp(dst, &trampoline, sizeof(trampoline))) {
+                       if (plt_entry_is_initialized(dst)) {
                                pr_err("ftrace: far branches to multiple entry points unsupported inside a single module\n");
                                return -EINVAL;
                        }
 
                        /* point the trampoline to our ftrace entry point */
                        module_disable_ro(mod);
-                       *mod->arch.ftrace_trampoline = trampoline;
+                       *dst = trampoline;
                        module_enable_ro(mod, true);
 
-                       /* update trampoline before patching in the branch */
-                       smp_wmb();
+                       /*
+                        * Ensure updated trampoline is visible to instruction
+                        * fetch before we patch in the branch.
+                        */
+                       __flush_icache_range((unsigned long)&dst[0],
+                                            (unsigned long)&dst[1]);
                }
-               addr = (unsigned long)(void *)mod->arch.ftrace_trampoline;
+               addr = (unsigned long)dst;
 #else /* CONFIG_ARM64_MODULE_PLTS */
                return -EINVAL;
 #endif /* CONFIG_ARM64_MODULE_PLTS */