Merge branch 'for-next/alternatives' into for-next/core

[platform/kernel/linux-starfive.git] / arch / arm64 / kernel / alternative.c

diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index a977759..64045e3 100644 (file)
--- a/arch/arm64/kernel/alternative.c
+++ b/arch/arm64/kernel/alternative.c
@@ -24,6 +24,9 @@
 #define ALT_ORIG_PTR(a)                __ALT_PTR(a, orig_offset)
 #define ALT_REPL_PTR(a)                __ALT_PTR(a, alt_offset)
 
+#define ALT_CAP(a)             ((a)->cpufeature & ~ARM64_CB_BIT)
+#define ALT_HAS_CB(a)          ((a)->cpufeature & ARM64_CB_BIT)
+
 /* Volatile, as we may be patching the guts of READ_ONCE() */
 static volatile int all_alternatives_applied;
 
@@ -136,8 +139,9 @@ static void clean_dcache_range_nopatch(u64 start, u64 end)
        } while (cur += d_size, cur < end);
 }
 
-static void __nocfi __apply_alternatives(struct alt_region *region, bool is_module,
-                                unsigned long *feature_mask)
+static void __nocfi __apply_alternatives(const struct alt_region *region,
+                                        bool is_module,
+                                        unsigned long *feature_mask)
 {
        struct alt_instr *alt;
        __le32 *origptr, *updptr;
@@ -145,30 +149,27 @@ static void __nocfi __apply_alternatives(struct alt_region *region, bool is_modu
 
        for (alt = region->begin; alt < region->end; alt++) {
                int nr_inst;
+               int cap = ALT_CAP(alt);
 
-               if (!test_bit(alt->cpufeature, feature_mask))
+               if (!test_bit(cap, feature_mask))
                        continue;
 
-               /* Use ARM64_CB_PATCH as an unconditional patch */
-               if (alt->cpufeature < ARM64_CB_PATCH &&
-                   !cpus_have_cap(alt->cpufeature))
+               if (!cpus_have_cap(cap))
                        continue;
 
-               if (alt->cpufeature == ARM64_CB_PATCH)
+               if (ALT_HAS_CB(alt))
                        BUG_ON(alt->alt_len != 0);
                else
                        BUG_ON(alt->alt_len != alt->orig_len);
 
-               pr_info_once("patching kernel code\n");
-
                origptr = ALT_ORIG_PTR(alt);
                updptr = is_module ? origptr : lm_alias(origptr);
                nr_inst = alt->orig_len / AARCH64_INSN_SIZE;
 
-               if (alt->cpufeature < ARM64_CB_PATCH)
-                       alt_cb = patch_alternative;
-               else
+               if (ALT_HAS_CB(alt))
                        alt_cb  = ALT_REPL_PTR(alt);
+               else
+                       alt_cb = patch_alternative;
 
                alt_cb(alt, origptr, updptr, nr_inst);
 
@@ -201,9 +202,9 @@ void apply_alternatives_vdso(void)
        const struct elf64_hdr *hdr;
        const struct elf64_shdr *shdr;
        const struct elf64_shdr *alt;
-       DECLARE_BITMAP(all_capabilities, ARM64_NPATCHABLE);
+       DECLARE_BITMAP(all_capabilities, ARM64_NCAPS);
 
-       bitmap_fill(all_capabilities, ARM64_NPATCHABLE);
+       bitmap_fill(all_capabilities, ARM64_NCAPS);
 
        hdr = (struct elf64_hdr *)vdso_start;
        shdr = (void *)hdr + hdr->e_shoff;
@@ -219,30 +220,31 @@ void apply_alternatives_vdso(void)
        __apply_alternatives(&region, false, &all_capabilities[0]);
 }
 
+static const struct alt_region kernel_alternatives = {
+       .begin  = (struct alt_instr *)__alt_instructions,
+       .end    = (struct alt_instr *)__alt_instructions_end,
+};
+
 /*
  * We might be patching the stop_machine state machine, so implement a
  * really simple polling protocol here.
  */
 static int __apply_alternatives_multi_stop(void *unused)
 {
-       struct alt_region region = {
-               .begin  = (struct alt_instr *)__alt_instructions,
-               .end    = (struct alt_instr *)__alt_instructions_end,
-       };
-
        /* We always have a CPU 0 at this point (__init) */
        if (smp_processor_id()) {
                while (!all_alternatives_applied)
                        cpu_relax();
                isb();
        } else {
-               DECLARE_BITMAP(remaining_capabilities, ARM64_NPATCHABLE);
+               DECLARE_BITMAP(remaining_capabilities, ARM64_NCAPS);
 
                bitmap_complement(remaining_capabilities, boot_capabilities,
-                                 ARM64_NPATCHABLE);
+                                 ARM64_NCAPS);
 
                BUG_ON(all_alternatives_applied);
-               __apply_alternatives(&region, false, remaining_capabilities);
+               __apply_alternatives(&kernel_alternatives, false,
+                                    remaining_capabilities);
                /* Barriers provided by the cache flushing */
                all_alternatives_applied = 1;
        }
@@ -252,6 +254,8 @@ static int __apply_alternatives_multi_stop(void *unused)
 
 void __init apply_alternatives_all(void)
 {
+       pr_info("applying system-wide alternatives\n");
+
        apply_alternatives_vdso();
        /* better not try code patching on a live SMP system */
        stop_machine(__apply_alternatives_multi_stop, NULL, cpu_online_mask);
@@ -264,15 +268,13 @@ void __init apply_alternatives_all(void)
  */
 void __init apply_boot_alternatives(void)
 {
-       struct alt_region region = {
-               .begin  = (struct alt_instr *)__alt_instructions,
-               .end    = (struct alt_instr *)__alt_instructions_end,
-       };
-
        /* If called on non-boot cpu things could go wrong */
        WARN_ON(smp_processor_id() != 0);
 
-       __apply_alternatives(&region, false, &boot_capabilities[0]);
+       pr_info("applying boot alternatives\n");
+
+       __apply_alternatives(&kernel_alternatives, false,
+                            &boot_capabilities[0]);
 }
 
 #ifdef CONFIG_MODULES
@@ -282,10 +284,18 @@ void apply_alternatives_module(void *start, size_t length)
                .begin  = start,
                .end    = start + length,
        };
-       DECLARE_BITMAP(all_capabilities, ARM64_NPATCHABLE);
+       DECLARE_BITMAP(all_capabilities, ARM64_NCAPS);
 
-       bitmap_fill(all_capabilities, ARM64_NPATCHABLE);
+       bitmap_fill(all_capabilities, ARM64_NCAPS);
 
        __apply_alternatives(&region, true, &all_capabilities[0]);
 }
 #endif
+
+noinstr void alt_cb_patch_nops(struct alt_instr *alt, __le32 *origptr,
+                              __le32 *updptr, int nr_inst)
+{
+       for (int i = 0; i < nr_inst; i++)
+               updptr[i] = cpu_to_le32(aarch64_insn_gen_nop());
+}
+EXPORT_SYMBOL(alt_cb_patch_nops);