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Diffstat (limited to 'arch/arm64/kernel/alternative.c')
-rw-r--r--arch/arm64/kernel/alternative.c60
1 files changed, 53 insertions, 7 deletions
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c
index b5d603992d40..a9b467763153 100644
--- a/arch/arm64/kernel/alternative.c
+++ b/arch/arm64/kernel/alternative.c
@@ -32,13 +32,23 @@
#define ALT_ORIG_PTR(a) __ALT_PTR(a, orig_offset)
#define ALT_REPL_PTR(a) __ALT_PTR(a, alt_offset)
-int alternatives_applied;
+static int all_alternatives_applied;
+
+static DECLARE_BITMAP(applied_alternatives, ARM64_NCAPS);
struct alt_region {
struct alt_instr *begin;
struct alt_instr *end;
};
+bool alternative_is_applied(u16 cpufeature)
+{
+ if (WARN_ON(cpufeature >= ARM64_NCAPS))
+ return false;
+
+ return test_bit(cpufeature, applied_alternatives);
+}
+
/*
* Check if the target PC is within an alternative block.
*/
@@ -145,7 +155,8 @@ static void clean_dcache_range_nopatch(u64 start, u64 end)
} while (cur += d_size, cur < end);
}
-static void __apply_alternatives(void *alt_region, bool is_module)
+static void __apply_alternatives(void *alt_region, bool is_module,
+ unsigned long *feature_mask)
{
struct alt_instr *alt;
struct alt_region *region = alt_region;
@@ -155,6 +166,9 @@ static void __apply_alternatives(void *alt_region, bool is_module)
for (alt = region->begin; alt < region->end; alt++) {
int nr_inst;
+ if (!test_bit(alt->cpufeature, feature_mask))
+ continue;
+
/* Use ARM64_CB_PATCH as an unconditional patch */
if (alt->cpufeature < ARM64_CB_PATCH &&
!cpus_have_cap(alt->cpufeature))
@@ -192,6 +206,12 @@ static void __apply_alternatives(void *alt_region, bool is_module)
dsb(ish);
__flush_icache_all();
isb();
+
+ /* Ignore ARM64_CB bit from feature mask */
+ bitmap_or(applied_alternatives, applied_alternatives,
+ feature_mask, ARM64_NCAPS);
+ bitmap_and(applied_alternatives, applied_alternatives,
+ cpu_hwcaps, ARM64_NCAPS);
}
}
@@ -208,14 +228,19 @@ static int __apply_alternatives_multi_stop(void *unused)
/* We always have a CPU 0 at this point (__init) */
if (smp_processor_id()) {
- while (!READ_ONCE(alternatives_applied))
+ while (!READ_ONCE(all_alternatives_applied))
cpu_relax();
isb();
} else {
- BUG_ON(alternatives_applied);
- __apply_alternatives(&region, false);
+ DECLARE_BITMAP(remaining_capabilities, ARM64_NPATCHABLE);
+
+ bitmap_complement(remaining_capabilities, boot_capabilities,
+ ARM64_NPATCHABLE);
+
+ BUG_ON(all_alternatives_applied);
+ __apply_alternatives(&region, false, remaining_capabilities);
/* Barriers provided by the cache flushing */
- WRITE_ONCE(alternatives_applied, 1);
+ WRITE_ONCE(all_alternatives_applied, 1);
}
return 0;
@@ -227,6 +252,24 @@ void __init apply_alternatives_all(void)
stop_machine(__apply_alternatives_multi_stop, NULL, cpu_online_mask);
}
+/*
+ * This is called very early in the boot process (directly after we run
+ * a feature detect on the boot CPU). No need to worry about other CPUs
+ * here.
+ */
+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]);
+}
+
#ifdef CONFIG_MODULES
void apply_alternatives_module(void *start, size_t length)
{
@@ -234,7 +277,10 @@ void apply_alternatives_module(void *start, size_t length)
.begin = start,
.end = start + length,
};
+ DECLARE_BITMAP(all_capabilities, ARM64_NPATCHABLE);
+
+ bitmap_fill(all_capabilities, ARM64_NPATCHABLE);
- __apply_alternatives(&region, true);
+ __apply_alternatives(&region, true, &all_capabilities[0]);
}
#endif