diff options
| -rw-r--r-- | arch/arm64/include/asm/alternative.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/alternative.c | 36 | ||||
| -rw-r--r-- | arch/arm64/kernel/smp.c | 6 |
3 files changed, 40 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/alternative.h b/arch/arm64/include/asm/alternative.h index 6e1cb8c5af4d..01792d5c95b6 100644 --- a/arch/arm64/include/asm/alternative.h +++ b/arch/arm64/include/asm/alternative.h @@ -19,6 +19,7 @@ struct alt_instr { u8 alt_len; /* size of new instruction(s), <= orig_len */ }; +void __init apply_alternatives_early(void); void __init apply_alternatives_all(void); void apply_alternatives(void *start, size_t length); diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c index 06d650f61da7..27a50cf02356 100644 --- a/arch/arm64/kernel/alternative.c +++ b/arch/arm64/kernel/alternative.c @@ -28,6 +28,18 @@ #include <asm/sections.h> #include <linux/stop_machine.h> +/* + * early-apply features can be detected using only the boot CPU (i.e. + * no need to check capability of any secondary CPUs) and, even then, + * should only include features where we must patch the kernel very + * early in the boot process. + * + * Note that the cpufeature logic *must* be made aware of early-apply + * features to ensure they are reported as enabled without waiting + * for other CPUs to boot. + */ +#define EARLY_APPLY_FEATURE_MASK BIT(ARM64_HAS_SYSREG_GIC_CPUIF) + #define __ALT_PTR(a,f) (u32 *)((void *)&(a)->f + (a)->f) #define ALT_ORIG_PTR(a) __ALT_PTR(a, orig_offset) #define ALT_REPL_PTR(a) __ALT_PTR(a, alt_offset) @@ -105,7 +117,7 @@ static u32 get_alt_insn(struct alt_instr *alt, u32 *insnptr, u32 *altinsnptr) return insn; } -static void __apply_alternatives(void *alt_region) +static void __apply_alternatives(void *alt_region, unsigned long feature_mask) { struct alt_instr *alt; struct alt_region *region = alt_region; @@ -115,6 +127,9 @@ static void __apply_alternatives(void *alt_region) u32 insn; int i, nr_inst; + if ((BIT(alt->cpufeature) & feature_mask) == 0) + continue; + if (!cpus_have_cap(alt->cpufeature)) continue; @@ -137,6 +152,21 @@ static void __apply_alternatives(void *alt_region) } /* + * 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 apply_alternatives_early(void) +{ + struct alt_region region = { + .begin = (struct alt_instr *)__alt_instructions, + .end = (struct alt_instr *)__alt_instructions_end, + }; + + __apply_alternatives(®ion, EARLY_APPLY_FEATURE_MASK); +} + +/* * We might be patching the stop_machine state machine, so implement a * really simple polling protocol here. */ @@ -155,7 +185,7 @@ static int __apply_alternatives_multi_stop(void *unused) isb(); } else { BUG_ON(patched); - __apply_alternatives(®ion); + __apply_alternatives(®ion, ~EARLY_APPLY_FEATURE_MASK); /* Barriers provided by the cache flushing */ WRITE_ONCE(patched, 1); } @@ -176,5 +206,5 @@ void apply_alternatives(void *start, size_t length) .end = start + length, }; - __apply_alternatives(®ion); + __apply_alternatives(®ion, -1); } diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index ef1caae02110..c20dba928c58 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -452,6 +452,12 @@ void __init smp_prepare_boot_cpu(void) * cpuinfo_store_boot_cpu() above. */ update_cpu_errata_workarounds(); + /* + * We now know enough about the boot CPU to apply the + * alternatives that cannot wait until interrupt handling + * and/or scheduling is enabled. + */ + apply_alternatives_early(); } static u64 __init of_get_cpu_mpidr(struct device_node *dn) |