This adds a fairly brain dead torture test for TLB flushes intended for stressing the MTTCG QEMU build. It takes the usual -smp option for multiple CPUs.
By default it will do a TLBIALL flush after each cycle. If you pass -append "page" to the kernel it will take it in turns to flush each of the computation functions. At the moment it doesn't do any re-mapping of pages but maybe that is something that could be done in the future. [DEV VERSION FOR COMMENT] Signed-off-by: Alex Bennée <[email protected]> --- arm/tlbflush.c | 163 +++++++++++++++++++++++++++++++++++++++++++ config/config-arm-common.mak | 4 +- lib/arm/asm/mmu.h | 11 +++ 3 files changed, 177 insertions(+), 1 deletion(-) create mode 100644 arm/tlbflush.c diff --git a/arm/tlbflush.c b/arm/tlbflush.c new file mode 100644 index 0000000..6eeff18 --- /dev/null +++ b/arm/tlbflush.c @@ -0,0 +1,163 @@ +#include <libcflat.h> +#include <asm/smp.h> +#include <asm/cpumask.h> +#include <asm/barrier.h> +#include <asm/mmu.h> + +#define SEQ_LENGTH 10 + +static cpumask_t smp_test_complete; +static int flush_count = 100000; +static int flush_self = 1; +static int flush_page = 0; + +__attribute__((aligned(0x1000))) unsigned int hash_array(int length, unsigned int *array) +{ + int i; + unsigned int sum=0; + for (i=0; i<length; i++) + { + unsigned int val = *array++; + sum ^= val; + sum ^= (val >> (val % 16)); + sum ^= (val << (val % 32)); + } + + return sum; +} + +__attribute__((aligned(0x1000))) void create_fib_sequence(int length, unsigned int *array) +{ + int i; + + /* first two values */ + array[0] = 0; + array[1] = 1; + for (i=2; i<length; i++) + { + array[i] = array[i-2] + array[i-1]; + } +} + +__attribute__((aligned(0x1000))) unsigned long long factorial(unsigned int n) +{ + unsigned int i; + unsigned long long fac = 1; + for (i=1; i<=n; i++) + { + fac = fac * i; + } + return fac; +} + +/* do some computationally expensive stuff, return a checksum of the + * results */ +__attribute__((aligned(0x1000))) unsigned int do_computation(void) +{ + unsigned int fib_array[SEQ_LENGTH]; + unsigned long long facfib_array[SEQ_LENGTH]; + unsigned int fib_hash, facfib_hash; + int cpu = smp_processor_id(); + int i, j; + + create_fib_sequence(SEQ_LENGTH, &fib_array[0]); + fib_hash = hash_array(SEQ_LENGTH, &fib_array[0]); + for (i=0; i<SEQ_LENGTH; i++) { + for (j=0; j<fib_array[i]; j++) { + facfib_array[i] = factorial(fib_array[i]+j); + } + } + facfib_hash = 0; + for (i=0; i<SEQ_LENGTH; i++) { + for (j=0; j<fib_array[i]; j++) { + facfib_hash ^= hash_array(sizeof(facfib_array)/sizeof(unsigned int), (unsigned int *)&facfib_array[0]); + } + } + +#if 0 + printf("CPU:%d FIBSEQ ", cpu); + for (i=0; i<SEQ_LENGTH; i++) + printf("%u,", fib_array[i]); + printf("\n"); + + printf("CPU:%d FACFIB ", cpu); + for (i=0; i<SEQ_LENGTH; i++) + printf("%llu,", facfib_array[i]); + printf("\n"); +#endif + + return (fib_hash ^ facfib_hash); +} + +static void * pages[] = {&hash_array, &create_fib_sequence, &factorial, &do_computation}; + +static void test_flush(void) +{ + int i, errors = 0; + int cpu = smp_processor_id(); + + unsigned int ref; + + printf("CPU%d online\n", cpu); + + ref = do_computation(); + + for (i=0; i < flush_count; i++) { + unsigned int this_ref = do_computation(); + + if (this_ref != ref) { + errors++; + printf("CPU%d: seq%d 0x%x!=0x%x\n", + cpu, i, ref, this_ref); + } + + if ((i % 1000) == 0) { + printf("CPU%d: seq%d\n", cpu, i); + } + + if (flush_self) { + if (flush_page) { + int j = (i % (sizeof(pages)/sizeof(void *))); + flush_tlb_page((unsigned long)pages[j]); + } else { + flush_tlb_all(); + } + } + } + + report("CPU%d: Done - Errors: %d\n", errors == 0, cpu, errors); + + cpumask_set_cpu(cpu, &smp_test_complete); + if (cpu != 0) + halt(); +} + +int main(int argc, char **argv) +{ + int cpu, i; + + report_prefix_push("tlbflush"); + + for (i=0; i<argc; i++) { + char *arg = argv[i]; +/* printf("arg:%d:%s\n", i, arg); */ + + if (strcmp(arg, "page") == 0) { + report_prefix_push("page"); + flush_page = 1; + } + } + + for_each_present_cpu(cpu) { + if (cpu == 0) + continue; + smp_boot_secondary(cpu, test_flush); + } + + test_flush(); + + while (!cpumask_full(&smp_test_complete)) + cpu_relax(); + + return report_summary(); +} diff --git a/config/config-arm-common.mak b/config/config-arm-common.mak index 0674daa..5b14db4 100644 --- a/config/config-arm-common.mak +++ b/config/config-arm-common.mak @@ -11,7 +11,8 @@ endif tests-common = \ $(TEST_DIR)/selftest.flat \ - $(TEST_DIR)/spinlock-test.flat + $(TEST_DIR)/spinlock-test.flat \ + $(TEST_DIR)/tlbflush.flat all: test_cases @@ -72,3 +73,4 @@ test_cases: $(generated_files) $(tests-common) $(tests) $(TEST_DIR)/selftest.elf: $(cstart.o) $(TEST_DIR)/selftest.o $(TEST_DIR)/spinlock-test.elf: $(cstart.o) $(TEST_DIR)/spinlock-test.o +$(TEST_DIR)/tlbflush.elf: $(cstart.o) $(TEST_DIR)/tlbflush.o diff --git a/lib/arm/asm/mmu.h b/lib/arm/asm/mmu.h index c1bd01c..2bb0cde 100644 --- a/lib/arm/asm/mmu.h +++ b/lib/arm/asm/mmu.h @@ -14,8 +14,11 @@ #define PTE_AF PTE_EXT_AF #define PTE_WBWA L_PTE_MT_WRITEALLOC +/* See B3.18.7 TLB maintenance operations */ + static inline void local_flush_tlb_all(void) { + /* TLBIALL */ asm volatile("mcr p15, 0, %0, c8, c7, 0" :: "r" (0)); dsb(); isb(); @@ -27,6 +30,14 @@ static inline void flush_tlb_all(void) local_flush_tlb_all(); } +static inline void flush_tlb_page(unsigned long vaddr) +{ + /* TLBIMVAA */ + asm volatile("mcr p15, 0, %0, c8, c7, 3" :: "r" (vaddr)); + dsb(); + isb(); +} + #include <asm/mmu-api.h> #endif /* __ASMARM_MMU_H_ */ -- 2.4.5 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
