When COROUTINES is enabled, schedule efi_disks_register() and efi_tcg2_register() as two coroutines in efi_init_obj_list() instead of invoking them sequentially. The voluntary yield point is introduced inside udelay() which is called frequently as a result of each function polling the hardware. This allows the two coroutines to make progress simultaneously and reduce the wall clock time required by efi_init_obj_list().
Tested on Kria KV260 with a microSD card inserted with the "printenv -e" command. With COROUTINES disabled, efi_init_obj_list() completes in 2821 ms on average (2825, 2822, 2817). With COROUTINES enabled, it takes 2265 ms (2262, 2260, 2272). That is a reduction of 556 ms which is not bad at all considering that measured separately, efi_tcg2_register() takes ~825 ms and efi_disks_register() needs ~600 ms, so assuming they would overlap perfectly one can expect a 600 ms improvement at best.
The code size penalty for this improvement is 1340 bytes.
Signed-off-by: Jerome Forissier jerome.forissier@linaro.org --- lib/efi_loader/efi_setup.c | 113 +++++++++++++++++++++++++++++++++++-- lib/time.c | 14 ++++- 2 files changed, 122 insertions(+), 5 deletions(-)
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c index aa59bc7779d..94160f4bd86 100644 --- a/lib/efi_loader/efi_setup.c +++ b/lib/efi_loader/efi_setup.c @@ -7,10 +7,12 @@
#define LOG_CATEGORY LOGC_EFI
+#include <coroutines.h> #include <efi_loader.h> #include <efi_variable.h> #include <log.h> #include <asm-generic/unaligned.h> +#include <stdlib.h>
#define OBJ_LIST_NOT_INITIALIZED 1
@@ -208,6 +210,46 @@ out: return -1; }
+#if CONFIG_IS_ENABLED(COROUTINES) + +static void efi_disks_register_co(void) +{ + efi_status_t ret; + + if (efi_obj_list_initialized != OBJ_LIST_NOT_INITIALIZED) + goto out; + + /* + * Probe block devices to find the ESP. + * efi_disks_register() must be called before efi_init_variables(). + */ + ret = efi_disks_register(); + if (ret != EFI_SUCCESS) + efi_obj_list_initialized = ret; +out: + co_exit(); +} + +static void efi_tcg2_register_co(void) +{ + efi_status_t ret = EFI_SUCCESS; + + if (efi_obj_list_initialized != OBJ_LIST_NOT_INITIALIZED) + goto out; + + if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) { + ret = efi_tcg2_register(); + if (ret != EFI_SUCCESS) + efi_obj_list_initialized = ret; + } +out: + co_exit(); +} + +extern int udelay_yield; + +#endif /* COROUTINES */ + /** * efi_init_obj_list() - Initialize and populate EFI object list * @@ -216,6 +258,12 @@ out: efi_status_t efi_init_obj_list(void) { efi_status_t ret = EFI_SUCCESS; +#if CONFIG_IS_ENABLED(COROUTINES) + struct co_stack *stk = NULL; + struct co *main_co = NULL; + struct co *co1 = NULL; + struct co *co2 = NULL; +#endif
/* Initialize once only */ if (efi_obj_list_initialized != OBJ_LIST_NOT_INITIALIZED) @@ -224,6 +272,53 @@ efi_status_t efi_init_obj_list(void) /* Set up console modes */ efi_setup_console_size();
+#if CONFIG_IS_ENABLED(COROUTINES) + main_co = co_create(NULL, NULL, 0, NULL, NULL); + if (!main_co) { + ret = EFI_OUT_OF_RESOURCES; + goto out; + } + + stk = co_stack_new(8192); + if (!stk) { + ret = EFI_OUT_OF_RESOURCES; + goto out; + } + + co1 = co_create(main_co, stk, 0, efi_disks_register_co, NULL); + if (!co1) { + ret = EFI_OUT_OF_RESOURCES; + goto out; + } + + co2 = co_create(main_co, stk, 0, efi_tcg2_register_co, NULL); + if (!co2) { + ret = EFI_OUT_OF_RESOURCES; + goto out; + } + + udelay_yield = 0xCAFEDECA; + do { + if (!co1->done) + co_resume(co1); + if (!co2->done) + co_resume(co2); + } while (!(co1->done && co2->done)); + udelay_yield = 0; + + co_stack_destroy(stk); + co_destroy(main_co); + co_destroy(co1); + co_destroy(co2); + stk = NULL; + main_co = co1 = co2 = NULL; + + if (efi_obj_list_initialized != OBJ_LIST_NOT_INITIALIZED) { + /* Some kind of error was saved by a coroutine */ + ret = efi_obj_list_initialized; + goto out; + } +#else /* * Probe block devices to find the ESP. * efi_disks_register() must be called before efi_init_variables(). @@ -232,6 +327,13 @@ efi_status_t efi_init_obj_list(void) if (ret != EFI_SUCCESS) goto out;
+ if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) { + ret = efi_tcg2_register(); + if (ret != EFI_SUCCESS) + efi_obj_list_initialized = ret; + } +#endif + /* Initialize variable services */ ret = efi_init_variables(); if (ret != EFI_SUCCESS) @@ -272,10 +374,6 @@ efi_status_t efi_init_obj_list(void) }
if (IS_ENABLED(CONFIG_EFI_TCG2_PROTOCOL)) { - ret = efi_tcg2_register(); - if (ret != EFI_SUCCESS) - goto out; - ret = efi_tcg2_do_initial_measurement(); if (ret == EFI_SECURITY_VIOLATION) goto out; @@ -350,6 +448,13 @@ efi_status_t efi_init_obj_list(void) !IS_ENABLED(CONFIG_EFI_CAPSULE_ON_DISK_EARLY)) ret = efi_launch_capsules(); out: +#if CONFIG_IS_ENABLED(COROUTINES) + co_stack_destroy(stk); + co_destroy(main_co); + co_destroy(co1); + co_destroy(co2); efi_obj_list_initialized = ret; +#endif + return ret; } diff --git a/lib/time.c b/lib/time.c index d88edafb196..c11288102fe 100644 --- a/lib/time.c +++ b/lib/time.c @@ -17,6 +17,7 @@ #include <asm/global_data.h> #include <asm/io.h> #include <linux/delay.h> +#include <coroutines.h>
#ifndef CFG_WD_PERIOD # define CFG_WD_PERIOD (10 * 1000 * 1000) /* 10 seconds default */ @@ -190,6 +191,8 @@ void __weak __udelay(unsigned long usec)
/* ------------------------------------------------------------------------- */
+int udelay_yield; + void udelay(unsigned long usec) { ulong kv; @@ -197,7 +200,16 @@ void udelay(unsigned long usec) do { schedule(); kv = usec > CFG_WD_PERIOD ? CFG_WD_PERIOD : usec; - __udelay(kv); + if (CONFIG_IS_ENABLED(COROUTINES) && + udelay_yield == 0xCAFEDECA) { + ulong t0 = timer_get_us(); + do { + co_yield(); + __udelay(10); + } while (timer_get_us() < t0 + kv); + } else { + __udelay(kv); + } usec -= kv; } while(usec); }