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drivers/intel/fsp2_0: Allow `mp_startup_all_cpus()` to run serially 

As per MP service specification, EDK2 is allowed to specify the mode
in which a 'func' routine should be executed on APs.

`SingleThread` sets to 'true' meaning to execute the function one by
one (serially) or sets to 'false' meaning to execute the function
simultaneously.

MP service API `StartupAllAPs` was designed to pass such options as
part of function argument.

But another MP service API `StartupAllCPUs` doesn't specify any such
requirement. Running the `func` simultaneously on APs results in
a coherency issue (hang while executing `func`) due to lack of
acquiring a spin lock while accessing common data structure in
multiprocessor environment.

BUG=b:199246420

Change-Id: Ia95d11408f663212fd40daa9fd9b0881a07f1ce7
Signed-off-by: Subrata Banik <subrata.banik@intel.com>
Signed-off-by: Ronak Kanabar <ronak.kanabar@intel.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/57343
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Maulik V Vaghela <maulik.v.vaghela@intel.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
This commit is contained in:
Subrata Banik 2021-09-02 21:05:29 +05:30
parent c69da57d63
commit 6af980a2ae
1 changed files with 15 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
src/drivers/intel/fsp2_0/ppi/mp_service_ppi.c
View File

@ -94,9 +94,21 @@ efi_return_status_t mp_startup_all_cpus(efi_ap_procedure procedure,
/* Run on BSP */ /* Run on BSP */
procedure(argument); procedure(argument);
/* Run on APs */ /*
if (mp_run_on_aps((void *)procedure, argument, * Run on APs Serially
MP_RUN_ON_ALL_CPUS, timeout_usec) != CB_SUCCESS) { *
* FIXME: As per MP service specification, EDK2 is allowed to specify the mode
* in which a 'func' routine should be executed on APs (i.e. execute serially
* or concurrently).
*
* MP service API `StartupAllCPUs` doesn't specify such requirement.
* Hence, running the `CpuCacheInfoCollectCoreAndCacheData`
* (UefiCpuPkg/Library/CpuCacheInfoLib/CpuCacheInfoLib.c#194)
* simultaneously on APs results in a coherency issue (hang while executing `func`)
* due to lack of acquiring a spin lock while accessing common data structure in
* multiprocessor environment.
*/
if (mp_run_on_all_aps((void *)procedure, argument, timeout_usec, false)) {
printk(BIOS_DEBUG, "%s: Exit with Failure\n", __func__); printk(BIOS_DEBUG, "%s: Exit with Failure\n", __func__);
return FSP_NOT_STARTED; return FSP_NOT_STARTED;
} }