diff options
| author | Andrey Petrov <andrey.petrov@intel.com> | 2016-12-07 10:47:46 -0800 |
|---|---|---|
| committer | Aaron Durbin <adurbin@chromium.org> | 2016-12-08 21:40:31 +0100 |
| commit | a697c19640527b67c4a25150ad8d01340d434a69 (patch) | |
| tree | 2e5e870dd317a86c553fbcf72ec816e264751d8f /src/soc/intel/apollolake/chip.c | |
| parent | b21e362e93993a8879906cf3fa56586b84226920 (diff) | |
| download | coreboot-a697c19640527b67c4a25150ad8d01340d434a69.tar.xz | |
soc/intel/apollolake: Move privilege drop to later stage
Previously privilege drop was happening "too early" and that caused some
PMC IPC programming (performed in FSP) to fail because sideband was
already locked out. This change set moves privilege drop to later stage,
after last FSP notify call.
BRANCH=reef
BUG=chrome-os-partner:60657
TEST=iotools rdmsr X 0x121, make sure they can't be read.
Also dmesg|grep -i IPC to make sure there are no errors related
Change-Id: Ia3a774aee5fbf92805a5c69093bfbd3d7682c3a7
Signed-off-by: Andrey Petrov <andrey.petrov@intel.com>
Reviewed-on: https://review.coreboot.org/17769
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Diffstat (limited to 'src/soc/intel/apollolake/chip.c')
| -rw-r--r-- | src/soc/intel/apollolake/chip.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/src/soc/intel/apollolake/chip.c b/src/soc/intel/apollolake/chip.c index 171e01e930..a24ca33530 100644 --- a/src/soc/intel/apollolake/chip.c +++ b/src/soc/intel/apollolake/chip.c @@ -21,6 +21,7 @@ #include <cbmem.h> #include <console/console.h> #include <cpu/cpu.h> +#include <cpu/x86/mp.h> #include <device/device.h> #include <device/pci.h> #include <fsp/api.h> @@ -499,11 +500,26 @@ struct chip_operations soc_intel_apollolake_ops = { .final = &soc_final }; +static void drop_privilege_all(void) +{ + /* Drop privilege level on all the CPUs */ + if (mp_run_on_all_cpus(&enable_untrusted_mode, 1000) < 0) + printk(BIOS_ERR, "failed to enable untrusted mode\n"); +} + void platform_fsp_notify_status(enum fsp_notify_phase phase) { - /* Hide the P2SB device to align with previous behavior. */ - if (phase == END_OF_FIRMWARE) + if (phase == END_OF_FIRMWARE) { + /* Hide the P2SB device to align with previous behavior. */ p2sb_hide(); + /* + * As per guidelines BIOS is recommended to drop CPU privilege + * level to IA_UNTRUSTED. After that certain device registers + * and MSRs become inaccessible supposedly increasing system + * security. + */ + drop_privilege_all(); + } } /* |