@@ -85,11 +85,11 @@ [PcdsFeatureFlag]
gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmBlockStartupThisAp|FALSE|BOOLEAN|0x32132108
## Indicates if SMM Stack Guard will be enabled.
- # If enabled, stack overflow in SMM can be caught which eases debugging.<BR><BR>
+ # If enabled, stack overflow in SMM can be caught, preventing chaotic consequences.<BR><BR>
# TRUE - SMM Stack Guard will be enabled.<BR>
# FALSE - SMM Stack Guard will be disabled.<BR>
# @Prompt Enable SMM Stack Guard.
- gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmStackGuard|FALSE|BOOLEAN|0x1000001C
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuSmmStackGuard|TRUE|BOOLEAN|0x1000001C
## Indicates if BSP election in SMM will be enabled.
# If enabled, a BSP will be dynamically elected among all processors in each SMI.
This Feature PCD causes PiSmmCpuDxe to catch SMM stack overflow at runtime, logging a clear error message, and entering a CPU dead loop. Compared to the chaotic and catastrophic consequences of the stack leaking into, and corrupting, the SMM page table, a stack guard that is enabled by default is vastly superior. We should not require sane platforms to explicitly opt in to this safeguard; instead, we should require platforms that prefer to live dangerously to opt out of it. Stack overflow in SMM might even give rise to security vulnerabilities. Cc: Jeff Fan <jeff.fan@intel.com> Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Jordan Justen <jordan.l.justen@intel.com> Cc: Michael D Kinney <michael.d.kinney@intel.com> Ref: http://thread.gmane.org/gmane.comp.bios.edk2.devel/12864 Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1341733 Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Laszlo Ersek <lersek@redhat.com> --- UefiCpuPkg/UefiCpuPkg.dec | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) -- 1.8.3.1 _______________________________________________ edk2-devel mailing list edk2-devel@lists.01.org https://lists.01.org/mailman/listinfo/edk2-devel