[PATCH 14/35] arm64: Disable traps for GCS usage at EL0 and EL1
Mark Brown
broonie at kernel.org
Sun Jul 16 14:51:10 PDT 2023
There are fine grained traps for GCS usage at EL0 and EL1, disable them
for the host kernel if we detect GCS.
Signed-off-by: Mark Brown <broonie at kernel.org>
---
arch/arm64/include/asm/el2_setup.h | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/arch/arm64/include/asm/el2_setup.h b/arch/arm64/include/asm/el2_setup.h
index 8e5ffb58f83e..c941b0dc0418 100644
--- a/arch/arm64/include/asm/el2_setup.h
+++ b/arch/arm64/include/asm/el2_setup.h
@@ -186,6 +186,15 @@
orr x0, x0, #HFGxTR_EL2_nPIR_EL1
orr x0, x0, #HFGxTR_EL2_nPIRE0_EL1
+ /* GCS depends on PIE so we don't check it if PIE is absent */
+ mrs_s x1, SYS_ID_AA64PFR1_EL1
+ ubfx x1, x1, #ID_AA64PFR1_EL1_GCS_SHIFT, #4
+ cbz x1, .Lset_fgt_\@
+
+ /* Disable traps of access to GCS registers at EL0 and EL1 */
+ orr x0, x0, #HFGxTR_EL2_nGCS_EL1_MASK
+ orr x0, x0, #HFGxTR_EL2_nGCS_EL0_MASK
+
.Lset_fgt_\@:
msr_s SYS_HFGRTR_EL2, x0
msr_s SYS_HFGWTR_EL2, x0
--
2.30.2
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