arm64: enable POE and PIE to coexist

Permission Indirection Extension and Permission Overlay Extension can be
enabled independently.

When PIE is disabled and POE is enabled, the permissions set by POR_EL0 will be
applied on top of the permissions set in the PTE.

When both PIE and POE are enabled, the permissions set by POR_EL0 will be
applied on top of the permissions set by the PIRE0_EL1 register.
However PIRE0_EL1 has encodings that specifically enable and disable the
overlay from applying.

For example:
	0001	Read, Overlay applied.
	1000	Read, Overlay not applied.

Switch to using the 'Overlay applied' encodings in PIRE0_EL1, so that PIE and
POE can coexist.

Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20240822151113.1479789-22-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: jgouly

arch/arm64/include/asm/pgtable-prot.h

@@ -154,10 +154,10 @@ static inline bool __pure lpa2_is_enabled(void)
 
 #define PIE_E0	( \
 	PIRx_ELx_PERM(pte_pi_index(_PAGE_EXECONLY),      PIE_X_O) | \
-	PIRx_ELx_PERM(pte_pi_index(_PAGE_READONLY_EXEC), PIE_RX)  | \
-	PIRx_ELx_PERM(pte_pi_index(_PAGE_SHARED_EXEC),   PIE_RWX) | \
-	PIRx_ELx_PERM(pte_pi_index(_PAGE_READONLY),      PIE_R)   | \
-	PIRx_ELx_PERM(pte_pi_index(_PAGE_SHARED),        PIE_RW))
+	PIRx_ELx_PERM(pte_pi_index(_PAGE_READONLY_EXEC), PIE_RX_O)  | \
+	PIRx_ELx_PERM(pte_pi_index(_PAGE_SHARED_EXEC),   PIE_RWX_O) | \
+	PIRx_ELx_PERM(pte_pi_index(_PAGE_READONLY),      PIE_R_O)   | \
+	PIRx_ELx_PERM(pte_pi_index(_PAGE_SHARED),        PIE_RW_O))
 
 #define PIE_E1	( \
 	PIRx_ELx_PERM(pte_pi_index(_PAGE_EXECONLY),      PIE_NONE_O) | \