feat(cpufeat): enable FEAT_PAuth to FEAT_STATE_CHECKED
FEAT_PAuth is the second to last feature to be a boolean choice - it's
either unconditionally compiled in and must be present in hardware or
it's not compiled in. FEAT_PAuth is architected to be backwards
compatible - a subset of the branch guarding instructions (pacia/autia)
execute as NOPs when PAuth is not present. That subset is used with
`-mbranch-protection=standard` and -march pre-8.3. This patch adds the
necessary logic to also check accesses of the non-backward compatible
registers and allow a fully checked implementation.
Note that a checked support requires -march to be pre 8.3, as otherwise
the compiler will include branch protection instructions that are not
NOPs without PAuth (eg retaa) which cannot be checked.
Change-Id: Id942c20cae9d15d25b3d72b8161333642574ddaa
Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
diff --git a/include/arch/aarch64/arch_helpers.h b/include/arch/aarch64/arch_helpers.h
index 569182a..9419583 100644
--- a/include/arch/aarch64/arch_helpers.h
+++ b/include/arch/aarch64/arch_helpers.h
@@ -238,7 +238,15 @@
/*******************************************************************************
* Strip Pointer Authentication Code
******************************************************************************/
-DEFINE_SYSOP_PARAM_FUNC(xpaci)
+static inline u_register_t xpaci(u_register_t arg)
+{
+ register u_register_t x0 asm("x0") = arg;
+
+ /* `xpaci x0` for compatibility with older compiler and/or older -march */
+ __asm__ (".arch armv8.3-a; xpaci %0\n" : "+r" (x0));
+
+ return x0;
+}
void flush_dcache_range(uintptr_t addr, size_t size);
void flush_dcache_to_popa_range(uintptr_t addr, size_t size);
diff --git a/include/arch/aarch64/asm_macros.S b/include/arch/aarch64/asm_macros.S
index dce07d9..da51bf8 100644
--- a/include/arch/aarch64/asm_macros.S
+++ b/include/arch/aarch64/asm_macros.S
@@ -329,7 +329,7 @@
.endm
/*
- * is_feat_sysreg128_present_asm - Set flags and reg if FEAT_SYSREG128
+ * is_feat_XYZ_present_asm - Set flags and reg if FEAT_XYZ
* is enabled at runtime.
*
* Arguments:
@@ -342,6 +342,15 @@
ands \reg, \reg, #(ID_AA64ISAR2_SYSREG128_MASK << ID_AA64ISAR2_SYSREG128_SHIFT)
.endm
+ .macro is_feat_pauth_present_asm reg:req, clobber:req
+ mrs \reg, ID_AA64ISAR1_EL1
+ mov_imm \clobber, ((ID_AA64ISAR1_GPI_MASK << ID_AA64ISAR1_GPI_SHIFT) \
+ | (ID_AA64ISAR1_GPA_MASK << ID_AA64ISAR1_GPA_SHIFT) \
+ | (ID_AA64ISAR1_API_MASK << ID_AA64ISAR1_API_SHIFT) \
+ | (ID_AA64ISAR1_APA_MASK << ID_AA64ISAR1_APA_SHIFT))
+ tst \reg, \clobber
+ .endm
+
.macro call_reset_handler
#if !(defined(IMAGE_BL2) && ENABLE_RME)
/* ---------------------------------------------------------------------