refactor(mpam): enable FEAT_MPAM for FEAT_STATE_CHECKED
At the moment we only support FEAT_MPAM to be either unconditionally
compiled in, or to be not supported at all.
Add support for runtime detection (ENABLE_MPAM_FOR_LOWER_ELS=2), by
splitting get_mpam_version() into an ID register reading
function and a second function to report the support status. That
function considers both build time settings and runtime information (if
needed), and is used before we access MPAM related registers.
Also move the context saving code from assembly to C, and use the new
is_feat_mpam_supported() function to guard its execution.
ENABLE_MPAM_FOR_LOWER_ELS defaults to 0, so add a stub enable function
to cover builds with compiler optimisations turned off. The unused
mpam_enable() function call will normally be optimised away (because it
would never be called), but with -O0 the compiler will leave the symbol
in the object file.
Change-Id: I531d87cb855a7c43471f861f625b5a6d4bc61313
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index c5f20ad..eb5d1db 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -498,9 +498,9 @@
sve_enable(ctx);
#endif
-#if ENABLE_MPAM_FOR_LOWER_ELS
- mpam_enable(el2_unused);
-#endif
+ if (is_feat_mpam_supported()) {
+ mpam_enable(el2_unused);
+ }
if (is_feat_trbe_supported()) {
trbe_enable();
@@ -834,6 +834,96 @@
write_hfgwtr_el2(read_ctx_reg(ctx, CTX_HFGWTR_EL2));
}
+static void el2_sysregs_context_save_mpam(el2_sysregs_t *ctx)
+{
+ u_register_t mpam_idr = read_mpamidr_el1();
+
+ write_ctx_reg(ctx, CTX_MPAM2_EL2, read_mpam2_el2());
+
+ /*
+ * The context registers that we intend to save would be part of the
+ * PE's system register frame only if MPAMIDR_EL1.HAS_HCR == 1.
+ */
+ if ((mpam_idr & MPAMIDR_HAS_HCR_BIT) == 0U) {
+ return;
+ }
+
+ /*
+ * MPAMHCR_EL2, MPAMVPMV_EL2 and MPAMVPM0_EL2 are always present if
+ * MPAMIDR_HAS_HCR_BIT == 1.
+ */
+ write_ctx_reg(ctx, CTX_MPAMHCR_EL2, read_mpamhcr_el2());
+ write_ctx_reg(ctx, CTX_MPAMVPM0_EL2, read_mpamvpm0_el2());
+ write_ctx_reg(ctx, CTX_MPAMVPMV_EL2, read_mpamvpmv_el2());
+
+ /*
+ * The number of MPAMVPM registers is implementation defined, their
+ * number is stored in the MPAMIDR_EL1 register.
+ */
+ switch ((mpam_idr >> MPAMIDR_EL1_VPMR_MAX_SHIFT) & MPAMIDR_EL1_VPMR_MAX_MASK) {
+ case 7:
+ write_ctx_reg(ctx, CTX_MPAMVPM7_EL2, read_mpamvpm7_el2());
+ __fallthrough;
+ case 6:
+ write_ctx_reg(ctx, CTX_MPAMVPM6_EL2, read_mpamvpm6_el2());
+ __fallthrough;
+ case 5:
+ write_ctx_reg(ctx, CTX_MPAMVPM5_EL2, read_mpamvpm5_el2());
+ __fallthrough;
+ case 4:
+ write_ctx_reg(ctx, CTX_MPAMVPM4_EL2, read_mpamvpm4_el2());
+ __fallthrough;
+ case 3:
+ write_ctx_reg(ctx, CTX_MPAMVPM3_EL2, read_mpamvpm3_el2());
+ __fallthrough;
+ case 2:
+ write_ctx_reg(ctx, CTX_MPAMVPM2_EL2, read_mpamvpm2_el2());
+ __fallthrough;
+ case 1:
+ write_ctx_reg(ctx, CTX_MPAMVPM1_EL2, read_mpamvpm1_el2());
+ break;
+ }
+}
+
+static void el2_sysregs_context_restore_mpam(el2_sysregs_t *ctx)
+{
+ u_register_t mpam_idr = read_mpamidr_el1();
+
+ write_mpam2_el2(read_ctx_reg(ctx, CTX_MPAM2_EL2));
+
+ if ((mpam_idr & MPAMIDR_HAS_HCR_BIT) == 0U) {
+ return;
+ }
+
+ write_mpamhcr_el2(read_ctx_reg(ctx, CTX_MPAMHCR_EL2));
+ write_mpamvpm0_el2(read_ctx_reg(ctx, CTX_MPAMVPM0_EL2));
+ write_mpamvpmv_el2(read_ctx_reg(ctx, CTX_MPAMVPMV_EL2));
+
+ switch ((mpam_idr >> MPAMIDR_EL1_VPMR_MAX_SHIFT) & MPAMIDR_EL1_VPMR_MAX_MASK) {
+ case 7:
+ write_mpamvpm7_el2(read_ctx_reg(ctx, CTX_MPAMVPM7_EL2));
+ __fallthrough;
+ case 6:
+ write_mpamvpm6_el2(read_ctx_reg(ctx, CTX_MPAMVPM6_EL2));
+ __fallthrough;
+ case 5:
+ write_mpamvpm5_el2(read_ctx_reg(ctx, CTX_MPAMVPM5_EL2));
+ __fallthrough;
+ case 4:
+ write_mpamvpm4_el2(read_ctx_reg(ctx, CTX_MPAMVPM4_EL2));
+ __fallthrough;
+ case 3:
+ write_mpamvpm3_el2(read_ctx_reg(ctx, CTX_MPAMVPM3_EL2));
+ __fallthrough;
+ case 2:
+ write_mpamvpm2_el2(read_ctx_reg(ctx, CTX_MPAMVPM2_EL2));
+ __fallthrough;
+ case 1:
+ write_mpamvpm1_el2(read_ctx_reg(ctx, CTX_MPAMVPM1_EL2));
+ break;
+ }
+}
+
/*******************************************************************************
* Save EL2 sysreg context
******************************************************************************/
@@ -859,9 +949,9 @@
#if CTX_INCLUDE_MTE_REGS
el2_sysregs_context_save_mte(el2_sysregs_ctx);
#endif
-#if ENABLE_MPAM_FOR_LOWER_ELS
- el2_sysregs_context_save_mpam(el2_sysregs_ctx);
-#endif
+ if (is_feat_mpam_supported()) {
+ el2_sysregs_context_save_mpam(el2_sysregs_ctx);
+ }
if (is_feat_fgt_supported()) {
el2_sysregs_context_save_fgt(el2_sysregs_ctx);
@@ -919,9 +1009,9 @@
#if CTX_INCLUDE_MTE_REGS
el2_sysregs_context_restore_mte(el2_sysregs_ctx);
#endif
-#if ENABLE_MPAM_FOR_LOWER_ELS
- el2_sysregs_context_restore_mpam(el2_sysregs_ctx);
-#endif
+ if (is_feat_mpam_supported()) {
+ el2_sysregs_context_restore_mpam(el2_sysregs_ctx);
+ }
if (is_feat_fgt_supported()) {
el2_sysregs_context_restore_fgt(el2_sysregs_ctx);