fix(amu): limit virtual offset register access to NS world
Previously the SCR_EL3.AMVOFFEN bit was set for all contexts, this
behavior is incorrect as it allows secure world to access the virtual
offset registers when it should not be able to. This patch only sets
AMVOFFEN for non-secure world.
Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I2c61fe0a8a0092df089f1cb2c0d8a45c8c8ad0d3
diff --git a/include/arch/aarch64/arch.h b/include/arch/aarch64/arch.h
index b4608ae..83c469b 100644
--- a/include/arch/aarch64/arch.h
+++ b/include/arch/aarch64/arch.h
@@ -483,7 +483,8 @@
#define SCR_HXEn_BIT (UL(1) << 38)
#define SCR_ENTP2_SHIFT U(41)
#define SCR_ENTP2_BIT (UL(1) << SCR_ENTP2_SHIFT)
-#define SCR_AMVOFFEN_BIT (UL(1) << 35)
+#define SCR_AMVOFFEN_SHIFT U(35)
+#define SCR_AMVOFFEN_BIT (UL(1) << SCR_AMVOFFEN_SHIFT)
#define SCR_TWEDEn_BIT (UL(1) << 29)
#define SCR_ECVEN_BIT (UL(1) << 28)
#define SCR_FGTEN_BIT (UL(1) << 27)
diff --git a/lib/el3_runtime/aarch64/context_mgmt.c b/lib/el3_runtime/aarch64/context_mgmt.c
index 47e7d8c..7a0073f 100644
--- a/lib/el3_runtime/aarch64/context_mgmt.c
+++ b/lib/el3_runtime/aarch64/context_mgmt.c
@@ -283,16 +283,6 @@
}
/*
- * FEAT_AMUv1p1 virtual offset registers are only accessible from EL3
- * and EL2, when clear, this bit traps accesses from EL2 so we set it
- * to 1 when EL2 is present.
- */
- if (is_armv8_6_feat_amuv1p1_present() &&
- (el_implemented(2) != EL_IMPL_NONE)) {
- scr_el3 |= SCR_AMVOFFEN_BIT;
- }
-
- /*
* Initialise SCTLR_EL1 to the reset value corresponding to the target
* execution state setting all fields rather than relying of the hw.
* Some fields have architecturally UNKNOWN reset values and these are
diff --git a/lib/extensions/amu/aarch64/amu.c b/lib/extensions/amu/aarch64/amu.c
index d329c3d..72566fd 100644
--- a/lib/extensions/amu/aarch64/amu.c
+++ b/lib/extensions/amu/aarch64/amu.c
@@ -75,7 +75,7 @@
((value << CPTR_EL2_TAM_SHIFT) & CPTR_EL2_TAM_BIT));
}
-static inline __unused void write_cptr_el3_tam(cpu_context_t *ctx, uint64_t tam)
+static inline __unused void ctx_write_cptr_el3_tam(cpu_context_t *ctx, uint64_t tam)
{
uint64_t value = read_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3);
@@ -85,6 +85,16 @@
write_ctx_reg(get_el3state_ctx(ctx), CTX_CPTR_EL3, value);
}
+static inline __unused void ctx_write_scr_el3_amvoffen(cpu_context_t *ctx, uint64_t amvoffen)
+{
+ uint64_t value = read_ctx_reg(get_el3state_ctx(ctx), CTX_SCR_EL3);
+
+ value &= ~SCR_AMVOFFEN_BIT;
+ value |= (amvoffen << SCR_AMVOFFEN_SHIFT) & SCR_AMVOFFEN_BIT;
+
+ write_ctx_reg(get_el3state_ctx(ctx), CTX_SCR_EL3, value);
+}
+
static inline __unused void write_hcr_el2_amvoffen(uint64_t value)
{
write_hcr_el2((read_hcr_el2() & ~HCR_AMVOFFEN_BIT) |
@@ -226,7 +236,7 @@
* in 'ctx'. Set CPTR_EL3.TAM to zero so that any accesses to
* the Activity Monitor registers do not trap to EL3.
*/
- write_cptr_el3_tam(ctx, 0U);
+ ctx_write_cptr_el3_tam(ctx, 0U);
/*
* Retrieve the number of architected counters. All of these counters
@@ -285,6 +295,13 @@
* used.
*/
write_hcr_el2_amvoffen(0U);
+ } else {
+ /*
+ * Virtual offset registers are only accessible from EL3
+ * and EL2, when clear, this bit traps accesses from EL2
+ * so we set it to 1 when EL2 is present.
+ */
+ ctx_write_scr_el3_amvoffen(ctx, 1U);
}
#if AMU_RESTRICT_COUNTERS