Use hardcoded pagetable initially.
This pagetable is built into the binary, and maps device memory and
enough RAM for the DT and image. It can later be replaced by a proper
pagetable built in Rust.
Using a hardcoded pagetable means we avoid making any memory access
before enabling it, which avoids a bunch of cache issues.
Bug: 223166344
Test: Ran unprotected VM under crosvm.
Change-Id: I567e377ab93881aa357428f750b11be6b3aad034
diff --git a/pvmfw/entry.S b/pvmfw/entry.S
index 25631cb..787b4ff 100644
--- a/pvmfw/entry.S
+++ b/pvmfw/entry.S
@@ -19,6 +19,57 @@
add \reg, \reg, :lo12:\sym
.endm
+.macro mov_i, reg:req, imm:req
+ movz \reg, :abs_g3:\imm
+ movk \reg, :abs_g2_nc:\imm
+ movk \reg, :abs_g1_nc:\imm
+ movk \reg, :abs_g0_nc:\imm
+.endm
+
+.set .L_MAIR_DEV_nGnRE, 0x04
+.set .L_MAIR_MEM_WBWA, 0xff
+.set .Lmairval, .L_MAIR_DEV_nGnRE | (.L_MAIR_MEM_WBWA << 8)
+
+/* 4 KiB granule size for TTBR0_EL1. */
+.set .L_TCR_TG0_4KB, 0x0 << 14
+/* 4 KiB granule size for TTBR1_EL1. */
+.set .L_TCR_TG1_4KB, 0x2 << 30
+/* Disable translation table walk for TTBR1_EL1, generating a translation fault instead. */
+.set .L_TCR_EPD1, 0x1 << 23
+/* Translation table walks for TTBR0_EL1 are inner sharable. */
+.set .L_TCR_SH_INNER, 0x3 << 12
+/*
+ * Translation table walks for TTBR0_EL1 are outer write-back read-allocate write-allocate
+ * cacheable.
+ */
+.set .L_TCR_RGN_OWB, 0x1 << 10
+/*
+ * Translation table walks for TTBR0_EL1 are inner write-back read-allocate write-allocate
+ * cacheable.
+ */
+.set .L_TCR_RGN_IWB, 0x1 << 8
+/* Size offset for TTBR0_EL1 is 2**39 bytes (512 GiB). */
+.set .L_TCR_T0SZ_512, 64 - 39
+.set .Ltcrval, .L_TCR_TG0_4KB | .L_TCR_TG1_4KB | .L_TCR_EPD1 | .L_TCR_RGN_OWB
+.set .Ltcrval, .Ltcrval | .L_TCR_RGN_IWB | .L_TCR_SH_INNER | .L_TCR_T0SZ_512
+
+/* Stage 1 instruction access cacheability is unaffected. */
+.set .L_SCTLR_ELx_I, 0x1 << 12
+/* SP alignment fault if SP is not aligned to a 16 byte boundary. */
+.set .L_SCTLR_ELx_SA, 0x1 << 3
+/* Stage 1 data access cacheability is unaffected. */
+.set .L_SCTLR_ELx_C, 0x1 << 2
+/* EL0 and EL1 stage 1 MMU enabled. */
+.set .L_SCTLR_ELx_M, 0x1 << 0
+/* Privileged Access Never is unchanged on taking an exception to EL1. */
+.set .L_SCTLR_EL1_SPAN, 0x1 << 23
+/* SETEND instruction disabled at EL0 in aarch32 mode. */
+.set .L_SCTLR_EL1_SED, 0x1 << 8
+/* Various IT instructions are disabled at EL0 in aarch32 mode. */
+.set .L_SCTLR_EL1_ITD, 0x1 << 7
+.set .L_SCTLR_EL1_RES1, (0x1 << 11) | (0x1 << 20) | (0x1 << 22) | (0x1 << 28) | (0x1 << 29)
+.set .Lsctlrval, .L_SCTLR_ELx_M | .L_SCTLR_ELx_C | .L_SCTLR_ELx_SA | .L_SCTLR_EL1_ITD | .L_SCTLR_EL1_SED
+.set .Lsctlrval, .Lsctlrval | .L_SCTLR_ELx_I | .L_SCTLR_EL1_SPAN | .L_SCTLR_EL1_RES1
/**
* This is a generic entry point for an image. It carries out the operations
* required to prepare the loaded image to be run. Specifically, it zeroes the
@@ -28,6 +79,41 @@
.section .init.entry, "ax"
.global entry
entry:
+ /* Enable MMU and caches. */
+
+ /*
+ * Load and apply the memory management configuration.
+ */
+ adrp x1, idmap
+ mov_i x2, .Lmairval
+ mov_i x3, .Ltcrval
+ mov_i x4, .Lsctlrval
+
+ /* Copy the supported PA range into TCR_EL1.IPS. */
+ mrs x6, id_aa64mmfr0_el1
+ bfi x3, x6, #32, #4
+
+ msr ttbr0_el1, x1
+ msr mair_el1, x2
+ msr tcr_el1, x3
+
+ /*
+ * Ensure everything before this point has completed, then invalidate any potentially stale
+ * local TLB entries before they start being used.
+ */
+ isb
+ tlbi vmalle1
+ ic iallu
+ dsb nsh
+ isb
+
+ /*
+ * Configure sctlr_el1 to enable MMU and cache and don't proceed until
+ * this has completed.
+ */
+ msr sctlr_el1, x4
+ isb
+
/* Disable trapping floating point access in EL1. */
mrs x30, cpacr_el1
orr x30, x30, #(0x3 << 20)