#include <asm/mach/map.h>
#include <asm/memory.h>
#include <asm/system_info.h>
+#include <asm/traps.h>
+
+#define TCMTR_FORMAT_MASK 0xe0000000U
static struct gen_pool *tcm_pool;
static bool dtcm_present;
return 0;
}
+/*
+ * When we are running in the non-secure world and the secure world
+ * has not explicitly given us access to the TCM we will get an
+ * undefined error when reading the TCM region register in the
+ * setup_tcm_bank function (above).
+ *
+ * There are two variants of this register read that we need to trap,
+ * the read for the data TCM and the read for the instruction TCM:
+ * c0370628: ee196f11 mrc 15, 0, r6, cr9, cr1, {0}
+ * c0370674: ee196f31 mrc 15, 0, r6, cr9, cr1, {1}
+ *
+ * Our undef hook mask explicitly matches all fields of the encoded
+ * instruction other than the destination register. The mask also
+ * only allows operand 2 to have the values 0 or 1.
+ *
+ * The undefined hook is defined as __init and __initdata, and therefore
+ * must be removed before tcm_init returns.
+ *
+ * In this particular case (MRC with ARM condition code ALways) the
+ * Thumb-2 and ARM instruction encoding are identical, so this hook
+ * will work on a Thumb-2 kernel.
+ *
+ * See A8.8.107, DDI0406C_C ARM Architecture Reference Manual, Encoding
+ * T1/A1 for the bit-by-bit details.
+ *
+ * mrc p15, 0, XX, c9, c1, 0
+ * mrc p15, 0, XX, c9, c1, 1
+ * | | | | | | | +---- opc2 0|1 = 000|001
+ * | | | | | | +------- CRm 0 = 0001
+ * | | | | | +----------- CRn 0 = 1001
+ * | | | | +--------------- Rt ? = ????
+ * | | | +------------------- opc1 0 = 000
+ * | | +----------------------- coproc 15 = 1111
+ * | +-------------------------- condition ALways = 1110
+ * +----------------------------- instruction MRC = 1110
+ *
+ * Encoding this as per A8.8.107 of DDI0406C, Encoding T1/A1, yields:
+ * 1111 1111 1111 1111 0000 1111 1101 1111 Required Mask
+ * 1110 1110 0001 1001 ???? 1111 0001 0001 mrc p15, 0, XX, c9, c1, 0
+ * 1110 1110 0001 1001 ???? 1111 0011 0001 mrc p15, 0, XX, c9, c1, 1
+ * [ ] [ ] [ ]| [ ] [ ] [ ] [ ]| +--- CRm
+ * | | | | | | | | +----- SBO
+ * | | | | | | | +------- opc2
+ * | | | | | | +----------- coproc
+ * | | | | | +---------------- Rt
+ * | | | | +--------------------- CRn
+ * | | | +------------------------- SBO
+ * | | +--------------------------- opc1
+ * | +------------------------------- instruction
+ * +------------------------------------ condition
+ */
+#define TCM_REGION_READ_MASK 0xffff0fdf
+#define TCM_REGION_READ_INSTR 0xee190f11
+#define DEST_REG_SHIFT 12
+#define DEST_REG_MASK 0xf
+
+static int __init tcm_handler(struct pt_regs *regs, unsigned int instr)
+{
+ regs->uregs[(instr >> DEST_REG_SHIFT) & DEST_REG_MASK] = 0;
+ regs->ARM_pc += 4;
+ return 0;
+}
+
+static struct undef_hook tcm_hook __initdata = {
+ .instr_mask = TCM_REGION_READ_MASK,
+ .instr_val = TCM_REGION_READ_INSTR,
+ .cpsr_mask = MODE_MASK,
+ .cpsr_val = SVC_MODE,
+ .fn = tcm_handler
+};
+
/*
* This initializes the TCM memory
*/
}
tcm_status = read_cpuid_tcmstatus();
+
+ /*
+ * This code only supports v6-compatible TCMTR implementations.
+ */
+ if (tcm_status & TCMTR_FORMAT_MASK)
+ return;
+
dtcm_banks = (tcm_status >> 16) & 0x03;
itcm_banks = (tcm_status & 0x03);
+ register_undef_hook(&tcm_hook);
+
/* Values greater than 2 for D/ITCM banks are "reserved" */
if (dtcm_banks > 2)
dtcm_banks = 0;
for (i = 0; i < dtcm_banks; i++) {
ret = setup_tcm_bank(0, i, dtcm_banks, &dtcm_end);
if (ret)
- return;
+ goto unregister;
}
/* This means you compiled more code than fits into DTCM */
if (dtcm_code_sz > (dtcm_end - DTCM_OFFSET)) {
dtcm_code_sz, (dtcm_end - DTCM_OFFSET));
goto no_dtcm;
}
+ /*
+ * This means that the DTCM sizes were 0 or the DTCM banks
+ * were inaccessible due to TrustZone configuration.
+ */
+ if (!(dtcm_end - DTCM_OFFSET))
+ goto no_dtcm;
dtcm_res.end = dtcm_end - 1;
request_resource(&iomem_resource, &dtcm_res);
dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
for (i = 0; i < itcm_banks; i++) {
ret = setup_tcm_bank(1, i, itcm_banks, &itcm_end);
if (ret)
- return;
+ goto unregister;
}
/* This means you compiled more code than fits into ITCM */
if (itcm_code_sz > (itcm_end - ITCM_OFFSET)) {
pr_info("CPU ITCM: %u bytes of code compiled to "
"ITCM but only %lu bytes of ITCM present\n",
itcm_code_sz, (itcm_end - ITCM_OFFSET));
- return;
+ goto unregister;
}
+ /*
+ * This means that the ITCM sizes were 0 or the ITCM banks
+ * were inaccessible due to TrustZone configuration.
+ */
+ if (!(itcm_end - ITCM_OFFSET))
+ goto unregister;
itcm_res.end = itcm_end - 1;
request_resource(&iomem_resource, &itcm_res);
itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
pr_info("CPU ITCM: %u bytes of code compiled to ITCM but no "
"ITCM banks present in CPU\n", itcm_code_sz);
}
+
+unregister:
+ unregister_undef_hook(&tcm_hook);
}
/*
Code Review / kvmfornfv.git / blobdiff