/*
- * Simple sanity test for emulate_step load/store instructions.
+ * Simple sanity tests for instruction emulation infrastructure.
*
* Copyright IBM Corp. 2016
*
#include <linux/ptrace.h>
#include <asm/sstep.h>
#include <asm/ppc-opcode.h>
+#include <asm/code-patching.h>
#define IMM_L(i) ((uintptr_t)(i) & 0xffff)
#define TEST_LXVD2X(s, a, b) (PPC_INST_LXVD2X | VSX_XX1((s), R##a, R##b))
#define TEST_STXVD2X(s, a, b) (PPC_INST_STXVD2X | VSX_XX1((s), R##a, R##b))
+#define MAX_SUBTESTS 16
+
+#define IGNORE_GPR(n) (0x1UL << (n))
+#define IGNORE_XER (0x1UL << 32)
+#define IGNORE_CCR (0x1UL << 33)
static void __init init_pt_regs(struct pt_regs *regs)
{
msr_cached = true;
}
-static void __init show_result(char *ins, char *result)
+static void __init show_result(char *mnemonic, char *result)
{
- pr_info("%-14s : %s\n", ins, result);
+ pr_info("%-14s : %s\n", mnemonic, result);
+}
+
+static void __init show_result_with_descr(char *mnemonic, char *descr,
+ char *result)
+{
+ pr_info("%-14s : %-50s %s\n", mnemonic, descr, result);
}
static void __init test_ld(void)
}
#endif /* CONFIG_VSX */
-static int __init test_emulate_step(void)
+static void __init run_tests_load_store(void)
{
test_ld();
test_lwz();
test_lfdx_stfdx();
test_lvx_stvx();
test_lxvd2x_stxvd2x();
+}
+
+struct compute_test {
+ char *mnemonic;
+ struct {
+ char *descr;
+ unsigned long flags;
+ unsigned int instr;
+ struct pt_regs regs;
+ } subtests[MAX_SUBTESTS + 1];
+};
+
+static struct compute_test compute_tests[] = {
+ {
+ .mnemonic = "nop",
+ .subtests = {
+ {
+ .descr = "R0 = LONG_MAX",
+ .instr = PPC_INST_NOP,
+ .regs = {
+ .gpr[0] = LONG_MAX,
+ }
+ }
+ }
+ }
+};
+
+static int __init emulate_compute_instr(struct pt_regs *regs,
+ unsigned int instr)
+{
+ struct instruction_op op;
+
+ if (!regs || !instr)
+ return -EINVAL;
+
+ if (analyse_instr(&op, regs, instr) != 1 ||
+ GETTYPE(op.type) != COMPUTE) {
+ pr_info("emulation failed, instruction = 0x%08x\n", instr);
+ return -EFAULT;
+ }
+
+ emulate_update_regs(regs, &op);
+ return 0;
+}
+
+static int __init execute_compute_instr(struct pt_regs *regs,
+ unsigned int instr)
+{
+ extern int exec_instr(struct pt_regs *regs);
+ extern s32 patch__exec_instr;
+
+ if (!regs || !instr)
+ return -EINVAL;
+
+ /* Patch the NOP with the actual instruction */
+ patch_instruction_site(&patch__exec_instr, instr);
+ if (exec_instr(regs)) {
+ pr_info("execution failed, instruction = 0x%08x\n", instr);
+ return -EFAULT;
+ }
+
+ return 0;
+}
+
+#define gpr_mismatch(gprn, exp, got) \
+ pr_info("GPR%u mismatch, exp = 0x%016lx, got = 0x%016lx\n", \
+ gprn, exp, got)
+
+#define reg_mismatch(name, exp, got) \
+ pr_info("%s mismatch, exp = 0x%016lx, got = 0x%016lx\n", \
+ name, exp, got)
+
+static void __init run_tests_compute(void)
+{
+ unsigned long flags;
+ struct compute_test *test;
+ struct pt_regs *regs, exp, got;
+ unsigned int i, j, k, instr;
+ bool ignore_gpr, ignore_xer, ignore_ccr, passed;
+
+ for (i = 0; i < ARRAY_SIZE(compute_tests); i++) {
+ test = &compute_tests[i];
+
+ for (j = 0; j < MAX_SUBTESTS && test->subtests[j].descr; j++) {
+ instr = test->subtests[j].instr;
+ flags = test->subtests[j].flags;
+ regs = &test->subtests[j].regs;
+ ignore_xer = flags & IGNORE_XER;
+ ignore_ccr = flags & IGNORE_CCR;
+ passed = true;
+
+ memcpy(&exp, regs, sizeof(struct pt_regs));
+ memcpy(&got, regs, sizeof(struct pt_regs));
+
+ /*
+ * Set a compatible MSR value explicitly to ensure
+ * that XER and CR bits are updated appropriately
+ */
+ exp.msr = MSR_KERNEL;
+ got.msr = MSR_KERNEL;
+
+ if (emulate_compute_instr(&got, instr) ||
+ execute_compute_instr(&exp, instr)) {
+ passed = false;
+ goto print;
+ }
+
+ /* Verify GPR values */
+ for (k = 0; k < 32; k++) {
+ ignore_gpr = flags & IGNORE_GPR(k);
+ if (!ignore_gpr && exp.gpr[k] != got.gpr[k]) {
+ passed = false;
+ gpr_mismatch(k, exp.gpr[k], got.gpr[k]);
+ }
+ }
+
+ /* Verify LR value */
+ if (exp.link != got.link) {
+ passed = false;
+ reg_mismatch("LR", exp.link, got.link);
+ }
+
+ /* Verify XER value */
+ if (!ignore_xer && exp.xer != got.xer) {
+ passed = false;
+ reg_mismatch("XER", exp.xer, got.xer);
+ }
+
+ /* Verify CR value */
+ if (!ignore_ccr && exp.ccr != got.ccr) {
+ passed = false;
+ reg_mismatch("CR", exp.ccr, got.ccr);
+ }
+
+print:
+ show_result_with_descr(test->mnemonic,
+ test->subtests[j].descr,
+ passed ? "PASS" : "FAIL");
+ }
+ }
+}
+
+static int __init test_emulate_step(void)
+{
+ printk(KERN_INFO "Running instruction emulation self-tests ...\n");
+ run_tests_load_store();
+ run_tests_compute();
return 0;
}
--- /dev/null
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Non-emulated single-stepping support (currently limited to basic integer
+ * computations) used to validate the instruction emulation infrastructure.
+ *
+ * Copyright (C) 2019 IBM Corporation
+ */
+
+#include <asm/asm-offsets.h>
+#include <asm/ppc_asm.h>
+#include <asm/code-patching-asm.h>
+#include <linux/errno.h>
+
+/* int exec_instr(struct pt_regs *regs) */
+_GLOBAL(exec_instr)
+
+ /*
+ * Stack frame layout (INT_FRAME_SIZE bytes)
+ * In-memory pt_regs (SP + STACK_FRAME_OVERHEAD)
+ * Scratch space (SP + 8)
+ * Back chain (SP + 0)
+ */
+
+ /*
+ * Allocate a new stack frame with enough space to hold the register
+ * states in an in-memory pt_regs and also create the back chain to
+ * the caller's stack frame.
+ */
+ stdu r1, -INT_FRAME_SIZE(r1)
+
+ /*
+ * Save non-volatile GPRs on stack. This includes TOC pointer (GPR2)
+ * and local variables (GPR14 to GPR31). The register for the pt_regs
+ * parameter (GPR3) is saved additionally to ensure that the resulting
+ * register state can still be saved even if GPR3 gets overwritten
+ * when loading the initial register state for the test instruction.
+ * The stack pointer (GPR1) and the thread pointer (GPR13) are not
+ * saved as these should not be modified anyway.
+ */
+ SAVE_2GPRS(2, r1)
+ SAVE_NVGPRS(r1)
+
+ /*
+ * Save LR on stack to ensure that the return address is available
+ * even if it gets overwritten by the test instruction.
+ */
+ mflr r0
+ std r0, _LINK(r1)
+
+ /*
+ * Save CR on stack. For simplicity, the entire register is saved
+ * even though only fields 2 to 4 are non-volatile.
+ */
+ mfcr r0
+ std r0, _CCR(r1)
+
+ /*
+ * Load register state for the test instruction without touching the
+ * critical non-volatile registers. The register state is passed as a
+ * pointer to a pt_regs instance.
+ */
+ subi r31, r3, GPR0
+
+ /* Load LR from pt_regs */
+ ld r0, _LINK(r31)
+ mtlr r0
+
+ /* Load CR from pt_regs */
+ ld r0, _CCR(r31)
+ mtcr r0
+
+ /* Load XER from pt_regs */
+ ld r0, _XER(r31)
+ mtxer r0
+
+ /* Load GPRs from pt_regs */
+ REST_GPR(0, r31)
+ REST_10GPRS(2, r31)
+ REST_GPR(12, r31)
+ REST_NVGPRS(r31)
+
+ /* Placeholder for the test instruction */
+1: nop
+ patch_site 1b patch__exec_instr
+
+ /*
+ * Since GPR3 is overwritten, temporarily restore it back to its
+ * original state, i.e. the pointer to pt_regs, to ensure that the
+ * resulting register state can be saved. Before doing this, a copy
+ * of it is created in the scratch space which is used later on to
+ * save it to pt_regs.
+ */
+ std r3, 8(r1)
+ REST_GPR(3, r1)
+
+ /* Save resulting GPR state to pt_regs */
+ subi r3, r3, GPR0
+ SAVE_GPR(0, r3)
+ SAVE_GPR(2, r3)
+ SAVE_8GPRS(4, r3)
+ SAVE_GPR(12, r3)
+ SAVE_NVGPRS(r3)
+
+ /* Save resulting LR to pt_regs */
+ mflr r0
+ std r0, _LINK(r3)
+
+ /* Save resulting CR to pt_regs */
+ mfcr r0
+ std r0, _CCR(r3)
+
+ /* Save resulting XER to pt_regs */
+ mfxer r0
+ std r0, _XER(r3)
+
+ /* Restore resulting GPR3 from scratch space and save it to pt_regs */
+ ld r0, 8(r1)
+ std r0, GPR3(r3)
+
+ /* Set return value to denote execution success */
+ li r3, 0
+
+ /* Continue */
+ b 3f
+
+ /* Set return value to denote execution failure */
+2: li r3, -EFAULT
+
+ /* Restore the non-volatile GPRs from stack */
+3: REST_GPR(2, r1)
+ REST_NVGPRS(r1)
+
+ /* Restore LR from stack to be able to return */
+ ld r0, _LINK(r1)
+ mtlr r0
+
+ /* Restore CR from stack */
+ ld r0, _CCR(r1)
+ mtcr r0
+
+ /* Tear down stack frame */
+ addi r1, r1, INT_FRAME_SIZE
+
+ /* Return */
+ blr
+
+ /* Setup exception table */
+ EX_TABLE(1b, 2b)
+
+_ASM_NOKPROBE_SYMBOL(exec_instr)
projects / linux-2.6-block.git / commitdiff