[PATCH v21 03/13] linux-user: Add LoongArch elf support

[Richard Henderson <richard.henderson@linaro.org>]

From: Song Gao <gaosong@loongson.cn>

Signed-off-by: Song Gao <gaosong@loongson.cn>
Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20220624031049.1716097-4-gaosong@loongson.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 linux-user/loongarch64/target_elf.h | 12 ++++
 linux-user/elfload.c                | 91 +++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+)
 create mode 100644 linux-user/loongarch64/target_elf.h

diff --git a/linux-user/loongarch64/target_elf.h b/linux-user/loongarch64/target_elf.h
new file mode 100644
index 0000000000..95c3f05a46
--- /dev/null
+++ b/linux-user/loongarch64/target_elf.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (c) 2021 Loongson Technology Corporation Limited
+ */
+
+#ifndef LOONGARCH_TARGET_ELF_H
+#define LOONGARCH_TARGET_ELF_H
+static inline const char *cpu_get_model(uint32_t eflags)
+{
+    return "la464";
+}
+#endif
diff --git a/linux-user/elfload.c b/linux-user/elfload.c
index 163fc8a1ee..1de77c7959 100644
--- a/linux-user/elfload.c
+++ b/linux-user/elfload.c
@@ -922,6 +922,97 @@ static void elf_core_copy_regs(target_elf_gregset_t *regs, const CPUPPCState *en
 
 #endif
 
+#ifdef TARGET_LOONGARCH64
+
+#define ELF_START_MMAP 0x80000000
+
+#define ELF_CLASS   ELFCLASS64
+#define ELF_ARCH    EM_LOONGARCH
+
+#define elf_check_arch(x) ((x) == EM_LOONGARCH)
+
+static inline void init_thread(struct target_pt_regs *regs,
+                               struct image_info *infop)
+{
+    /*Set crmd PG,DA = 1,0 */
+    regs->csr.crmd = 2 << 3;
+    regs->csr.era = infop->entry;
+    regs->regs[3] = infop->start_stack;
+}
+
+/* See linux kernel: arch/loongarch/include/asm/elf.h */
+#define ELF_NREG 45
+typedef target_elf_greg_t target_elf_gregset_t[ELF_NREG];
+
+enum {
+    TARGET_EF_R0 = 0,
+    TARGET_EF_CSR_ERA = TARGET_EF_R0 + 33,
+    TARGET_EF_CSR_BADV = TARGET_EF_R0 + 34,
+};
+
+static void elf_core_copy_regs(target_elf_gregset_t *regs,
+                               const CPULoongArchState *env)
+{
+    int i;
+
+    (*regs)[TARGET_EF_R0] = 0;
+
+    for (i = 1; i < ARRAY_SIZE(env->gpr); i++) {
+        (*regs)[TARGET_EF_R0 + i] = tswapreg(env->gpr[i]);
+    }
+
+    (*regs)[TARGET_EF_CSR_ERA] = tswapreg(env->pc);
+    (*regs)[TARGET_EF_CSR_BADV] = tswapreg(env->CSR_BADV);
+}
+
+#define USE_ELF_CORE_DUMP
+#define ELF_EXEC_PAGESIZE        4096
+
+#define ELF_HWCAP get_elf_hwcap()
+
+/* See arch/loongarch/include/uapi/asm/hwcap.h */
+enum {
+    HWCAP_LOONGARCH_CPUCFG   = (1 << 0),
+    HWCAP_LOONGARCH_LAM      = (1 << 1),
+    HWCAP_LOONGARCH_UAL      = (1 << 2),
+    HWCAP_LOONGARCH_FPU      = (1 << 3),
+    HWCAP_LOONGARCH_LSX      = (1 << 4),
+    HWCAP_LOONGARCH_LASX     = (1 << 5),
+    HWCAP_LOONGARCH_CRC32    = (1 << 6),
+    HWCAP_LOONGARCH_COMPLEX  = (1 << 7),
+    HWCAP_LOONGARCH_CRYPTO   = (1 << 8),
+    HWCAP_LOONGARCH_LVZ      = (1 << 9),
+    HWCAP_LOONGARCH_LBT_X86  = (1 << 10),
+    HWCAP_LOONGARCH_LBT_ARM  = (1 << 11),
+    HWCAP_LOONGARCH_LBT_MIPS = (1 << 12),
+};
+
+static uint32_t get_elf_hwcap(void)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(thread_cpu);
+    uint32_t hwcaps = 0;
+
+    hwcaps |= HWCAP_LOONGARCH_CRC32;
+
+    if (FIELD_EX32(cpu->env.cpucfg[1], CPUCFG1, UAL)) {
+        hwcaps |= HWCAP_LOONGARCH_UAL;
+    }
+
+    if (FIELD_EX32(cpu->env.cpucfg[2], CPUCFG2, FP)) {
+        hwcaps |= HWCAP_LOONGARCH_FPU;
+    }
+
+    if (FIELD_EX32(cpu->env.cpucfg[2], CPUCFG2, LAM)) {
+        hwcaps |= HWCAP_LOONGARCH_LAM;
+    }
+
+    return hwcaps;
+}
+
+#define ELF_PLATFORM "loongarch"
+
+#endif /* TARGET_LOONGARCH64 */
+
 #ifdef TARGET_MIPS
 
 #define ELF_START_MMAP 0x80000000
-- 
2.34.1