From 9776f636455b6f0d9c14dce112242ed653f954b4 Mon Sep 17 00:00:00 2001 From: Peter Crosthwaite Date: Fri, 4 Mar 2016 11:30:21 +0000 Subject: [PATCH] arm: boot: Support big-endian elfs Support ARM big-endian ELF files in system-mode emulation. When loading an elf, determine the endianness mode expected by the elf, and set the relevant CPU state accordingly. With this, big-endian modes are now fully supported via system-mode LE, so there is no need to restrict the elf loading to the TARGET endianness so the ifdeffery on TARGET_WORDS_BIGENDIAN goes away. Signed-off-by: Peter Crosthwaite Reviewed-by: Peter Maydell [PMM: fix typo in comments] Signed-off-by: Peter Maydell --- hw/arm/boot.c | 93 +++++++++++++++++++++++++++++++++++++++----- include/hw/arm/arm.h | 9 +++++ 2 files changed, 92 insertions(+), 10 deletions(-) diff --git a/hw/arm/boot.c b/hw/arm/boot.c index 17400beb58..8ba0e4272a 100644 --- a/hw/arm/boot.c +++ b/hw/arm/boot.c @@ -518,9 +518,34 @@ static void do_cpu_reset(void *opaque) cpu_reset(cs); if (info) { if (!info->is_linux) { + int i; /* Jump to the entry point. */ uint64_t entry = info->entry; + switch (info->endianness) { + case ARM_ENDIANNESS_LE: + env->cp15.sctlr_el[1] &= ~SCTLR_E0E; + for (i = 1; i < 4; ++i) { + env->cp15.sctlr_el[i] &= ~SCTLR_EE; + } + env->uncached_cpsr &= ~CPSR_E; + break; + case ARM_ENDIANNESS_BE8: + env->cp15.sctlr_el[1] |= SCTLR_E0E; + for (i = 1; i < 4; ++i) { + env->cp15.sctlr_el[i] |= SCTLR_EE; + } + env->uncached_cpsr |= CPSR_E; + break; + case ARM_ENDIANNESS_BE32: + env->cp15.sctlr_el[1] |= SCTLR_B; + break; + case ARM_ENDIANNESS_UNKNOWN: + break; /* Board's decision */ + default: + g_assert_not_reached(); + } + if (!env->aarch64) { env->thumb = info->entry & 1; entry &= 0xfffffffe; @@ -638,6 +663,62 @@ static int do_arm_linux_init(Object *obj, void *opaque) return 0; } +static uint64_t arm_load_elf(struct arm_boot_info *info, uint64_t *pentry, + uint64_t *lowaddr, uint64_t *highaddr, + int elf_machine) +{ + bool elf_is64; + union { + Elf32_Ehdr h32; + Elf64_Ehdr h64; + } elf_header; + int data_swab = 0; + bool big_endian; + uint64_t ret = -1; + Error *err = NULL; + + + load_elf_hdr(info->kernel_filename, &elf_header, &elf_is64, &err); + if (err) { + return ret; + } + + if (elf_is64) { + big_endian = elf_header.h64.e_ident[EI_DATA] == ELFDATA2MSB; + info->endianness = big_endian ? ARM_ENDIANNESS_BE8 + : ARM_ENDIANNESS_LE; + } else { + big_endian = elf_header.h32.e_ident[EI_DATA] == ELFDATA2MSB; + if (big_endian) { + if (bswap32(elf_header.h32.e_flags) & EF_ARM_BE8) { + info->endianness = ARM_ENDIANNESS_BE8; + } else { + info->endianness = ARM_ENDIANNESS_BE32; + /* In BE32, the CPU has a different view of the per-byte + * address map than the rest of the system. BE32 ELF files + * are organised such that they can be programmed through + * the CPU's per-word byte-reversed view of the world. QEMU + * however loads ELF files independently of the CPU. So + * tell the ELF loader to byte reverse the data for us. + */ + data_swab = 2; + } + } else { + info->endianness = ARM_ENDIANNESS_LE; + } + } + + ret = load_elf(info->kernel_filename, NULL, NULL, + pentry, lowaddr, highaddr, big_endian, elf_machine, + 1, data_swab); + if (ret <= 0) { + /* The header loaded but the image didn't */ + exit(1); + } + + return ret; +} + static void arm_load_kernel_notify(Notifier *notifier, void *data) { CPUState *cs; @@ -647,7 +728,6 @@ static void arm_load_kernel_notify(Notifier *notifier, void *data) uint64_t elf_entry, elf_low_addr, elf_high_addr; int elf_machine; hwaddr entry, kernel_load_offset; - int big_endian; static const ARMInsnFixup *primary_loader; ArmLoadKernelNotifier *n = DO_UPCAST(ArmLoadKernelNotifier, notifier, notifier); @@ -733,12 +813,6 @@ static void arm_load_kernel_notify(Notifier *notifier, void *data) if (info->nb_cpus == 0) info->nb_cpus = 1; -#ifdef TARGET_WORDS_BIGENDIAN - big_endian = 1; -#else - big_endian = 0; -#endif - /* We want to put the initrd far enough into RAM that when the * kernel is uncompressed it will not clobber the initrd. However * on boards without much RAM we must ensure that we still leave @@ -753,9 +827,8 @@ static void arm_load_kernel_notify(Notifier *notifier, void *data) MIN(info->ram_size / 2, 128 * 1024 * 1024); /* Assume that raw images are linux kernels, and ELF images are not. */ - kernel_size = load_elf(info->kernel_filename, NULL, NULL, &elf_entry, - &elf_low_addr, &elf_high_addr, big_endian, - elf_machine, 1, 0); + kernel_size = arm_load_elf(info, &elf_entry, &elf_low_addr, + &elf_high_addr, elf_machine); if (kernel_size > 0 && have_dtb(info)) { /* If there is still some room left at the base of RAM, try and put * the DTB there like we do for images loaded with -bios or -pflash. diff --git a/include/hw/arm/arm.h b/include/hw/arm/arm.h index 52ecf4aa8f..b2517f9a43 100644 --- a/include/hw/arm/arm.h +++ b/include/hw/arm/arm.h @@ -16,6 +16,13 @@ #include "qemu/notify.h" #include "cpu.h" +typedef enum { + ARM_ENDIANNESS_UNKNOWN = 0, + ARM_ENDIANNESS_LE, + ARM_ENDIANNESS_BE8, + ARM_ENDIANNESS_BE32, +} arm_endianness; + /* armv7m.c */ DeviceState *armv7m_init(MemoryRegion *system_memory, int mem_size, int num_irq, const char *kernel_filename, const char *cpu_model); @@ -103,6 +110,8 @@ struct arm_boot_info { * changing to non-secure state if implementing a non-secure boot */ bool secure_board_setup; + + arm_endianness endianness; }; /** -- GitLab